Home |
Search |
Today's Posts |
|
#1
posted to rec.boats.electronics
|
|||
|
|||
diode in charging circuit
I have an older Honda 10 hp outboard that has a charging circuit. The
small boat that it is on has a bilge pump and small AGM battery. The outboard's charging circuit puts out over 15 volts. Can I put a diode in the circuit to reduce the voltage? If so what kind of diode? thanks |
#2
posted to rec.boats.electronics
|
|||
|
|||
diode in charging circuit
Is the "more than 15 v " with the battery connected to the generator or when
disconnected and open circuit? The simplest solution is probably a series resistor to limit the charge to about 1 amp or less which should not upset a reasonably sized battery. Try a 21W car bulb and measure the current. Alec wrote in message ups.com... I have an older Honda 10 hp outboard that has a charging circuit. The small boat that it is on has a bilge pump and small AGM battery. The outboard's charging circuit puts out over 15 volts. Can I put a diode in the circuit to reduce the voltage? If so what kind of diode? thanks |
#3
posted to rec.boats.electronics
|
|||
|
|||
diode in charging circuit
On Nov 14, 8:01 am, wrote:
On Tue, 13 Nov 2007 19:23:43 -0000, "Alec" wrote: Is the "more than 15 v " with the battery connected to the generator or when disconnected and open circuit? The simplest solution is probably a series resistor to limit the charge to about 1 amp or less which should not upset a reasonably sized battery. Try a 21W car bulb and measure the current. Alec What? This is gibberish. Hmmm. Makes perfect sense to me. Maybe you could ask a question about what you don't understand, and then we can all learn something. Limiting the charging current to avoid damaging the battery is certainly a workable approach. |
#4
posted to rec.boats.electronics
|
|||
|
|||
diode in charging circuit
On Nov 12, 3:12 pm, wrote:
I have an older Honda 10 hp outboard that has a charging circuit. The small boat that it is on has a bilge pump and small AGM battery. The outboard's charging circuit puts out over 15 volts. Can I put a diode in the circuit to reduce the voltage? If so what kind of diode? thanks You could put a galvanic isolator in line with the alternator output. This will drop the voltage to about 13.6 and can handle the current. Eric |
#5
posted to rec.boats.electronics
|
|||
|
|||
diode in charging circuit
Well, you might be right about the common cable and the cheaper route/solution being the flooded battery, but I can find a 30 amp isolator for $140. But if you must have that overpriced Guest stuff, yeah, you'll pay $300 for it. BTW, agm's are not quickly ruined by having over 14 volts on them. We use hundreds of Lifeline agm's where I work and the bulk charge spec. for them is 14.2-14.4 volts. Float charge should be kept at 13.3 or under. And once fully charged, can be equalized at 15.5 volts for 8 hours when neccessary. As stated in their documentation: "Regardless of what some rumors portray, AGM batteries are not as sensitive as once believed. They often get confused with Gel Batteries, which are very sensitive to voltage and they need a special charger." Eric On Nov 14, 9:06 am, wrote: Yeah, and a 30 amp galvanic isolator to protect that $150 AGM battery will run you about $300 or more! If the Honda outboard in question has electric start, you will need one that will handle 100 amps, as that is about what the starter motor draws, and the same cables from the motor to the battery are used for both starting and charging. I'll repeat: A new flooded battery will solve the issue for about $50. |
#7
posted to rec.boats.electronics
|
|||
|
|||
diode in charging circuit
On Nov 15, 6:56 am, wrote:
Confused? I'm not the one who thinks a $140 work-ariound is superior to a $50 Solution. :') Neither am I. He asked if he could use a diode to drop the voltage and if so, what kind. And here's a little tip: An AGM battery can be effectively charged at 13.5 volts. And your point? A flooded battery needs more than that just to begin charging. FALSE! difference in internal resistance. And for purposes of this thread, the essentially unregulated voltage from a 10 hp Honda outboard IS enough to quickly ruin an AGM battery. Quickly? I doubt it. I doubt the thing can output more than 10 amps if even that much. Once the AGM is fully charged, it can still stand the 15v for several hours with no ill effects. I have a Lifeline AGM GPL-24T right here in the shop that's fully charged but been sitting for a while (no surface charge). I just put a constant 15v on it and it started charging at 4 amps. After 5 minutes it's down to 2 amps and in the next few minutes it will be down to a couple hundred milliamps. I can leave it on this way for hours and it ain't gonna hurt the battery. I can fully test this battery with my carbon pile load tester to prove that the battery hasn't been quickly ruined. Eric |
#8
posted to rec.boats.electronics
|
|||
|
|||
diode in charging circuit
On Nov 15, 12:59 pm, wrote:
Suit yourself. I don't have much faith at this point in your ability to accurately test and diagnose a battery sitting in front of you. I'm not even convinced you know the difference between voltage and current. And Iv'e only been an electronics technician for 32 years. Gee, I guess I better go look for another profession. Eric |
#9
posted to rec.boats.electronics,alt.usenet.legends.lester-mosley
|
|||
|
|||
diode in charging circuit
wrote in message ... .. And Iv'e only been an electronics technician for 32 years. everything is fantastic Gee, I guess I better go look for another profession. if you are for real, and not teasing, then hey let's do it. mk5000 'what am i supposed to do!? Help them you git! but-but-- I don't know what to do! How about pointing your wand at that thing and yelling a spell or something! I can't! I can't do anything! Why not!? ' Malfoy |
#10
posted to rec.boats.electronics
|
|||
|
|||
diode in charging circuit
wrote:
I have an older Honda 10 hp outboard that has a charging circuit. The small boat that it is on has a bilge pump and small AGM battery. The outboard's charging circuit puts out over 15 volts. Can I put a diode in the circuit to reduce the voltage? If so what kind of diode? thanks Changing to a flooded battery sounds reasonable, but if you're determined to use the AGM, place a high current diode in series with the battery lead. It will drop 0.6 to 0.9 volts as long as the current is greater than a few tens of milliamperes. Couple of bucks. Bolt it to a chunk of aluminum as a heat sink and make sure it is rated to handle the current involved. No need to use a galvanic isolator at all. Chuck ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
Reply |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Diode question | Electronics | |||
Charging circuit, 200Merc Help | Electronics | |||
Diode question for Brian or Larry | Cruising | |||
Circuit Breaker trips while charging?? | Electronics | |||
Bow thruster charging circuit | Electronics |