Trolling Motor Question 2 of 2

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LDUBS

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I would like to charge the TM battery from my outboard’s alternator.

My outboard’s alternator has 17 amps net available for charging batteries. Because my primary use is trolling, my outboard is running most of the time I’m on the water.

I would use an Automatic Charging Relay to manage charging both batteries.

My question is twofold. First, is my outboard’s 17 charging amps sufficient to maintain two 12V batteries? Second, is there is any reason not to charge the starter battery and the TM deep cycle battery at the same time from my outboard?

Thanks for any help you can offer.
 
LDUBS said:
I would like to charge the TM battery from my outboard’s alternator.

My outboard’s alternator has 17 amps net available for charging batteries. Because my primary use is trolling, my outboard is running most of the time I’m on the water.

I would use an Automatic Charging Relay to manage charging both batteries.

My question is twofold. First, is my outboard’s 17 charging amps sufficient to maintain two 12V batteries? Second, is there is any reason not to charge the starter battery and the TM deep cycle battery at the same time from my outboard?

Thanks for any help you can offer.

You'd be asking a lot of the outboard charging system. 17 amps between two batteries is not much, especially when other demands are considered. That 17 amps is at WOT too, it's probably less than half that at idle or trolling speeds. My guess is that with the TM running hard, the charging system would not be able to keep up at all.

I'd probably try to get a second trolling battery and a good onboard charger. I have two group 29s, and have yet to run them below 50%, even trolling with my Terrova for 4-5 hours straight.
 
MrGiggles said:
LDUBS said:
I would like to charge the TM battery from my outboard’s alternator.

My outboard’s alternator has 17 amps net available for charging batteries. Because my primary use is trolling, my outboard is running most of the time I’m on the water.

I would use an Automatic Charging Relay to manage charging both batteries.

My question is twofold. First, is my outboard’s 17 charging amps sufficient to maintain two 12V batteries? Second, is there is any reason not to charge the starter battery and the TM deep cycle battery at the same time from my outboard?

Thanks for any help you can offer.

You'd be asking a lot of the outboard charging system. 17 amps between two batteries is not much, especially when other demands are considered. That 17 amps is at WOT too, it's probably less than half that at idle or trolling speeds. My guess is that with the TM running hard, the charging system would not be able to keep up at all.

I'd probably try to get a second trolling battery and a good onboard charger. I have two group 29s, and have yet to run them below 50%, even trolling with my Terrova for 4-5 hours straight.

Thanks MrG -- you are making me reconsider that 2nd battery.
 
The way I understand it, the main will not push enough amps to make a noticeable difference in charging deep cycle batteries. I only hook my cranking battery up to the main's alternator. And lead acid deep cycles stay healthier when they are fully charged directly after discharging. That means you want a very good stand alone charger to top off your deep cycle(s) promptly after using them.
 
Thanks. This feedback from everyone is ultimately very valuable. Sadly for my pocketbook, I think I recognize the benefit of a 24V system. The good news is the cost of the battery charger will be covered by what I thought I would spend on a long run of heavy gage battery cable, battery switch, and the ACR. I need to get out the measuring tape and see how or where I can put two batteries up front.

What batteries are you guys using for your TM?
 
LDUBS said:
Thanks. This feedback from everyone is ultimately very valuable. Sadly for my pocketbook, I think I recognize the benefit of a 24V system. The good news is the cost of the battery charger will be covered by what I thought I would spend on a long run of heavy gage battery cable, battery switch, and the ACR. I need to get out the measuring tape and see how or where I can put two batteries up front.

What batteries are you guys using for your TM?

Everstart 29DC.
 
LDUBS said:
Thanks. This feedback from everyone is ultimately very valuable. Sadly for my pocketbook, I think I recognize the benefit of a 24V system. The good news is the cost of the battery charger will be covered by what I thought I would spend on a long run of heavy gage battery cable, battery switch, and the ACR. I need to get out the measuring tape and see how or where I can put two batteries up front.

What batteries are you guys using for your TM?

Only Interstate for me. Group 29's. Well taken care of they seem to last more than any of the others. And good choice deciding on the 24v system. I had the same debate between a 24 and a 36v system. Ultimately, I know that that the run time and power will not be something I would regret having, but undersizing the system would be a major disaster.
 

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