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

[Carlos Rodrigues]

So the actual problem is the nominal battery value being used to scale
the graphics?

I don't think there's anything that the driver can do about this.
Perhaps the graphics should use a dynamic scale instead of a fixed
scale (there are many other models out there reporting nominal
voltages of 12V and then ~2V for the current battery voltage).

I don't exactly know who maintains that part of NUT. Please keep the list CC:ed.

Regards,

On Wed, Oct 8, 2008 at 8:38 PM, Luiz Angelo Daros de Luca
<luizluca at gmail.com> wrote:
> 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
>



-- 
Carlos Rodrigues