[OT] Charging UPS batteries outside the UPS
Jim Kuzdrall
gnhlug at intrel.com
Tue Aug 7 07:39:12 EDT 2007
On Monday 06 August 2007 22:10, Ben Scott wrote:
> Hi all,
>
> Off-topic but still techie question: Does anyone know anything
> about charging the batteries from a UPS using external equipment
> (i.e., not the charger built-in to the UPS)?
>
> The battery consists of eight smaller units, wired together. The
> wiring is easily disconnected. Each unit is labeled "12 V, 7.2
> Ah/20HR". Anyone if I can just hook each unit up to a regular
> automotive battery charger (one at a time) and charge them that way?
It is safe to recharge them with a conventional automotive battery
charger as you suggest. Recharge them at a low rate. If anything goes
wrong, they will just get hot or not take a charge.
At a low charge rate, the battery cannot get hot enough to burn up
or damage its surrounding. My auxiliary charger has a 6 amp and 2 amp
setting. (You are welcome to use it - I will email it to you.) 2 amps
at 13V is only 26W, which is not going to raise the temperature of a
large surface area by much.
> V DC is. [4] Severe discharge typically also means the battery will
> not hold a load to spec, so it's an indication the battery is no
> good; no point in a UPS without a battery; loose battery connector
> indication;
Actually, when lead-acid batteries lose capacity after many partial
discharges, the recommendation is to have a "deep discharge" and
complete recharge. That brings back some of the capacity.
> what if the customer is stupid and didn't connect the battery.
Most batteries, particularly lead-acid batteries, self discharge
whether connected or not. Keeping them in the refrigerator helps - if
you can get the cooperation of the rest of the household.
Jim Kuzdrall
More information about the gnhlug-discuss
mailing list