How to make battery reading more accurate?

I have a 12s4p battery with Samsung 30Q cells, and one of these battery displays. Currently I have two issues:

  • The battery percentage is only correct when there is no draw from the battery, i.e. when I’m standing still. Whenever I pull the throttle, voltage drops and the reading is incorrect.

  • The first 10% go away immediately after just going a couple of 100 meters. After that battery readings seems to be about right. But then the last 15-20% last forever. How can I make this strange curve more into a straight line, as it should be?

Your battery has sag, which decreases voltage, the only more accurate display would be coulomb counter, which calculates how much mAh went in and out but it’s not 100% accurate as not everything will go out of what you putted in the battery.

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I’m still in awe about battery sag. What can one do to prevent sag? I would think the 12s4p 30q would fair better?

I posted this a while ago, same kinda issue. But my drop in the LCD reading was huge! Consensus was aged cells in my 10s3p 25R pack. To this day I’m still able to ride 10-11 miles with it. I just freak out if I look down while throttling. Read up

P count doesn’t mean anything if you pulling more than your batteries can provide, plus battery pack build quality, wires and all work in resistance which causes voltage drop under load.

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You may be interested in a smart solution that displays charge level based not on the current voltage, but consumed mAh, such as DieBieMS :wink:



Havent bought one myself but it counts mah. maybe the shunt could be smaller.

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I have exactly the opposite problem, The last 15-20% goes away immediately after around 100 meters. But 100% down to 25/30% is a steady fall…

The curve relating the % left vs battery voltage must be different in your meter.