On 05/23/2021 18:16, Peri Hartman via EV wrote:
Somewhat off topic...
For some time, I've been meaning to get a small UPS to power my
router, laptop, and other electronics in case of an emergency. Well,
our power will be off monday for utility work and so I bought a small
UPS. But, I'm disappointed with it.
Most small consumer UPSes are good for 15 - 20 at their rated load (when
the battery is new). Yes, that varies A LOT. Based on your around 100
WH, that would make it about right for a 250 - 300 VA UPS (a quite small
one). Yes, you can usually connect a larger battery, but be a little
careful. Most of these consumer UPSes were not designed to operate in
inverter mode for long periods of time. As a result, they can't handle
the heat from an extended run time at anywhere close to rated load.
Same problem on battery recharge - it is going to be asked the charge
for a far longer time than expected so again, heat can be an issue.
Heat is generally not that hard to deal with with some forced cooling,
but that may or may not totally mitigate the problem. This computer is
being powered by a 1500VA APC UPS that has about 50AH at 24 volts of
external battery, but under worst cast, the load is only about 300 watts.
There are more professional inverters that will happily run forever in
invert mode For example, we are running a bunch of these in a public
safety environment at work where they run in invert mode 24x7
essentially forever. These can also run with AC input in either AC
preferred or DC preferred. Note, this is just the inverter. You supply
the battery plant (we have 3,600 AH at 48 volts in a bunch of places -
that's about 5 tons of lead).
https://www.amazon.com/gp/product/B07C3BKZ2F/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
--
73
-------------------------------------
Jim Walls - K6CCC
j...@k6ccc.org
Ofc: 818-548-4804
http://members.dslextreme.com/users/k6ccc/
AMSAT Member 32537 - WSWSS Member 395
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