APC 1400 UPS - modifying to use external batteries instead?

alan_d

I have a (fairly old) APC 1400 freestanding UPS, which has a light load, powering a router, network switch, NAS etc.
It's complaining that the batteries are faulty after a failed self-test. so won't support the load if the power goes out.
This is the 2nd or 3rd battery replacement it's had. The last set were a genuine APC replacement pack, and have lasted just under 3 years.
I suspect part of the reason that they suffer is because they get rather warm inside the UPS enclosure - it's currently reporting 44 degrees internal temperature.
The standard batteries are 2x 18Ah gel-cells, in series, giving 24v.
For about the same cost, I can buy 2x 26Ah batteries, which would provide longer run-time. It would be straightforward to have these outside the UPS enclosure, which would help with cooling, as well as making future battery changes easier.
Has anyone done similar? Any reason NOT to do this?

arciere

I would replace it like for like. 3 years for a UPS battery is not that bad, considering that they are continuously charged. I think they are designed to work between 3 and 5 years anyway

I doubt that another battery can have a much longer lifespan, or longer enough to justify having it work outside the enclosure (safety, etc)

that

alan_d wrote: »

Has anyone done similar? Any reason NOT to do this?

Those battieries may explode, seen this happen 2 times at work within 20 years, and both times have brought down our data center. The first explosion would have been big enough to kill a person. The second one was apparently bigger, but I never visited this one.

Also the batteries we have on our 15 year old centre has car size batteries. Some of these batteries have factory fitted temperature sensitive self adhesive sticker on them, and the theory was if they get hot, they permanently change colour. In use they got so hot the self adhesive glue melted and the stickers fell off.

If one cell shorts, all the current from the other cells will discharge through that one cell.

alan_d

that wrote: »

Those battieries may explode

That risk is the same regardless if the batteries are the same capacity or bigger. There is no temperature sensor on the batteries currently, just on the control PCB.

that

Sorry, under stated it, the exploding battery blew the metal door clean off its hinges to the other side of the room - about 3m.

We also have a ups room for one of our datacenters that contain about 240 oversized car battery size deep cycle units sitting on racks. The ups company test these with a handheld laser ir thermometer - the hot ones get changed. Nothing has exploded here.