how to check and to know you bought a bad battery

[BillP]

hi guys,

i just want to know what tools to use and how to use them when checking for a bad ups battery.

thank you in advance!

[BillP]

Hi

There are many things that can indicate a battery is bad

One of the simplest things you can do with a multimeter set to VDC is measure the voltage across the terminals, if for instance the battery is a 12v battery if it was below ~9.6v it would be considered bad. 

A battery might show a good voltage when it isn't connected in circuit so it is worth also measuring when it is connected as well.

It is also worth doing a run time test as even if all the above is ok you might find that you get a short run time when the battery is actually in use.

Regards

Matt

[BillP · Accepted solution]

thanks for the tips matt. and oh i have a 12v battery and measured it using a digital meter the result is 12.47V based on your answer its a good battery, but when i installed it in my ups it gives out a constant tone along with the on line led and replace battery led alternating.