Inverter Charging Voltage

Martin99

New member
Jul 11, 2014
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Merry Christmas, everyone!

I have what I think is a simple question, and just spent quite a bit of time searching through old threads and couldn't find what I was looking for (lots of great info on inverters, batteries, and installation, though!). What is the correct (or typical) charging voltage that an inverter should be supplying to the batteries while street power is on?

A little background: I recently replaced my four batteries (in use for about seven months) because one of them was fried. Battery company rep denied warranty coverage because the batteries showed signs of overheating. Fortunately, the local guy I bought them from was willing to let me have them at his cost (50% off retail). When I installed the new batteries, I had our electrician check things out, and he said all was well. However, after only about three weeks, I'm already having to add a lot of water to the new batteries, and they seem to be running hot. I measured the voltage from the inverter to the batteries when street power was on, and it was around 32-33 volts, which seems high to me.

Any help will be appreciated!

Marty
 

donP

Newbie
Dec 14, 2008
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Overcharging Batteries

I measured the voltage from the inverter to the batteries when street power was on, and it was around 32-33 volts, which seems high to me.

I assume you have a 24 V battery system (4 x 6 V) and Deep Cycle Lead & Acid batteries.
In that case at 29.2 V Bulk Voltage is reached and after absorption time Float Voltage is maintained at 26.6 V (provided the battery bank capacity is set correctly).
A good inverter can be set to a corresponding charging rate.


donP
 

botemon

Active member
Jun 28, 2008
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You also said you have 4 batteries correct? In other words is your battery bank larger than 4 batteries and you replaced 4 of them? Just checking. Its never a good idea to replace "just some" of your batteries. For the best results, unfortunately you need to replace them all. Also remember that your battery bank is only as good as your very worst battery. 32 to 33 volts is to high and they will get hot. Like DonP said you can adjust your charging voltage on a good inverter. You need a volt meter, take the cover off and find the correct potentiometer...adjust with small screwdriver while motoring the voltage. Make note of where the "pot" was before adjusting in case you pick the wrong one. I originally had a standard Dominican Inverter and had the same problem as you are experiencing. I adjusted the voltage "many times", but the voltage still wandered around and I ruined an 8 battery bank. (expensive). Oh yeah....the last straw was when it caught on fire! I now have a 3KW inverter purchased from TRACE and another one for backup. They are a 4 stage charger and are pretty good for your batteries (health). Also TRACE offers a warrentee....and they a good with honoring it. I believe a Dominican inverter is only two stage. Have Fun!!!!
 

Martin99

New member
Jul 11, 2014
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Thanks for the quick replies, donP and botemon. Sorry I left off the system specs. Yes, it is a 24V system with four 6V batteries. All four were replaced with new ones. It is a generic Dominican inverter, and I've located the pot I believe is the one to adjust. I'll give this a try before the inverter fries these new batteries!