Troubleshooting Progressive PD9160ALV Lithium Charger Only Providing 13.5v to Battery

Updated 10/05/2021 | Published 10/01/2021

Question:

I replaced my WFCO 55 amp charger and two 6 volt batteries. I installed one 100 Ah lithium battery and the PD9160ALV charger. My question is I will discharge the battery down below 50 voltage according to my Victron 217 battery monitor and when it is charging it charges at a maximum of about 36 amps and starts tapering off over the charge cycle. The voltage to about 13.52 - 13.57 for about 90 of the charge cycle and then twice it jumped to 14.44 and 14.60 for 2 seconds and then it was done charging, went to 0.0 amps. Three other time it did not go past 13.7 volts through the charging cycle. Is this normal or should I be see 14.6 volts while charging and higher amperage while charging? The converter is beside the stairs in my 5th wheel and the battery is in the front compartment.

asked by: Dan H

Expert Reply:

If you've recently upgraded to lithium batteries, and that's what has precipitated your installation of the # PD9160ALV, the most likely explanation here is that your coach does not have the appropriate gauge wiring between the batteries and charger to get the full 14.6v you would normally see; lower gauge wiring would likely cause about a 10% drop in power and the numbers that you've provided seem to line up with that. You're not going to hurt the batteries at all but you will see a slightly longer charge time on your battery bank than if you were receiving the full 14.6v.

You might consider re-wiring your connections and the grounds with a heavier gauge of wire to allow more current to travel through, but as I mentioned, the current state of your charger isn't going to damage the battery bank and the only draw back is the longer charge time.

expert reply by: Erik B