Waking up an e bike

[hemo]

Had a chat with an ebike shop proprietor today on exactly this topic, my friends having experienced this issue.

Simple answer, if you leave a ebike for an extended period, with a low battery plugged into the bike, it will discharge and irrecoverably die.

He says they see it all the time because so many people buy and ebike, use it for a bit, ignore it for the winter then come back to find it dead in the spring .

If there is a way of recovering these batteries I smell a real business opportunity out there

The legality is sending batteries via courier for repairing as they are deemed as damaged and unstable, some companies do manage it though and have obviously insurance and a business agreement with a courier who is aware of the business nature. For private individuals the process is not worth the risk or cost.


As already mentioned if you are up for it I we/I can guide you in to some voltage checks to see if the battery is feasible to recover.

[hemo]

It feels like e-Bike batteries are going to become rather like car batteries in practice - despite the different chemistries (which are not THAT different deep down, arguably).

Lead-acid car batteries are consumables. Their lifespan is highly dependent on how you use them and maintain them.

Hopefully owners will quickly learn about these foibles and they won't impact the popularity of e-bikes. If people realise the similarity with car batteries, that should help.

Similarity with SLA are totally different.
SLA is a high drain one off starting device that likes to be kept fully charged, they are crap at continual/slow drain.
Lithium is opposite it doesn't like to be sat at high charge rate for very long and is happier at lower SOC, they are designed for energy release. A Lithium battery at full charge is only happy if it is used often and regularly, that is why a battery car will never be of use to me but a bike is for it's versitality.

[mattheus]

Similarity with SLA are totally different.

OK.

[kwackers]

Some batteries have a sleep/hibernation mode. If it has a button to press for switching on, try depressing it for 10 - 15 seconds.

Are you sure about that?

Given the current pull can be hundreds of amps, fitting expensive semiconductors to do the switching along with heatsinks etc seems a bit OTT.
Are you sure it's not just the controller going to sleep?

(I'm not saying it isn't possible and I certainly don't have enough experience of bike batteries but it seems massively overkill plus I'm not sure what problem it would be solving and the switching would need to be bi-directional otherwise you wouldn't be able to charge them).

[hemo]

Most generic BMS don't have this function but some BMS do have sleep functions built in to them for long term inactivity, typically most legally marketed ebikes/kits have 7 - 10a continuous controllers so not 100's of amps.
Wisper bike batteries have a hibernation function and I believe Suntour.

Generic batteries have a simple two wire switch, others have an extra pair of white sense wires that also connect to the BMS/pcb.


The ebike controller is less sophisticated then the battery BMS.