Electric bike batteries

[Kittyhawk]

Have been looking at electric bikes and undoubtedly the most expensive component of these things is the battery.
A 36V 17ah Li-on bicycle specific battery costs ( in NZD) between $900 -$1000. At a general purpose battery retailer I can buy a known brand automotive style battery with the same Li-on chemistry and internal whizz bang electronics - 36v 200ah for around $1400. Why the hugs disparity, are electric bike manufacturers ripping us off?

 

[John Brown]

Have been looking at electric bikes and undoubtedly the most expensive component of these things is the battery.
A 36V 17ah Li-on bicycle specific battery costs ( in NZD) between $900 -$1000. At a general purpose battery retailer I can buy a known brand automotive style battery with the same Li-on chemistry and internal whizz bang electronics - 36v 200ah for around $1400. Why the hugs disparity, are electric bike manufacturers ripping us off?

Probably.

I recently bought a 36V 10.5aH ebike battery for £135, including next day delivery, not too bad, really.
The situation is made worse by ebike manufacturer's locking their controllers to the battery via CANBUS, thus stopping the use of generic batteries, although they would claim to do this for safety reasons.

 

[Dabop]

When looking at lithium batteries- it pays to look specifically at the chemistry- there are different types...

NMC/LiPO have more storage per kg- but also the ones that do the 'burny,burny thing far too often...

LFP/LiFePO4 have less storage for the same weight, but have FAR more charge cycles (500-1000) for the NMC type, versus 3000-5000 for LFP!!!, and are also FAR more stable- it's almost impossible to get them to 'catch fire'- even driving a steel prybar through them repeatedly or massively overcharging them only results in venting- no fire... (theres one on U Tube showing a guy trying to make a LFP catch fire)
So avoid the NMC/LiPO ones...

LFP might need some 'conversion' (I've ordered one for my 25 year old mountain bike I fitted with an electric front hub drive- ordered before christmas and still waiting grrr) on backorder from Amazon lol- I tested the motor with three old car batteries in the milk crate to check its performance- obviously they aren't ideal for normal usage lol

Basically identical to this- I plan on just mounting it under the bikerack on the back- lol- the milk crate iis bolted on that so I can carry shopping bags- should hide it nicely lol...