OpenXSensor 2 batteries with 2 cells voltage problem

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Astro
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OpenXSensor 2 batteries with 2 cells voltage problem

Post by Astro » Thu Oct 04, 2018 5:23 pm

Hello,
I have 2 batteries with 2 cells each one.
Is it possible to measure voltage of each cell separately?
When I try to do it, I just get the values of first battery cells fine, but when I try to get the values of the second battery (1st cell) It shows a wrong value because It's trying to get this value like "a 3rd cell" of the first battery minus the value of the 2nd cell of the first battery"

How can I do it cell by cell with 2 batteries and not only 1 battery?

Can you help me with oXs config files??

Thanks in advance


rdeanchurch
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Re: OpenXSensor 2 batteries with 2 cells voltage problem

Post by rdeanchurch » Fri Oct 05, 2018 12:50 am

I assume you mean two batteries in serial. How do you have the balance plugs connected?
Do you have two sensors setup, one for each battery?
If so, they need to have two different ids.
Dean
OldDmbThms: 1. Takeoff, 2. Crash, 3. Repair, GOTO 1

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kalle123
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Re: OpenXSensor 2 batteries with 2 cells voltage problem

Post by kalle123 » Fri Oct 05, 2018 5:44 am

A bit more information is needed.

Please make a drawing of the wiring, you plan to use.

And what hardware (RX - TX) are you using?

But, as Dean says, I would also go for two oXs sensors.

br

mstrens
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Re: OpenXSensor 2 batteries with 2 cells voltage problem

Post by mstrens » Fri Oct 05, 2018 7:48 am

Can you first explain how are your batteries connected
- in serie so making a 4S battery
- in parallel so making a 2S
- only with a common ground (e.g. to make a backup system)

Astro
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Re: OpenXSensor 2 batteries with 2 cells voltage problem

Post by Astro » Sat Oct 06, 2018 12:20 am

I add a drawing, trying to explain it better.
► Show Spoiler
They have a common ground.

Thank you!


Carbo
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Re: OpenXSensor 2 batteries with 2 cells voltage problem

Post by Carbo » Sat Oct 06, 2018 9:30 am

As proposed two sensors with different sensor ID is the way to go. If you want to stay with one sensor, you can make a workaround with an ADS1115 using it's two differential inputs for the second battery transmitting the cell voltages in A3 and A4 field for example. A calculated sensor can be used for the total voltage of the second battery.

mstrens
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Re: OpenXSensor 2 batteries with 2 cells voltage problem

Post by mstrens » Sat Oct 06, 2018 11:34 am

With your config, oXs can measure 4 voltages:
- cell 1 of battery 1
- total of cell1 + cell2 of battery 1
- cell 1 of battery 2
- total of cell1 + cell2 of battery 2
This is done defining 4 pins for voltage measurement.
Based on this oXs can calculate voltage of cell2 (by differerence between total and cell2) but only for one the battery (the one connected to the VOLT1 and VOLT2 pins). You have to declare that there are 2 cells in your config.
oXs can't currently calculate the voltage of cell2 of battery 2 but you can let opentx calculate it on Tx side if you ask oXs to send the 2 voltages measured by oXs for battery 2.
Otherwise, as said before you can use 2 oXs with different ID.

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kalle123
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Re: OpenXSensor 2 batteries with 2 cells voltage problem

Post by kalle123 » Sat Oct 06, 2018 12:49 pm

mstrens wrote:
Sat Oct 06, 2018 11:34 am
Otherwise, as said before you can use 2 oXs with different ID.
With all protocols? "FRSKY_SPORT , FRSKY_HUB , FRSKY_SPORT_HUB , MULTIPLEX , HOTT; JETI"

That would be new, at least for me. ;)

Therefore I asked for the hardware, he is using.

br

Astro
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Re: OpenXSensor 2 batteries with 2 cells voltage problem

Post by Astro » Sat Oct 06, 2018 4:34 pm

I have an FrSky SPort

Thank you!


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