For Traction Batt Fail - limp mode idea?

I don't have a definitive answer for you, but maybe I can fill some gaps.

I think it will put a stop to the hybrid system if either the battery or the inverter gets too hot. Same with the transaxle. If it was the battery getting too hot, I'd think you would have heard the cooling fan trying to cool it off. The battery would get hot if the cabin was hot or if the cooling fan wasn't moving enough air.

I'm more inclined to guess that it was the inverter or transaxle that got hot because of the high temperatures and low speeds involved.

Shorting (or cutting) the sensor wires would only make the computer think that the temperature had gone to infinity at one end or the other. Even if you could make that work, you'd stand a good chance of causing some serious and expensive damage by bypassing a system meant to protect some very expensive components.

 

Were you running the AC for your errands? The AC does use a lot of energy to keep the car cool. So when the AC is running the battery down to the point where the engine kicks in to recharge the traction battery, you use gasoline, hence your low MPG. That is something I experience a lot when I get out of work in the afternoon when temperature is usually in the 90's and with high humidity and with a few long red lights getting away from work.

 

if the engine starts, the battery is working. it may be limiting charge and discharge rates though.

hard to gauge all your parameters, but its probably fine.

 

It's summertime so we're getting a bulk handful of similar threads; hv bat overheats and ICE only propels. Pull over and put on Park, keep AC on, HV intake fan will suck in cool air into the pack. Once it's cool enough, you can drive with both hv bat and ICE together and not be a traffic hazard.

 

It was 104F on way back home today and still yield great MPGs with AC on w/intake mod

 

There’s one thing most people don’t know and don’t think of if you’re just a few ounces low on refrigerant the air conditioning programming does not know this when it looks at the sensor to see if the cabin has been cool enough based upon your temperature selected but because there’s not enough refrigerant we cannot meet these parameters so it tells the compressor to wind up its RPMs to work A little harder which uses more power and after a period of time if it still does not see that temperature has been satisfied it will wind up the compressor even more this is a never ending loop of self-destruction and low gas mileage . That was 33 miles to the gallon on my trip below with the air conditioning at the lowest setting with the fan speed at the highest setting over 800 pounds of tools and equipment inside the car over 500 pounds of tools and equipment towing a trailer with a oversized extra large roof rack on top. I have a little bit of experience with Prius air-conditioning and if I could tell you one thing for sure a few ounces of refrigerant make a difference in your gas mileage. And the longevity of your electric compressor it also causes your HV battery to cycle more often which also shortens the life of your HV battery over the long run .

 

That sounds plausible, but is it robbing Peter to pay Paul? I guess I'm at loggerheads with the lot of AC-to-cool-the-battery proponents here. My take, AC is a net minus in that endeavour.

 

With my mod, no winds for the last 7 work day commutes and same cruise control set points, I’m typically down 1 to 2 mpg loss overall with AC while hv bat remains in the low 80Fs range. 64mpgs with AC, 65 to 66 mpgs w/o AC. So Not that big of a loss of mpgs instead of letting hv bat go up to 100F +

 

I won't hurt to change it, but if it won't help. If it was clogging, you'd be having huge problems.

 

I use it to cool me. The battery gets cooled as a bonus. But w/o the A/C, I'd smell REALLY bad in short order. And so would the car. I'd also be minus a wife because there's no way she'd tolerate sweating like a horse for no good reason.