I recently had my cargo bike (Surly Big Dummy) converted to electric by a local shop who do a few. It’s running a Bafang BBS02 motor, limited to 250W, with a 48V 17.5ah battery. It’s not a ‘clever’ set up and has no torque sensing or similar, but it works well with my CVT hub gear so far. It’s made life much easier for local trips – I cycled 2 of my 3 kids to school this morning and didn’t have to break into a sweat or push. I can carry all three OK so far

The chap in the shop said to run the battery down to less than 10% for the first 7 cycles to get the most out of the battery in the long term. Now I’m not necessarily saying he’s wrong, but I can’t find any supporting theories for this anywhere else. A quick google of the model of the battery looks like it’s a common battery pack running on samsung 18650 batteries (I think)

The main theories mostly being charge to max when you first get it (the shop did that for me), ideally top up to around 80% for longevity of the battery, don’t let it get too hot or cold

Does anyone know if the advice about 7 times to less than 10% charge is right? I’d like to do whatever I can to preserve the life of the battery. I’ve had a chat with a couple of other e bike owners (OEM MTB e bikes) and they didn’t get any similar advice.

Doesn’t sound right to me. I work with Li-Ion batteries quite a lot but I’m no chemist. Definitely avoid full charge when it makes sense and full discharge. As you said, avoid extremes of temperature where possible.

I’m not sure how much this advice applies to batteries constructed with a decent Battery Management System controlling things. The BMS could prevent each cell being fully discharged for instance, so you don’t have to worry about completely discharging the battery for instance. I’d just follow whatever the manufacturer of the battery recommends.

That used to be standard advice for new batteries, something to do with conditioning the cells, but I thought more modern batteries didn’t require it.

Yeah, back in the Ni-Cd / NimH days when battery memory was a thing, Li-On is not prone to this issue, even less so with management systems as per the comments above.