Battery Behavior on Charger
Just finished putting four Trojan T-105 AGM batteries in a Torklift box on the tongue of my toyhauler.
Previously I was running two Trojan T-105 wet cell batteries which I removed and hooked up to an 8-AMP Battery Minder charger. I had the new batteries on the same charger while waiting to install and they would show 14.4 volts and then down to 13.55+ on float. The Battery Minder is supposed to charge at 14.4 and then reduce to 13.6 volts.
The three year "old" wet cells have been on a Progressive Dynamics 9200 charger-inverter 24/7 when not on the road. I've tried to never discharge below 12.2 volts, but have went to 12 volts a couple times. We have solar and a generator to recharge when out camping.
The "old" batteries are showing 14.2 volts, then dropping to 13.4 volts while on the Battery Minder charger - a little short of the stated charging voltage of the Battery Minder.
1) Can anyone explain why there is a voltage drop between new and old batteries while on the same charger?
2) If anyone has experience with Battery Minder chargers, do you think the desulfating process may bring the voltage up some if I leave the batteriess on the charger for a couple weeks? I'm giving a friend the old batteries and I'd like to be able to accurately describe their condition and/or improve them if possible..
I've not taken the "old" batteries off the charger and rested them for a day to get their base charge level.
Desert Fox Toyhauler
Hauls Husqvarna, KTM and BMW Bikes
Likes to Boondock since solar install!