TSDZ2 860C - Battery voltage displayed is wrong.

The voltage displayed on my 860C is about 1 volt higher than the actual battery voltage. (860C V1.0.0 OSF)

For example, the display is showing 53.3V at the moment when the actual battery voltage, measured with two different high quality volt meters, is actually 52.26 V. One volt difference is a lot in this context. I first noticed this with my fully charged battery and it was showing 1+ volt more than a 52V battery is capable of.

Any ideas why this error might exist?

Alphonse,

I was just about to post a similar question. My 860C (V1.0 OSF) display is indicating a battery voltage 0.5 volts higher than that measured by a good quality voltmeter with the battery on a bench. Agreed, it's a fair amount in this context. The battery is a 52V nominal 14S6P Mega Hailong Shark.

I've also noticed that as more current is drawn by the motor, the battery voltage on the display also increases. This may have to do with not having the correct battery resistance set. The default value was set at 300 milliohms. I tried getting a resistance estimate using the described procedure, but a value never shows up in the field, and always says 0. I'm probably doing something incorrectly.

Not sure if the resistance setting has anything to do with displayed voltage when at rest - I'm not knowledgeable about electronics.

cobiecat

cobiecat said:

Alphonse,

I was just about to post a similar question. My 860C (V1.0 OSF) display is indicating a battery voltage 0.5 volts higher than that measured by a good quality voltmeter with the battery on a bench. Agreed, it's a fair amount in this context. The battery is a 52V nominal 14S6P Mega Hailong Shark.

I've also noticed that as more current is drawn by the motor, the battery voltage on the display also increases. This may have to do with not having the correct battery resistance set. The default value was set at 300 milliohms. I tried getting a resistance estimate using the described procedure, but a value never shows up in the field, and always says 0. I'm probably doing something incorrectly.

Not sure if the resistance setting has anything to do with displayed voltage when at rest - I'm not knowledgeable about electronics.

cobiecat

Click to expand...

I think we have the same 52V 21ah battery.

I did set the battery resistance per the wiki. Yes, the default was at 300 and my test runs yielded 117 consistently. Therefore I changed that setting.

However I believe this battery resistance setting is independent of the battery voltage displayed. Hopefully someone in the know about the controller may be able to give us some insights why there is a difference.

Thanks Alphonse,

Can you give me a quick description of the procedure you used for getting the estimated resistance? Do you have to ride around with the screen showing the resistance estimate visible on the display, or can you be watching one of the three main screens and then stop and go to the configuration screen to view the resistance estimate? Not sure why I'm only seeing a zero value, as I've followed the instructions in the wiki. I'll try again today.

Yes, sounds like we have the same battery - I'm pretty impressed with it so far. I ride for exercise in a hilly area, so maybe the assist levels I've been using are lower than some use, but I know I won't have any range anxiety with it, even if I normally charge to only 80%. I'm also happy that I can ride easily with the TSDZ2 at assist level 0 if necessary. The drive is very quiet too.

cobiecat

Ref. Battery Resistance - I used the WIKI - see the section on Battery. I sent you a PM on this.

Ref. Voltage being displayed too high - I found a thread today that referred to this issue as causing the motor to not run in a non OSF version. It said that the voltage sensor was faulty in this case. It also says the the OSF version can handle a too high of a voltage reading in that it doesn't shut the motor down. Here's the thread: https://endless-sphere.com/forums/viewtopic.php?p=1577460#p1577460 (about the 13th post down).

Meanwhile there are things like battery SOC, human power, motor power, plus more I am sure that rely on a proper voltage reading. So if the voltage sensor is bad, the package is going to hinge off that and generate a lot of inaccurate results.

Alphonse said:

The voltage displayed on my 860C is about 1 volt higher than the actual battery voltage. (860C V1.0.0 OSF)

For example, the display is showing 53.3V at the moment when the actual battery voltage, measured with two different high quality volt meters, is actually 52.26 V. One volt difference is a lot in this context. I first noticed this with my fully charged battery and it was showing 1+ volt more than a 52V battery is capable of.

Any ideas why this error might exist?

Click to expand...

I have this issue too.
It's a cheap crap Chinese controller issue.
Either return it and hope to get one that's accurate, or fudge the figures.

For whatever it is worth, I measured voltage at the input pins to the 860C and it is receiving an accurate battery voltage as I expected. So the system is sending actual battery voltage to the display and in my case, the display is then showing a voltage that is 1.5 volts higher. So I believe it is the display that has the gremlin and not the motor controller.

If the display is showing that voltage then the question becomes how the other variables and settings that rely on voltage are affected. Should one compensate in some of the settings for this gremlin or not?

I don't find this level error to be acceptable in a display that costs $100.

I have had an indication from someone who knows, that the motor controller is what sends the voltage report to be displayed.
While there is actual battery voltage provided to the display, the displayed value evidently is being reported from the motor controller over the UART connection.

I assume the actual battery voltage is the power supply to the display and also provides the current for the system on/off switch.

Did anyone in this thread get this figured out? I am also using the 860C with OSF v1.1.0. (Casainho)

Also not able to get resistance reading by the method described in the wiki. My display is actually reading almost two volts lower than my volt meter. So I think I am getting short changed on range.

Not sure how the resistance ties into this (still a lot to learn). Anyway the battery is a 52V 6ah/312Wh 14S2P mini cube which I got for a 6 mile commute.

The default is set to 300 milliohms. Any thoughts on guesstimating this number upwards or downwards?

Based on what was stated below this might not make a difference on voltage reading but hopefully I can get an improvement in battery performance.

I have the same issue and I am using the Mbrusa version v20.1C.3-NEW and it is also about a volt too high from the stock firmware for the 860c. I read on a thread Mbrusa was going to add code to allow you to offset the voltage.

Todd

Possible to change the scaling on the input value?
Se max scaling lower will decrease the reading and be correct.

Call it calibration of analog input signal (voltage).