Howdy,

New guy here. Love the forum. Many dumb questions to follow....

I searched, but didn't see anything so I'm going to ask;

Has anyone looked into using an automotive electric blanket for keeping the batteries warm? I thought I read somewhere that the battery pack in the 2nd gen Hybrids were more drastically effected by the cold. If that is the case, what about covering the pack with an electric blanket controlled by a thermostat?


Something like this:

http://www.jegs.com/webapp/wcs/store...53877_-1_11161

Just thinking out loud here.

 

I haven't run the numbers, but I strongly suspect that you would spend more energy to heat the blanket/pad that you would recover from the warm battery. I don't use a tank heater, but in my heated garage/shop the TCH will run the ICE most mornings just to get the catalytic and coolant up to temp, and the batteries warm up pretty quickly once they start charging/discharging.

 

Hey FastMover,

I haven't run any numbers either. But I suspect you may be correct. What if you used it like an engine block heater? Leave it plugged in over night, and not use it when the car is on?

Maybe the problem isn't as bad as I understand it. I've been known to fix problems that don't exist.

 

please don't take this the wrong way......





i gotta show this to the wife. she gave me crap for getting heating pads for the inside cats......

 

No offense taken. I figured I'd get some grief being this is my first post, and it's little out there.

But you have to admit most of the people posting here go through some pretty extreme measures to eek out that extra .2 MPG. I figured, I'd contribute to that extremity.

 

Even if you did eek out another 0.2 MPG.

The energy to run that heater had to come from somewhere.
I'd guess the overall carbon footprint is higher using such gadgets.

Just a guess though.
I'm not smart enough to run the numbers.

 

Not a bad idea. However...

All latest hybrids with NiMH packs are affected by extreme temperatures, that is true. But in colder temperatures the greatest offender is not the actual temperatures of the battery and the scaled down contribution of the hybrid's electric systems. Because most hybrids get their thermal management from the passenger cabin in addition to the heat that the power units produce, warming them up is not a problem at all. Even in -40F weather, they will warm up pretty fast sometimes with the help of a forced regen that is often induced to facilitate this.

By far, the biggest offender in low winter FE performance is the gas engine. That's is where the slightest inputs in optimization yield the greatest downstream benefits. If it is too cold, the gas engine will be running in closed loop longer and consuming more gas at least until it warms up. While it warms up the electric functions will be paired down regardless of whether the battery pack is warm or not. That's life. Also the battery temperature while significant, is not the only input the IPU uses to determine the electric state and functions.

So the best we can do in these extreme cases is to install and use a block heater. Taking it one step further by blocking the front grille will make it even better.

Besides, wrapping an electric blanket around the battery pack would be quite a feat since the space is tight, and almost off-limits without making some large "warranty voiding" changes.


Cheers;

MSantos

 

Ah well, just throwing it out there. Santos's explanation makes sense. I had read that the NiMh pack had more issues with the colder weather than previous packs. And this caused the ICE to run more to help regen the packs.

Meh. I'll go back to lurking now.

Thanks for listening.