On 10/09/2012 08:20 PM, mike wrote:
On 10/9/2012 1:02 PM, Phil Hobbs wrote:
On 10/09/2012 03:50 PM, Dave Platt wrote:
I had to do an emergency replacement last weekend. The bad
battery was:

12vdc, 4 amp hour gell cell

All I could find locally was:

12vdc, 5 amp hour gell cell


The batteries are identical except for the amp hour ratings.

I don't *think* moving up an amp hour should be a problem with this
type of battery. Am I right?

Very probably. It is *possible* that the new battery may have
slightly different charging requirements than the old one, if you want
to get the maximum service life out of it, but that's by no means
certain. Aside from that, the two should be compatible.


Watch out for gel cells that aren't rated for SMPS service. Those
suckers get drawn down _fast_, and lots of the cheaper ones won't
survive. (Ask me how I know.)

Cheers

Phil Hobbs

I've had that same question. I get that cheapo batteries are typically
lower quality. But how do you tell that an expensive battery isn't just
a cheapo battery with a higher price tag? They all seem to have the same
specs.
Any advice on brands?

I've had good luck with the on-shore and European brands, e.g. Varta.
IME usually there's a sticker inside the unit or a table in the manual
that gives recommended battery types.

I tend to buy used IBM e-server UPSes, which are rebranded APC SmartUPS
units, and seem to go much cheaper than the APC-branded ones. I've got
three 750 VA ones for $50 each, so even with a $60 battery it's still
pretty affordable. (The supplies themselves seem pretty bulletproof.)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net