mike4947
N. Syracuse, NY
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Not to mention that most battery manufacturers give values of 5-10 complete discharges (apx 10.5 volt) as the service life of a deep cylce wet cell battery.
Sounds like someone has confused NiCads with lead/acid batteries.
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They say you learn by your mistakes, in that case I must be a genius.
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bill h
el segundo
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Joined: 08/02/2001
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32TKB_Owner wrote:Hello;
The info I’ve read states that the SOC can be determined by an accurate voltmeter, but the reading is only valid if the batteries have not been charging or discharging for several hours.
In my RV, the batteries are constantly in use, so a “resting” measurement is not practical.
Would you consider a short resting period? To give you an idea, here are my notes from a test last year:
I ran my pair of elderly T125 Trojans with a 26 amp load for 4 hrs until the TriMetric meter showed 50% and 11.4 volts. After the load was removed, the meter went to 11.8 volts.
Let sit for 1 hour, and voltage read 12.0 volts. After sitting 2 hours, still read 12.0 volts.
24 hours later, batts read 12.1 volts, which is exactly 50% according to Trojan’s chart.
All voltages were verified with a calibrated Fluke.
So, from that, I would say that adding a tenth of a volt to the reading after a one hour rest would be pretty close. I suspect a rest period of under an hour would give a volt reading that would be variable, depending on the load or charge in the previous hour or so. An hour seems like a good period for things to stabilize.
Bill and Susan
84 Barth 30 tag powered by ht502/Thorley, Gear Vendors OD
Siamese Calvin and Airedale Hobbes
4WD Toyota toad
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Salvo
California
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bill h wrote:
I ran my pair of elderly T125 Trojans with a 26 amp load for 4 hrs until the TriMetric meter showed 50% and 11.4 volts. After the load was removed, the meter went to 11.8 volts.
Bill- I'm curious, did you disconnected the batteries during the 'rest period'? Or were the batteries under a typical quiescent load of perhaps 1A during the rest period?
I would have thought a unloaded battery would increase more than 0.2V during the 4 hrs rest period.
Sal
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Oswald38
3rd Rock
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smkettner wrote:
From link: Assuming that your batteries have the expected Amp-hour capacity, the break-in discharge(s) will take about 20 hours. Let the discharge continue until the battery voltage reaches 10.5 Volts.
WOW. They suggest 100% discharge about five times to break in a battery. I can see 50 to 80% discharge but 100 seem like a bit much to me.
That's a very good point. I've seen numerous references to that site and get blown away some times. I'm not sure why anybody would suggest completely drain their battery and I bet if I looked hard enough, it might suggest not to store them on concrete floors.
I'm off for another look at that program of thinking over there.
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bill h
el segundo
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Salvo wrote:
Bill- I'm curious, did you disconnected the batteries during the 'rest period'? Or were the batteries under a typical quiescent load of perhaps 1A during the rest period?
They were disconnected.
Quote:I would have thought a unloaded battery would increase more than 0.2V during the 4 hrs rest period.
Sal
Well, just out of curiosity, I might try it again sometime. It has been several years, and it is getting dark earlier now.
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