HV Hybrid Battery Cooling Question

[jediboytj]

Hey guys!

 

I have a 2012 Lincoln MKZ Hybrid. I was reading about the way the HV battery is cooled, and how it uses the cabin air to cool it, rather than its own separate cooling system.

 

However, there are times when I like to just drive with no a/c and the windows down, even if its kinda hot outside (I'm in south florida). Is this possibly harming the battery? I figure if the battery was possibly "overheating", there would a message on the dash indicating so, and so far I haven't gotten anything. But I just got a little worried because of how often I like to run the car without a/c (also I tend to get 3-4+ mpg on trips when I don't run a/c).

 

I plan to keep this car for a very long time, and I just don't want to do anything that would harm the system. It still has 4+ years on its hybrid/battery warranty so I know I should be fine in this period, but I worry for after that warranty is up.

 

[lolder]

I'm in your same situation and do the same but when it gets over about 85º F., I usually put the AC on unless it's just a short trip. I wouldn't drive around a lot at 90. There are warnings and the HVB temp is monitored and there is a battery fan but i can hardly hear mine. I air a heat soaked car out with everything open for a few blocks and then turn the AC on. When in doubt, turn the AC on. A few extra bucks a month in gas is cheap insurance for a long HVB life.

[md13ffhguy]

I don't have a scientific answer, but I can't imagine that the battery requires AC cooling at any ambient temperature. If it does, it should be noted in the manual.

[corncobs]

I don't have a scientific answer, but I can't imagine that the battery requires AC cooling at any ambient temperature. If it does, it should be noted in the manual.

It's a very hidden and closed in space so the fan will help lower the temps which would otherwise be much higher the ambient. Even my lawnmower battery comes with a fan which is always one when charging.

[raadsel]

I'd be curious what the optimal temperature range is for the Lithium Polymer batteries most hybrids use. The closest I can find is this from Battery University, "All batteries achieve optimum service life if used at 20°C (68°F) or slightly below. If, for example, a battery operates at 30°C (86°F) instead of a more moderate room temperature, the cycle life is reduced by 20 percent. At 40°C (104°F), the loss jumps to a whopping 40 percent, and if charged and discharged at 45°C (113°F), the cycle life is only half of what can be expected if used at 20°C (68°F)." The issue with that is that the polymer can change the operating temperature of the battery. One of the big issues Honda has had with their hybrids is short battery life, though that was with NiMH batteries, and cars in hot climates appear to have fared far worse.

 

From what I've read, Ford has done quite a bit of heat testing of the batteries -- testing them in cars in Phoenix. From what I understand, even with the heat in Phoenix, the cars and batteries are engineered to give the batteries to try and ensure they will last a minimum of 150,000 miles and/or 10 years. Having said that, using your air conditioner to help keep the interior of your car cool should lengthen battery life.

[acdii]

Here is something to think about though, the AC uses power from the batteries so they draw and heat the batteries, and recharging heats them. Kinda funny when you think about it, turn on the AC to help cool the batteries the the AC is heating up. :) Anyhow, for long battery life it is always a good idea to keep them cool.

[billford]

I used a scangauge to check the HV battery, interior and exterior temperatures.

 

Not being scientific, but I found the hv battery temp stabilizes about 15 to 20 degrees above the interior temp. The last few days were warm and sunny, the interior was about 78 to 80, the hv battery just touched 100. This is with the windows open and ambient temp about 75.

 

After I turned the a/c on, it lowered the hv battery temp only a few degrees. This took at least 30 minutes on a city drive.

 

I didn't listen for the hv battery fan being turned on. I'll try that over the next few days. Also on the next hot day, I'm going to try and position the rear seatbacks forward, interested to see if that makes any difference in temperature.

 

I never had a dark car, my exterior paint is oxford white. Do you think that the white paint will help keep the interior and battery cooler when parked in the hot summer sun?

[Hybrider]

...

 

I never had a dark car, my exterior paint is oxford white. Do you think that the white paint will help keep the interior and battery cooler when parked in the hot summer sun?

 

The white paint will definitely keep all parts of the car cooler, when in the sun, than the darker colors will.

[billford]

Ford has done quite a bit of heat testing of the batteries -- testing them in cars in Phoenix. From what I understand, even with the heat in Phoenix, the cars and batteries are engineered to give the batteries to try and ensure they will last a minimum of 150,000 miles and/or 10 years. Having said that, using your air conditioner to help keep the interior of your car cool should lengthen battery life.

What if your car is just parked in the hot sun, interior temperatures can get pretty hot, do you think that will shorten battery life on its own? Maybe its best to keep the car covered when parked on hot days?

[Hybrider]

That is the main reason I leave so early for work, at 7am, is so I can beat enough people to work so I can get a spot in the covered garage. But the main reason I park in the garage is because the sun is so brutal on everything it touchs here in the Southwest: paint, cloth, vinyl, etc. I never really gave the battery much thought in that regards.

 

The sun here is so brutal, it can yellow a newspaper in a matter of hours, and start disintegrating the newspaper to a state of crumbles in a matter of days.

 

I once even had a rearview mirror fall off of the windshield while parked in a temperature of 100+° and in direct sun, because with repeated exposure, the sun basically caused the adhesive on the rearview mirror post to crystallize into powder.