|
Powering a boat with AC and DC (was) WTB: Marine Inverter
Hi, Y'all...
Well... "Larry W4CSC" wrote in message ... (Me, he) Battery killing inverter? Most of what I read these days suggests a static load of well under an amp, some are milliamps. Running any electrical device will kill a battery eventually if it's not got the power replaced (which we expect to do in spades, or, as you've noted, our own power company should be able to cope with extended periods of no-replacement) - how's this different? Do the math. Let's say we have a BIG inverter, 4KW continuous. This is great for TEMPORARY loads that need 4KW for a few minutes, like your coffee maker. But, as I jokingly put it, may boaters think they have their own "power station" when they buy one of these beasts. Case in point: 1500W heater - 12.5A@120VAC - about 120A at 13V.....x 24 hrs = 2880AH To provide for a simple electric heater and only drawing the battery banks down to 70%, not zero which destroys them....2880/.30 (30% of battery capacity) = 9,600AH battery bank. How big did you say those cells were?...(c; Hence my comment, "The funniest thing is to see a boater with a new 4KW inverter carrying his electric heater down the dock with that smug grin on his face." I've seen them incredulous that their 5KW inverter can't run the boat's air conditioner for the weekend anchored out. Math is not one of their majors...(c; Yes - but apparently you're assuming there's lots of continous load. Like Lionheart, there will be only very incidental use of AC; everything else will be 12V. So, I presume it's a non-issue here. That is, inverters are not inherently "battery killers" - only continuous large loads are "battery killers" (?). We'll not have any such. As we next to never expect to be at shorepower except during haulouts (and even then, should have no particular need, with our solar and wind), we'll want to make our various outlets be both - inverter and shorepower. Hmm...5A from a big solar panel or 15A from a wind generator = 5X12hrs=60AH per day if the sun shines or 360AH wind power in a full gale 24/7. Not much of a real powerhouse, is it, huge batteries or small batteries... Plan on using the big alternator on the engine every day in this configuration. Hm. Help me with the math. As a lapsed math, physics and chem major, I don't remember my stuff all that well. However, I'll have right in the neighborhood of 500W solar, and a KISS wind generator in the Caribbean. Various vendors suggest I take the wattage and divide by 3, or 4 if really lousy weather, for a reasonable typical AH input, daily. My math has that at 170-125AH/day, plus some other unknown - but apparently pretty substantial - AH from a KISS. Our anticipated daily budget is about 125AH; we'll have (for simplicity in this calculation) ~1250AH capacity. It's our presumption that we'll have 4-5 days capacity, in the most unimaginable (in the Caribbean) circumstance of continuous no wind or sun. Have I missed something here? The "drop cords" aren't laying around. You can use electrical cable if you like, wired into the boat. The inverter electrical system on Lionheart is wired into the boat and plugged into the inverter. All of the current house locations are already wired. I'll only be adding a few. As to powering the boat from shore and inverter, you install a transfer switch between the sources, ensuring the inverter is never connected in parallel with the power company from the dock. It's, essentially, a double pole switch, mounted in a box with a lockout so you can't run both, simultaneously. Any home generator transfer switch will work on your inverter system. Given. It's the "plug this 3-prong into your Sam's Club inverter" part I don't like. On another's comment in this thread, I've seen enough negative comments (including some agreement from my expected vendor) about Xantrex to want to avoid them. I recognize that solar and wind are relatively few in the total cruiser universe, so my sample potential here is limited. However, plunging ahead, I solicit positive experience stories about inverters (and, for that matter, systems) used with large solar and wind inputs. Thanks. L8R Skip (about to head back to the boat for another couple weeks, this time, this part, of the refit) -- Morgan 461 #2 SV Flying Pig http://tinyurl.com/384p2 "There is nothing-absolutely nothing-half so much worth doing as simply messing about in boats. In or out of 'em, it doesn't matter. Nothing seems really to matter, that's the charm of it. Whether you get away, or whether you don't; whether you arrive at your destination or whether you reach somewhere else, or whether you never get anywhere at all, you're always busy, and you never do anything in particular; and when you've done it there's always something else to do, and you can do it if you like, but you'd much better not." |
I don;t see what the problems is. An inverter represents a load on the DC
system. It has be be managed the same as any other load. No magic, no mystery. The biggest load on our boat is the microwave. 100A for 2 or three minutes, no problem. The inverter itself is no demon. The usage is the thing that has to be managed. Doug "Skip Gundlach" skipgundlach sez use my name at earthlink dot fishcatcher (net) - with apologies for the spamtrap wrote in message ... Hi, Y'all... Well... "Larry W4CSC" wrote in message ... (Me, he) Battery killing inverter? Most of what I read these days suggests a static load of well under an amp, some are milliamps. Running any electrical device will kill a battery eventually if it's not got the power replaced (which we expect to do in spades, or, as you've noted, our own power company should be able to cope with extended periods of no-replacement) - how's this different? Do the math. Let's say we have a BIG inverter, 4KW continuous. This is great for TEMPORARY loads that need 4KW for a few minutes, like your coffee maker. But, as I jokingly put it, may boaters think they have their own "power station" when they buy one of these beasts. Case in point: 1500W heater - 12.5A@120VAC - about 120A at 13V.....x 24 hrs = 2880AH To provide for a simple electric heater and only drawing the battery banks down to 70%, not zero which destroys them....2880/.30 (30% of battery capacity) = 9,600AH battery bank. How big did you say those cells were?...(c; Hence my comment, "The funniest thing is to see a boater with a new 4KW inverter carrying his electric heater down the dock with that smug grin on his face." I've seen them incredulous that their 5KW inverter can't run the boat's air conditioner for the weekend anchored out. Math is not one of their majors...(c; Yes - but apparently you're assuming there's lots of continous load. Like Lionheart, there will be only very incidental use of AC; everything else will be 12V. So, I presume it's a non-issue here. That is, inverters are not inherently "battery killers" - only continuous large loads are "battery killers" (?). We'll not have any such. As we next to never expect to be at shorepower except during haulouts (and even then, should have no particular need, with our solar and wind), we'll want to make our various outlets be both - inverter and shorepower. Hmm...5A from a big solar panel or 15A from a wind generator = 5X12hrs=60AH per day if the sun shines or 360AH wind power in a full gale 24/7. Not much of a real powerhouse, is it, huge batteries or small batteries... Plan on using the big alternator on the engine every day in this configuration. Hm. Help me with the math. As a lapsed math, physics and chem major, I don't remember my stuff all that well. However, I'll have right in the neighborhood of 500W solar, and a KISS wind generator in the Caribbean. Various vendors suggest I take the wattage and divide by 3, or 4 if really lousy weather, for a reasonable typical AH input, daily. My math has that at 170-125AH/day, plus some other unknown - but apparently pretty substantial - AH from a KISS. Our anticipated daily budget is about 125AH; we'll have (for simplicity in this calculation) ~1250AH capacity. It's our presumption that we'll have 4-5 days capacity, in the most unimaginable (in the Caribbean) circumstance of continuous no wind or sun. Have I missed something here? The "drop cords" aren't laying around. You can use electrical cable if you like, wired into the boat. The inverter electrical system on Lionheart is wired into the boat and plugged into the inverter. All of the current house locations are already wired. I'll only be adding a few. As to powering the boat from shore and inverter, you install a transfer switch between the sources, ensuring the inverter is never connected in parallel with the power company from the dock. It's, essentially, a double pole switch, mounted in a box with a lockout so you can't run both, simultaneously. Any home generator transfer switch will work on your inverter system. Given. It's the "plug this 3-prong into your Sam's Club inverter" part I don't like. On another's comment in this thread, I've seen enough negative comments (including some agreement from my expected vendor) about Xantrex to want to avoid them. I recognize that solar and wind are relatively few in the total cruiser universe, so my sample potential here is limited. However, plunging ahead, I solicit positive experience stories about inverters (and, for that matter, systems) used with large solar and wind inputs. Thanks. L8R Skip (about to head back to the boat for another couple weeks, this time, this part, of the refit) -- Morgan 461 #2 SV Flying Pig http://tinyurl.com/384p2 "There is nothing-absolutely nothing-half so much worth doing as simply messing about in boats. In or out of 'em, it doesn't matter. Nothing seems really to matter, that's the charm of it. Whether you get away, or whether you don't; whether you arrive at your destination or whether you reach somewhere else, or whether you never get anywhere at all, you're always busy, and you never do anything in particular; and when you've done it there's always something else to do, and you can do it if you like, but you'd much better not." |
The long winded point is that a 900AH Battery and an inverter will not run a
Heater or an Air Conditioner 24/7 through the weekend without being able to recharge the batteries at substantial rate. A good sized generator will be needed! "Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in message ... I don;t see what the problems is. An inverter represents a load on the DC system. It has be be managed the same as any other load. No magic, no mystery. The biggest load on our boat is the microwave. 100A for 2 or three minutes, no problem. The inverter itself is no demon. The usage is the thing that has to be managed. Doug "Skip Gundlach" skipgundlach sez use my name at earthlink dot fishcatcher (net) - with apologies for the spamtrap wrote in message ... Hi, Y'all... Well... "Larry W4CSC" wrote in message ... (Me, he) Battery killing inverter? Most of what I read these days suggests a static load of well under an amp, some are milliamps. Running any electrical device will kill a battery eventually if it's not got the power replaced (which we expect to do in spades, or, as you've noted, our own power company should be able to cope with extended periods of no-replacement) - how's this different? Do the math. Let's say we have a BIG inverter, 4KW continuous. This is great for TEMPORARY loads that need 4KW for a few minutes, like your coffee maker. But, as I jokingly put it, may boaters think they have their own "power station" when they buy one of these beasts. Case in point: 1500W heater - 12.5A@120VAC - about 120A at 13V.....x 24 hrs = 2880AH To provide for a simple electric heater and only drawing the battery banks down to 70%, not zero which destroys them....2880/.30 (30% of battery capacity) = 9,600AH battery bank. How big did you say those cells were?...(c; Hence my comment, "The funniest thing is to see a boater with a new 4KW inverter carrying his electric heater down the dock with that smug grin on his face." I've seen them incredulous that their 5KW inverter can't run the boat's air conditioner for the weekend anchored out. Math is not one of their majors...(c; Yes - but apparently you're assuming there's lots of continous load. Like Lionheart, there will be only very incidental use of AC; everything else will be 12V. So, I presume it's a non-issue here. That is, inverters are not inherently "battery killers" - only continuous large loads are "battery killers" (?). We'll not have any such. As we next to never expect to be at shorepower except during haulouts (and even then, should have no particular need, with our solar and wind), we'll want to make our various outlets be both - inverter and shorepower. Hmm...5A from a big solar panel or 15A from a wind generator = 5X12hrs=60AH per day if the sun shines or 360AH wind power in a full gale 24/7. Not much of a real powerhouse, is it, huge batteries or small batteries... Plan on using the big alternator on the engine every day in this configuration. Hm. Help me with the math. As a lapsed math, physics and chem major, I don't remember my stuff all that well. However, I'll have right in the neighborhood of 500W solar, and a KISS wind generator in the Caribbean. Various vendors suggest I take the wattage and divide by 3, or 4 if really lousy weather, for a reasonable typical AH input, daily. My math has that at 170-125AH/day, plus some other unknown - but apparently pretty substantial - AH from a KISS. Our anticipated daily budget is about 125AH; we'll have (for simplicity in this calculation) ~1250AH capacity. It's our presumption that we'll have 4-5 days capacity, in the most unimaginable (in the Caribbean) circumstance of continuous no wind or sun. Have I missed something here? The "drop cords" aren't laying around. You can use electrical cable if you like, wired into the boat. The inverter electrical system on Lionheart is wired into the boat and plugged into the inverter. All of the current house locations are already wired. I'll only be adding a few. As to powering the boat from shore and inverter, you install a transfer switch between the sources, ensuring the inverter is never connected in parallel with the power company from the dock. It's, essentially, a double pole switch, mounted in a box with a lockout so you can't run both, simultaneously. Any home generator transfer switch will work on your inverter system. Given. It's the "plug this 3-prong into your Sam's Club inverter" part I don't like. On another's comment in this thread, I've seen enough negative comments (including some agreement from my expected vendor) about Xantrex to want to avoid them. I recognize that solar and wind are relatively few in the total cruiser universe, so my sample potential here is limited. However, plunging ahead, I solicit positive experience stories about inverters (and, for that matter, systems) used with large solar and wind inputs. Thanks. L8R Skip (about to head back to the boat for another couple weeks, this time, this part, of the refit) -- Morgan 461 #2 SV Flying Pig http://tinyurl.com/384p2 "There is nothing-absolutely nothing-half so much worth doing as simply messing about in boats. In or out of 'em, it doesn't matter. Nothing seems really to matter, that's the charm of it. Whether you get away, or whether you don't; whether you arrive at your destination or whether you reach somewhere else, or whether you never get anywhere at all, you're always busy, and you never do anything in particular; and when you've done it there's always something else to do, and you can do it if you like, but you'd much better not." |
"John Cassara" wrote in message ... The long winded point is that a 900AH Battery and an inverter will not run a Heater or an Air Conditioner 24/7 through the weekend without being able to recharge the batteries at substantial rate. A good sized generator will be needed! Absolutely! No heater or AC can be run off of an inverter in any practical manner. "Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in message ... I don;t see what the problems is. An inverter represents a load on the DC system. It has be be managed the same as any other load. No magic, no mystery. The biggest load on our boat is the microwave. 100A for 2 or three minutes, no problem. The inverter itself is no demon. The usage is the thing that has to be managed. Doug "Skip Gundlach" skipgundlach sez use my name at earthlink dot fishcatcher (net) - with apologies for the spamtrap wrote in message ... Hi, Y'all... Well... "Larry W4CSC" wrote in message ... (Me, he) Battery killing inverter? Most of what I read these days suggests a static load of well under an amp, some are milliamps. Running any electrical device will kill a battery eventually if it's not got the power replaced (which we expect to do in spades, or, as you've noted, our own power company should be able to cope with extended periods of no-replacement) - how's this different? Do the math. Let's say we have a BIG inverter, 4KW continuous. This is great for TEMPORARY loads that need 4KW for a few minutes, like your coffee maker. But, as I jokingly put it, may boaters think they have their own "power station" when they buy one of these beasts. Case in point: 1500W heater - 12.5A@120VAC - about 120A at 13V.....x 24 hrs = 2880AH To provide for a simple electric heater and only drawing the battery banks down to 70%, not zero which destroys them....2880/.30 (30% of battery capacity) = 9,600AH battery bank. How big did you say those cells were?...(c; Hence my comment, "The funniest thing is to see a boater with a new 4KW inverter carrying his electric heater down the dock with that smug grin on his face." I've seen them incredulous that their 5KW inverter can't run the boat's air conditioner for the weekend anchored out. Math is not one of their majors...(c; Yes - but apparently you're assuming there's lots of continous load. Like Lionheart, there will be only very incidental use of AC; everything else will be 12V. So, I presume it's a non-issue here. That is, inverters are not inherently "battery killers" - only continuous large loads are "battery killers" (?). We'll not have any such. As we next to never expect to be at shorepower except during haulouts (and even then, should have no particular need, with our solar and wind), we'll want to make our various outlets be both - inverter and shorepower. Hmm...5A from a big solar panel or 15A from a wind generator = 5X12hrs=60AH per day if the sun shines or 360AH wind power in a full gale 24/7. Not much of a real powerhouse, is it, huge batteries or small batteries... Plan on using the big alternator on the engine every day in this configuration. Hm. Help me with the math. As a lapsed math, physics and chem major, I don't remember my stuff all that well. However, I'll have right in the neighborhood of 500W solar, and a KISS wind generator in the Caribbean. Various vendors suggest I take the wattage and divide by 3, or 4 if really lousy weather, for a reasonable typical AH input, daily. My math has that at 170-125AH/day, plus some other unknown - but apparently pretty substantial - AH from a KISS. Our anticipated daily budget is about 125AH; we'll have (for simplicity in this calculation) ~1250AH capacity. It's our presumption that we'll have 4-5 days capacity, in the most unimaginable (in the Caribbean) circumstance of continuous no wind or sun. Have I missed something here? The "drop cords" aren't laying around. You can use electrical cable if you like, wired into the boat. The inverter electrical system on Lionheart is wired into the boat and plugged into the inverter. All of the current house locations are already wired. I'll only be adding a few. As to powering the boat from shore and inverter, you install a transfer switch between the sources, ensuring the inverter is never connected in parallel with the power company from the dock. It's, essentially, a double pole switch, mounted in a box with a lockout so you can't run both, simultaneously. Any home generator transfer switch will work on your inverter system. Given. It's the "plug this 3-prong into your Sam's Club inverter" part I don't like. On another's comment in this thread, I've seen enough negative comments (including some agreement from my expected vendor) about Xantrex to want to avoid them. I recognize that solar and wind are relatively few in the total cruiser universe, so my sample potential here is limited. However, plunging ahead, I solicit positive experience stories about inverters (and, for that matter, systems) used with large solar and wind inputs. Thanks. L8R Skip (about to head back to the boat for another couple weeks, this time, this part, of the refit) -- Morgan 461 #2 SV Flying Pig http://tinyurl.com/384p2 "There is nothing-absolutely nothing-half so much worth doing as simply messing about in boats. In or out of 'em, it doesn't matter. Nothing seems really to matter, that's the charm of it. Whether you get away, or whether you don't; whether you arrive at your destination or whether you reach somewhere else, or whether you never get anywhere at all, you're always busy, and you never do anything in particular; and when you've done it there's always something else to do, and you can do it if you like, but you'd much better not." |
"Skip Gundlach" skipgundlach sez use my name at earthlink dot
fishcatcher (net) - with apologies for the spamtrap wrote in : Hm. Help me with the math. As a lapsed math, physics and chem major, I don't remember my stuff all that well. However, I'll have right in the neighborhood of 500W solar How big are these solar panels? A Kyocera KC120 panel at 120 watts is: Max power: 120 Watts Max voltage: 16.9 Volts Max current: 7.10 Amps Dimensions (LxWxD): 56.1" x 25.7" x 2.2" Weight: 26.3 lbs 4 of those kinda hinders going on deck, I suppose. Or, do you mean 500 watt-hours per day?? 500 watts x 8 hours = 4 KWh/day...pretty nice! , and a KISS wind generator in the Caribbean. Various vendors suggest I take the wattage and divide by 3, or 4 if really lousy weather, for a reasonable typical AH input, daily. My math has that at 170-125AH/day, plus some other unknown - but apparently pretty substantial - AH from a KISS. Solar is useless on cloudy days, but that's when the wind is usually blowing so you got it covered. Speaking of wind power, have you see http://www.otherpower.com/ These homebrewers are really producing KWh! Our anticipated daily budget is about 125AH; we'll have (for simplicity in this calculation) ~1250AH capacity. It's our presumption that we'll have 4-5 days capacity, in the most unimaginable (in the Caribbean) circumstance of continuous no wind or sun. Have I missed something here? No, not at all. The big inverters are great for QUICK and TEMPORARY loads, even heavy loads if the battery banks can produce the heavy load currents without sagging a lot. Too bad boats don't use 48 volts instead of "car power". The whole thing becomes much more efficient as the voltage rises. |
"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in
: Absolutely! No heater or AC can be run off of an inverter in any practical manner. You would be amazed at how many sailors buying 4KW inverters cannot comprehend this concept..... Of course, these sailors have money (lawyers, doctors, businesspersons). Ever watch a lawyer load new batteries into a flashlight?...(c; |
"Larry W4CSC" wrote in message ... "Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in : Absolutely! No heater or AC can be run off of an inverter in any practical manner. You would be amazed at how many sailors buying 4KW inverters cannot comprehend this concept..... No I wouldn't :) Of course, these sailors have money (lawyers, doctors, businesspersons). Ever watch a lawyer load new batteries into a flashlight?...(c; |
"Larry W4CSC" wrote in message ... "Skip Gundlach" skipgundlach sez use my name at earthlink dot fishcatcher (net) - with apologies for the spamtrap wrote in : Hm. Help me with the math. As a lapsed math, physics and chem major, I don't remember my stuff all that well. However, I'll have right in the neighborhood of 500W solar How big are these solar panels? A Kyocera KC120 panel at 120 watts is: Max power: 120 Watts Not really. That is advertising hype. Max voltage: 16.9 Volts Max current: 7.10 Amps Dimensions (LxWxD): 56.1" x 25.7" x 2.2" Weight: 26.3 lbs 4 of those kinda hinders going on deck, I suppose. Or, do you mean 500 watt-hours per day?? 500 watts x 8 hours = 4 KWh/day...pretty nice! Useful power is more like 4 hours a day. 10AM to 2PM. Before and after it is vastly reduced. , and a KISS wind generator in the Caribbean. Various vendors suggest I take the wattage and divide by 3, or 4 if really lousy weather, for a reasonable typical AH input, daily. My math has that at 170-125AH/day, plus some other unknown - but apparently pretty substantial - AH from a KISS. KISS is a great generator. Solar is useless on cloudy days, but that's when the wind is usually blowing so you got it covered. Depends upon where you are. Speaking of wind power, have you see http://www.otherpower.com/ These homebrewers are really producing KWh! Sure, with 6' or better blades. Our anticipated daily budget is about 125AH; we'll have (for simplicity in this calculation) ~1250AH capacity. It's our presumption that we'll have 4-5 days capacity, in the most unimaginable (in the Caribbean) circumstance of continuous no wind or sun. Have I missed something here? No, not at all. The big inverters are great for QUICK and TEMPORARY loads, even heavy loads if the battery banks can produce the heavy load currents without sagging a lot. Too bad boats don't use 48 volts instead of "car power". The whole thing becomes much more efficient as the voltage rises. |
On Sun, 20 Mar 2005 21:23:15 -0500, Larry W4CSC
wrote: Too bad boats don't use 48 volts instead of "car power". The whole thing becomes much more efficient as the voltage rises. =========================================== It's not unheard of to use a 48 volt inverter bank. You lose the ability to tie into your alternators for charging but if you have reduntant generators and inverters that is not really an issue. |
On Sun, 20 Mar 2005 19:38:13 -0500, "John Cassara"
wrote: The long winded point is that a 900AH Battery and an inverter will not run a Heater all weekend. ================================= That's true but it will run a heater for 7 or 8 hours at night which is all you really need (assuming you can recharge in the morning). |
On Sun, 20 Mar 2005 21:23:15 -0500, Larry W4CSC
wrote: "Skip Gundlach" skipgundlach sez use my name at earthlink dot fishcatcher (net) - with apologies for the spamtrap wrote in : Hm. Help me with the math. As a lapsed math, physics and chem major, I don't remember my stuff all that well. However, I'll have right in the neighborhood of 500W solar How big are these solar panels? A Kyocera KC120 panel at 120 watts is: Max power: 120 Watts Max voltage: 16.9 Volts Max current: 7.10 Amps Dimensions (LxWxD): 56.1" x 25.7" x 2.2" Weight: 26.3 lbs 4 of those kinda hinders going on deck, I suppose. Or, do you mean 500 watt-hours per day?? 500 watts x 8 hours = 4 KWh/day...pretty nice! , and a KISS wind generator in the Caribbean. Various vendors suggest I take the wattage and divide by 3, or 4 if really lousy weather, for a reasonable typical AH input, daily. My math has that at 170-125AH/day, plus some other unknown - but apparently pretty substantial - AH from a KISS. Solar is useless on cloudy days, but that's when the wind is usually blowing so you got it covered. Speaking of wind power, have you see http://www.otherpower.com/ These homebrewers are really producing KWh! Our anticipated daily budget is about 125AH; we'll have (for simplicity in this calculation) ~1250AH capacity. It's our presumption that we'll have 4-5 days capacity, in the most unimaginable (in the Caribbean) circumstance of continuous no wind or sun. Have I missed something here? No, not at all. The big inverters are great for QUICK and TEMPORARY loads, even heavy loads if the battery banks can produce the heavy load currents without sagging a lot. Too bad boats don't use 48 volts instead of "car power". The whole thing becomes much more efficient as the voltage rises. Design development is under way for 42 volt car systems Brian W |
"Brian Whatcott" wrote in message
... Design development is under way for 42 volt car systems It's already there. AFAIK all new VW marine diesels have a 42V system to power the injectors. Meindert |
"Meindert Sprang" wrote in
: It's already there. AFAIK all new VW marine diesels have a 42V system to power the injectors. Meindert I think the Toyota Prius hybrid takes this even further with a 480VDC system, doesn't it? A friend has one and it's quite impressive, once you get used to NOT starting the engine to take off from the parking lot. That's a bit unnerving, just turning it on and driving away...(c; |
"Wayne.B" wrote in message ... On Sun, 20 Mar 2005 19:38:13 -0500, "John Cassara" wrote: The long winded point is that a 900AH Battery and an inverter will not run a Heater all weekend. ================================= That's true but it will run a heater for 7 or 8 hours at night which is all you really need (assuming you can recharge in the morning). Nope. Our Pelonus ceramic cube heater draws around 110A. With a 900AH battery bank you would be lucky to get 4 hours. Probably less since it is drawing much more than the 20 hour rate from which your 900AH rating is based. We have a 500AH+ bank in our mobile canvas shop. The heater is good for about an hour. Doug |
Hi Doug
You mean 110 Volts not amps don't you? About 13.5 amps. JR; Doug Dotson wrote: "Wayne.B" wrote in message ... On Sun, 20 Mar 2005 19:38:13 -0500, "John Cassara" wrote: The long winded point is that a 900AH Battery and an inverter will not run a Heater all weekend. ================================= That's true but it will run a heater for 7 or 8 hours at night which is all you really need (assuming you can recharge in the morning). Nope. Our Pelonus ceramic cube heater draws around 110A. With a 900AH battery bank you would be lucky to get 4 hours. Probably less since it is drawing much more than the 20 hour rate from which your 900AH rating is based. We have a 500AH+ bank in our mobile canvas shop. The heater is good for about an hour. Doug |
You are right. Sorry about that. I should have read the whole thing.
JR JR Gilbreath wrote: Hi Doug You mean 110 Volts not amps don't you? About 13.5 amps. JR; Doug Dotson wrote: "Wayne.B" wrote in message ... On Sun, 20 Mar 2005 19:38:13 -0500, "John Cassara" wrote: The long winded point is that a 900AH Battery and an inverter will not run a Heater all weekend. ================================= That's true but it will run a heater for 7 or 8 hours at night which is all you really need (assuming you can recharge in the morning). Nope. Our Pelonus ceramic cube heater draws around 110A. With a 900AH battery bank you would be lucky to get 4 hours. Probably less since it is drawing much more than the 20 hour rate from which your 900AH rating is based. We have a 500AH+ bank in our mobile canvas shop. The heater is good for about an hour. Doug |
On Mon, 21 Mar 2005 17:09:48 -0500, "Doug Dotson"
dougdotson@NOSPAMcablespeedNOSPAMcom wrote: Nope. Our Pelonus ceramic cube heater draws around 110A. With a 900AH battery bank you would be lucky to get 4 hours. Probably less since it is drawing much more than the 20 hour rate from which your 900AH rating is based. We have a 500AH+ bank in our mobile canvas shop. The heater is good for about an hour. ============================================= That assumes continuous duty. Unless you have a really large cabin and/or a really cold night, the heater is actually on less than 30% of the time. I had a 440 AH bank on my old boat and we would usually make it through the night. I could hit the generator start button in the morning without getting out of bed. :-) |
"Wayne.B" wrote in message ... On Mon, 21 Mar 2005 17:09:48 -0500, "Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote: Nope. Our Pelonus ceramic cube heater draws around 110A. With a 900AH battery bank you would be lucky to get 4 hours. Probably less since it is drawing much more than the 20 hour rate from which your 900AH rating is based. We have a 500AH+ bank in our mobile canvas shop. The heater is good for about an hour. ============================================= That assumes continuous duty. Unless you have a really large cabin and/or a really cold night, the heater is actually on less than 30% of the time. I had a 440 AH bank on my old boat and we would usually make it through the night. I could hit the generator start button in the morning without getting out of bed. :-) Depends upon alot of things, like the outside temperature, the insulation of the boat, etc. I keep an electric heater on all winter and if the temp is below 40, it runs alot more than 30%. |
On Tue, 22 Mar 2005 20:47:30 -0500, "Doug Dotson"
dougdotson@NOSPAMcablespeedNOSPAMcom wrote: Depends upon alot of things, like the outside temperature, the insulation of the boat, etc. I keep an electric heater on all winter and if the temp is below 40, it runs alot more than 30%. ====================================== I'm sure that's true but I'd probably be plugged into dock power in that kind of weather. |
Well whats wrong with a good electric blanket and a heavy comforter to keep
warm over night. That would be alot less taxing on an electrical system. You still have to be able to recharge, but getting through the night should be easy. John "Larry W4CSC" wrote in message ... "Meindert Sprang" wrote in : It's already there. AFAIK all new VW marine diesels have a 42V system to power the injectors. Meindert I think the Toyota Prius hybrid takes this even further with a 480VDC system, doesn't it? A friend has one and it's quite impressive, once you get used to NOT starting the engine to take off from the parking lot. That's a bit unnerving, just turning it on and driving away...(c; |
John Cassara wrote:
Well whats wrong with a good electric blanket and a heavy comforter to keep warm over night. That would be alot less taxing on an electrical system. You still have to be able to recharge, but getting through the night should be easy. John "Larry W4CSC" wrote in message ... "Meindert Sprang" wrote in : It's already there. AFAIK all new VW marine diesels have a 42V system to power the injectors. Meindert I think the Toyota Prius hybrid takes this even further with a 480VDC system, doesn't it? A friend has one and it's quite impressive, once you get used to NOT starting the engine to take off from the parking lot. That's a bit unnerving, just turning it on and driving away...(c; The eliica car seen recently on Discovery uses 8 each 100 brake horse power electric motor regenerators built into the wheels, lithium ion batteries, and would need high voltage and high variable frequency switching I expect. It goes 350 KM and about 400 KPH and 0-100 in FOUR seconds! Not all ot once, I expect. Would not one such wheel motor be capable of driving a boat and regenerating charge with the propellor providing the juice on a good day? Why haul useless lead ballast if a keel was all batteries immune to sea water / chlorine gas dangers? A 5 horse genny could wait for an excuse for quite a while, if solar cells were in the mix and harbour navigation was all that was really needed. Even a long haul in doldrums would be tolerable at two or three knots, using the genny if the batteries were flat. Relatively slow water transport takes little energy, while a good sailing day would likely keep batteries up unless you ran an air conditioner or heater. Terry K |
Using my old 22ft Catalina as the example, quite a bit of drag is felt with
the O/B in the water while sailing. The prop-driven recharge would produce alot of drag, but as they say there's no such thing as a free lunch! John "Terry Spragg" wrote in message ... John Cassara wrote: Well whats wrong with a good electric blanket and a heavy comforter to keep warm over night. That would be alot less taxing on an electrical system. You still have to be able to recharge, but getting through the night should be easy. John "Larry W4CSC" wrote in message ... "Meindert Sprang" wrote in : It's already there. AFAIK all new VW marine diesels have a 42V system to power the injectors. Meindert I think the Toyota Prius hybrid takes this even further with a 480VDC system, doesn't it? A friend has one and it's quite impressive, once you get used to NOT starting the engine to take off from the parking lot. That's a bit unnerving, just turning it on and driving away...(c; The eliica car seen recently on Discovery uses 8 each 100 brake horse power electric motor regenerators built into the wheels, lithium ion batteries, and would need high voltage and high variable frequency switching I expect. It goes 350 KM and about 400 KPH and 0-100 in FOUR seconds! Not all ot once, I expect. Would not one such wheel motor be capable of driving a boat and regenerating charge with the propellor providing the juice on a good day? Why haul useless lead ballast if a keel was all batteries immune to sea water / chlorine gas dangers? A 5 horse genny could wait for an excuse for quite a while, if solar cells were in the mix and harbour navigation was all that was really needed. Even a long haul in doldrums would be tolerable at two or three knots, using the genny if the batteries were flat. Relatively slow water transport takes little energy, while a good sailing day would likely keep batteries up unless you ran an air conditioner or heater. Terry K |
"Wayne.B" wrote in message ... On Tue, 22 Mar 2005 20:47:30 -0500, "Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote: Depends upon alot of things, like the outside temperature, the insulation of the boat, etc. I keep an electric heater on all winter and if the temp is below 40, it runs alot more than 30%. ====================================== I'm sure that's true but I'd probably be plugged into dock power in that kind of weather. Any warmer than 40 and you don't need a heater at night anyway. |
With a good heavy comforter you don;t need the electric
blanket. I've have no idea the wattage of an electric blanket. We have a small Glomate butane heater to take off the chill. If it's really cold then we power up the Espar. "John Cassara" wrote in message ... Well whats wrong with a good electric blanket and a heavy comforter to keep warm over night. That would be alot less taxing on an electrical system. You still have to be able to recharge, but getting through the night should be easy. John "Larry W4CSC" wrote in message ... "Meindert Sprang" wrote in : It's already there. AFAIK all new VW marine diesels have a 42V system to power the injectors. Meindert I think the Toyota Prius hybrid takes this even further with a 480VDC system, doesn't it? A friend has one and it's quite impressive, once you get used to NOT starting the engine to take off from the parking lot. That's a bit unnerving, just turning it on and driving away...(c; |
On Wed, 23 Mar 2005 18:13:28 -0500, "Doug Dotson"
dougdotson@NOSPAMcablespeedNOSPAMcom wrote: I've have no idea the wattage of an electric blanket. ========================================= Relatively low. Our queen size draws 300 watts peak but averages much less. |
Well, back from the boat for a bit, and trying to keep up...
"Larry W4CSC" wrote in message ... "Skip Gundlach" skipgundlach sez use my name at earthlink dot fishcatcher (net) - with apologies for the spamtrap wrote in : Hm. Help me with the math. As a lapsed math, physics and chem major, I don't remember my stuff all that well. However, I'll have right in the neighborhood of 500W solar How big are these solar panels? A Kyocera KC120 panel at 120 watts is: Max power: 120 Watts Max voltage: 16.9 Volts Max current: 7.10 Amps Dimensions (LxWxD): 56.1" x 25.7" x 2.2" Weight: 26.3 lbs 4 of those kinda hinders going on deck, I suppose. Or, do you mean 500 watt-hours per day?? 500 watts x 8 hours = 4 KWh/day...pretty nice! Well, that's sorta what I thought. First, these (whatever they turn out to be, based solely on first, space, and second, availability) will be run through an MPPT which will allow me higher voltage/smaller wires - for example, ones designed for 24V systems.. Second, it appears I'll not be able to get the 500W I wanted - but quite possibly more than 450, e.g 3x http://www.partsonsale.com/bp4170.pdf 170w 63x31, 34v or 4x http://www.affordable-solar.com/kc125g125watt.html 125w 56x26 24v but Third, these are going on our arch http://www.justpickone.org/skip/gall...rch&star t=42 which, on construction, appears not to have the space above I'd expected. So, back to the drawing boards for what will fit up there. You can muck around in the rest of that gallery to see what else we'd looked at in coming up with the specs and drawings. In any event, moving about on deck won't be an issue.. None the less, 400W isn't out of the realm of possibility. Real world experience suggests "normal" accumulation of something above 125AH/day... The arch is in the rough welded stage, without any of the custom hang-ons, at the moment. I assume it will be finished by my next time down there, which I expect to be 10 days or so, when I'll take up the regimen of staying on the boat for 3 weeks and coming home for one, in hopes of finishing in May, as I have another surgery scheduled for June 6th, this time to relocate muscle from my back to replace the dead ones in the rotator cuff... L8R Skip and Lydia, refitting as fast as we can -- Morgan 461 #2 SV Flying Pig http://tinyurl.com/384p2 "There is nothing-absolutely nothing-half so much worth doing as simply messing about in boats. In or out of 'em, it doesn't matter. Nothing seems really to matter, that's the charm of it. Whether you get away, or whether you don't; whether you arrive at your destination or whether you reach somewhere else, or whether you never get anywhere at all, you're always busy, and you never do anything in particular; and when you've done it there's always something else to do, and you can do it if you like, but you'd much better not." |
Im not sure the MPPT controller allows for higher voltage/smaller wires. PV arrays are to some
extent constant current and a "12 volt" array will put out its maximum power at a voltage typically higher than the battery. So if you hook the array up to a battery with a "cheap" controller, it is basically a direct connection and the PV current stays about the same but the PV array voltage drops to the battery voltage so you can lose a fair amount of delivered power. The MPPT controller allows the array voltage to operate for maxiimun power while supplying current to the battery at the batteries charge current. I have a 160 watt pannel (2x80w Kyocera) and typically I might have 8 amps comming out of the panel and maybe 10.5 going into the battery (the currents will of course vary all over depending on how much sunlight, angle, ect). Also, the MPPT charger I have (Blue Sky - company used to be called RV) is intelegent about properly charging the batteries which can make them last longer. Ive only had this product for several months but think it was a good investment. wh Skip Gundlach wrote: Well, back from the boat for a bit, and trying to keep up... "Larry W4CSC" wrote in message ... "Skip Gundlach" skipgundlach sez use my name at earthlink dot fishcatcher (net) - with apologies for the spamtrap wrote in : Hm. Help me with the math. As a lapsed math, physics and chem major, I don't remember my stuff all that well. However, I'll have right in the neighborhood of 500W solar How big are these solar panels? A Kyocera KC120 panel at 120 watts is: Max power: 120 Watts Max voltage: 16.9 Volts Max current: 7.10 Amps Dimensions (LxWxD): 56.1" x 25.7" x 2.2" Weight: 26.3 lbs 4 of those kinda hinders going on deck, I suppose. Or, do you mean 500 watt-hours per day?? 500 watts x 8 hours = 4 KWh/day...pretty nice! Well, that's sorta what I thought. First, these (whatever they turn out to be, based solely on first, space, and second, availability) will be run through an MPPT which will allow me higher voltage/smaller wires - for example, ones designed for 24V systems.. Second, it appears I'll not be able to get the 500W I wanted - but quite possibly more than 450, e.g 3x http://www.partsonsale.com/bp4170.pdf 170w 63x31, 34v or 4x http://www.affordable-solar.com/kc125g125watt.html 125w 56x26 24v but Third, these are going on our arch http://www.justpickone.org/skip/gall...rch&star t=42 which, on construction, appears not to have the space above I'd expected. So, back to the drawing boards for what will fit up there. You can muck around in the rest of that gallery to see what else we'd looked at in coming up with the specs and drawings. In any event, moving about on deck won't be an issue.. None the less, 400W isn't out of the realm of possibility. Real world experience suggests "normal" accumulation of something above 125AH/day... The arch is in the rough welded stage, without any of the custom hang-ons, at the moment. I assume it will be finished by my next time down there, which I expect to be 10 days or so, when I'll take up the regimen of staying on the boat for 3 weeks and coming home for one, in hopes of finishing in May, as I have another surgery scheduled for June 6th, this time to relocate muscle from my back to replace the dead ones in the rotator cuff... L8R Skip and Lydia, refitting as fast as we can -- Morgan 461 #2 SV Flying Pig http://tinyurl.com/384p2 "There is nothing-absolutely nothing-half so much worth doing as simply messing about in boats. In or out of 'em, it doesn't matter. Nothing seems really to matter, that's the charm of it. Whether you get away, or whether you don't; whether you arrive at your destination or whether you reach somewhere else, or whether you never get anywhere at all, you're always busy, and you never do anything in particular; and when you've done it there's always something else to do, and you can do it if you like, but you'd much better not." |
Where did the extra 2.5 amps come from?
Roger http://home.earthlink.net/~derbyrm "Walt" wrote in message ... snip ... I have a 160 watt pannel (2x80w Kyocera) and typically I might have 8 amps coming out of the panel and maybe 10.5 going into the battery (the currents will of course vary all over depending on how much sunlight, angle, ect). |
The MPPT controller allows the PV array to operate at its maximum power point
which for example might be 8 amps at 16.4 volts. So the power output is 8*16.4 = 131 watts. The MPPT controller using some sort of power switching topology transfers almost all of the power to the battery which is for example at 12.5 volts. The current at 131 watts and 12.5 volts is 10.5 amps. So its 8 amp in at 16.4 volts and 10.5 amps out at 12.5 volts - ie,. the power is maintained. If you simply had connected the PV array to the battery (which is essentially what most controllers do), the current output of the PV array would have remianed constant but the voltage would have dropped to the battery voltage so the power delivered would have been approx 8amps * 12.5 volts = 100 watts - ie, significantly less than with the MPPT controller. The one I have draws about 100 ma so it doesnt "break even" until its running about .5 amps to the battery. MPPT contollers are also a fair amount more expensive so must compete with simply adding more solar panel area. However, if you want to keep the PV area as small as possible (like on a boat), it seems like a good product. Roger Derby wrote: Where did the extra 2.5 amps come from? Roger http://home.earthlink.net/~derbyrm "Walt" wrote in message ... snip ... I have a 160 watt pannel (2x80w Kyocera) and typically I might have 8 amps coming out of the panel and maybe 10.5 going into the battery (the currents will of course vary all over depending on how much sunlight, angle, ect). |
That's a lot more sophisticated that I expected from a "controller!" Can it
charge the batteries even if the solar cell voltage drops below the battery voltage? Do they have the "secondary" considerations such as RFI and waterproofing dealt with as well? Roger http://home.earthlink.net/~derbyrm "Walt" wrote in message ... The MPPT controller allows the PV array to operate at its maximum power point which for example might be 8 amps at 16.4 volts. So the power output is 8*16.4 = 131 watts. The MPPT controller using some sort of power switching topology transfers almost all of the power to the battery which is for example at 12.5 volts. The current at 131 watts and 12.5 volts is 10.5 amps. So its 8 amp in at 16.4 volts and 10.5 amps out at 12.5 volts - ie,. the power is maintained. If you simply had connected the PV array to the battery (which is essentially what most controllers do), the current output of the PV array would have remianed constant but the voltage would have dropped to the battery voltage so the power delivered would have been approx 8amps * 12.5 volts = 100 watts - ie, significantly less than with the MPPT controller. The one I have draws about 100 ma so it doesnt "break even" until its running about .5 amps to the battery. MPPT contollers are also a fair amount more expensive so must compete with simply adding more solar panel area. However, if you want to keep the PV area as small as possible (like on a boat), it seems like a good product. Roger Derby wrote: Where did the extra 2.5 amps come from? Roger http://home.earthlink.net/~derbyrm "Walt" wrote in message ... snip ... I have a 160 watt pannel (2x80w Kyocera) and typically I might have 8 amps coming out of the panel and maybe 10.5 going into the battery (the currents will of course vary all over depending on how much sunlight, angle, ect). |
"Walt" wrote in message ...
Im not sure the MPPT controller allows for higher voltage/smaller wires. PV arrays are to some extent constant current and a "12 volt" array will put out its maximum power at a voltage typically higher than the battery. So if you hook the array up to a battery with a "cheap" controller, it is basically a direct connection and the PV current stays about the same but the PV array voltage drops to the battery voltage so you can lose a fair amount of delivered power. The MPPT controller allows the array voltage to operate for maxiimun power while supplying current to the battery at the batteries charge current. I have a 160 watt pannel (2x80w Kyocera) and typically I might have 8 amps comming out of the panel and maybe 10.5 going into the battery (the currents will of course vary all over depending on how much sunlight, angle, ect). Also, the MPPT charger I have (Blue Sky - company used to be called RV) is intelegent about properly charging the batteries which can make them last longer. Ive only had this product for several months but think it was a good investment. wh Blue sky was the make my installer (svhorizon.com, KISS US distributor) recommended. It was his suggestion that I go to the higher voltage panels in order to make for smaller wires possible with the same voltage drop (thus the need for MPPT). As much wattage as we'll have, and as far as it has to run to the ER, after the trip down the (tall) arch, drop is of concern. Unfortunately, they're driving to the Oakland show and won't be available to start on the project for nearly a month. Then, I hope to get the electrical stuff buttoned up quickly, as I have what is now a very short window to get the boat finished before my surgery. L8R Skip -- Morgan 461 #2 SV Flying Pig http://tinyurl.com/384p2 "Twenty years from now you will be more disappointed by the things you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover." - Mark Twain |
"Skip Gundlach" skipgundlach sez use my name at earthlink dot fishcatcher (net) - with apologies for the spamtrap wrote in message ... Hi, Y'all... Well... "Larry W4CSC" wrote in message ... snipped bit was here Hmm...5A from a big solar panel or 15A from a wind generator = 5X12hrs=60AH per day if the sun shines or 360AH wind power in a full gale 24/7. Not much of a real powerhouse, is it, huge batteries or small batteries... Plan on using the big alternator on the engine every day in this configuration. Hm. Help me with the math. As a lapsed math, physics and chem major, I don't remember my stuff all that well. However, I'll have right in the neighborhood of 500W solar, and a KISS wind generator in the Caribbean. Various vendors suggest I take the wattage and divide by 3, or 4 if really lousy weather, for a reasonable typical AH input, daily. My math has that at 170-125AH/day, plus some other unknown - but apparently pretty substantial - AH from a KISS. Our anticipated daily budget is about 125AH; we'll have (for simplicity in this calculation) ~1250AH capacity. It's our presumption that we'll have 4-5 days capacity, in the most unimaginable (in the Caribbean) circumstance of continuous no wind or sun. Have I missed something here? Hi Skip, I'm looking at your math and trying to work out how you came up with 170-125AH/day generated by your solar panels. Will this 500 watt panel array ever actually put out 500watts? Or, as you said above, will it really be only a quarter to a third of this ? If so, how many hours a day will this panel put out this kind of wattage? Perhaps a couple of hours on either side of noon with diminished output before and after this time? 500 watt panel /14.5 volt supply = 35 amps of current. A third of this is only about 12 amps or so. For about 4 hours is 4 hours x 12 amps = 48 AH per day. Perhaps you will get some useful power out of the rest of the available daylight, perhaps another 22 AH or so, that still only gives you 60 AH per day or so, no? Which doesn't seem to come close to filling your anticipated daily power budget, let alone leave anything to replenish the batteries from the drawdown on cloudy days. Perhaps I've missed somthing here? More snipped bits Thanks. L8R Skip (about to head back to the boat for another couple weeks, this time, this part, of the refit) -- Morgan 461 #2 SV Flying Pig http://tinyurl.com/384p2 "There is nothing-absolutely nothing-half so much worth doing as simply messing about in boats. In or out of 'em, it doesn't matter. Nothing seems really to matter, that's the charm of it. Whether you get away, or whether you don't; whether you arrive at your destination or whether you reach somewhere else, or whether you never get anywhere at all, you're always busy, and you never do anything in particular; and when you've done it there's always something else to do, and you can do it if you like, but you'd much better not." -- Ken Heaton & Anne Tobin Cape Breton Island, Canada kenheaton AT ess wye dee DOT eastlink DOT ca |
"Ken Heaton" wrote in
news:xh05e.4996$VF5.1702@edtnps89: Will this 500 watt panel array ever actually put out 500watts? Another interesting point is that a solar cell is very poor efficiency. Here's a report on a new Sanyo HIT cell hitting 21.3%.... "The resulting efficiency level exceeds 21.3 percent, which until now, was the highest level delivered by SANYO HIT solar cells. The HIT solar cell is 10cm square, nearly the same size as solar cells currently used for home and industrial applications." Regular silicon solar cells are like 6% efficient! Even if we get this supercell technology, to get 500 watts out, we're going to have to put 2500 watts of sunshine in and cool the cells of 2000 watts of heat! Will that be fresh water or seawater cooling??...(c; Maybe we can use the heat to cook lunch on the metal heat sinks...saving the drain from the microwave oven! Wonder why we can't run a little water pump in the loop to the water heater? The waste heat from the solar charging could give us all HOT SHOWERS AND DISHWATER! The big panel on Lionheart puts out 5A on its best day and only if the boom is out wide and not shading anything on top of the cockpit hardtop it covers.... |
Hi, Y'all,
I'm getting a little out of my depth, my last physics classes having been nearly 40 years ago, but... "Ken Heaton" wrote in message news:xh05e.4996$VF5.1702@edtnps89... Hi Skip, I'm looking at your math and trying to work out how you came up with 170-125AH/day generated by your solar panels. I'm not so much doing that as passing on the conventional and experienced (that is, by folks who have SPs installed) wisdom that one may take the wattage of current technology solar panels and divide by 3 (typical) to 4 (cloudy, etc.) for a real-world daily AH result. Not having same installed on our boat (where there will be minimal or no shading), I can't do more than speculate. Will this 500 watt panel array ever actually put out 500watts? Or, as you said above, will it really be only a quarter to a third of this ? If so, how many hours a day will this panel put out this kind of wattage? Perhaps a couple of hours on either side of noon with diminished output before and after this time? 500 watt panel /14.5 volt supply = 35 amps of current. Ah - but I'm going with the higher voltages, for a couple of reasons. One is easier transmission - smaller wires - for the same voltage drop. The other is for more flexibility when tied to an MPPT. Typical peak voltage would be in the 30s. So, presumably, at least, more amps result. A third of this is only about 12 amps or so. For about 4 hours is 4 hours x 12 amps = 48 AH per day. Perhaps you will get some useful power out of the rest of the available daylight, perhaps another 22 AH or so, that still only gives you 60 AH per day or so, no? Which doesn't seem to come close to filling your anticipated daily power budget, let alone leave anything to replenish the batteries from the drawdown on cloudy days. Agreed. However, that (your scenario above) would make for a very small output. I believe the 3 or 4 divider isn't at any given minute - else, why would they be rated at any given wattage? - but, rather, a full-day experience, ameliorated by darkness, clouds, shadows, and other impedimentia to a 24-hour, full output, result. Perhaps I've missed somthing here? I dunno - perhaps *I've* missed something in all the research I've done. I could swear that various posters to these fora have provided real-world experiences on which I base my assumptions, backed up by various vendor claims (as taken with the requisite grain of salt). That I'll be in the Caribbean has got to help, too, but it's not the presumption with which I started. L8R Skip, home for a couple more days before - this time - a 4 week working visit to the boat-on-the-hard -- Morgan 461 #2 SV Flying Pig http://tinyurl.com/384p2 "And then again, when you sit at the helm of your little ship on a clear night, and gaze at the countless stars overhead, and realize that you are quite alone on a wide, empty sea, it is apt to occur to you that in the general scheme of things you are merely an insignificant speck on the surface of the ocean; and are not nearly so important or as self-sufficient as you thought you were. Which is an exceedingly wholesome thought, and one that may effect a permanent change in your deportment that will be greatly appreciated by your friends."- James S. Pitkin |
My 0.0002, could be wrong..
I have a 160 watt panel and when the sun is shining and the panel is aimed right, and Im using an MPPT controller, Im getting reasonably close to 160 watts out of it - like maybe 150.. What Ive seen are calcutions based on the rated power of the PV panel and assuing that you get 5 hours of sunlight per day. On good sunny days, this possibly underestimates the power. On cloudy days, you might get a lot less. Using current to compare things is ok but it doesnt take into account voltage. What really is important is power. Here are some rough calcs.. At 450 watts PV power and assuming using MPPT (which works and improves efficiency for either 12 or 24 volt systems), the output current at full power is (power = voltage * current) 15 amps for 24 volts system (15 = 450/30 volts - assumes MPPT allows panel to operate at 30 volts rather than battery voltage) 30 amps for 12 volts system (30 = 450/15 volts - assumes MPPT allows panel to operate at 15 volts) So if this current were available for an average of 5 hours per day, you would have 12 volts system : 5hours * 30 amps = 150 amp hours 24 volt system: 5 hours * 15 amps = 75 amp hours Note that the amp hours is different but the power is the same - which is why you should really look at watt hours and not amp hours to see what capacity is. The watt hours is then: 12 volt system: 5 hours * 30 amps * 12.5 volts = 1875 watt hours 24 volts system: 5 hours * 15 amps * 25 volts = 1875 watt hours To consider what long wire runs do, a lot of PV runs use 10 guage wire which has an impedance of "about" .00118 ohms per foot. So if you had for exampe 40 foot of wire between the PV array and the battery, the resistance which disipates power would be the combination of the two wires (ie, the total wire length is 80 foot) so the power disipating resistance of the wire is 2 * 40 foot * .00118 ohms/ft = .0944 ohms. So the power lost by the long wires would be ( power = current**2 * R) 12 volt system: 30**2 * .0944 ohms = 84.96 watts 24 volt system: 15**2 * .0944 ohms = 21.24 watts For long wires and higher current, the 24 volts system looks a fair amount better to me. You would be loosing nearly 20% just by the wire if you used 12 volts with this system. MPPT will help and I think a good application here but I personally dont think MPPT is about 12 or 24 volts - its about better utilizing either voltage system. I could be wrong or have bad calculation so dont take any of this seriously (and Im sure someone can find something wrong with it..) Wally Hall Denver Skip Gundlach wrote: Hi, Y'all, I'm getting a little out of my depth, my last physics classes having been nearly 40 years ago, but... "Ken Heaton" wrote in message news:xh05e.4996$VF5.1702@edtnps89... Hi Skip, I'm looking at your math and trying to work out how you came up with 170-125AH/day generated by your solar panels. I'm not so much doing that as passing on the conventional and experienced (that is, by folks who have SPs installed) wisdom that one may take the wattage of current technology solar panels and divide by 3 (typical) to 4 (cloudy, etc.) for a real-world daily AH result. Not having same installed on our boat (where there will be minimal or no shading), I can't do more than speculate. Will this 500 watt panel array ever actually put out 500watts? Or, as you said above, will it really be only a quarter to a third of this ? If so, how many hours a day will this panel put out this kind of wattage? Perhaps a couple of hours on either side of noon with diminished output before and after this time? 500 watt panel /14.5 volt supply = 35 amps of current. Ah - but I'm going with the higher voltages, for a couple of reasons. One is easier transmission - smaller wires - for the same voltage drop. The other is for more flexibility when tied to an MPPT. Typical peak voltage would be in the 30s. So, presumably, at least, more amps result. A third of this is only about 12 amps or so. For about 4 hours is 4 hours x 12 amps = 48 AH per day. Perhaps you will get some useful power out of the rest of the available daylight, perhaps another 22 AH or so, that still only gives you 60 AH per day or so, no? Which doesn't seem to come close to filling your anticipated daily power budget, let alone leave anything to replenish the batteries from the drawdown on cloudy days. Agreed. However, that (your scenario above) would make for a very small output. I believe the 3 or 4 divider isn't at any given minute - else, why would they be rated at any given wattage? - but, rather, a full-day experience, ameliorated by darkness, clouds, shadows, and other impedimentia to a 24-hour, full output, result. Perhaps I've missed somthing here? I dunno - perhaps *I've* missed something in all the research I've done. I could swear that various posters to these fora have provided real-world experiences on which I base my assumptions, backed up by various vendor claims (as taken with the requisite grain of salt). That I'll be in the Caribbean has got to help, too, but it's not the presumption with which I started. L8R Skip, home for a couple more days before - this time - a 4 week working visit to the boat-on-the-hard -- Morgan 461 #2 SV Flying Pig http://tinyurl.com/384p2 "And then again, when you sit at the helm of your little ship on a clear night, and gaze at the countless stars overhead, and realize that you are quite alone on a wide, empty sea, it is apt to occur to you that in the general scheme of things you are merely an insignificant speck on the surface of the ocean; and are not nearly so important or as self-sufficient as you thought you were. Which is an exceedingly wholesome thought, and one that may effect a permanent change in your deportment that will be greatly appreciated by your friends."- James S. Pitkin |
In article xh05e.4996$VF5.1702@edtnps89,
"Ken Heaton" wrote: Will this 500 watt panel array ever actually put out 500watts? Yes, it will, and for the first few years, more. 34 amps times 8 hours (and that's conservative) is 250 AH. Our little panel puts out its rated power from dawn to dusk if I realign it from time to time. -- Jere Lull Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD) Xan's Pages: http://members.dca.net/jerelull/X-Main.html Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/ |
Thanks for the real life info Jere. I've been wondering the same things as
Skip, but I will be using a much smaller panel. And Anon had some good info on calculating power output. I'll have to go Google MPPT controllers now... -- Ken Heaton & Anne Tobin Cape Breton Island, Canada kenheaton AT ess wye dee DOT eastlink DOT ca "Jere Lull" wrote in message ... In article xh05e.4996$VF5.1702@edtnps89, "Ken Heaton" wrote: Will this 500 watt panel array ever actually put out 500watts? Yes, it will, and for the first few years, more. 34 amps times 8 hours (and that's conservative) is 250 AH. Our little panel puts out its rated power from dawn to dusk if I realign it from time to time. -- Jere Lull Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD) Xan's Pages: http://members.dca.net/jerelull/X-Main.html Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/ |
| All times are GMT +1. The time now is 06:14 PM. |
Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 BoatBanter.com