This post is a follow on from the one I made several months ago reporting my range in a warm climate. The eagle eyed among you will have noticed that the five-week rolling average I reported then was not correct in my spreadsheet, so I have fixed that up for this post (see 2nd chart). In late 2019, I changed out the tyres from the original Nexans, which were too skittish for my liking, and replaced them with XK. This lead to an increased rolling resistance which in turn converted into less efficiency. The consumption jumped from about 12.1 to 14.0 kilowatt hours per 100 kilometres. That's about 16%, but I'm happy enough because I don't need the range and now we enjoy a much better set of tyres and superior handling than we had before. My main point for this post, however, is to report the improvement in range after the installation of the new traction battery replaced under warranty about a month ago. I recorded the GOM readings at various SOCs in the two weeks before and after installation (first chart below). As you can see, I have about a 14% improvement in range according to the GOM. (I don't have an obd to record actual SOC). Fourteen percent seems to be a lot to have lost in the original battery capacity, for only two and a half years and 30,000 kilometres driven. Was there an adjustment in the BMS updates prior to battery replacement that might have indicated a GOM reading that was reduced regardless of the actual capacity? Or is it indeed indicative of a 14% loss of battery capacity?
Hi, glad to hear you have gained the full potential of the battery again. I too thought I had a small improvement when i got mine replaced. Not 14% though
My understanding is that a BMS update accompanies battery replacement so at minimum its software-based battery model is starting from new. Because the GOM is so sensitive to temperature and other things I'd be wary of concluding that this confirms 14% degradation. I'd also say that SoC(displayed) is more than an estimate - it has a very close and repeatable relationship with SoC(bms). I tend to use the displayed SoC value because that represents what Hyundai has sold us. I graphed this GoM data 2 years ago that does show quite a difference summer/winter. These days I'm using the OBD coulomb counters because they should be much more accurate. This graph is from Dec 2021 (probably 15 to 25°C) and the trendline slopes of cumulative Ah and kWh draws (extrapolated over 0-100% SoC) show how closely the obtained (3-year old) battery capacity aligns with the rated values of 180 Ah and 64 kWh. It also shows that SoC is based on coulombs rather than energy, even though the difference is not huge.
I love reading posts like this one. A boost in range is awesome, considering Kona EV's frugal consumption any addition is always a huge bonus...for whatever reason. Nice the new pack is working well for you. I am sure as @KiwiME mentioned above the numbers will level out at some point, but just the same, great to see.
