Battery Charging Question

[JohnWedell]

I just finished installing 2 -300 ah lifepo4 batteries in parallel in my fiver. I am charging them with a progressive PD9180AL charger. With both batteries connected i can only get 13.6 charging volts with 80 amps and the batteries are not being fully charged. However when i charge each battery separate i get 14.6 charging volts with 80 amps. I called progressive for help but they were useless. Anyone have an idea why this is happening.

[RoadrunnerII]

Does your progressive have the lithium switch set?

RoadrunnerII

[Onyrlef]

Originally Posted by JohnWedell

I just finished installing 2 -300 ah lifepo4 batteries in parallel in my fiver. I am charging them with a progressive PD9180AL charger. With both batteries connected i can only get 13.6 charging volts with 80 amps and the batteries are not being fully charged. However when i charge each battery separate i get 14.6 charging volts with 80 amps. I called progressive for help but they were useless. Anyone have an idea why this is happening.

It has something to do with the resistance in the jumper wires. There are you tube videos describing this phenomenon when charging batteries connected in parallel.

[craigav]

I suspect what you are seeing is normal. When you have a lot of battery capacity as you do, even at 80a it will take a while for the voltage to come up. What I would suspect is that if you check the voltage every 30 minutes or more that the voltage will be a little higher each time until the batteries come up to full voltage. ~CA

[Nature Ist]

Also look closely at your battery wire configuration. There are recommendations that the connections for the positive and negative leads to the load (chassis) be on each battery rather than both on one battery. Jumpers obviously still go + to + and - to - on the paired batteries, but the load connections are + on one battery and - on the other. There are good diagrams available on websites.