Re: Battery Load Testing

[JoeRaisin <joeraisin@xxxxxxxxxxx>]

Jim wrote:
> On May 11, 6:04�pm, JoeRaisin <joerai...@xxxxxxxxxxx> wrote:
>> When performing PM services, how you you guys load test sealed lead acid
>> batteries?
>>
>> I'm seeing two schools of thought around here:
>>
>> Some say to disconnect the AC from the panel and let it sit for one
>> minute, then check to ensure the battery has dropped less than 1 volt.
>>
>> Some say to disconnect the battery from the panel check the voltage the
>> battery holds at, connect a 1 amp load for a minute, remove the load and
>> ensure the voltage has dropped less than 1 volt.
>>
>> For the most part I am talking about household systems generally using
>> FA162's-168's or commercial situations using fire rated vista's or first
>> alerts.
>>
>> Thoughts?
>
> I have a 10 Ohm 25 watt, wirewound resistor with clipleads soldered on
> the end.
>
> Disconnect the battery from the panel, put your volt meter across the
> battery terminals. (should read something over 12 volts) Clip the
> resistor across the battery terminals. Watch the voltmeter. If the
> reading goes below 12 volts within aprox a minute, change the
> battery.
>
> Watch it .......... the resistor gets hot.

LOL - now you tell me!

I decided to get fancy and tried to build a load tester with a built-in
meter.  My theory was, connect the leads and read the voltage, throw a
switch to connect the load (same resistor you use) and watch how things
progress.  The whole thing was to be in a plastic project box from
rat-shack - but I didn't think it through.  Luckily I tested the
circuits outside the box first so I never got to smell the melting plastic.

I now have a 12volt, 12 watt light bulb externally mounted.  The box has
a magnet on the back which makes it a handy meter for all my panel
metering needs...