After more than 3 years since the last capacity test and a full balancing just 2 weeks earlier, I was now ready to combine pleasure with some research: how much capacity has the pack lost?
I decided to drive to Strassbourg and back – like last time – to test this.
Since this is an exercise in extreme hypermiling – not only do I want to know the pack’s capacity, but also how far I could, in theory, drive on a charge – I will have to start pretty early.
I get up at 530 am and say hello to my TWIKE that has been charging at 1A during the night for a full trickle-charge style charge.
I start the TWIKE and am greeted with the first screen:
I had to make an assumption how bad the degradation was – with my assumptions, I will be able to drive about 430km @ 35Wh/h.
After a night charging, all temperatures are at an ideal level. Hopefully this will translate to a few more kilometres available to drive.
I was surprised to see that the pack was at 415V and not 417 or 418V as previously. This is a sign of cell degradation as I charged to 420V and a 5v drop is pretty significant.
I start up my phone to log my trip and off we go!
The first thing I’m thankful for is that I am wearing a jacket. The weather is cold and humid and grey.
Driving along the Rhine on the German side had me see lots of whisps of fog and low clouds.
Thankfully, a little later the weather started to clear up and temperatures rose with the sun rising.
At 400V the pack gives me around 10km less than usual. Let’s hope this isn’t a sign of even more degradation!
When crossing into France temperatures are high enough to rid myself of my jacket.
Always a picture I like to take: TW560 crossing into another country!
At 100km, the pack hasn’t really shown any change from 10km earlier. Let’s see if this positive trend continues!
Driving along the flatlands of the Elsass, I chose a new road I hadn’t taken before and am greeted with no traffic at all for the most of the drive. Am I just early or did all motorbike riders choose to take another road?
Shortly before Strassbourg we get to 200km and I’m impressed how high the OCV remains!
At 300+ km things are markedly different. There was a major drop in voltage around 250km which was absent previously. Before the drop was near linear with capacity, now it seems that I’m seeing some kind of chemical slump at 30%. I was getting worried that I would no longer be able to make it back home!
Since temperatures were still soaring, I decided to head into a fuel station to get a drink and was pleasantly surprised that they prominently displayed the price of electricity when entering and that the consumption could be paid by credit card directly at the shop itself – like when pumping gasoline!
I got an energy drink for myself and fell for the marketing of a local brand: I definitely want “BÄÄÄM”! 🙂
Close to home I was getting worried that my consumption would rise significantly due to rain and a storm that my weather app had consistently been warning me about for around a half an hour – It looked pretty impressive!
On another note: I’m constantly amazed about the ignorance of some companies when it comes to the design of their logos – were there no English speakers around when the logo below was approved?
Around 400km I was getting somewhat worried that I wouldn’t make it home as the range prediction was around 11km below the actual distance I had to go!
This is where I doubled down on my hypermiling efforts!
At 420V the battery warning light lit up – a rare occurrence, indeed!
To cut a long story short: I made it home…barely. With probably just 10-20Wh left, I pulled up in front of my house! A close call!
Let’s see how this looks in perspective!
It seems that the capacity loss has slowed down even more!
| Date | Wh Capacity | Loss since last check |
Total loss | 38.5Wh | 55.5Wh |
|---|---|---|---|---|---|
| 11.08.16 | 17,722 | 460km | 319km | ||
| 01.05.17 | 17,172 | -3.10% | -3.10% | 446km | 309km |
| 10.09.18 | 16,601 | -3.32% | -6.33% | 431km | 299km |
| 16.03.19 | 15,916 | -4.12% | -10.19% | 413km | 287km |
| 17.07.19 | 15,873 | -0.27% | -10.43% | 412km | 286km |
| 28.02.21 | 15,758 | -0.72% | -11.08% | 409km | 283km |
| 22.05.22 | 15,703 | −0.34% | -11.13% | 408km | 282km |
| 01.06.25 | 15,572 | −0.73% | -12.13% | 404km | 281km |
After 9 years of use, I’m still well on-track to overachieve on my stated goals for the pack back then:
Being able to drive 200+ km @ 55.5 Wh/km!
Really looking forward to having this pack for many years to come!