24 Volt Charging Question

I recently picked up a 24v Terrova to replace my 12v Powerdrive. I have a 2 bank charger in my boat now, one to the trolling motor battery, one to the starting battery.

If I link my 2 new batteries (Interstate SRM31) together, can I just hook one line from my bank to the pair and the other to the motor or do I have to have both batteries in the pair hooked up individually?

Now that I’m thinking of it, will my 2 bank 12v charger even work on a 24 volt system without unhooking the pair from each other?

You will need to hook one bank to each battery of the 24 volt system. Going to have to find a different solution for the starting battery.

I have both banks of my 12 volt charger hooked to the two trolling motor batteries and the batteries are hooked together for 24 volt motor. no problems

In my experience, the alternator does a sufficient job at keeping the starting battery charged. Put the 2 bank on your trolling motor batteries.

BoatsHateMe wrote:

I have to have both batteries in the pair hooked up individually

Sticker answered it correctly. The above statement is true.

The only way you can hook up one charger bank between 2 batteries in series is if you have a 24v charger. These aren’t common.

SuperDave1959 wrote:

In my experience, the alternator does a sufficient job at keeping the starting battery charged. Put the 2 bank on your trolling motor batteries.

Results may vary.

I run 2 group 29 interstate in parallel for my starter. I’ll be sure it is on the charger every day.
Cold weather trim draws a lot.
To big graphs draw a lot.
Plus other stuff.

To the original poster.
You need 3 Banks. One for each battery.

Your going to want 2 dedicated batteries for you trolling motor, never good practice to tie a trolling motor to your cranking battery. Would recomend geting the connect ease sytem for hooking up batterys and chargers for the diy guy’s. Allows you to hook up chargers to battery properly as well. your going to want a 3 bank charger to charge properly

Josh wrote:

going to want a 3 bank charger to charge properly

Maybe but not necessarily. They’re correct above that one bank per battery. however you can do it a few different ways.

Option 1: put your existing 2 bank on the tm batteries. Then either rely on the alternator for the starter or get an additional single bank charger. Personally I’m with FBRM and have a dedicated bank for my starter.

Option 2: Sell your existing 2 bank and buy a 3 bank to cover all batteries. More money but somewhat cleaner.

Here is a VERY REASONABLY priced charger. They are discontinued and were quite spendy. However at close-out pricing its hard to beat. I’ve had mine for well over 13 years. Rock solid units. The 24V w/ the alt module just didn’t get popular and they discontinued it.

https://www.amazon.com/Marinco-36202-24-Battery-Charger-Alternator/dp/B001J2KF9E

Here’s another cheap option.

NOCO Genius G3500 6V/12V 3.5A UltraSafe Smart Battery Charger https://www.amazon.com/dp/B004LWVEKS/ref=cm_sw_r_cp_api_i_1BsNCb2CW3FKK

I put one of these on my boat because one bank on my 4 bank charger died. So far so good. I really like it.

Ok, as long as we’re at it, how/where are you powering your electronics? Off the starter battery or a dedicated battery hooked to a charging bank?

I have a 36 volt trolling motor system. I’ve got one 3 bank 10 amp/per cell battery charger dedicated to it. These run my TM only.

Everything else runs off my main battery that has its own 10 amp charger tied to it.

Batteries are @ your own discretion. Mine are Interstate AGMs, all 4 of them. I charge the main battery because I may not trailer overnight when fishing and keep fish and or bait live in the wells.

BoatsHateMe wrote:

Ok, as long as we’re at it, how/where are you powering your electronics? Off the starter battery or a dedicated battery hooked to a charging bank?

Your trolling motor batteries should only run your trolling motor. It’s my understanding that you want a matched set of trolling motor batteries so that they are alway working together at the same voltage. Otherwise one will draw the other down and shorten their life.

Run all your electronics, lights, radios,etc… off your starting battery.