ChozoGhost79 said:
Yes, it was on the first red line, so technically not overheating, but still the charge rate was about half what it would be on a cool battery. This reduces the usefulness of the car considerably, since only one DC fast charge can be used in a day without the charge rate being reduced.
There are a number of things that can affect the speed of the charging rate, one of which is the charging profile programming of the car that takes into consideration the temperature of the battery, the number of charges in a time period, and the level of charge in the battery. This is set by the manufacturer, and while they are all different, they all have commonality of how they taper the charge rates over time and for many irrespective of the internal temperature of the battery.
But the other thing that is often overlooked in how fast the charge will be is the charger pedestal itself and how it is configured by the provider.
For CHAdeMO there are two generic amperages 100 and 125 amps but that is only the rated service capability for the charger. Add into that if the charger is sharing a service line with another charger, the ambient temperature of the charger which may cause it to reduce the energy provided, and how the service provider has the charger profile set to be to avoid demand charges from the utility, or to just increase their revenue on a per-minute-based session.
For example, my local EVgo charger (as others in the vicinity are) is rated at 100 amps, and are labeled as 50 kW chargers, but the most that it will provide to any BEV at any temperature is 35 kW tops. I've charged LEAFs, VWs, Bolts, iPaces, Niros and Konas at this charger using either the CHAdeMo or CSS plug, and it's always the same.
But others that have access to 125 amp 50 kW chargers report initial charging rates of 45 kWs. Even the 85 kW chargers in our area only provide 58 kW regardless of plug or vehicle.
The moral is that charging times are not black and white nor set in stone, and that your charging rate and time may/will vary.
In a test that I did with a 40kWh LEAF that I drove for 7 hours continuously, pausing only for three 45 minute quick charges (which is the default for a charging session with the EVgo chargers that I use.) I drove the car at speeds in excess of 80mph including into 35 Kt. headwinds, and noted that a 45 minute charge provided me fills of 92%, 88% and 62% percent of the battery. These sessions were 35kW/28kW, 32kW/24kW, and 18 kW/18kW. Each of the sessions started with a battery that was 20-22% charged.
During the 7 hours of the test the battery temperature went from one third of the normal range to mid-range for the first and second sections of the drive and then close to the first red mark on the last section before the third quick charge, and then after the 3rd quick charge the indicated battery temperature went back down to about 3/4 of normal. After the last session, I let the car sit for 30 minutes, and it was back to the mid range again.
This behavior isn't unique to the LEAF, to one degree or another it happens to all BEVs regardless if they are passively or actively cooled. It's part of each vehicles temperature management profile.
This is why I don't recommend any BEV for a long distance trip unless you have the patience for the extended charging times. It's not because the BEV is overheating or defective, it is doing what it is programmed to do, which is to taper the charge as the battery fills up or reaches higher temperatures, to protect the battery from damage.
Until BEVs can meet or beat the 80/400/30/30 rule, this will be the downside of trying to use a BEV for long distance travel. If you need to get from point A to Point B in a day which is more than 250 miles and insist in driving it in a BEV, then patience is the keyword.