Testing 1500 VA Battery

[pcerna_apc]

We would like to use a amp/hr tester on our 1500 VA batteries. What type/brand of battery tester should we use?

[Techie_apc]

Patty,

I do not think that there is a need for separate battery tester to check the UPS batteries condition. The Replace battery indicator is lit whenever the automatic diagnostic test has determined the battery is near the end of its useful life. It is a warning that the battery needs to be replaced within 4 weeks. APC Smart UPS performs a self test at start up and every 14 days automatically in order to warn the Customer if the battery needs replacement.

[upsguy_apc]

The best way to determine a batteries status is to check its internal impedance under load. To do this the best meter you can use is an Alber Cellcorder.

http://www.alber.com/ProdPageCellcorderCRT300.htm

However this meter will cost more than 10 of the UPS's that you are checking the batteries on. If you think your batteries are bad disconnect your computer load and hook a lamp up with a 100W bulb. Open the supply circuit breaker that feeds the outlet the UPS is in and measure how long the battery run time is.

Go to the APC website and and perform a runtime calculator on the model UPS you have and see if your UPS is performing with ~25% of what its supposed to be. If not the battery is getting old and needs to be replaced.

Just a note on a common practice I see recommened is to just unplug the UPS from the wall to test it. This is not safe to do. When you unplug the UPS from the wall you remove the ground from the UPS and from the supplied load. Always open the supply breaker if you want to do a battery discharge test.

[Erasmus_apc]

Our APC units already have a self test function in place that will determine the total health of your UPS' battery. If this is insufficient enough for "data" gathering, APC cannot make a recommendation on third party testing solutions. Perhaps another customer on the forums can give more input?

[HDRW_apc]

I have a West Mountain Radio Computer Battery Tester II (CBA II) which I've used to test VRLA batteries, but not APC ones.

It connects to the USB port of a PC onto which you load their software, and once it's up and running you connect it to the battery, and set the parameters to match the battery. I always find it suggests a larger discharge current than I like, so I wind that down to something like C/10 (so about 1.5A for a 17Ah battery). It then draws that current and measures the voltage across the battery, and plots a graph of it until it reaches the shut-down voltage you've set, when you can read the number of Amp-hours it's achieved. (Charge it up again straight away - shouldn't leave Lead-Acid batteries discharged!)

Since some batteries are rated at C/20, you almost never get the rated capacity when testing at C/10! But it gives you an idea of the health of the battery.

They cost about US$120, and googling for "CBA II" will find where to get them, although I like Impulse Electronics in California.

They come with "PowerPole" connectors for the battery, so you may want to get some of these at the same time, to make up your own leads for connecting the battery.

I have no connection with West Mountain Radio or Impulse Electronics, other than being a happy customer!

Hope this helps...

Cheers, Howard

[MarkGinger_apc · Accepted solution]

You could always charge the unit up to 100%, pull it out of the unit, attach a 5A load and measure how fast the voltage drops. If it doesn't drop from 24V too fast, you're in good shape. If all of a sudden it drops to 16V and then to 12V, you know your battery can't handle a load. I have to say that I agree with the other users in this thread, you don't really need to perform this kind of testing on the UPS. The 1500VA is pretty good at moderating itself and determining the life time of the battery. It aint perfect, but it works and saves a lot of labor hours.