storage battery question

I have two car type batteries that I have in my basement. One is to start my generator and the other is a spare. I charge them once a week at 1.5A for three hours. I check the voltage before charging. One of them usually reads 12.60 volts and the other 12.76 volts. I checked the acid level on the 12.76 volt one and it is OK. Why would it read so high?
---MIKE---

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On Mar 15, 7:21 pm, snipped-for-privacy@webtv.net (---MIKE---) wrote:

You are concerned about a .16 v difference between the two?
JK
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Normal variance.
--
Joseph Meehan

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wrote:

altough they are all lead acid, resting voltages vary a little depending on what chemical besides lead were used. car batteries are actuall complex designs.
the more important question is what are their load test voltage, after 500 amps at 30 seconds.
lead acid batteries have a realtively short but robust life.
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wrote:

Sounds normal, especially if you're measuring the voltage immediately after charging. If you wait a day after charging, I'll bet the higher one drops down closer to 12.6.
If it were me, I'd get a battery tender connected so I didn't have to charge them periodically.
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Trader4 wrote:

This was measured a week after charging - just before charging
---MIKE---

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On Mar 15, 7:21pm, snipped-for-privacy@webtv.net (---MIKE---) wrote:

You dont need but to charge them every few months , charge them to 13.3v not 12.76 , a discharged batter is ruined quickly by sulfation. 12.76 is maybe 80% charged. Some chargers can be adjusted if you open them up.
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