Advice for reconfiguring batteries and 4 bank charger?

[Timmer]

Hi all,

I am still learning all the ins and outs of my 2 year old boat. I left my boat plugged in charging all winter but my kicker battery was dead when I went to use it this spring. I found that it's not plugged into my 4 bank charger. I'd like to change my configuration and am looking for advice. Here is my current set up -

- 3 batteries in a crossed 36v configuration for my trolling motor. Each battery is on a charging bank, using 3 out of 4 of the banks.
- 1 battery for my main big motor, also on a charging bank, thus using 4 out of the 4 banks.
- 1 battery for my kicker motor, not on a charging bank.

I'm no electrical expert. My thought is that I might benefit from having the 2 starting batteries in a parallel configuration. I could then use the one charging bank to charge them both? Any issue with this idea? My one concern is that I understand you are supposed to match batteries when running in parallel, and therefore I would have to match my big starting battery which is a Interstate 31M. I looked online and the MSRP for that is $435..yikes! Based on that cost my other thought is I could replace my charger with a 5 bank? One consideration is I have a female charging plug built into the hull of the boat, back by my motors. I'm not sure how difficult it would be to splice a new unit into that.

 

[Andrebass]

A reasonable priced charger that you hook up to your kicker with an additional extension cord, might be the cheaper way to achieve what you need.

 

[Ltwrangler]

I added a battery selector switch for the two engine batteries as I end up anchored more than running. So I run the charger line to the boat supply side of the switch including the kicker motor and when I use the boat I set the switch to just 1 battery. That way I also have a fresh battery if all the electronics run down the one and then I can switch to the second to start the motor If needed . When it’s at home I turn the switch to all and that way all 5 batteries are getting charged.

 

[Starbanker]

Hi all,

I am still learning all the ins and outs of my 2 year old boat. I left my boat plugged in charging all winter but my kicker battery was dead when I went to use it this spring. I found that it's not plugged into my 4 bank charger. I'd like to change my configuration and am looking for advice. Here is my current set up -

- 3 batteries in a crossed 36v configuration for my trolling motor. Each battery is on a charging bank, using 3 out of 4 of the banks.
- 1 battery for my main big motor, also on a charging bank, thus using 4 out of the 4 banks.
- 1 battery for my kicker motor, not on a charging bank.

I'm no electrical expert. My thought is that I might benefit from having the 2 starting batteries in a parallel configuration. I could then use the one charging bank to charge them both? Any issue with this idea? My one concern is that I understand you are supposed to match batteries when running in parallel, and therefore I would have to match my big starting battery which is a Interstate 31M. I looked online and the MSRP for that is $435..yikes! Based on that cost my other thought is I could replace my charger with a 5 bank? One consideration is I have a female charging plug built into the hull of the boat, back by my motors. I'm not sure how difficult it would be to splice a new unit into that.

You could use one bank to charge two batts in parallel but with one problem a ten amp charger would act as a 5 amp charger and the last battery will never get a full charge because of the resistance losses from and between the batteries. It will take twice as long to charge them and the last battery will always be undervolt. By crossed, you mean in series? Go buy a 5 amp single bank charger for the kicker which doesn't need a 31M battery, buy a smaller battery for it. Use the same outlet if you have one installed in the boat and get a two or three way 120 volt adapter ($3.99 at Menards) and connect it to the battery charger leads for both battery chargers. Or you can use your current charger for all but the trolling motors like I do for my four lithiums (3 for the Ghost and 1 for the stereo/amp, cooling system for the the stereo , amp and Active Target computer and USB outlets everywhere; and one NoCo 10x1 for the AGM starter batt. Both are NoCo chargers that have lithium,lead acid, AGM and 6V settings. Bought the NoCo 10x1 at Amazon $85 on sale, about the same as eBay. The temp gauge shows the temps under the console in the shade and the temp inside the waterproof/insulated cabinet in the rightside rod locker with the electronics.