Nut upsdev - Oct 2008 - UPS (Megatec) with strange voltage values

Hello Nut List!

I have 2 "Lacerda 10KVA" UPS that returns strange values for Q1 and F
commands:

Q1
(215.0 215.0 219.0 004 60.0 2.27 39.0 00000001

F
#220.0 045 240.0 60.0

At least what I know about Megatec, It seems to say that it has a 240.0 V
battery with currently 2.27V. Quite strange.
I contacted Lacerda to help me interpret this values and they said that 2.27
is just 1 element from 6 inside the battery. This
way:

 2.27V x 6 = 13,62V
This are 12V batteries

13,62V should be the real battery measure?

This UPS has 20 batteries in series:

20 x 12 = 240

This is the nominal battery value returned by F command.

When power is lost, the 2.27V drops very quickly to 2.06V

2.06V x 6 = 12.36V

Which seems to be correct for a 12V battery.

To top it up, I command returns an empty string, which would help "a
lot" to
identify it.

OK, my questions are:

1) Is 2.27V plausible for battery voltage or should it be 13,62V?
2) Is 240V plausible for battey nominal voltage or should it be 12V?
3) Wich can I consider battery full? 2.27V or 2.06V?
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?

Thanks,

-- 
     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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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

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

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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On Thu, Oct 9, 2008 at 8:03 AM, Arjen de Korte <nut+devel at de-korte.org>
wrote:
> Citeren Arjen de Korte <nut+devel at de-korte.org>:
>
>>> 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).
>>
>> This is the case. The problem here is that in this case the megatec
>> driver reports 'battery.voltage' as single cell and
>> 'battery.voltage.nominal' as the total string voltage.
>
> Have a look at changeset 1337 for the bestups driver, this suffered from a
> similar problem a while back. It won't be a drop in replacement here
since
> that one didn't report a nominal battery voltage, so we try to guess
that
> based on the reported low/high battert voltage. But it too uses a battery
> voltage multiplier so that the graphics report the battery string voltage,
> instead of just the single cell voltage.
The attached patch adds a "battvoltmult" parameter to the megatec
driver in the trunk.

It should work, but I'm away from a development environment, so it is
totally untested (it wasn't even compiled to check for syntax errors).
The changes are mostly harmless, though.

-- 
Carlos Rodrigues
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