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The capacitors in the controller and the inductors (phase windings) in the motor act together to some extent like a buck converter so both ways of seeing it are useful, especially 'average' voltage and current. In a basic hub motor system as the bike slows the back EMF from the motor falls, so...

That sounds like a potential gain - if LFP fires don't develop as fast (through needing air) that would be some improvement. I don't know if they're right but a couple of places say LFP don't catch fire on impact/puncture or shorting. I didn't find anything about other causes nor about LFP...

There's a strong lobby pushing for regulation that would mean reconditioned batteries couldn't be sold, and perhaps not used, so you'd have difficulty charging for this service. Also a bike battery fire is often very quick to develop and intense. For working with batteries ideally you need...

If it fails through reasonable consumer misuse I think of a battery as poorly built, as in the case of falling from hand height, overcharging or an incorrect charger. Would the bodies working on regulation be open to viewing it this way? It would make for easier and safer solutions.

Is this right? "If all Li-ion were replaced with LiFePO4 ebike fires would cease." Figures here suggest that the space for a 500Wh Li-ion battery would hold about 450Wh of LiFePO4.

That's great progress. Is there mileage in taking it a logical step further? The certifiable black box has shifted from ebike model to closed electronics system, could it become the consumer-proof battery (perhaps alongside systems)? By that I mean one with all the protections that can keep...

Monitoring and datalogging are available (openly) via a Bluetooth BMS, fast charging commonly uses comms but doesn't need to. Comms moves info and that lets you relocate circuitry should you choose to. I explained how legislating to obligate that can make products less safe.

I'm glad to learn cost isn't a major issue and maybe compatability could be achieved. I wrote "if a BMS works properly mischarging can't cause a problem, and as part of the battery a BMS's protection is permanent" ...and so it's tamperproof and effective even in mismatched systems. For many...

Regretably that's what the certification lobbying is all about, they even spell it out, look: 3 (1) (1) The Secretary of State must, within 12 months of the passing of this Act, make regulations: (b) Requiring that all micromobility vehicles have either (i) a non-proprietary charging system...

"stupid user behaviour..." A BMS cuts off if you pull too much current, or if high current persists making the cells too hot. It cuts off the wrong charger when current, voltage or temperature gets too high. It's there to take consumer grade misuse out of the equation, among other things...

Agree 100%. Lithium ion cells have quite stringent requirements for stability, for example they tolerate a similar temperature range to a beeswax candle. The socio-economic aspect to fires needs public education to tackle them effectively.

The BMS is there to protect the cells, weak or otherwise, by cutting off. If charging causes a problem it's because the BMS isn't protecting the cells adequately. Charging does warm up cells but less than strong sunlight and much less than hard riding. I think we should turn our attention to...

Nightmare :( As far as I can see mechanical indexing could be used to pair the right battery with a model of bike, and these awkward connectors only serve to tie the consumer to the brand.

Someone posted not long ago showing pics of their old battery and its similarly specced replacement but the sockets were incompatible. If anyone can point me to that thread I'd be really grateful, I've done a looong search.

That's certainly prudent. Proper storage and use affect safety but charging not so much (unless the BMS is cr*p). There's a pressing need to understand charging well because inept and harmful legislation is entering the pipeline based on the media's ignorance about it.

"The charger isn’t in control, the BMS is." That's key, and it means if the BMS is working as it should you can't overcharge a battery. A decent BMS provides Low Voltage Cutoff (LVC), HVC, overcurrent in/out and short cutoffs, as well as overtemperature, balance etc. functions. If too fast...

1. Many BMS start cell balancing when the battery's nearly full so it's useful to leave a 'full' battery on charge for an hour or two every few weeks, some say more often. 2. Overall battery voltage doesn't say much about balance because some cells can be under and others over (4.2V is chosen...

My controllers have stall cut-out but I don't know if that's usual, without it MOSFETs could last seconds. A hub motor shell is well separated from the windings, so the windings can smoke and smell while the casing's still warming up. For an EAPC system 30 seconds and up is probably the better...

Depending on your long steep hills you might need a big battery and a TA. Our hills are around 8% 0.7 miles and 12% 200 metres and for that I've a Gran Camino with DWG22C at 36V 17Ah, it's a well built bike and works a treat (although TBH the drivability of the 2021 speed firmware is pretty rough).

Wear can be down to age or usage, the cell resistances and self discharge increase and their capacities reduce. The BMS optimises use of available capacity by balancing the voltages but it can't reverse actual capacity loss, so an old pack ought to charge to full but discharge too quickly in...