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#21
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Hi amp DC wiring
"Dick Locke" wrote in message ... I am thinking about installing dual electric primary winches, which are 1500 watt 12 v motors (still waiting on the electric specs to see breaker size which will define wiring size. I believe that's startup wattage.) The breaker should be sized appropriately to protect the wiring, not the load. For most motor applications you can ignore the startup draw if you use a slow blow fuse or a thermal breaker. This is because the startup current only last for a second or two and a thermal breaker won't trip that fast. A winch, however, is a different story since it is likely that you could encounter stall situations during use. A heavy load on the winch will draw a lot of current, which will cause a voltage drop, which reduces the torque of the motor which further leads to stall, which makes it want to draw even more current. I would recommend using wire of sufficient size to handle the maximum current with a minimum of voltage drop. Hopefully the manufacturer of the winch can tell you what the minimum voltage to the motor should be (hopefully it will be something like 10 volts). Establish what the voltage of the batteries is likely to be when you are using the winches (11 volts would not be an unreasonable number). The difference between these two (1 volt in this case) is the maximum drop you can tolerate. Leave a little for the connections and you can tolerate a 10% drop in voltage. The boat has two sets of house batteries, one set on starboard about 6 feet forward of the starboard winch, one on port almost directly under the port winch. Your 1500 watts at 10 volts will draw 150 amps. I would expect that 6 foot run to require 20 feet of wire (10 for the positive and another 10 for the return). Choose whose table you want to believe. For reasons I never understood this seems to be a big variable. The manufacturer of the wire you intend to use should be a good source. Here is one such source: http://www.ancorproducts.com/ Go to the their "technical informatio", "Wire Size", enter the parameters (20 feet, 150 amps, 12 volts, 10%) and it indicates that you need a minimum of 4 awg wire. If it was me, I would hedge my bets and install 2 awg wire just because I hate voltage drops. Also look at the maximum current for the wi 4awg has a maximum current of 160 amps, 2 awg can handle 210 amps. The circuit breaker you install should not be larger than these respective currents. Is there any reason why I need to wire the port winch all the way across the boat to the distribution panel? I'm inclined to hook it up just after the disconnect switch (or with its own disconnect switch) directly to the port batteries. It would have a circuit breaker, of course. Sounds like a good idea to me, as long as you can count on having reasonable state of charge in both batteries. I can imagine sailing home from a weekend and not being able to use the port winch because that battery is dead! Rod |
#22
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Hi amp DC wiring
On Mon, 5 Apr 2004 12:38:32 -0700, "Rod McInnis"
wrote: Sounds like a good idea to me, as long as you can count on having reasonable state of charge in both batteries. I can imagine sailing home from a weekend and not being able to use the port winch because that battery is dead! Right, that's a downside I can see...or even worse one battery bank crumps somehow on a long trip. The winch is sized large enough that we can crank by hand (or change course and go around the world ;-)) |
#23
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Hi amp DC wiring
On Mon, 5 Apr 2004 12:38:32 -0700, "Rod McInnis"
wrote: Sounds like a good idea to me, as long as you can count on having reasonable state of charge in both batteries. I can imagine sailing home from a weekend and not being able to use the port winch because that battery is dead! Right, that's a downside I can see...or even worse one battery bank crumps somehow on a long trip. The winch is sized large enough that we can crank by hand (or change course and go around the world ;-)) |
#24
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Hi amp DC wiring
On Sun, 04 Apr 2004 15:23:39 GMT, Gualtier Malde
wrote: I think that if I needed a winch with that much power I'd look into hydraulic ones, or those operated with 120vAC. =========================================== Hydraulic or 120 AC require that an engine be running at all times that you need the sheet winches. Not really an option except for the very largest boats, and undesirable even then. Electric sheet winches are only used for 10 to 15 seconds at a time in my experience which is no problem for a decently sized battery bank. They are a huge convenience for cruising boats in the 40+ range. |
#25
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Hi amp DC wiring
On Sun, 04 Apr 2004 15:23:39 GMT, Gualtier Malde
wrote: I think that if I needed a winch with that much power I'd look into hydraulic ones, or those operated with 120vAC. =========================================== Hydraulic or 120 AC require that an engine be running at all times that you need the sheet winches. Not really an option except for the very largest boats, and undesirable even then. Electric sheet winches are only used for 10 to 15 seconds at a time in my experience which is no problem for a decently sized battery bank. They are a huge convenience for cruising boats in the 40+ range. |
#26
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Hi amp DC wiring
Wayne.B wrote:
On Sun, 04 Apr 2004 15:23:39 GMT, Gualtier Malde wrote: I think that if I needed a winch with that much power I'd look into hydraulic ones, or those operated with 120vAC. =========================================== Hydraulic or 120 AC require that an engine be running at all times that you need the sheet winches. Not really an option except for the very largest boats, and undesirable even then. Electric sheet winches are only used for 10 to 15 seconds at a time in my experience which is no problem for a decently sized battery bank. They are a huge convenience for cruising boats in the 40+ range. Wait... this is a Sail Boat? And you aren't talking about ANCHOR winches? Whoa. No wonder this question is getting a variety of replies. I believe I'm not the only one who thought "anchor" when responding. As Emily Latilla used to say: "Never mind". |
#27
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Hi amp DC wiring
Wayne.B wrote:
On Sun, 04 Apr 2004 15:23:39 GMT, Gualtier Malde wrote: I think that if I needed a winch with that much power I'd look into hydraulic ones, or those operated with 120vAC. =========================================== Hydraulic or 120 AC require that an engine be running at all times that you need the sheet winches. Not really an option except for the very largest boats, and undesirable even then. Electric sheet winches are only used for 10 to 15 seconds at a time in my experience which is no problem for a decently sized battery bank. They are a huge convenience for cruising boats in the 40+ range. Wait... this is a Sail Boat? And you aren't talking about ANCHOR winches? Whoa. No wonder this question is getting a variety of replies. I believe I'm not the only one who thought "anchor" when responding. As Emily Latilla used to say: "Never mind". |
#28
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Hi amp DC wiring
125 amps isn't much of a big deal. My microwave oven draws 100+.
Windlass draws over 80 with peaks beyond that. Doug s/v Callista "Gualtier Malde" wrote in message news:frEbc.65804$w54.401828@attbi_s01... Dick Locke wrote: I am thinking about installing dual electric primary winches, which are 1500 watt 12 v motors (still waiting on the electric specs to see breaker size which will define wiring size. I believe that's startup wattage.) 1500 Watts? Are you sure? The formula P=IE, or I=P/E = I=1500/12=125Amps. Thats a whole lot of juice. Do you have water cooled jacketed batteries? |
#29
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Hi amp DC wiring
125 amps isn't much of a big deal. My microwave oven draws 100+.
Windlass draws over 80 with peaks beyond that. Doug s/v Callista "Gualtier Malde" wrote in message news:frEbc.65804$w54.401828@attbi_s01... Dick Locke wrote: I am thinking about installing dual electric primary winches, which are 1500 watt 12 v motors (still waiting on the electric specs to see breaker size which will define wiring size. I believe that's startup wattage.) 1500 Watts? Are you sure? The formula P=IE, or I=P/E = I=1500/12=125Amps. Thats a whole lot of juice. Do you have water cooled jacketed batteries? |
#30
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Hi amp DC wiring
Hmm....I could run the sheets back through the blocks, then up to the drum
side of the windlass....hmm....Sure gets wet up there in a blow, though....(c; All in good fun. Larry W4CSC Gualtier Malde wrote in news:T6Bcc.83915$K91.182379@attbi_s02: Wait... this is a Sail Boat? And you aren't talking about ANCHOR winches? Whoa. No wonder this question is getting a variety of replies. I believe I'm not the only one who thought "anchor" when responding. As Emily Latilla used to say: "Never mind". |
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