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Bene505 02-17-2013 03:00 PM

(Saved by CO detector overvoltage beeping) -- Gel cell charge voltage settings?
Any opinions on this?

Background: We have a Solar Boost 3024i solar charge controller that I installed on our 170 watts of solar panels.

Yesterday while working on the boat, the CO detector went off. I was a little apprehensive until I read the top of the detector where it said that the slow blinking light means over/under voltage. Quickly looking at the Victron battery monitor, I saw the voltage at 15v and current at 3.86 amps. Not sure if that current was hurting our 330 amp-hour Gel cell bank, but seeing 15 volts was scary.

It turns out that I had the internal microswitch set for monthly equalize. I must have gotten the on-off direction confused. So I took the opportuniy to review the other settings. Here's what I have it set for:
charge voltage 14.4v
charge time: 2 hours
float voltage 13.2
This means that the solar panels will charge the batteries until they hit 14.4 volts for 2 hours. Then it will lower the voltage to 13.2 hours. (Of course, when the sun goes down, the charging stops.)

Any opinions on whether those are the right settings?

I can change the settings up or down in 0.2 volt increments. (If I get a separate device that programs the controller, I can be more precise. But for now, it's 0.2 volt increments.)


Maine Sail 02-17-2013 06:49 PM

Re: (Saved by CO detector overvoltage beeping) -- Gel cell charge voltage settings?

Here's some advice for those with solar controllers that have auto equalize...


As for GEL batteries (most are Sonnenschein or Deka/East Penn) absorption should be about 14.1V. Deka has recently upped this "allowable" voltage on their GEL batteries but when I see properly charged GEL batteries going 8 to 12 years I have to assume that they really like 14.1V and the people who invented the technology, Sonnenschein, knew what they were talking about when they advised 14.1V...

My concern with this new Deka charging voltage allowance is that is to "accommodate" potential buyers with "dumb" chargers and not in the best interest of longevity, which is where GEL's really win..

On your float voltage gels actually float (Sonnenschein & Deka) at higher than one would assume. They like to be floated at 13.6V to 13.8V with 13.8V being preferred...

I would highly recommend the IPN ProRemote especially with GEL or AGM batteries...

Bene505 02-18-2013 10:49 AM

Re: (Saved by CO detector overvoltage beeping) -- Gel cell charge voltage settings?
Thanks Maine! Now I have another reason to buy you a beer sometime.

I'll immediately increase the float voltage to 13.8 and decrease the charge voltage to 14.2. And I'm putting the IPN ProRemote is on my list of things to get.


Bene505 11-22-2015 09:28 PM

best lead acid charge voltage settings?
Back around to this question again. We replaced the 2x4 gel cells with a single 4D lead acid. (LED lighting and dumping extra solar to the fridge/freezer compressor mean less drawdown. That and 540 watts of solar mean plenty of charging available. Next time around, I'll go for a bigger bank.)

If I may ask, what are the optimum voltage settings to use now that we have a lead acid battery?

In a way this a 2-part question. In the summer we live on the boat a lot. In the fall, we hardly do. So I've been wondering if the summer settings are too aggressive for a battery that sees very little discharge now (maybe down to 90% of capacity each day).

I'm not on the boat now, but my guess is that our settings are something like this:

charge voltage 14.2v
charge time: 2 hours
float voltage 13.4


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