Degradation at 37k miles...

Perhaps I had it wrong. I know there's a buffer and 71 came into my head.

 

The battery is rated by Hyundai at 356V x 180Ah which is 64.08 kWh. The evidence based on SoC(BMS) v.s. SoC(displayed) that LG Chem/Mobis have apparently started with a slightly larger size to meet Hyundai's life specifications is really only of academic interest to us since we can't directly use it.

 

While the BMS numbers are interesting too look at on every EV, they are just a guess/estimate by the BMS. The only accurate way to measure degradation in usable capacity is to run battery down from 100% to as close to 0% as possible and measure the kWh you are able to pull from the battery. If you're going to compare degradation over time, you also need to have a consistent battery temperature and discharge rate for each test.

It's probably a waste of time for most people. The rest of the car will likely fall apart long before the battery becomes unusable.

 

326 miles on 100% charge? Wow .. The most I've ever gotten was 311 .. and I've had the BMS Update a couple months ago. I typically only charge to 80% unless I have a major trip. and only have 3,400 miles on my 2020 Ultimate

 

I got 261 one of the few time I've charged to 100%. It's only used locally so I've gone to the charge at 20% to 80% which is suppose to be better for the battery. I would charge to 100% if going on a long trip which I probably won't do, I've got a PHEV for that. I did charge to 100% the first couple of time before I found out about the 20/80 routine.

 

But 356 miles noted above is quite a bit of "underrated". Was that a typo?

Tesla derates quickly as speed goes up (above 60 mph) and temp goes down (60F) and the Kona EV seems to hold up much better in real world driving.

 

I recently got 340 miles actual(not a GOM guestimate) with 5% SOC left. The key seems to be warm ambient temps around 25C that does not require any HVAC involvement and an urban driving cycle with appreciable regen activity. I can't say I was otherwise hypermiling or anything. Unfortunately in my climate I only get about 4 months of great energy economy. The cold temps are creeping back in. In another month or so my mileage figures will drop by at least 20-40%. I suppose the cold temps are relatively good for battery longevity .

 

Wow.. we consistently get only on average 3.7-3.8 mi/kwh. Mostly hw speeds around 70mph. I think we generally get about 230-240 miles if we charge to 100%.

 

As I typically do more frequent and shallower recharges i.e. from 50-80% SOC I had an opportunity to recently do a couple of deeper rebalancing charges from 15-100% and my BMS now reports 95.5% at 100% recharge which is suggesting just 0.5% degradation in the first calendar year of driving. That's pretty awesome if degradation actually stays linear and the battery doesn't blow up, lol.