UPS Battery Backup Replacement Batteries

exalted512

I need a couple of batteries for my UPS. Old ones crapped out I guess. The one's it had were Yuasa NPW36-12. Through some research, the Yuasa NP7-12T is a better battery.

My question is, both of these batteries are 7Ah. But you can get a 8 or 9Ah battery which are the same size. Does anyone have any recommendations on manufacturers? I don't want worse quality, but if I can get a 9Ah battery for close to the cost of a 7, I wouldn't mind spending the extra money.

Here's a few on Amazon I've found, I do need 2 of these, as it's wired in series.

$24:
http://www.amazon.com/ZEUS-12V-9Ah-Battery-VOLT/dp/B000BPCUXY/ref=sr_1_1?s=electronics&ie=UTF8&qid=1338768623&sr=1-1

$22:
http://www.amazon.com/12V-GP1272-PS1270-ES7-12-Battery/dp/B006LO8MAE/ref=sr_1_3?s=electronics&ie=UTF8&qid=1338768740&sr=1-3

$23 ($45.74/2):
http://www.amazon.com/UB1290-Computer-Back-Power-Battery/dp/B007XIUPCU/ref=sr_1_5?s=electronics&ie=UTF8&qid=1338768740&sr=1-5

$24:
http://www.amazon.com/Power-Sonic-PS-1290-Rechargeable-Battery-Terminals/dp/B002L6R130/ref=sr_1_9?s=electronics&ie=UTF8&qid=1338768740&sr=1-9

And here is the NP7, which looks like it's the closest to what I had before:
$22:
http://www.amazon.com/Yuasa-Enersys-Genesis-NP7-12T-Fast/dp/B0009339C4

Any advice on brands to go with or stay away from or any other things to be aware of when purchasing?

Thanks,
-Cody

Serendipity

I wouldn't recommending using a 8 or 9Ah battery in place of a 7Ah battery. The reason is because the engineers that designed the UPS calibrated the microprocessor to work with a 7Ah battery. Using a larger Ah battery may sometimes yield strange/unexpected results. Not saying that it can't be done, but why not go with what the engineers designed the unit to work properly with?

exalted512

The simple answer to your question would be a longer run time. Does it really matter?
-Cody

Serendipity

It might matter depending on the UPS unit. There is a chance that it might run even shorter. Since the microprocessor is calibrated for a 7Ah battery, putting in a 8 or 9Ah battery may confuse the unit. Or, it may just have the same run time as the 7Ah battery.

Serendipity

Why don't you try it and then find out what happens? Worst thing is it won't work (the battery level meter) and/or shut off prematurely.

txcoastal1

We use everything from 2ah batteries to 24ah batteries in our security, fire alarm, and back-up systems, most UPS's only monitor voltage drops. The speculations from a 7ah and an 8ah battery is alot like amp calc from AVR companies

Serendipity

That is correct. The run time calculations on most UPS units are usually a ballpark estimate. The problem comes when you use a battery that is significantly over or under the capacity specified by the UPS manufacturer. I'm betting the unit will say "Low Battery" at the wrong time.

Serendipity

exalted512,

The charging circuitry expects a battery with a certain internal resistance. If a larger battery with a lower internal resistance is placed in the UPS, the unit will still try to charge the larger battery. Depending on the design, it may cause the charging circuitry to overheat and then shut down. Or, it may just charge the battery 75% or so and then stop.

The runtime of the UPS is also matched to the 7Ah batteries currently in the unit. Put in larger batteries, and the unit may go into protection mode, since the additional run time causes the inverter to overheat, or the microprocessor shuts the unit down prematurely.

Last, you might get lucky and get a longer run time from the unit.

exalted512

After researching and reading reviews, I ended up going with the Power-Sonic PS-1290 12 Volt 9 Amp Hour battery. It seems to have very good reviews.
-Codys