[Tip] Yamaha PW - How to check the number of cycles & absolute battery capacity

JayVee

Well-Known Member
21020 kilometers, absolute battery capacity still between 75 and 100%.

The cycles are no longer "countable" because I have more than 700 cycles.
 

Ghostman_132

New Member
21020 kilometers, absolute battery capacity still between 75 and 100%.

The cycles are no longer "countable" because I have more than 700 cycles.
Have you remembered to calibrate the battery often? It can be calibrated only when charging from fully depleted to 100% in one charge. One calibration charge will only correct 1/4 part of the real capacity value. So if you have capacity value of 500wh and you make one calibration charge which read out to be 400wh, it will change the capacity value only by 25wh -> new capacity value will be 475wh. That is why only one calibration charge is not enough to correct real value.

At least this is what I have understood on how it works...
 

Bicyclista

Active Member
Have you remembered to calibrate the battery often? It can be calibrated only when charging from fully depleted to 100% in one charge. One calibration charge will only correct 1/4 part of the real capacity value. So if you have capacity value of 500wh and you make one calibration charge which read out to be 400wh, it will change the capacity value only by 25wh -> new capacity value will be 475wh. That is why only one calibration charge is not enough to correct real value.

At least this is what I have understood on how it works...
Thank you for the information, but as has been pointed out previously the readout provided by Yamaha is too coarse. It's provided only in blocks of 25%, and there is no readout in watt-hours.

Also, please clarify. Are you advocating fully depleting a battery to 0% in order to calibrate, and to do it several times in order to calibrate completely? My understanding is that discharging a battery to 0% is something to be avoided. From batteryuniversity.com: "Li-ion batteries contain a protection circuit that shields the battery against abuse. This important safeguard also turns the battery off and makes it unusable if over-discharged."
 

Brooks

Member
Huh?^^ Calibration charge? Deplete the battery? Post link to this info please.
Sounds like old info for lead acid battery.
 

33red

Member
I am no chemist, i pedal recharge to 100% the lowest i went is 2% left. With 3,600kms all works great. I ride daily.
 

JayVee

Well-Known Member
There's no doubt in my mind that 80/20 works better because I have two batteries. The one I report in this thread is the "knock around" battery which I charge to 100% quite frequently and sometimes even leave charged like that for a couple of hours. This is definitely not a best practice and should be avoided if possible. The 80/20 gets around 10-15% more range than the knock around. This is why I'm interested in the new 745Wh clone battery that Ravi posted about. 80/20 would be much easier to implement for me on a daily basis with 745Wh and a 7 Amp charger....

I almost never go under 20% on either battery. I balance the cells on the 80/20 battery from time to time by charging to 100%, but I ride the bike immediately after it's fully charged. You want to leave the cells at 100% as little time as possible. In the long run, it makes a difference.
 

Ghostman_132

New Member
yes, you guys are correct. It is best to stick between 20-80% for longetivity. But it is not possible to do calibration or balancing with those levels. Li-ion batteries voltage levels are quite static on those levels of charge -> impossible to know what the real charge level is if you only look at the voltage level. Only way to give that information is to calculate watt hours. This is the same with all electronics which have BMS.

Yamahas absolute capacity may be intened to be that coarce just to avoid "unneccessary" warranty claims. They could have made it to work with 4 LEDs like they made the charge cycle counter but chose not to.