I suspect one cell of my battery is getting fast damage:
1st trip. Barcelona-Piera 44 km 400m uphill. When I was about to arrive at Piera the red battery light turned on, with six bars in the display. The 6 bars started to fall down very quickly!
1st recharge in Piera: The recharge was halted when the bike reached 152v, CP 152v, 5C ambient, 20c battery, 14/17bars in display. It cooled down 15 minutes and started again the recharge at 10A, within 2 minutes the voltage reached 152v and the recharge was stopped again....
2nd trip. Piera-Barcelona 74km 400m downhill: It was a very careful ride back to Barcelona. After reaching Barcelona I've ridden the bike to red battery light. I managed to ride 74 km, 10 km less than the usual mark under this kind careful conditions.
2nd recharge: despite driving the bike only at 50-60 km/h at the end of the trip the battery got pretty hot, 35C. Outside the temperature was 5C!! The recharge was halted, as like as in the first recharge: at 152v, but 16/17 bars in the display...It cooled down 15 minutes and tried again the recharge at 10A, in 2 minutes the voltage reached 152v and the recharge was stopped again.. I've taken a pair of pictures during this second try:
The system tries to recharge again the battery. After 2 minutes it reaches 152v.
Some seconds later the recharging is halted and the system waits 15 minutes before it tries to "unsuccessfully" insert more amps inside the battery...
Any thoughts?
Exactly like mine, when the battery pack was dieing. You're gonna get less and less range and your damaged cell will get hotter and hotter until you won't be able to drive more than 5 km as snails pace.
My guess is that several cells are partially discharged due to uneven heating of the pack.
An EQ charge might sort things out. If for example 8 cells are 30% lower in SOC than the rest (most likely the top right side row in the front battery) then the charge terminates each time that the remaining 94 cells are full. But the 8 low cells can never catch up, unless a long EQ charge is performed.
The low SOC cells get heated by reverse charging each time you ride as far as you can, increasing their self discharge rate and worsening the imbalance.
The worst thing you can do is to ride it as far as you can each time, before balancing. That will indeed kill the weakened cells pretty soon!
It might be too late and the damage is already done.
When was your last EQ charge?
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There is always a way if there is no other way!
Thanks for all coments!
Just like I suspected. Therefore I should locate this damaged cell and...? Maybe I may install a device to prevent reverse polarity when the main battery is almost empty?
Ridding to red battery light every week is recommended by vectrix, to keep the battery ok. It is obvius that I must not do a full discharge any more. What is the easiest way, in your opinion, to keep those imabalanced cells ok?
I leave the bike plugged all night long every Friday. I d0n't check if the EQ is done, I just assume the bike will do it if needed. I assumed wrong... I wish I could force an EQ on demand.
But sometimes I need to ride almost as far as I can. If the product has a defective core design inside the battery, it is not may fault....
1. You could shunt the damaged cell, just like Megendez did.
2. That's why I never drive below 5 battery bars left. Usually I drive only as far as 7 battery bars left (125V). I do EQ every 1000km and that's it (I'm just about to do another one).
3. It's not your fault, but there's nothing you can do, except get a new battery and learn a lesson. I did it too... the hard way.