Battery/Charging Problem

[JLR]

Just spoke with Vanner. Unless and until the lead battery voltage drops below the second battery, the Vanner will not come on to permit a charge to go to the second battery. In our case, the lead battery is remaining being charged and its voltage does not drop down. So, if I understand Vanner, we need to try to load up the first battery to get its voltage down. However, none of this makes much sense since upon installation, we were able start the port engine. Thereafter, the lead battery continues to get charged but the aft battery does not. More work to be done tomorrow including swapping Vanners and then perhaps taking the Vanner out of the loop completely. The saga continues.

[Reefgeorge]

What model Vanner do you have?

[JLR]

I believe it is a 65-60.

[Reefgeorge]

I am not following the description of the system with lead vs aft battery. Can you supply a crude drawing and show the failing battery?

[JLR]

New Vanner going in tomorrow. According to Vanner, one of the 12v batteries is the lead or "A" battery. The other is the B battery. When the voltage of A drops below B, the Vanner kicks on to equalize both A and B. If the voltage of A never drops below B, as I have experienced, the Vanner never kicks on to equalize both. Hopefully, the new Vanner will cure the A battery being hot all the time and the B battery being undercharged. If not, it's time for plan B, whatever that might end up being.

[davidwigler]

A and B should always be the same in a series 24 volt bank. That’s made for separate banks.

[davidwigler]

Do you have any 12 volt loads on one of the batteries?

[JLR]

Not that I am aware of. All breakers are off for the house.

[davidwigler]

Not that I am aware of. All breakers are off for the house.

That may be the problem. The purpose of the Vanner is to run both 12 and 24 volt loads off of one bank. Without a 12 volt load the batteries should have the same voltage.

[JLR]

Agreed. The house was shut off while measurements were being taken of the battery voltages. Without a separate charger being hooked up to the B battery ( the aft one) just to get it up to snuff, it is receiving no charge from the regular boat charger. Once that jury rigged charger for the B batteryis removed, and a load is put on that bank of two batteries, the B battery voltages drops and never again gets charged by the boat charger while the A battery continues to receive a charge, all the time.