Solar charging voltage and battery acid

X2 on 14.4. Last set of Costco 6v batts I got, brought voltage up slowly with manual charger. Between 14.7 and 14.8 it really got to bubbling. Great for eq not so good for daily charging.

Mark (the TC one) has 14.7 at 77F being 15.06 at 50F so 15.2 is high on 14.8. First IMO, confirm your multimeter battery is not low, which makes it read high. Then try some comparisons with other meters and with your meter to make sure readings are reasonable to get an idea if the C35 is calibrated right.

A recent thread had the same thing where it turned out the controller was wonky and the controller part was exchanged under warranty by the kit supplier.

I run mine at just 14.35 temperature compensated. Automatically adjusts from 15 minutes in storage to 2 hours absorption time while in use. Equalization is off.

I speculate your controller hit 15.2 either from temperature compensation or was in an equalization cycle. I suggest you try 14.4 for regular charging and see how it goes. Also I would stick to manual equalization unless you are full time use and primarily depending on solar for battery charge.

Just wipe up the electrolyte with a paper towel and toss it away.

As your batteries age they will gas more.

Roy,
I thought our PDs went into 15+ v during equalization.
But maybe not.
But I remember when 13.8 was normal charging for 12v batts ? Then it was 14.2 ??
Now its 14,6. And now this so called smart stuff is pushing 15+ ?? Something is going to break,....sooner or later ! :)

I am just now looking at SOLAR PANELS for my OFF-ROAD POPUP trailer and it seems the SOLAR CONTROLLER specs mimics my smart mode converter/charger very nicely.

To me the solar controller should produce the same charging voltages my on-board smart mode converter/charger does. My PD9260C highest DC voltage is 14.4VDC when doing smart mode charging. Even when the PD9260C goes into EQUALIZATION MODE it only produces 14.4VDC for 15 minutes every 21 hours. I have seen other converter/chargers went to around 15VDC doing this equalization mode but was for only a short 15 minutes time.

It appears to me the SOLAR CONTROLLER is just another SMART MODE Electonic Charger device except its input is being fed by the SOLAR PANEL OUTPUTs and regulated down to the optimum required battery charging DC requirements.

I used to boil out my battery fluids with my single mode converter/charger running a continuous 13.6VDC for a long period of time but after installing the PD9260C this has completely gone away. I still check my fluids or a regular basis but always find them where they are suppose to be.

Roy Ken

What is recommend by the battery manufacturer and if it is not clear call their engineers.

I always fill right up to the tube, but always on fully charged batteries. I have never had trouble. Maybe you have a bad cell ??
But then, my inexpensive controller does not charge over 14.6.