Hot temps and Prius battery questions

not exactly sure if it's the chem, the quality, or some other factors. but the consensus seems to be that the II was built like a tank to prove the reliability of the system, and the III was built to improve efficiencies and reduce cost.

 

It's not prius specific, but no doubt still applies.

Nickel–metal hydride battery - Wikipedia, the free encyclopedia

 

Friendly jacek, I kept trying, finally got the hang of XGauge entry, added battery temp!

Just went around the block a couple of times, one with windows up and AC (set to 25C), one with the system off and windows down.

Obviously a very small sample, dropped to 80F with AC (was 84F at the outset) and after AC shutdown climbed back to 82F. So there appears to be a cause-and-effect there.

Thanks for the tip, will be trying this out more, and exploring other XGauges I'm sure.

 

Have said this in another post, if you take it apart to clean it and you use compressed air hold onto the fan and don't let it spin. It can generate a current and blow its circuitry.

 

You can, but they don't feel pain!

 

I've also said this in another post. It cools significantly better if you set it to flow-through not recirc. Tested this and posted the results.

 

^ There's a temperature sensor somewhere in vicinity of the hybrid battery, and yes it's controlling the fan. It would only be for cooling.

 

How did you find the xgauge for the battery temp?? i have a scangauge 2

 

^ First hit if you google "xgauge".

X-Gauge Commands : Linear Logic - Home of the ScanGauge

There's a column down the right side of page, go to "Toyota... specific", and follow the trail. There's basically 5 entries you need to do. The controls on the Scangauge are rudimentary, but sufficient.

And first hit if you google "youtube xgauge data entry":

(The above was really helpful, nothing like a hands-on demonstration. The first steps, getting into XGauge entry were a little different for me, but similar. It's explained in the manual (paper or pdf).)

 

Awesome! learn something new today.. Thanks mendel.. now i have to find a good spot for the scan gauge lol

 

I must have misread something because I thought someone said just the opposite.

 

Now I have to find a good space for the second one..., once I load up all these XGauges. Just kidding, have just the one, so far...

It's a bit overwhelming though, looking through the available Xgauges. It's going to turn me into a hypochondriac, I think. Seriously, Inverter Coolant temp looks interesting, I might add that one next.

 

Where does the air to cool the battery go after it passes over the battery, and when there has been air passed over the battery where does the fan continue to draw from?

 

Not necessarily! Opposite opinions are not unheard of here.

What Feri said makes sense to me. If you set to flow through, the a/c fan will be drawing air from outside and slightly pressurizing the cabin. The air will need to escape from the cabin and will follow the easiest routes. If the windows are closed, the path through the battery fan may be the easiest route. You can think of it as a mild turbocharge for the battery fan!

 

That was my thinking all along until I read the opposite. I'm going back to using A/C the way I always have, recirc initially to cool down, then flow-through.

 

Does anyone know what constitutes good temperatures for the hybrid battery. I've added the XGauge for battery temp to my ScanGauge.

Highest I've seen is 86F, fairly extensive drive today, without AC. It often seems highest right at start up, when the car's been run for a while, then sat. I switched on AC once, but not for very long, and temp drop about 3F.

It was pretty mild temps, almost springlike, not really that hot. It seems like the temperature can be held pretty constantly around 84~86F, I'd assume due to the battery fan.

 

I am tracking BT2 battery temperature and BFM battery fan motor using a Scanguage II for last 8000 miles. AC on vs windows down does seem to help HV battery cool down, at the expense of a noticeably decreased mpg. If I am correct, The increased HV batter cooling is ultimately fueled by the increased gasoline consumption of the ICE --> mg1 --> DC-DC converter --> AC compressor.
Since BFM shuts off completely when the ignition is turned off, I have noticed the biggest spikes in HV battery temps after doing mountain driving in the summer, then stopping for 30-60 minutes to eat , after which I find BT2 at 44-48 degrees Celsius, which is quite high, but with AC on the BFM will kick in at level 4 and gradually decreases the HV temp to the normal 35-40 degrees Celsius range.
Bottom line: my experience confirms using AC as method to reduce high HV battery temps. (YMMV, but I would like to see empirical data from other folks.)

 

Make sure you have the current newest chips for your Scanguage II. I could not get mine to work until I sent my unit in to manufacture to be upgraded to the newest chipset for $25. Then I tediously used new instruction book and the Xgauge query codes given in that spreadsheet I found on Priuschat to program the new "gauges". I use BT2 for HV temp as that sensor runs hottest , and BFM to track the battery fan motor power setting from 0-6 on my Gen 3. It works well; I might be older and certainly less nimble than you!