How to read battery voltage and how that translates to battery life?

[BKW]

I don't know enough about voltage and how people measure it as an indicator of battery life for EUCs. On my Sherman Max there is an option on the screen that allows you to see the voltage at that current time. I hear reading the voltage is the most precise way of telling the true battery life. Can someone please explain to me what I am looking for when I see the voltage and how that translates to battery life (specifically for the Sherman Max if possible)? Thanks.

For example, I hear mid-80s is low battery life, etc. What is top battery life when looking at voltage, etc.?

Edited May 3, 2022 by bkw

[bracky72]

For 100 volt wheels a good rule is  (Voltage - 80) x 5 = percent remaining. 

[BKW]

24 minutes ago, bracky72 said:

For 100 volt wheels a good rule is  (Voltage - 80) x 5 = percent remaining. 

I did 25 miles on the Max and it read 96.1 voltage at that time. So, (96.1 - 80) * 5 = 80.5% battery life left. That means 25 miles is ~20% battery consumption. Since 20% * 5 = 100%, then 25 miles * 5 should have given me ~125 miles if I rode the same throughout?

Edited May 3, 2022 by bkw

[meepmeepmayer]

One battery cell is full at 4.2V and empty at 3.0V - 3.3V (depending on what the manufacturer says is empty, often 3.15V). Multiply that number by 20 (for 84V wheels), 24 (for 100V wheels like your Sherman Max), 30 (for 126V wheels, only the S22 for now) or by 32 (for 134V wheels, only the Master for now). Then you know what the full and empty voltage is.

Not sure what the 0% voltage of the Sherman Max is. If we go by 3.15V per cell, it is 24*3.15V = 75.6V.

You can just ride it down and check when it starts beeping and is no longer nice to ride. That's your real world minimum voltage, which is better to know than some theoretical number. You will get an intuition for which number means what if you ride and have an eye on the voltage from time to time.

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Problem is, usable range is not truly linear between full and empty voltage. Usually at maybe 20-30% (no load, which goes towards 0% under load), a wheel beeps at you and you have to stop riding soon. Something like 65% is closer to a halfway point. 50% is maybe... 1/3rd of range left?

EUC World offers an alternative algorithm where the percentage tells you what range you have left. So 50% would actually mean you have half the range left, as opposed to being 50% between full and empty voltage.

Edited May 3, 2022 by meepmeepmayer

[DjPanJan]

Can confirm Eucworld algorythm is very usefull and precise. Manufacturer numbers i too mutch optimistic.