On Fri, 13 Jun 2014 20:45:29 +0000 (UTC), Andrew Gabriel wrote:

Their argument for high charge rate is that the UPS needs to be ready
for use again within a short time.

Which is valid. If the thing switches off with flat batteries they
have to be suffciently recharged to enable any attached kit to shut
down gracefully should the power disappear again.

That isn't a valid excuse to carry on cooking the batteries once they
are charged, which is what used to happen in one we had at work.

Quite agree it's a poor design but common across APC UPS's. As some
one else said, replacement batteries to APC are like ink cartridges
to printer makers. Last set of batteries I bought (Mar 14) where
£29.99 delivered from Value Power Systems, their "own brand"
replacement pack, cheaper than 2 x Yusa NP batteries from them, the
pack used Yusa... APC wanted getting on for £50.00...
Car batteries are not normally run down at all. Starting the engine
requires only a tiny proportion of their capacity, and they're
normally recharged from this within a minute or two even on tickover.
They are excellent at providing high current, but running them
flat kills them very quickly.

Like once can be enough ... Thats why you can get deep discharge wet
lead acid batteries, sometimes termed caravan batteries.

--
Cheers
Dave.