Battery went to zero

[Jdarr]

My battery was at approximately 40% and suddenly went to zero then started to steadily come back up slowly. Had anyone else had this issue?
Jon

 

[tomjasz]

My battery was at approximately 40% and suddenly went to zero then started to steadily come back up slowly. Had anyone else had this issue?
Jon

How are you viewing voltage or %? Display? I’d use a rc watt meter or multimeter to see actual battery level.

 

[harryS]

Those RC wattmeters can be frustrating as far as accuracy. I own a few, and they vary as much as volt apart at 54V. One of mine reads about 33% lower on amps too. Well, I buy the cheapest ones I can find, like $12.
,

 

[rich c]

It's called voltage sag, very common. I assume you were using a throttle? Gets much worse in the winter as cold performance can be cut in half.

 

[tomjasz]

rich c is correct. How old is your battery? Who made the cell pack?

I have a 52V 20Ah from 2016. If I keep the throttle at 500w to 700w it still delivers 30 miles. If I hit full throttle it drops to 28v and shuts down. If I use lower level PAS I get a bit more. I overbought batteries and my health this year has nearly shut down riding. The golden years!

 

[tomjasz]

RC wattmeters

There are versions that are better, but cost $30-$40. I use a shunt and CA3 from Grin. Definitely much more expensive but incredible data mining.

 

[Jdarr]

Thank you folks! Not using throttle. Pedaling flat ground and felt it kick off. I turned the bike off and then back on and it came back at 35%. Bike had about 100 miles on it. It kicked off again shortly after and came back up on its own as I rode to about 17%.

 

[roshan]

Thank you folks! Not using throttle. Pedaling flat ground and felt it kick off. I turned the bike off and then back on and it came back at 35%. Bike had about 100 miles on it. It kicked off again shortly after and came back up on its own as I rode to about 17%.

Change the display from percentage to voltage if you can. That would show you much more accurate info on what's going on.