[Nut-upsdev] Fwd: UPS (Megatec) with strange voltage values

[Luiz Angelo Daros de Luca]

I missed the CC:

---------- Forwarded message ----------
From: Luiz Angelo Daros de Luca <luizluca at gmail.com>
Date: 2008/10/8
Subject: Re: [Nut-upsdev] UPS (Megatec) with strange voltage values
To: Carlos Rodrigues <cefrodrigues at gmail.com>


Hello Carlos,

This information I got from Lacerda that assembles this UPS:

"2.27V is the voltage when the battery is being recharged. This is constant
until AC goes off.
In one or two minutes" (while capacitors/some other thing are unloading?) ",
it drops to 2.05V and keeps this way
stable for some time until it starts to drop slowly." I didn't used it until
battery is low but, according to Lacerda,
the UPS shuts down automatically at 1.75V.

However, as the nominal battery is 240V, NUT battery graphic is not very
useful. I uses an scale up to 240V and
2.27V (AC on) or 2.0xV (AC off) is not visible. If I divide the nominal
voltage (hack) by 120, NUT avoids to generate a graphic.
The only situation that looks better was when I multiplied 2.xx by 120. I
also tested dividing nominal voltage by 20 and multipling battery voltage by
6 to get 12V but I think this is worse as it's not equal to neither values
(and needs two modifications).

Which solution is the best? Hack the graphics, the nominal voltage or the
voltage measure? There is an LCD in front of the UPS that shows some
information and it does the "120 times" trick with the battery voltage.

Thanks,

2008/10/7 Carlos Rodrigues <cefrodrigues at gmail.com>

On Mon, Oct 6, 2008 at 11:00 PM, Luiz Angelo Daros de Luca
> <luizluca at gmail.com> wrote:
> > To top it up, I command returns an empty string, which would help "a lot"
> to
> > identify it.
>
> Onle a few models return anything for the "I" command, unfortunately.
>
> > 1) Is 2.27V plausible for battery voltage or should it be 13,62V?
>
> Many manufacturers choose to output the cell voltage instead of the
> battery voltage. No docs I have ever seen mention anything about what
> the battery voltage should be, so this isn't either right or wrong.
>
> > 2) Is 240V plausible for battey nominal voltage or should it be 12V?
>
> See 1).
>
> > 3) Wich can I consider battery full? 2.27V or 2.06V?
>
> Whichever gives you 100% charge when connected to mains (in this case,
> 2.27V).
>
> > 4) Any tips to solve this problem? Divide and multiply inside megatec
> > driver? Is there any chance to some UPS hacks in megatec driver
>  (parameters
> > in config file) get upstream?
>
> A line could be added to the driver with that model's voltage values
> (since the nominal battery voltage is different from any of the
> others), but just using the "battvolts" parameter in the config file
> is the recommended way to go.
>
> If you also tell me the low battery voltage I'll add that model to the
> compatibility list with a reference to the correct "battvolts" values.
>
> Regards,
>
> --
> Carlos Rodrigues
>



-- 
     Luiz Angelo Daros de Luca
           luizluca at gmail.com
             ICQ: 19290419

I Know, "Where you wanted to go today",
   but I decided to stop here instead!
                       MS Windows



-- 
     Luiz Angelo Daros de Luca
           luizluca at gmail.com
             ICQ: 19290419

I Know, "Where you wanted to go today",
   but I decided to stop here instead!
                       MS Windows
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