Connecting an AGM 100ah battery to a 105ah AGM battery.
Snubby said
02:22 PM Nov 29, 2025
My van has a100AH AGM battery and I also have a 105AH AGM battery that I would like to install in my van. What is the downside ( if any) to connecting and charging them together.
TimTim said
09:31 PM Dec 1, 2025
You then have a 205Ah pack and they tend to balance themselves towards the end of the discharge and at the top of charging as the internal resistance changes. Easiest way is to test the setup is with a fairly deep discharge and then a recharge. But with such a small difference in battery capacity there will be very little difference in the current draw from each battery.
Plenty of videos out there to explain what happens.
My van has a100AH AGM battery and I also have a 105AH AGM battery that I would like to install in my van. What is the downside ( if any) to connecting and charging them together.
You then have a 205Ah pack and they tend to balance themselves towards the end of the discharge and at the top of charging as the internal resistance changes. Easiest way is to test the setup is with a fairly deep discharge and then a recharge. But with such a small difference in battery capacity there will be very little difference in the current draw from each battery.
Plenty of videos out there to explain what happens.
https://www.youtube.com/watch?v=dmVao8gtLFQ
Good luck.
-- Edited by TimTim on Monday 1st of December 2025 09:48:25 PM