[Nut-upsuser] Device recommendation Salicru

Manuel Wolfshant wolfy at nobugconsulting.ro
Tue Aug 18 00:15:15 BST 2020

On 8/18/20 1:20 AM, Tim Dawson wrote:
> My experience on situations like this is that it is almost always a 
> bad battery.  Once load is removed, the voltage bounced back, and thus 
> you show time/capacity, but it's possible that the sag under load 
> drops you into LB, and causes the shutdown.
> If the UPS has a battery test, give it a try, or load test the battery 
> external to the UPS if you can - I suspect that the UPS will be fine, 
> and the battery degraded.
> - Tim

My thoughts exactly. I suggest to take the battery out after fully 
charging it and discharge it using a load like an incandescent bulb for 
a car headlight or a 12V motor ( like a fan ). I preserved a bulb 
suitable for my old car especially for that: with both short and long 
range filaments connected in parallel it draws somewhere around 
80-90W/12V. You could use a voltage meter to monitor the (dis)charging 
status , although the intensity of the light will be a very good indicator.

In any case, do not let the voltage drop below 10V in order to avoid 
damaging the battery ( assuming it is not dead already ). My bet is that 
one of the elements is defective and under load it gets short-circuited, 
thus leading the global voltage to drop fast with cca 2...2.2V below its 
standard 12...14.2V.


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