Warm up the traction battery?

I do not bwlieve your premise is true, can you document where you got the idea that hybrid battery neefs to be warm?

 

I'm not so sure if it's true or not, but It seems when it's really cold mpg loss isn't all because the engine isn't running efficiently, the battery also isn't "running" efficiently when it's cold. And a heater may help.
For instance, I'll drive down the road when it's 25 degrees f out and for the first 5-10 mins the battery seems to not assist very much. But when it's 55 out, both battery and engine seem to work together sooner to run more efficiently down the road. So is this how your car acts?

 

It's not the battery. The engine and catalytic converter has to warm to operating temperature before the hybrid system kicks in full blast. It has to do with emissions and meeting California Emission Standards. I don't remember the specifics, but there are numerous past posts about it. Please don't try to warm up your battery, that is the opposite of what you want to do... Trust me on this!

 

I don't think keeping a hybrid battery slightly warm (probably not even warm, more like NOT super cold) in a cold climate is a problem..

 

Well, what do we know for sure?

The Hybrid System IS designed to primarily run the engine until the coolant is warm enough and the temperature of the catalytic converter is warm enough to maintain lower emission standards.

My feeling is this process, pretty much guarantees the vehicle---including the battery---will be up to temp before HSD is used fully.

Since the Hybrid Battery is located within the cabin of the vehicle, albeit in the hatch area, unless you are sitting motionless, running the engine with all the windows rolled down and perhaps the hatch open on a very, very cold day I don't see how the battery isn't "warm enough" simply as a process of the entire operation of the vehicle.

As has been pointed out, Toyota includes design additions (a fan) in an attempt to keep the battery "cool". I think summer concerns about keeping the battery cool much more valid than winter concerns about keeping the battery warm or "pre-warming" the battery. Infact, I can't remember ever really reading anyone with this concern.

The "vehicle" warms up. And in doing so this includes the hybrid battery. Not enough evidence, as well as the climate I'm living in is NOT that harsh, so this is an issue I'm not worrying about.

 

In my experience the battery is used extensively as the engine warms up using battery power to remove load from the engine as it warm up reducing emissions.
My situation may be different to many as I live near the top of a hill. My cold start consisting of rolling down the hill in EV mode "European model" fully charging the HV battery. The engine then starts at the bottom of the hill dropping out of EV then running mostly on battery power until the engine has warmed up.
It is possible that the battery being charged down the hill warms it slightly.

John (Britprius)

 

For those of us who have been observing live data via aftermarket gauges for many years, we can point out how Toyota simplies information down to the most basic... since they know those who are interested will seek out the real-world detail. After all, text descriptions leave much to be desired.

There are indeed aspects of warm-up at play, but the hybrid system is very much active the moment you start it... even after sitting outside all night with temperatures well below freezing.

 

i think someone in the pip forum put a blanket on his battery.

 

Am I to understand that the temperature of the "traction battery" dictates when the Prius enters "full hybrid operation"? I have always been under the belief that the Prius entered "full hybrid operation" only when the coolant reached a specific temperature. Hobbit wrote up a very lengthy article about the subject.

I am referring to the proverbial S4 Mode which the Prius enters into when it finally reaches the "full hybrid operation" aspect. At no time in the article is the traction battery temperature referred to.

But now today, I am reading that the traction battery temperature also comes into play? All I can say is this. The Prius is a complicated machine with many systems and subsystems. I do admit that resistance values do change when temperature changes. But to say that the temperature of the "traction battery" dictates when the Prius reaches "full hybrid operation" also known as S4 mode IMO is not correct.

Please refer to the link below in my signature file which explains the coveted S4 mode and what "full hybrid operation" really is.

 

In all the years I have been learning about the Prius, I was always under the impression that heat is detrimental to the health of the battery. Hence, the cooling fan. Also, heat is a natural condition that occurs in the battery as the chemical reactions take place during the charge/discharge cycle. This can occur for some time AFTER the vehicle is turned off. You do not want additional heat. I can tell you emphatically that warming your battery is NOT a good idea. Batteries that get too hot all have one thing in common, they prematurely fail!

I would think that in cold climates, an engine block heater would assist in bringing the hybrid system into S4 mode more quickly.

Also, in my 20 years of experience working on computers and servers, I have never had a failure from cold, only from heat. Obviously though, if it got too cold, condensation would be a bad thing... But, this is a motor vehicle, it is tested in extreme operating temperatures. I would NOT worry about the battery being cold. Unless you were frozen in an iceberg, I think the battery would be happy in a colder environment then in Death Valley.

PLEASE. DO NOT RIG ANYTHING TO WARM YOUR BATTERY. Just MHO!

 

Okay. I could be wrong when I say that the temperature of the battery is not a factor when it comes to complete utilization of the hybrid system. I am willing to admit that. I just think that trying to pre-warm the battery is NOT a good idea. How many pennies are we trying to save. It doesn't take that long to warm up! Also, we are not experimenting with a couple of AA batteries.

 

I think you'll find that the car's priority is to get the engine up to closed loop clean running temperature as soon as possible. It really is primarily a gasoline powered car.

The NiMh battery in the non-plug-in Prius seems to work fine when it's cold.

I'd leave well enough alone.

 

when the battery is cold, the software does not allow discharge as quickly as at higher temps.