Shore power charging house batteries

[Glenn Briglio]

What voltage should the house batteries be charged at when hooked up to shore power? 2018 Axis 25.2

[Grumpy Grampa]

If they are 6 volts each battery should be around 6 volts, or 12 volts.

[DavidEM]

The WFCO converter that came with your Axis has a very dumb charger. It puts out a steady 13.6 volts. That works if the batteries are well discharged but doesn't supply much amperage when they get up to 75% or more. I replaced mine with a Progressive Dynamics 9260 charger module which does much better.

David

[lwmcguire]

Download the spec sheet for the exact battery you have

On that data subset will be the correct voltage for bulk, float, adsorption and if you have a really smart charger perhaps even more stages

Set up your charger per that data for the maximum battery performance and longevity

[DavidEM]

Originally Posted by lwmcguire

Download the spec sheet for the exact battery you have

On that data subset will be the correct voltage for bulk, float, adsorption and if you have a really smart charger perhaps even more stages

Set up your charger per that data for the maximum battery performance and longevity

You can't do that with the WFCO charger. It has only one, dumb setting.

David

[lwmcguire]

Originally Posted by DavidEM

You can't do that with the WFCO charger. It has only one, dumb setting.

David

Not good, upgrade perhaps?

[Beau388]

Originally Posted by DavidEM

You can't do that with the WFCO charger. It has only one, dumb setting.

David

Not Quite. My old WFCO 8955 had three settings: bulk when the batteries were below 12.4 volts resting voltage, with the inverter showing voltage between 13.6 to 14.2 volts. If the resting voltage was above 12.4 and below 12.7 volts resting, the converter go into equalization mode and the inverter would show 14.2 volts. When the resting battery voltage was above 12.6 volts, the converter would go into float mode and the inverter would show 13.3 to 13.6 volts depending on inside temperature. This was with the original Harris, group 27 12 volt flooded batteries. You will have to draw a 12 volt battery down to around 12.2 volts (60%) to watch the charger go through its profile. When I converted to a 50 amp coach, I used the PPS 5375 power center. It works about the same except it monitors battery temperature to determine the charging profile of the VRLA sealed group 29 batteries.

[DavidEM]

I guess you are right Beau but I wouldn't call them settings, stages maybe. I am used to smart, 3 step chargers on boats that would ramp up to 14.5 or so volts to keep the amperage up as the battery nears 100% charge and then switches to float when it gets there.

As you note the 8955 has a much more leisurely approach and I also noted that unless below 75% I couldn't get much current out of it, maybe a few amps. The PD 9260 that I replaced it with pushes much more amperage, about 30-40 amps at that SOC as I recall.

But it only has one battery setting, no AGM or Li just "something".

[16ACE27]

Originally Posted by Glenn Briglio

What voltage should the house batteries be charged at when hooked up to shore power? 2018 Axis 25.2

To answer your question simply:
Your converter will put out at least 13.1 VDC to charge the 12 volt house battery(s). You may see 13.6 VDC or up to 14.5 VDC depending on what stage the converter is charging.

Once the batteries are fully charged, the converter stays in the float mode at 13.1 to 13.3 VDC.

If you disconnect the converter a fully charged 12 volt battery will display 12.6 to 12.7 VDC once the surface charge has dissipated.