# Battery Specification

Discussion in 'Electronic Basics' started by Jack// ani, Apr 6, 2005.

1. ### Jack// aniGuest

Hi all,

I just took out a dead Panasonic lead acid battery form my UPS and
trying to understand the specifications written on it

Voltage Regulation
Cycle use : 14.5 - 14.9V
Initial current : less than 2.8A
Standby use : 13.6 - 13.8V

TIA

2. ### Lord GarthGuest

When you charge the battery, limit the applied voltage to between 14.5 and
14.9 volts DC
and limit the current to no more than 2.8 Amperes. As the battery charges,
the current will fall.
If you wish to 'top off' the battery or trickle charge it, keep the applied
voltage between
13.6 and 13.8 volts DC.

Beware that hydrogen gas forms during charging so vent the area.

3. ### John FieldsGuest

---

First, go to:

http://www.panasonic.com/industrial/battery/oem/chem/seal/index.html

and then click on:

VRLA Charge Methods

4. ### Jack// aniGuest

Thanks Lord. BTW this battery is sealed form every where( as I can
see), so where does the Hydrogen escapes??

5. ### Byron A JeffGuest

That's a bit high for standard gel cels. They usually want 14.4V.
Correct. A fully depleated battery can draw a lot of current if you allow
it to.
Correct. The basic 3 stage charging algorithm for lead acid batteries are:

1) Bulk charge with highest allowable voltage and current until battery
reaches 2.4V/cell (14.4V for a 12V battery).

2) You then fix the voltage to 14.4V and start watching the current. Continue
in this phase until the current draw drops to C/100, where C is the Amp-Hour
capacity of the batter. So for example with my 33 AHr battery, C/100 would be
330 mA.

3) Then go into float/trickle/top off voltage discussed below.
This voltage is safe indefinitely without venting.

If a sealed lead acid gel cell is venting, then you have big problems.
It's one of the reasons why the specifications listed on the battery are
in place.

BAJ

6. ### Lord GarthGuest

There is likely a hidden vent that opens if the pressure gets too high.
If that happens, I'd guess the electrolyte would either leak or evaporate.
That's pretty standard for a *sealed* battery.

7. ### Jack// aniGuest

Thaks all. A little doubt left..... is there any relation between
maximum charging current and ampere-hour rating of the battery?

Like maximum charging current above was 40% of the AH rating!

Thanks again

8. ### Peter BennettGuest

Depends on the battery. For most flooded lead-acid batteries, a
maximum charge rate of 1/5 of the AH rating is generally suggested.
Some gel and AGM batteries can be charged at higher rates.