E bike project advice and help

Electrically assisted bikes, trikes, etc.
Posts: 109
Joined: 6 Jun 2018, 10:24am

Re: E bike project advice and help

Postby stodd » 20 Aug 2018, 9:25am

Quick comment about initial battery use (whatever you decide to buy).
When I installed ours I quickly wanted to establish range so ran the battery pretty much out on the first few charges; I am sure others are tempted the same way.

I now see this is exactly what is NOT recommended. You should always try to keep the battery at least 20% full (lots of references say that), and especially for its early use you should probably keep it higher than that (I can't find the references right now, may be rubbish advice)

Good info at https://batteryuniversity.com/index.php/learn/article/how_to_prolong_lithium_based_batteries The smaller the discharge (low DoD), the longer the battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine. There is no memory and the battery does not need periodic full discharge cycles to prolong life. The exception may be a periodic calibration of the fuel gauge on a smart battery or intelligent device. (See BU-603: How to Calibrate a “Smart” Battery)

Posts: 475
Joined: 16 Nov 2017, 5:40pm
Location: West Sussex

Re: E bike project advice and help

Postby hemo » 20 Aug 2018, 10:40pm

If you were to get the max ah/capacity out of a typical battery the DOD would be down to 2.8v per cell however generally the BMS has a LVC ( low voltage cutoff ) which is usually at or about 3.3 - 3.4v.

Below 3.3V there is little capacity left maybe 3 or 4% at most. It is the same with the top end, between 4.1 - 4.2v again there is little capacity and only accounts for < 5%.

When I'm out for a long run I will use the batteries full capacity down to LVC, often I will parallel two batteries together and they will provide greater range and longer lasting power.