Charging Question

[rjn cajun]

hey all I posted this in the outboard section also. I`m new and not sure where it should be posted. I have an 8hp yamaha 2 stoke motor. I also have a minnkota trolling motor and a depth finder. I talked to a guy at the lake and he told me I could charge my battery with my 8 horse by doing something with the magneto I think that`s what it`s called.I`m wondering if there is any truth to this or if someone could point me in the right direction. Thanks

[Bassinkorea]

I cannot answer your question, but I hope it is possible as I have a small motor and would like to know the same information.

[TProud]

I have an unrelated charging question but a charging question none the less. I have 4 12v batteries for my reservoir rig and want to charge them at once can this be done?like hooking all 4 up parallel or will this hurt the battery life and or ruin the batteries?

[CatFan]

hey all I posted this in the outboard section also. I`m new and not sure where it should be posted. I have an 8hp yamaha 2 stoke motor. I also have a minnkota trolling motor and a depth finder. I talked to a guy at the lake and he told me I could charge my battery with my 8 horse by doing something with the magneto I think that`s what it`s called.I`m wondering if there is any truth to this or if someone could point me in the right direction. Thanks

Even if you could somehow modify the engine to charge the battery, it would have to run for many, many hours to charge it.  Not likely a worthwhile endeavor.

[CatFan]

I have an unrelated charging question but a charging question none the less. I have 4 12v batteries for my reservoir rig and want to charge them at once can this be done?like hooking all 4 up parallel or will this hurt the battery life and or ruin the batteries?

The problem is that unless the batteries are exactly the same age and model, and they are discharged the same amount every time, some batteries will be overcharged doing this.  You'd also need a charger with 20A minimum, and you'd probably be way happier with a 40A charger.  I don't know of any good chargers suitable for marine use that have that kind of capacity.  The cheap automatic or manual chargers are just for occasional use to recover from a battery drain, not really for frequent use on a battery.

Far better to get a 4-bank onboard charger.

[Creel Limit Zero]

I believe what you need to get is an alternator kit.  I'm not sure if they make them for Yamaha's, but I know they have them for Nissan 8HP outboards, so I don't see why they wouldn't make them for a yamaha.  What you need is an alternator coil and a rectifier.  I don't think it is something you can build on your own, you'll need to get specific parts for the outboard you have, so it matches up and produces a charge for your batteries when you hook the coil up.  If they don't make them, you might be  out of luck.  Call up or go on Yamaha and see if they have something.  If they do, sweet action.