Solar Overcharging?

[gavinwibrow]

Because I store our van under cover, I have a solar panel outside which I leave permanently connected to the van Anderson plug to keep the 2 x AGM house batteries charged up.

The solar panel has a MPPT, but I notice that the panel inside the van can show the battery voltage as high as 15.4 during the day.

Is this normal/OK as I thought up to 14.4 was about the preferred voltage limit?

[simonmelb]

My AGM battery Neuton Power 11 years old, says on the side - continuous float charge voltage should be 13.6 to 13.8v And cycling volt charging 14.4 to 14.9v

So if you’re leaving it hooked up all the time the float voltage applies. What does you battery manufacturer spec say?

[Don 130]

Is your MPPT charge controller capable of individually managing the charge on two batteries?
Don.

[drivesafe]

Hi Gavin, if you can access the house battery terminals, measure the voltage at the batteries when your van panel shows 15.4v.

This voltage, if a constant voltage, is way too high for any battery, AGM or Flooded/Wet cell and Lithium batteries.

You will simply cook the batteries if this is actually the voltage at the battery terminals and it is regularly applied to the batteries.

Check the settings on the MPPT regulator and make sure it is set to AGM mode, not Flooded / Wet cell.

Flooded / Wet cell batteries can take 15.4v as a short term BOOST charge every so often but AGMs must never go over 14.9v.

For storing the batteries, as Simon posted, 13.6v to 13.8v is the maximum constant long term voltage.