Doug McIntyre wrote on 8/22/2017 3:18 PM:
> rickman  writes:
>> Dave Liquorice wrote on 8/17/2017 5:40 AM:
>>> On Wed, 16 Aug 2017 08:08:17 +0100, Folderol wrote:
>>>
>>>> The fire alarms and emergency lighting are all SLA powered. The
>>>> batteries are still good after about 10 years ...
>>>
>>> Not APC kit then, thier stuff cooks batteries in around 3 to 4 years.
>
>> That's just not true.  I have APC units that have lasted over a decade and
>> still going strong.  It might actually be closer to two decades.
>
>
> Not sure what you are doing different, my experience is very inline
> with the reply you followed up to.
>
> Dozens of APC SmartUPS units in data centers and in the field. Their
batteries
> last between 3 and 5 years and require replacement in 100% of my
> units. I wouldn't say just APC is at fault, but this is just how long
> car and motorcycle/lawn motor lead-acid cells last that the standard
> UPS vendors use.
>
> Much like my much bigger online UPS units. They all use car batteries,
> and have a definiate maintenance cycle for how often those batteries
> need to be replaced, just like in your car for it's lead acid battery.

Three years is *NOT* the expected lifetime of lead acid batteries of *any*
kind.  When I buy a quality battery for my car it lasts five years or more
and automotive use is one of the worst applications for lead acid.

I worked for the rail road and we had batteries in service for 20 years
before they needed replacing.  That was an optimal application for lead
acid.  They were trickle charged with very intermittent use, nearly the same
as UPS (I don't expect they trickle charge once the cells have been used).
Phone company use is the same, large batteries that are on trickle charge
99.9% of the time and are discharged once or twice a year during power
failures.

Replacing the battery every 3 years is recommended by the UPS companies
because they make a lot of money on the replacement batteries.

--

Rick C

Viewed the eclipse at Wintercrest Farms
On the centerline of totality since 1998
O)

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