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KRumm
03-14-2020, 05:53 PM
I want to create a 400ah battery bank by putting two 12v 200ah batteries in parallel... A single 200ah battery has a rated max charge current of 60amps...

My question in when I have two of these in parallel does the max charge current stay the same (60A) or does to double to 120A?

chuckster57
03-14-2020, 06:02 PM
I would think the charge rate would be set by the charging device. If your trailer converter is 40A max I would think that’s all your going to get no matter how many batteries you have.

KRumm
03-14-2020, 07:06 PM
I would think the charge rate would be set by the charging device. If your trailer converter is 40A max I would think that’s all your going to get no matter how many batteries you have.
My rig has 55a converter... I want to add a second 55a so I can reduce generator time...

JRTJH
03-14-2020, 07:12 PM
It depends more on how you wire the charger to the battery bank than "just in parallel"... Take a look at this article, it explains how to wire the batteries so you equalize the charge to each battery and draw from the batteries "equally". If you wire them "incorrectly" you will essentially charge/draw from one battery while the other is "in reserve" and once the active battery is worn, it will bring down the other battery.

Take a look at this link: https://www.impactbattery.com/blog/tutorials/how-to-charge-marine-and-rv-batteries-in-parallel/

KRumm
03-14-2020, 07:28 PM
It depends more on how you wire the charger to the battery bank than "just in parallel"... Take a look at this article, it explains how to wire the batteries so you equalize the charge to each battery and draw from the batteries "equally". If you wire them "incorrectly" you will essentially charge/draw from one battery while the other is "in reserve" and once the active battery is worn, it will bring down the other battery.

Take a look at this link: https://www.impactbattery.com/blog/tutorials/how-to-charge-marine-and-rv-batteries-in-parallel/

Thanks!... Great article that answers my question...

flybouy
03-14-2020, 07:32 PM
My rig has 55a converter... I want to add a second 55a so I can reduce generator time...

Then you would need to disconnect the two batteries in order to use 2 chargers. Also, to use 2 chargers simultaneously AND use the battery while charging would require rewiring so the "house" 12 v would come from one battery. A look at how to properly wire 2 12v batteries will make this evening as the trailer's batteries should be wired positive to positive and neg to neg with wires of equal gauges and length. However, the connection to the load should be the pos load connected to the pos terminal on one battery and the neg load connected to the neg terminal of the second battery.