Displaying 4 results from an estimated 4 matches for "11v".
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2007 May 03
4
Re: Changes to megatec.c
...ping voltage, but more than 42V will move it into the
regions of 48V power supplies.
- Battery manufacturers recommend a minimum of 10.8V for a 12V battery
as the cutoff discharge voltage (further discharge will cause battery
damage) but the UPS is likely to shut off before that, so I
guesstimated 11V for a 12V cell to be a reasonable "empty battery"
voltage.
- The float charge (clamping) voltage for a fully charged 36V battery
if 40.9V but I've subtracted 100mV to allow for tolerances
Kind regards,
Frank van Wensveen
---
* Origin: www.vanwensveen.nl (80.253.112.29)
2015 Dec 28
3
Server not shutting down before power loss
Hi I hope someone can please help.
I have an Ubuntu Server running 14.04.3 LTS and using an APC ES550 UPS
connected via USB.
I've installed Nut and can see it does monitor the UPS correctly and give
the correct stats with battery percentage etc.
But on doing a "real" test and unplugging the UPS from the power supply,
after watching the battery drop slowly suddenly the server just
2015 Dec 29
0
Server not shutting down before power loss
...ead easy,
Then much more important: calculate internal resistance of each battery.
Batteries go bad after some years, even on trickle charge.
Measure voltage drop when driving a load such as 1 or a few car
headlamp bulbs in parallel. Then its simply Ohms law V=IR,
If voltage drops from say 13V to 11V & if you use 1 headlamp that
uses maybe 4 amps, then 13-11 / 4 = 2/4 = 0.5 which is on high side,
you dont want higher, better 0.3 or less.
Your UPS for PC's will prob. want a lot more than 4 amps, so low
internal resistance is critical to good UPS performance.
If you decide to use compu...
2015 Dec 29
2
Server not shutting down before power loss
...e important: calculate internal resistance of each battery.
> Batteries go bad after some years, even on trickle charge.
> Measure voltage drop when driving a load such as 1 or a few car
> headlamp bulbs in parallel. Then its simply Ohms law V=IR,
>
> If voltage drops from say 13V to 11V & if you use 1 headlamp that
> uses maybe 4 amps, then 13-11 / 4 = 2/4 = 0.5 which is on high side,
> you dont want higher, better 0.3 or less.
>
> Your UPS for PC's will prob. want a lot more than 4 amps, so low
> internal resistance is critical to good UPS performance.
>...