BATTERY TEST ON BATTERY #10 (UPDATE: TEST #2)

Another great day. Overcast but comfortable  Temp 19 C.

Watt hours = 677.13

Amp hours = 14.38

Odometer = 11,006 km.

Very disappointed in today's test. #10 battery is supposed to be one of my better batteries. I expected about 720 W/h. The Ah are also low. I will update this post when I recharge the battery. Perhaps it wasn't fully charged. 

NOTE: I just unwrapped the battery. When I test a single battery I put it in my rear basket and I wrap the battery in a beach towel in order to cushion it from road shock. When I unwrapped the battery it was hot to the touch. Perhaps the battery overheated and the BMS shut it down early. I'll keep you updated when I do a second test without the wrap.

Test #2

Watt hours = 691.24

Amp hours = 14.54

Odometer = 11,046

While I kept the battery uncovered there was not much improvement in its performance. Still disappointing.

77 km today. 2.5 hours saddle time. Not at all tired.

BATTERY TEST ON BATTERY #11

Another great day. Lots of sunshine. Temp about 19 C.

Watt hours = 646.66

Amp hours = 13.76

Odometer = 10,969 km.

As you can see, the W/h and Ah are very nearly identical to the previous four tests.

Summary of #11 through to #15

#11 = 646.66 W/h    13.76 Ah

#12 = 640.82 W/h    13.86 Ah

#13 = 639.60 W/h    13.74 Ah

#14 = 641.40 W/h    13.13 Ah

#15 = 642.70 W/h    13.27 Ah

BATTERY TEST ON BATTERY #12

Great day. Lots of sunshine. Temp about 19 C.

Watt hours = 640.82

Amp hours = 13.82

Odometer = 10,930 km.

As you can see, the W/h and Ah are very nearly identical to the previous three tests.

BATTERY TEST ON BATTERY #13 (MY PSYCHO BATTERY)

Watt hours = 639.6

Amp hours = 13.74

Odometer = 10,900 km.

Battery #13 is my worst battery - at least it was. It has (had?) a bad cell which had premature voltage sag (and none of us wants premature voltage sag). This caused the BMS to shut down the battery and caused the bike to stall on acceleration from a standing start. Today, there was no problem. Why is this?

I can't answer this definitively but I will tell you this: even when batteries are not in use there is electrical activity going on. I have not used #13 for a year now. I have kept in indoors and kept its storage charge at a steady 85%. Somehow, during this extended interval of non-use its molecules have rearranged themselves so as to "cure" the premature voltage sag. Pure speculation on my part, though.

HOPING FOR SOME DECENT WEATHER

It's 5:01 am here in Richmond , BC. The sky is quite overcast and it is cool: 13 C. The last couple of days have been rainy and cool. I'm chomping at the bit to do some more testing. We'll see.

BATTERY TEST ON BATTERY # 14

Watt hours = 641.40

Ah hours = 13.13

I repeat: These figures are very good considering the battery's about 18 months old. When it was new I tested it and got about 660 Wh. So the loss is only 2% or 3%.

That said, this battery (and the four others purchased at the same time: batteries #s 11 through 15) have a lot more voltage sag than batteries #s 1 through 10.

So, when the battery has used up about 40% of its energy the voltage sag is sufficient to cause the bike to stall out when accelerating from a standing start. To avoid stalling one must accelerate from a standing start very gingerly.

Odometer reading 10871 km.

BATTERY TEST ON BATTERY #15

Watt hours = 642.70

Ah hours = 13.27

These figures are very good considering the battery's about 18 months old. When it was new I tested it and got about 660 Wh. So the loss is only 2% or 3%.

That said, this battery (and the four others purchased at the same time: batteries #s 11 through 15) have a lot more voltage sag than batteries #s 1 through 10.

So, when the battery has used up about 40% of its energy the voltage sag is sufficient to cause the bike to stall out when accelerating from a standing start. To avoid stalling one must accelerate from a standing start very gingerly.

Odometer reading 10835 km

Update:

These batteries (#s 11 - 15) are poor performers when used singly but are very good when used in tandem.

When one battery is reduced to 60% of its charge it results in problems with stalling on full acceleration. Using two batteries in parallel gives us 200% of power. We can use 140% before we get down to the 60% of power before problems begin. 

This means that the second battery can utilise 100% of its power. It gets even better when you use three batteries in parallel (which is what I use when I pull a trailer).