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what voltage is lower limit for stored battery? - Page 5

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Posted by Jim Wilkins on August 28, 2009, 12:56 am

Good advice. The Hawker Cyclon manual says to recharge when the cells
drop to ~2.0V, and the discharge limit is ~1.5V. That's 12V and 9V for
you young ones.

I'm not kidding. A Subway foot-long costs $.81 with tax, I give
$.01, they all look very confused.


Posted by Ulysses on August 28, 2009, 3:17 pm

should be

connected a

12.5 volts sounds pretty darn close to what I think it should be.  Keep in
mind a trickle charger will probably only bring it up to 13.5 or 13.6 volts.
That is fine for *maintaining* the battery but when you are charging it the
voltage should be brought up to about 14.5 (this varies a little with
manufacturer so ask them) and held there until the specific gravity reaches
1.280 (or close to that) on ALL of the cells.  This can take some practice
but after a few times you'll have a pretty good idea how long it will take.
Occasionally (every 30-45 days if you are using the batteries) they should
be brought up to about 15-15.5 (equalize) volts and held there for perhaps
30-60 minutes or until all of the cells are very even.  This can also take
some practice and you do not want to let the batteries get hot or exceed 60
minutes which is the upper limit IMHO.  Sometimes, with sulfated batteries,
you may need to equalize a little over several days to get them nice and
even.  Most battery manufacturers seem to be very happy to supply the
voltage/SG info that you need.

Posted by ben91932 on August 28, 2009, 8:19 pm

Anytime a battery drops below 10 volts, whether under a load or
resting, damage is occurring.

Also, the post about equalizing the batteries was spot on. To get
optimum life, the 6 cells must be as similar as possible, so a mild
overcharge, ie 14.8 or so, is a good thing.
The best way if you have the time is to charge at 5 amps or so until
the voltage stops rising. Then you know that all 6 cells are as
charged as they can be.
A charge much higher than 15 v can hurt them as well.

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