KentuckyKen
Well-Known Member
Your hypothesis about how the FIt EV charged and PCs sounds reasonable. It would be as if at the end of charging when the charging tapers down there isn’t enough power to fully handle the rather high demand of the PC. So then it pulls from the battery. Poor design.I'll monitor it more closely. I had a Fit EV before my Clarity PHEV, and it would show 100% SOC after pre-conditioning, but it wasn't "real". You could literally drive a few miles and the range would drop like 10+ miles. It was a frequent loop to drop my kids off at school, so I had the opportunity to test plenty of times the affect with/without PC. The L2 charger (one that came with the car, forget what brand off-hand) would turn on when PC was turned on, but this is my guess only, the heater probably pulled directly from the car and the charger was trying to fill the car back up but when near 100% SOC the heater was pulling from the battery faster than the car would allow the charger to push energy back in, and the SOC meter didn't seem to pick that up if you weren't driving. Similarly, IIRC if you PC without a charger on car it would still show 100% SOC until you drove it even though clearly that wasn't possible.
I don't know if Clarity is set up same way rather than pulling 'direct' from the plug, maybe someone with access to Honda Tech can understand the schematics/programming enough to conclude?
I had gotten in the habit of charging to less than 100% and then turning on PC and charging before leaving which seemed to help with the issue with the Fit, and have done that with the Clarity sometimes too. Did it this AM, started at around 91% charged and cabin temp of 20's. Left home with 98-99% SOC and cabin temp of 70ish. Range showed 70 miles; 35 EV and 35 HV. EV did NOT appear to drop like the Fit used to. I used HV for a stint in the middle on the highway since it showed my EV wouldn't make it all the way. I missed the mark a bit b/c arrived with 2.x EV miles. On a 43 mile drive to work I ended up with a remaining range of roughly 20 miles, so original est range was about 10% off.
I've taken a few long trips with the car but haven't yet settled into the daily routine because of the charging issue at work but now the SB is done hopefully I am in the clear and can start so will keep an eye out. I need to watch total range and gas MPG too, because on my trip up to VT it seemed poor. When I fill up today will see what my HV range goes to, I think it will be in the mid-200's but I've seen people say 357 for theirs. I typically run the cabin around 62-64* and run 74mph on the highway for 1/2 the trip and roughly 45mpg avg speed (30 to 50) for the rest so not like I'm trying to make it summer time or go CRAZY high speed so would have expected the gas mpg to be higher. Maybe the cold affects that more than I imagined...
I’m not having this problem with my Charge Point Home level 2 EVSE.
When topping off a charge for a long trip, I started PCing when the taper was at a very low point (first small peak, then large PC peak), then the power spikes for the ~30 min of PCing. I left with full bars and 100% SOC on HL. Range was normal.

I have also PCed after charging is over and likewise left with a full SOC and normal range.

So it’s apparent that preconditioning uses well over a kWh with temps in the 30s F, and if it’s not coming from the EVSE, you battery’s SOC (and range) are going to take a big hit. I don’t know why yours is acting the way you describe.
Notes:
The time scales of the two graphs are very different. The first is just 30 min while the second is 7 hours.
In both, the preconditioning used about 1.3 kWh. This was with temps in the 30s F. I expect bigger draws as the winter gets colder.