Kalkhoff Li-ion Battery capacity vs Power output

[George588]

I recently bought a cheap 4 year old Kalkhoff Agattu, with a spare battery included. It doesn't seem as powerful as my Giant Lafree (with a 7 year old NIMH battery)

The Battery capacity, by pressing the Meter test button for more than 5 seconds shows only 3 of the 5 LEDS, whether the battery is charged or discharged. I understand this to mean that the battery is down to 60% of it's capacity - and is to be expected after 4 years, as LI-ION technology suffer significant ageing.

My question is, whilst I understand this is the reason for a reduced range of about 15 hilly miles, does it also mean that the actual Power delivered to assist my pedalling is also reduced proportionally?

I'd be grateful for any advice regarding this
Thanks

 

[Deleted member 4366]

Yes and no. Your battery will be 29.4v when fully charged and 21v when empty. Power is proportional to voltage, so that means you only get 2/3 the power just before your battery is totally flat. The less capacity it has, the sooner your voltage drops, so you spend more time in the low power zone.

Having said that, it may make some contribution to lower power, but I don't believe that it's the main reason. For the LEDs, you need to do the recalibration procedure to reset the meter to confirm whether it's right.

Also, it's probable that it has different software to the Giant, so different power algorithms. I know that the later 26v Panasonics gave more power than the early ones.

 

[George588]

Thanks d8veh

I guess I need to follow the recalibration route, having only just learnt about the totally different maintenance of these batteries, compared with NIMH I recently decided to run the battery right down once.
At the end of the journey, I travelled over 4 hilly miles with one single LED flashing and the assistance kept working!
Once home, before connecting to the charger, it was still showing 26.7 Volts (Battery pins 2-5). and took 3 hours 53 minutes to complete the charge (10AH battery)

You mentioned 21v when empty which suggests mine had more range than I thought, perhaps next time I should run it until it cuts out, before recharging.

Can anyone else confirm the voltage of one of these 10AH batteries, when down to a single flashing LED

Thanks in anticipation