Posts: 70
Joined: Fri May 20, 2016 12:22 pm
Location: The Valley of the Sun

The cooling problems continue

Sat Feb 27, 2021 12:17 pm

So, at this point we've replaced:
  • The AC compressor
  • The AC compressor harness/pigtail
  • Battery loop pump
  • Coolant Filter X2
  • Replace Chiller line X2
  • Replace Chiller block
When I last picked it up the tech had been unable to get the battery to go above 86F. That's while it's in the 60's outside. They put it on their L2 charger and called me to come get it. They felt confident it was solved after the chiller block replacement.

By the time I got there it had finished charging and was at 100F - it would have kicked on the chiller at 97F. I took the freeway route home, putting about 25 miles on it and had it at 108F when it was plugged into my L2. Again, while it's in the 60s for ambient temp.

A half hour later, it had climbed to 113F and stayed there while charging for about 2 hours. After that 2 hours it ran the chiller alone for another hour, during which the temp dropped to 111F and I unplugged it so it could ACTUALLY cool off and stop wasting electricity.

So, at this point I need to charge on L1 anytime my battery is anywhere near the chiller trigger temp, or it will start running the chiller and somehow adding thermal energy instead of taking it away.

I have a feeling I'm going to need to pull the battery or otherwise test the coolant flow through different parts of the system to see if something has gummed up.

Anyone have recommendations for in-line flow meters? Is it possible to even "get to" the coolant channels on the pack if I go through the effort of pulling it out?
2012 Candy Blue FFE
33.5kWh battery pack
CHAdeMO DC Fast Charging

Posts: 1129
Joined: Tue Aug 16, 2011 11:40 am
Location: Toledo, Ohio

Re: The cooling problems continue

Sat Feb 27, 2021 5:54 pm

Sounds like you may have a dead pump or clogged coolant filter. the battery cooling passages are practically foil thin metal plates sandwiched between the cells in the pack. taking apart the pack would accomplish nothing.

The battery loop also goes thru the charger. there are any number of hoses you could undo to very coolant flow but that would make one hell of a mess.
2014 Blue Candy FFE (since this forum doesn't allow BBcode in sigs)

Posts: 140
Joined: Thu Feb 21, 2019 11:46 pm

Re: The cooling problems continue

Sat Feb 27, 2021 11:42 pm

So just off the top of my head, has a vacuum air purge/coolant refill been performed? A large air gap in the coolant line might prevent sufficient coolant flow to cool the battery.

Also, I noticed that in my FFE, the solenoid for controlling the valve for the chlller refrigerant gets substantially hot. Stupidly hot. Might that solenoid have burned out? Is it hot or cold when the battery is to be cooled? This is the black "cube" under the coolant bottle.

So when the thermal management is supposed to be cooling the battery:
Are the pumps running? Check requested speed and measured/actual speed.
Are the valves in the correct positions? Check requested position and measured/actual position.
Is the A/C compressor running? Check compressor speed.
Is there sufficient coolant in the loop? Listen for the coolant pumps to go from a whine sound to a high speed rattle sound and then back to a whine sound. An air gap in the pump makes the rattle sound.
Is the temperature really hot enough to justify the cooling mode? Check the coolant into battery temperature vs the coolant out of battery temperature. If there is a large delta, the thermal management system is probably working. If the two temperatures are similar but low, like ambient, or if the temperatures are similar but high, like around 105, then the thermal management system is probably not working. Either not necessary (too low) or something wrong (too high)

You can check these parameters with forscan.
Good Luck!

Posts: 70
Joined: Fri May 20, 2016 12:22 pm
Location: The Valley of the Sun

Re: The cooling problems continue

Mon Mar 01, 2021 7:04 pm

The second filter replacement was one of the most recent things done. The solenoid has been checked this time and the previous. No indications of cavitation. Compressor turns on fine. The chiller and line are cold. Valves and diverters signaling as expected. No large delta, just "high". When it gets warm out for real, the car will stop giving me AC in the cabin because it's trying fruitlessly to get the battery temp under control. In the dead of winter I was actually able to get the battery hot enough to throw a "stop now" warning. The pump is running and the coolant has been totally drained and refilled by the dealer at least twice.

I figured, if I can hook into each end of the battery I could measure the actual flow rate and possibly back wash the coolant channels if they can't otherwise be serviced. Hell, if I can measure actual flow rate through the loop I'll be able to infer a lot more about what's happening. The pump and filter don't feel particularly cold - if not for that being the case before and after the filter swap if think it was the cause, but that's specifically why I had them change it.

Anyone know the locations of each temperature probe?
2012 Candy Blue FFE
33.5kWh battery pack
CHAdeMO DC Fast Charging

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