On Thu, 12 Apr 2018 22:47:44 +0100, Andy Burns wrote:

Johnny B Good wrote:

Float charging at a constant 13.8v per 6 cell pack 24/7 365 days a year
is bad enough without pushing it even higher to almost 13.9v!

What is the real-world temperature within the UPS case? Check how the
battery manufacturer de-rates their charge voltage per degree above 25°C
or whatever they set as 'normal'.

This particular model of APC UPS, a SmartUPS2000, is a split design
where the inverter/control gubbins is housed in a separate box which sits
atop of a battery box. I purchased the unit 2nd hand at a radio ham rally
sans battery box so have had to connect to a separate battery bank on the
shelf below the one that the UPS sits upon.

The shelving unit is one I made up from dexion shelving with a
supplementary MDF shelf slung under the top shelf using threaded stud
iron to house a set of 25AH and 7AH SLAs which have now long since been
scrapped. The middle dexion shelf below that still houses my second lot
of cheap 36AH car batteries, also long since knackered and awaiting
disassembly for carting off to my local scrappy when I get a round tuit.

This means that the batteries are even more isolated from the heat of
the UPS inverter/control components than normal (which was pretty well
isolated to begin with) being essentially at the cellar's ambient
temperature somewhere around the 12 to 15 deg C mark making the UPS
temperature somewhat immaterial in this case. Despite the cool
conditions, the use of a 13.8v per 12v SLA float charging setting still
managed to shorten the life of the battery packs through accelerated
corrosion.

The dexion shelving housing the UPS and its batteries lives in the very
same coal hole part of the basement that provides early warning of
flooding which this time round I'm beginning to suspect may be due to a
leaking water main modulating the local water table.

I just checked the water level in the coal hole a couple of hours ago,
about an hour after I turned the mains water supply back on, and it has
now dropped about an inch or so, coinciding with the late night drop in
mains water pressure that I typically notice just after midnight.

It seems the blocked drain wasn't to blame this time round, merely a
discovery prompted by my checking it for a repeat performance of it
causing basement flooding some 30 years earlier. Despite my managing to
successfully unblock the drain, the basement flooding issue most
definitely hasn't gone away this time round and all the signs suggest a
strong possibility of a water main leak (a lack of recent rainfall and no
foul smell to the water leaking in).

I'll be phoning the water company tomorrow to report the problem as well
as getting hold of a suitable water pump to keep the flooding under
control whilst I wait for the water company to respond (I'm expecting
some resistance to acknowledging their responsibility in this matter).

--
Johnny B Good