Baboonking

The BMS could be working exactly as designed but still not be capable of balancing the cells except over a very long period of time. For example Take a 36v 15AH battery pack with this commonly used bms https://vruzend.co.uk/products/10s-36v-15a-lithium-battery-bms-balance-function-18650-li-ion-uk-seller-stock it has a balancing current of just 40ma. Now imagine said battery pack has been left in a damp garage for 6 months and corrosion means there's a higher self discharge rate for one of the parallel groups, or maybe through bad luck one of the cells happens to have a higher self discharge rate from the factory. So one group has only 1ah left whilst the rest has 14ah. The owner then puts it on the charger and it appears to finish quickly because most groups have only 1ah to fully charge. How long would the owner have to leave the battery on charge to allow the BMS to fully balance the pack? The BMS needs to add 13AH and can only balance at 40ma, so 13000/40 =325 hours or 13.5 days to balance the pack.

Yes, a small current flowing in a high impedance path from from the positive to negative casing which is physically only circa 1mm away at the positive terminal. In theory the BMS should rebalance the cells but how long this takes depends on the balancing current, whether the BMS throttles said current because it overheats, at what voltage the BMS starts to balance and whether the charger voltage is precisely set with respect to the BMS balancing voltage. I've heard stories of batteries only balancing when left on the charger for 2 weeks which may raise safety anxiety if charging indoors and the provenance of the battery is unknown.

Water from condensation can cause a battery to becoming unbalanced through a small short circuit. Not enough to do any noticeable damage but enough for the pack to become unbalanced over time. When batteries are properly assembled gloves are used so human sweat which contains salts does not contact the metal. Salt makes condensation more likely. Leave said battery in an unheated outdoor environment and moisture from the air will get inside and settle on the salt patch and cause a slow short circuit. Electronics need to be well designed and assembled to prevent this happening in an outdoor environment. I remember reading that Justin from ebikes.ca found that most of the damaged china sourced ebike battery returns were caused by corrosion, water had got in somehow, my guess would be from moist air. His solution was potting the batteries in epoxy hence the development of his Ligo packs. A way round the problem of battery or for that matter motor corrosion is to keep your bike in a heated indoor environment where condensation will not occur.

Whats involved?

I think its a good idea to do something like that - bolt on plate to attach the bafang motor, hookup to the original battery. Is the company that made the Impulse motors also dead like 50 cycles? Kind of a shame for all the bikes to become toast as being Kalkhoff I imagine they are good. Given that many more Kalkhoff ebikes are sold on the continent I wonder what they are doing there, it might be worth checking the German pedelec forums to see how they are handling the situation.

Yes it is. Still lots of them around as its a popular bike on the continent. https://www.ridewill.it/p/en/connex-3050502600-sprocket-1-2-x-3-32-11-teeth-increasingly-for-panasonic-e-bike-engine/121582/

Ha ha, bet that flies up the hills. If you want yet more speed and power I recommend the 11 tooth mod, nice a simple to do, you might need extra chain links.

Check out fleccs page, you can add a little more torque by change the drive sprocket to an 11 tooth, you can also add more speed by changing the sprocket on the rear wheel. The controller is inside the housing and is potted, you can add sodder to the busbar to boost the amps and thus torque further but I would be wary of doing that because it might overheat the components on the controller which is potted. If you do make any mods let us know how you get on.

Sold. Not sure how to mark the original post or delete the post.

Price drop to £80 plus postage

Price drop to £95 plus postage.

Reasonably cheap battery here if you wanted to take the risk https://www.allbatteries.co.uk/electric-bike-battery-panasonic-type-36v-14-5ah-468wh-li-ion-aml9124.html

The downside of C is that the Panasonic drive system works with a torque sensor which a cheap controller won't be able to use. In addition you might have trouble finding the phase wires inside the motor housing,as Flecc says the controller has shielding or potting in the 26 volt version which would be a nightmare to remove. You could wind up wrecking the drive unit for a possibly unusable bike. You could just buy a new or second hand 36 volt battery and charger and hope it works with the bike. If you can find someone selling it you could ask to try before you buy just to see that the bike works OK before hand. Out of curiosity are you sure the 42v battery does not work on the bike? On my 26v version it works OK with any source of the right voltage but the indicator lights on the throttle don't work which doesn't really matter.

Price drop to £105 plus postage.

Hi Graham, yes still available.