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Old Aug 07, 2008, 02:53 AM
Smeagle is offline
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Munich, Germany
Joined Nov 2003
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Originally Posted by junsi
For a liquid lead battery,we decided to add this function of adjusting the "Termination Voltage".
Will it be suitable if the voltage is ranged from 2.2-2.5V ?
Hi, I think, this should be ok. 2,3V is the safe voltage which should work for every lead battery and the highest I've seen spec'ed is 2.47V. So the range 2,2-2,5 should be very good. I cannot find it now, but a studied some papers some years ago, they stated for fast charging (> 1/10C) the current should be dropped significantly when first reaching 2,45V. To be safe, I would prefer to drop voltage to 2,3V in the moment, the set voltage is reached. Most (if not all) lead batteries are safe to be hold at 2,3V/cell 24h a day. (Standby-voltage) But it's not that important, i prefer to charge lead batteries at 13,8V (2,3V per cell) anyways. It takes longer, but as charing lead takes at least "one night", it's no real problem if it takes 10 or 14h... And they will die quite fast if they stay near the maximum voltage for a long time...

So in short:

- The setable range you suggested is very good and enough.
- Even better would be to drop the voltage from the set voltage to 2,3V when set voltage is reached. But this may lead to confusion with customers, as the lead battery will react very slowly, it will take some time at this point for the voltage to drop and a current to flow. So maybe it is not worth the hussle. How do the others think about it?

- Oliver
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