FalconFour
Well-known member
I've searched around a fair bit on these matters, and I think I might be onto something. I live in Fresno, where heat is a big concern for EVs like the Leaf. My 2013 Leaf S usually starts a morning at 6 temp bars, ends on the high end of 7, was even driving around on 8 not too long ago. No fast chargers (probably for good reason now that I consider it). Very few places other than home to charge. It's all environmental heat, and that poses an interesting set of conditions for experimenting.
The big problem is that the battery stores a lot of heat energy - a sort of napkin-sketch example would be to say it probably has 1 kWh of energy stored as a heat differential between the environment and the battery temp at night. So even though it's 70F outside, the battery might only get down from 100F to 90F by the morning, then back to 100 where it's driven and cycled, rinse and repeat. Not so great for lithium chemistry.
I also found that the motor/controller under the hood has a *very* bad effect on this, caused by its cooling system behavior. I went out to check on it today, after it'd been charging from 20% to 90% at 4kW, and found that under the hood was hotter than I'd ever felt it before! I'm talking ICE engine hot. But the fan wasn't running! I left the hood open and ran the A/C at 82 for about 20 minutes, which ran the cooling fans constantly with the A/C cycling on and off (slowly, with low heat output/power consumption). Only way I knew to get the fans to run. It cooled off the block to lukewarm temp, but during that time, you wouldn't believe how much heat billowed out from the hood before the air was cool again.
All that heat was typically stored in the car from night to night, which in turn transfers to the battery (which I'd think would be cooled by the chilly motor components). I would think the cooling fan would be running, at least at a low speed, while charging. Seems pretty obvious to me - laptops have done it from the start, even modern desktop PCs vary their fans as needed. With the concerns about battery heat and longevity, how could Nissan forget this important detail?
So, what I've been doing lately - before discovering the motor heat issue - I've been playing with placing ice-chest freezer blocks in the emergency disconnect switch box. There's a fairly large space in there to put them, and since cold air falls while heat rises, the cold air circulates and conducts through the metal of the battery pack, rather effectively using the ice to cool the battery overnight. That day I came home with 8 bars was when I started playing with the concept, and the next morning, I started off with 6 bars, only hitting 7 halfway through the day. It's only been a week, so I don't have much data to play with... but I figured I should get a topic and discussion going on this.
Anyone know how to kick that cooling fan on while charging? Maybe a command through the OBDII interface through the Leaf Spy app?
The big problem is that the battery stores a lot of heat energy - a sort of napkin-sketch example would be to say it probably has 1 kWh of energy stored as a heat differential between the environment and the battery temp at night. So even though it's 70F outside, the battery might only get down from 100F to 90F by the morning, then back to 100 where it's driven and cycled, rinse and repeat. Not so great for lithium chemistry.
I also found that the motor/controller under the hood has a *very* bad effect on this, caused by its cooling system behavior. I went out to check on it today, after it'd been charging from 20% to 90% at 4kW, and found that under the hood was hotter than I'd ever felt it before! I'm talking ICE engine hot. But the fan wasn't running! I left the hood open and ran the A/C at 82 for about 20 minutes, which ran the cooling fans constantly with the A/C cycling on and off (slowly, with low heat output/power consumption). Only way I knew to get the fans to run. It cooled off the block to lukewarm temp, but during that time, you wouldn't believe how much heat billowed out from the hood before the air was cool again.
All that heat was typically stored in the car from night to night, which in turn transfers to the battery (which I'd think would be cooled by the chilly motor components). I would think the cooling fan would be running, at least at a low speed, while charging. Seems pretty obvious to me - laptops have done it from the start, even modern desktop PCs vary their fans as needed. With the concerns about battery heat and longevity, how could Nissan forget this important detail?
So, what I've been doing lately - before discovering the motor heat issue - I've been playing with placing ice-chest freezer blocks in the emergency disconnect switch box. There's a fairly large space in there to put them, and since cold air falls while heat rises, the cold air circulates and conducts through the metal of the battery pack, rather effectively using the ice to cool the battery overnight. That day I came home with 8 bars was when I started playing with the concept, and the next morning, I started off with 6 bars, only hitting 7 halfway through the day. It's only been a week, so I don't have much data to play with... but I figured I should get a topic and discussion going on this.
Anyone know how to kick that cooling fan on while charging? Maybe a command through the OBDII interface through the Leaf Spy app?