Switching from 2 batts to 4 battery 's ?

[fishinaddict]

Can I make my 24 volt system a 48 volt system using the same battery switch? For example; when its on one, batts A & B are being used. On 2 batts C & D being used. On all, all 4 being used. Just curious. I would like to have 2 starting and 2 deep cycle batterys. Thanks

 

[legoman67]

Re: Switching from 2 batts to 4 battery 's ?

i dont think a starters are designed to use 48 volts. What you want is to run the new batterys parrell to the old(red to red, black to black) this will give you more juice, but still at 12 volts. You can run 2 batterys in parrell to one point on the switch.

My question is, why 4 batterys? thats alot of weight. 1 good deep cycle can run cabin lights and stuff for a long time.

 

[fishinaddict]

Re: Switching from 2 batts to 4 battery 's ?

So I can just add a battery to each side of the switch? I dont think I understand what would make it a true 24volt system. I thought if you had 2 batts it was a 24 volt system. When the switch is on both, that makes it a 24 volt system, Right? What if add the other 2 batts? When the switch is on both it would be 4 batts, 48 volt right? Maybe someone can clear it up for me. Definately not my strong point. Thanks

 

[fishrdan]

Re: Switching from 2 batts to 4 battery 's ?

I thought if you had 2 batts it was a 24 volt system. When the switch is on both, that makes it a 24 volt system, Right?

Nope

The battery switch combines the potential amperage of the batteries through a parallel connection, but it still remains at the same voltage. IE: 12V 600 amp battery + 12V 700 amp battery connected in parallel through the battery switch = 12V at 1300 amps,,, it just looks like a bigger 12V battery.

To get 24V (36V or 48V,,, though I haven't seen a need for 48V) you would combine the batteries in series. + on 1st battery going to your trolling motor, - of that battery going to + of the second battery, - of the second battery going to your trolling motor. IE: 12V 600 amp battery + 12V 700 amp battery = 24V 600 amp battery (though you are really concerned about reserve capacity of the batteries and not cranking amps for trolling motors or other accessories)

BTW, if you connect the batteries in parallel to get 24V it will cook your starter, gauges, etc,,, this is only for the trolling motor.

Here's how I'm connecting 4 batteries in my boat, this provides for
- a start battery on the battery switch position #1 (12V engine)
- 2 "house" batteries in parallel on battery switch position #2 (12V lights and accessories)
- 2 batteries in series (24V trolling motor)
- The option for combining the house batteries to the start battery if needed, battery switch "all" or "common"

(the second battery from the bottom is shared between the 12V and 24V circuits)

 

[Silvertip]

Re: Switching from 2 batts to 4 battery 's ?

Here are two diagrams that illustrate 12 volt parallel and 24 volt series connection of two batteries.
This diagram illustrates a 24 volt system with two batteries in SERIES. Note the POS to NEG connection between the two batteries.

The diagram below illustrates two batteries in parallel which still results in 12 volts but doubles the amp hour capacity.