Hybrid Battery Temperature Monitoring

[HeyBales]

The temperature of the stator in the drive motor may get too hot or much more likely somewhere in the electronics. Driving stop and go in "L" up to 60 mph will activate engine braking in 3-4 miles on no more than a few +/- 15 feet elevation.
Someone has posted that he leaves home and has a long downhill (3-5?) miles and his regen stops before he gets to bottom.

Easily because he reaches 70% HVB SOC going down that long hill.

I can reach that in 1/2 mile and have engine braking.

That's not temp anywhere being a limitation.

But temp's elsewhere might be interesting.
Except Mavster has reported how low the temps are towing a trailer uphill with the traction motor being used.
So I'm kinda doubting that as a reason.
But he's got those temps too!

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[Mavster Mechanic]

By indirect inference only, it seems like my battery coolant water is not circulating at below 120°F.

The water does not warm up.
The battery does not cool down.
I'd expect them to "meet in the middle" if circulating, but I never see that.

At the same time, no warning messages, lights, or codes. So no reason to take it to a dealer.

 

[Mavster Mechanic]

The Big Q:

Let's all agree for sake of (no) argument that 120°F is OK.

If it's a nice cool day, 60°F, and you have ability to cool that battery to under 100°F with very little energy or effort....

WHY WOULDN'T YOU???

 

[MakinDoForNow]

The Big Q:

Let's all agree for sake of (no) argument that 120°F is OK.

If it's a nice cool day, 60°F, and you have ability to cool that battery to under 100°F with very little energy or effort....

WHY WOULDN'T YOU???

If 120°F is ok why waste energy?

 

[Chops]

The temperature of the pavement in my town rarely gets below 60 but often gets above 120. Plenty of days above 150.

I’ll be lucky to get three years out of my 12V EB’s battery.

My pets sprint across the sunny pavement in my courtyard to reach the shady bits six months a year. Granted not a hot tin roof - but still very hot here. Not sure if it is ideal HVB environment here.

 

[Jasun]

111°F is nothing to worry about. Battery can handle up to 140°F before thermal management kicks in aggressively. Coolant following ambient is normal. I've seen mine hit 122°F on a hot day with AC blasting and heavy stop-go traffic. Still fine. Your numbers are textbook normal

 

[Cherokee]

All of this thread was about, “ textbook normal”
It seems.
The outstanding reliability, resilience and longevity of these hybrid battery systems should indicate no need to monitor temps at all.
This was a very interesting thread but I’d bet it’s perfectly safe to simply
Fagetaboutit and put all this energy into something else.

I have one last question for the Mavbrid guys.
Are there any visible heat sinks protruding anywhere ?
There’s a lot of air flowing under there when driving.
We used to clamp a small aluminum heat sink on our 540 electric R/C motors and greatly reduce motor heat.

A few guys heat sinked the battery back in the NiMi and NiCad days.

 

[Mavster Mechanic]

Yes. The point of this discussion is to figure out what is to be considered normal.

I am aware up to 120°F is "ok".

But seems a shame not to keep it closer to 95°F which would be easy on a 63°F day. It's just not trying.

FWIW the hybrids with NiMH batteries conditioned to 85°F using a Freon heat exchanger. (They would condition to 75°F if the driver had cabin A/C on.)

I'm just feeling "ok" ≠ healthy.

 

[Darryl]

I mentioned elsewhere one time at above 120°F I had no regen with "L" but still had regen using the brake pedal.

Still odd to me I saw no effort to cool the battery. I just had to wait for it to come down below 120°F by not using it for a while.

Has it ever gotten above 120? If so, does it immediately cool down to 120 or below?

 

[Mavster Mechanic]

Has it ever gotten above 120? If so, does it immediately cool down to 120 or below?

Just once (that I noticed).

Took some time to cool down under 120.
Maybe 5 minutes of gentle use while still driving. Like what natural cooling would look like.

I feel the battery coolant is just acting like a heat sink. Feels like it is not pumping / circulating. But I don't have proof.

 

[Ranko Kohime]

The Big Q:

Let's all agree for sake of (no) argument that 120°F is OK.

If it's a nice cool day, 60°F, and you have ability to cool that battery to under 100°F with very little energy or effort....

WHY WOULDN'T YOU???

I saw some mention of temperature specs in one of the posts in this thread, but I don’t remember exactly what it was, but I would expect 120° F to be optimal operating temperature for a Li-Ion battery. Currently sitting exactly there myself, or rather 49°C.

I definitely would not expect that to be a point of thermal throttling.

For comparison, my 2017 Toyota Prius with the li-Ion battery never once activated the cooling fan, which many people complained about since it is in the passenger compartment. I never had a thermal throttle event with it either, even when pushing it very hard on the battery.

 

[Ranko Kohime]

When I wrote that reply, the battery coolant was in the mid 30s, outdoor was 35°C. Now that the sun has gone down, 32°C outdoors, 43°C battery, and 40°C coolant.

 

[Cherokee]

I feel the battery coolant is just acting like a heat sink. Feels like it is not pumping / circulating. But I don't have proof.

No pump needed, the varying temp of the fluid would cause it to flow/move/circulate
Hot rises and cools down then falls etc ?

Or the coolant reacts as a heat sink due to its mass and thermal transfer properties.

Hahaha
I just made that up out of thin air!

Pretty good bullshit from an old fart that don’t know jack.

All you Youngers are going to really miss us old knowledgeable guys when we all die out.
You’re so screwed. Hahahaha.

Sometimes I scare myself :’P

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