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| I'm curious if anyone else used their cigarette lighter outlet (or direct connection to a cranking battery) connected to an inverter, then plugged in their on board charger to the invertor while running the outboard before? I've done this a few times and it seems to work like a champ to charge trolling motor batteries. I know they make a number of different inverters, but since the draw isn't too much for my on board unit I think just about any inverter would do. I see that minn kota now offers a unit that does the same thing in one box for ~$150...but I can't really justify getting it since my getto approach seems to be working just fine. I assume there are lots of other folks that have done this through the years, but can't seem to find anything when I have been searching. Maybe I'm missing something? I don't know too much about electrons and crap, but it sure seems reasonable to power the on board via the cranking battery and outboard to me anyway. |
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Location: Green Bay, WI | Well, I'd be careful...
If your trolling motor batteries aren't terribly discharged, then you'll probably be alright. And I suppose it depends upon how powerful (in terms of current charging capacity) your charger is. But I'll bet you have a 5-amp fuse on that lighter circuit, so if your charger is powerful and the batteries are drawing a lot of current because they are in a low-charge state, then you may blow the fuse for the lighter. But if the trolling motor batteries are relatively charged, and/or your charger doesn't draw a lot of current straight away, you'll probably do OK. You should investigate those things.
The worst that will happen, I guess, is that you'll blow the fuse (assuming you have an inline fuse for the 12v socket), and have to replace it. But if you do not have it fused, then I think you're asking for problems. That wire, depending upon the gauge, is probably not rated for the kind of current you'll see if the batteries are discharged. So at the very least, make sure the 12v outlet is fused. You do not want an electrical fire on-board while underway.
Also, this is a good time to make sure that you have a Class C extinguisher on your boat.
TB
EDIT: I forgot to say that as far as I've seen, the cheaper inverters are only good for about 1/2 amp, which is far less than most battery charger will draw with low trolling motor batteries. And many of those inverters have their own over-current protection, so you may be popping their circuit breakers/fuses with some chargers.
Edited by tcbetka 5/18/2010 10:00 PM
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Location: Twin Cities | If you're serious about this, hit up the car electronics pro shops and get a hi output alternator and charge from that, you'd have to run a harness back to the boat etc. It's fairly common to find 120-200amp alternators out there, lots of companies that will rewind/rebuild your existing one for heavier use. |
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Posts: 1901
Location: MN | Check out Stay-n-Charge. For $79.95 you can charge them while you're driving. Hooks up to your battery vehicle, run the wire under the frame and back to the rear, plugs into your TM blug in the boat. So you'll need an extra plug too. Or you could get an All Charge or whatever he calls it and charge your tm batteries off the alternator of your outboard. |
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Location: Green Bay, WI | ACR = Automatic Charging Relay
http://bluesea.com/products/7600
The "proper" way to do this would be to install one of those, and let the engine alternator recharge the trolling motor batteries. You can either get the automatic one, which would constantly monitor and charge the weakest battery--or you can get one that allows manual selection of the battery to be charged.
TB |
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Posts: 1453
Location: Kronenwetter, WI | I've been knocking the idea around of getting one of these in the link. I normally don't have an issue but on those trips when I'm fishing looooonnggg days, it sucks to run out of juice when you'd rather hit a couple more spots:
http://www.starmarinedepot.com/Minn+Kota+MK-3+Alternato...
I've heard tell you need to be making some long runs to get the benefit so I'm not sure...maybe best to bring along a couple spare batteries and just put them on a charger at the cabin and swap batteries during the afternoon break, but then the cost of the batteries....not sure which way to go
Oh, yeah, what I WANT to do is upgrade to a 36v system, that I think would take care of that problem, but not in the $$$ cards this season.
Edited by Cowboyhannah 5/19/2010 10:54 PM
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Posts: 3480
Location: Elk River, Minnesota | Hiya,
I'd say if you have the room and can handle the weight, add the batteries and run them in parallel. Same Juice, but more running time. In my humble opinion, charging on the go is not going to be a real "bang for the buck" so to speak since deep cycle batteries are not meant for a fast recharge, and the little bit of charging from your alternator is not very much. The only benefit is if you make long runs constantly, but then if you are doing that, you are spending more time running and less time fishing...
Now...add the extra batteries and you have the power you need on those long days. Plus when charging back at camp, the time to charge the batteries will be overnight at most and you are good to go for another long day.
Steve |
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Posts: 1453
Location: Kronenwetter, WI | Steve,
Am I understanding correctly that I can run my 24v system off 3 batteries and get extended run time?
Could you explain what that would look like? Also I'm running a 3-bank charger so I'd either need to put the 4th battery on a regular battery charger or go to a 4 bank charger, eh? |
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