Yesterday I was going on a small errand. I notice the car was weak off the line. Then I notice it would not go into EV even with a full battery (two below). I stopped at the ATM and left the car running. It never switched to EV. A few minutes later I was coasting without being on the gas (glide) and then it started engine braking really hard as the EV finally came on. Afterward it behaved normally. What could have been going on here? I am in Central Florida, it was hot but not crazy hot. We went on a long commute the prior day, one hour each way. I have never experienced this but notice it because it lack the off the line punch I was used to.
The A/C was going full bore so I could not hear the HV fan. This was about 5pm, car had been sitting outside from previous trip 5 hours earlier. I just hop in and go. Don't know if the heat and the 45 seconds it runs on battery could cause it to overheat. It was not an unusually hot day for Central Florida.
It does sound like an overheated battery. Or a condition where the car THINKS the battery is too hot. It appears that under certain conditions the software will lock out the battery to prevent damage.
how many miles on her? i have read that the car will repress battery usage if the temp is too high, until it cools down.
It's 110+ in the shade here and I've never had a problem, though we don't have the humidity Florida does. Maybe a sensor thought the engine was cold and needed to warm up or something.
I've been monitoring battery temp, and find a goodly drive in hot weather, then park for a bit, then start up again, yields the highest temperatures I've seen, around 46C.
I had a ELM327 (Bluetooth OBD scanner) in the glove box so I plugged it in afterward thinking it might be the 12v battery having low voltage. I'll make sure I make a screen with the battery voltage(s) so that I can check this if it happens again.
46°C is about when the ECU starts really protecting the battery. My personal observations in dealing with this for 3 summers now (all temps from BT2 battery temp sensor via ScanGauge II): Anything >40°C, I've observed reduced regen current during breaking, but regen demand is still honored. Anything >45°C, the engine will idle, and max 20A regen if B mode is used. Friction brakes engage immediately. Car is somewhat sluggish. Engine will return from higher revs very slowly unless in B mode. Regen demand isn't really honored. Battery allowed to discharge to 2 bars, and will only be charged at 20A or less by the engine. Fuel economy takes a hit. Anything > 50°C, the car will be very sluggish. A/C output will be cut to 0 watts during moderate acceleration for load shedding. Engine must spool up before any acceleration is given (surges, and weak performance). Little to no battery assist, except to run A/C. Engine will always idle. Battery allowed to discharge to 2 bars. Fuel economy takes a bigger hit. I've seen as high as 58°C this summer after parking in the sun 1-2 hours after a trip (battery chemically active). I'm not sure what would happen if it reached 60°C. Even at stop, the battery fan isn't running fiercely - only at speed. I help it out by running the A/C in fresh mode to help direct more cool air toward the rear of the car (forcing hot air out the rear body vents). I haven't yet determined if solar panel vent makes this better or worse.
it happened only once to me when my wife drove the car with her usual lead foot and parked in sun in mid day on a hot day. however, i observed battery fan at the highest speed all the time, this was the hint what happened. i doubt fresh mode helps (even though i use it all the time), as the battery exhaust is not sealed from cabin air. i like to think that my way of driving, pulse/glide with battery sparing, prevents battery from overheating (good MPG is a side effect).
While not perfectly sealed, cabin air is drawn in via the battery vent/fan from above the raised floor (right-rear seat), and exhausted below the floor and spare tire well, to which the only real "passage" out is the rear body vents.