I am facing a loss in battery capacity, which is frightening me.
My Zero SR16 ZF13.0 has not been used in the last 8 months. It was standing at about 80% SOC in my garage. Now I charged it to 100% and went out for a ride. Everything smooth, except the range estimation was rather low: at a mixed riding between 50-80km/h I typically always got at least 150km range, this time the estimate was 100-120km.
I thought that my Zero needs more usage, so I rode and charged it several times over the last days. The range estimation and the range I achieved (e.g. 56km when SOC went down to 52%) were still too low. I then remembered that I had the "Zero Voltage" app, which also shows battery capacity. So, I opened it and it showed at that time (90% SOC) "75/80Ah".
I thought "80Ah"? That's too low! The battery should have >100Ah. So, I went to a friend of mine, who had been a local dealer but then closed his business. He pulled the logs from the bike and showed me this:
ZERO MBB> bms
****************************************
* BMS Data *
****************************************
************* BMS #0 ***************
- BMS Board Rev : 03
- BMS Firmware Rev : 40
- BMS Serial Number : 2015_bms_48e0f7_02634
- Battery Serial Number : 16xxxxxx
- CAN Rx in last second : 167
- Pack SOC : 56%
- Fuel Gauge : 54%
- Age of SOC Data : 37 ms
- Model Year : 2016
- Pack Capacity : 81 AH
- Pack Capacity Remaining : 43 AH
- Total Energy Used : 293 KWH
- Number Of Bricks : 4
- Pack Discharge Current : 0 A
- Pack Sum Voltage : 103.863 V
- Sag-Adj Pack Sum Voltage : 103.876 V
- Bank Voltages : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
: 3705 3708 3707 3708 3710 3709 3710 3710 3709 3709 3709 3710 3708 3709 3708 3710 3709 3710 3708 3711 3710 3711 3709 3710 3710 3710 3711 3708
- Lowest Cell Voltage : 3705 mV ( Cell 1 )
- Highest Cell Voltage : 3711 mV ( Cell 20 )
- Pack Balance : 5 mV
- Lowest Cell mV : 3706 mV
- Age of Bank Voltage Data : 81 ms
- Isolation Resistance : 32766 KOhms (0x7FFE)
- Least Isolated Cell : 28
- Instant Iso Resistance : 1 KOhms (0x0001)
- Instant Least Iso Cell : 28
: 0 1 2 3 4 5 6 7
- Pack Temps : 17C 18C 17C 18C 18C 18C 18C 18C
- Lowest Present Pack Temp : 17 C
- Max Pack Temp This Ride : 18 C
- Min Pack Temp This Ride : 17 C
- Age of BMS Temp Data : 79 ms
- Min Discharge Temp : -30 C
- Max Charge Temp : 50 C
- Min Charge Temp : 0 C
- Max Charge C-Rate : 1.0
- Min Discharge C-Rate : 7.5
- Discharge Scale Value : 255/255
- Num Charge Cycles : 64
- BMS Total Bike Run Time : 00:01:54
- BMS Clock : 03/27/2019 00:49:08 ( 1553672948, 0x5C9B2AF4 )
- Age of BMS Time Data : 192 ms
- Age of BMS Status Data : 205 ms
- Discrete Throttle En : Enabled
So, the line "Pack capacity" shows "81 AH". The ex-dealer told me that he normally sees "104 AH" at that place. So, he concluded, he thinks my battery is defect.
Is there anybody who can confirm that? Or has some other explanation?
Thanks for any help!
Short update:
So I went to a ride yesterday, trying to drain the battery as much as possible. I started recording the battery voltages in between to be sure that I won't get stranded somewhere:
27% : 101.12V
14% : 99.50V
11% : 98.90V
4% : 97.77V
0% : 96.8V (135km)
95.0V (145km)
When SOC showed 0% I had traveled 135km on the full charge. I was able to get another 10km until the bike went into "limb" mode. That was fortunately only about 0.5km away from my home, so it was easily possible to get back.
At home, I charged the bike over night to full SOC. Now the "Zero Voltage app" shows "97 AH" as full capacity. So, this indeed demonstrates that "Pack Capacity" is only calculated. So, no clear indicator of what the health of the battery is.
Its calculated capacity of "97 AH" is, however, still significantly below what to expect of a 2016 13.0 battery, if I read the unofficial manual correctly (which states 100AH for a 2013 model and probably at least 10% more for the 2016er). And additionally, the range estimation is now at 142km, which is pretty close to the 145km I managed to get. This is still very much on the low side, I think. I remember that I typically had 150km at the very least, in most cases between 160 and 220km, depending on the mixture of country vs city riding.
Today I will let my local dealer do a firmware update. Then I will see over the next days, what range I am still able to reach. Now, that the "Pack Capacity" is not really a measured value, I guess it would be difficult to prove battery degradation only on the range.