27DCs and SG Lag Problems

lawrosa wrote:

BFL13 wrote:
It doesn't take long to get from 14.8 to 16, when Mex says to stop and go to Float (at 13.x depending on temperature). I suspect the torture aspect would only be if you stayed longer at the high voltages with SG not rising anymore?

Not a clue. Anyway, I have a way to try that has to be better than before.

"Moderation in all things" is for losers! Ha. We'll see. :)

Yes you have the benefit of adjustable voltage. When I desulfated mine I only had that dumb charger. Had all the cells bubbling slowly.

I cant find that post to go back and reflect. But I remember hitting it for 8 hours one day, 8 hours the next, and 4 hours the final day.

And if I remember right it was up in the 15.3 volts area. It was on the 10 amp setting. With I believe 5-6 amps going in.

Got the SG up to 1.60-65 but it wouldn't go any higher. I thought that was it.

So from that time ago until now the batts have just been running off the PD. 13.2v. with the 14.4 hit every 21 hours. And probably 3 or 4 times I went in the camper and pushed the button to get it up to the 13.6 for the said 30 hours.

As stated before the batts are now 1.275 or better SG.

Now in real world I am not sure the SG lagged because of that heavy load drawdown test I did with microwave and toaster oven? Essentially sulfating the batts?

Now if I do a normal weekend camping scenario with minimal draw down at a slower rate, possible during solar recharge or generator charge the SG will follow along in a more normal way...

But now if I remember I charged for 3-4 hours and SG did not get much past 1.225 And this was pushing the button for 14.4v but only 1 -2 amps going into the batteries. WTF it would seem the batts were charged but SG dont lie I guess..




So this machine got me back to 1.60 -1.65.SG




And I assume the floating got me to here....

You need to find out what the approximate AH capacity of the battery is now, as is. Then see if you can improve that any by overcharging technique. You cant tell if you did any good unless you know what it is like to start with.

You need an hydrometer and a voltmeter. If you have an ammeter and an AH counter, even better.

Get the battery as full as you can get it and note the SG. Now disconnect form shore power and solar, and run a 20 hr rate load. This will be 5 amps for a 100AH battery, eg. or 4 amps for an 80AH battery. One light is 3 amps, two is 6 amps. Or a 50w bulb in an inverter draws 5 amps.

Run that for ten hours or until you get to 50% SOC (1.200 ish on the hydrometer) Voltage will be 11.x. Remove load, let voltage bounce back. If you were at 50% it should climb back to 12.15 or so in a few hours.

So if it took only 8 hours to get there you have capacity of 80% of rated. Or whatever your results are. That's where you are at. An AH counter is confirmation.

If you only take 6 hours to get to 50% then you will know the horrible truth about what you have now. Do the test in your yard at home instead of going camping and finding out the hard way. :(