77' Merc 1150 charging system capabilities for trolling motor battery bank

[skilet]

I'm thinking of replacing the 1/2/both/off battery selector switch back into the boat after having taken it out a couple years ago during a rewire.

I'm wondering if the charging capability of the system is worth the effort in terms of how much charge I would get in a half dozen 5 minute WOT trips per day.

Also would like some input on potential issues running two deep cycle batteries in parallel (1 group 24, 1 group 27) on position two of the switch. Any significant problem in terms of discharge, equalization, or anything else?

Essentially, I am looking to be able to get a week out of my trolling motor batteries at a remote lake with no power at camp. It's a minn Kota 12v 55lb bow mount.

The main power is a 77' merc 1150. I think it charges at 10A.

Thanks

 

[Silvertip]

Five minute runs will do little to maintain full charge but that depends on how hard the stroller is used. Consider one hour pulling 40 amps. From your motor at 10 amps would require 4 hours run time.

 

[Georgesalmon]

Sorry, your not going to gain much. That 5 minute run probably won't even bring your starting battery back up just from the loss from starting the big motor each time much less help your trolling batteries. I would for sure install that switch so you can keep your starting battery separated, those motors are hard to rope start. Best bet (I've been there) is to buy, beg, borrow, steal, or rent a small generator and plug a 110v battery charger into that when not fishing.

In a pinch I have removed my trolling motor batteries from the boat and used jumper cables from my truck with a brick on the gas pedal to hold about 2000rpm and used my 70 amp truck alternator to charge them for a couple of hours every day or so. Works good to hook up your boat battery in the truck if you run to town for supplies to. Not the best ideas maybe but it did help me keep fishing the way I wanted to.

You can parallel two different size batteries they will equalize themselves and it won't hurt anything. I think you will get double the amp hours of the smallest one but no expert here. Used to go deer hunting in a trailer and hooked up as many as 8 different kind/size (whatever the guys could come up with) batteries in parallel to keep the 12v heater and fridge running then used a small generator and battery charger to charge from the time we came in from hunting until we filled it up with gas the last time and went to bed. Then it just ran until out of gas. Made everything work for two weeks that way.

Good luck and happy fishing.

 

[skilet]

Thanks for the responses... Only makes sense to run a charger and steal a generator then ....
The starting battery and the trolling motor batteries are physically isolated already, so I don't think there's much point in putting the switch back into the system if the charge from the merc is negligible anyways.

 

[Silvertip]

You have a car or truck! It has a very high output generator. Configure a charging hookup in that vehicle. Still not ideal but faster than your motor or a generator.. Besides, you will likely need to make a trip or two into civilization for supplies so stow the batteries in the car and charge them while going to town.

 

[skilet]

If the truck outputs 50+ amps... Would there be any concern with too much heat or anything else?
Had heard somewhere about keeping the charging amperage under 10% of batteries Amp hour rating. If not, I should be able to rig up a charge from the truck.

 

[Silvertip]

The battery will take what it needs. What about the battery permanently installed in the car? Up here in the tundra it is not uncommon to have a dead battery on a -30 degree morning. A jump from another car or tow truck fires up the beast and the battery survives just fine. Certainly not a recommended practice to run a battery stone dead but it is a daily happening.