Will the BMS stop the discharge before batteries are beyond point of recharging?

Michael Love

Pedelecer
Aug 26, 2018
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Crud, never mind, just googled calculate Ah of ebike battery, some reading to be done. :)



So I am thinking of buying something like this to see how long it takes for battery to discharge.

At a 5A draw, if the battery was 36V 10Ah then the power should last for 2 hours, correct?

Will the BMS turn off the battery at 30V and if so, what does that actually mean for the Ah figure?
What I mean is, the Ah figure that is given for the battery, is that the discharge figure from full until BMS stops the power drain, or is the Ah figure - the number on each cell multiplied by how many cells in parallel,and the BMS is not taken into consideration?

I hope I have explained that well enough.


Thank you.
 
Last edited:

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
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Don't forget to factor in 10-20% less Ah than on the label:

- salesmen are sometimes overly optimistic :rolleyes:
- over time the total capacity will diminish to about 80% of rated capacity so it is better to buy a larger battery than you think you need
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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As AK has said you will never get the full capacity stated out of a battery.
Manufacturers and independent data show that you need to discharge to 2.8v per cell to achieve this, for battery/cell longevity typically 3.2v - 3.3v is the minimum practical use of any capacity, 10- 20% of capacity isn't typically usable.