hot ambient and charging

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Jan 6, 2022
Hi all, there's a few posts out here about the ambient temperature but nothing addresses if the car will charge when it's hot outside! I've tried a few times now this summer at over 105 F and keep noticing the charger stops or at least cycles between pause and charge. Once I parked over asphalt that was at least 150 F and the car quit charging within 30 mins.

Is it known that the car simply will not charge once the pack reaches a hot temperature? I see the posts say there isn't active battery cooling, but who knows? There is some sort of cooling fluid up front and lots of hoses and a radiator. They might be circulating coolant to the battery pack too. That's why I was hoping you can charge in the heat but am seeing it simply won't happen.

Maybe this is why the Tesla will make a fan sound while charging and our Egolfs are silent.
Motor and power electronics have a cooling system, but NOT the battery pack. You can look under the hood for yourself or look at car schematics - this is well known and not a mystery.

A charging station can overheat, the car’s charger can overheat (unlikely given the cooling system) or the battery could overheat.

I have seen a charging station (L1 unit included with car) overheat when it was in mid day sunlight on a warm day. Keep the charging station in the shade.

E-Golf is not silent when charging on a hot day - I have heard coolant pump running many, many times. FYI, e-Golf and Leaf are two cars produced in significant volume that have no active pack cooling - pretty much all other EVs have a pack cooling system. Tesla is not special in this way.

Every summer I take road trips where ambient temp is above 105 F and BMS reduces DCFC rate to around 25 to 28 kW instead of normal max of 39 kW. DCFC generates a LOT more pack heat than L2 or L1 charging, so I am skeptical that the car would interrupt a charging session at home.

The next time this happens, please check battery pack temps (using OBD dongle and software), on board charger and coolant temps, and also check your L1 or L2 station for overheating.
In fact, my e-Golf is not silent, when charging, even on mild days. I routinely hear the coolant pump(s) running, and have felt the flow in coolant piping feeding the OBC. I have not noticed the radiator fan come on during home charging, but it might happen occasionally. When I charge in 105 F heat on a road trip, I have the A/C running while charging, so there is plenty of noise under the hood from the radiator fan.
Thanks for the information. I'm technically savvy, yet never looked into where there are schematics of cooling system nor the way to plug into OBD port and read temperatures. Where did you learn how?

As for the cooling, yes I heard a humming up front from inside, so I guess that's the pump. But NO fan. Weird the fan won't run if the coolant is maybe 120 F and it's 110 F ambient. The radiator cannot do much to bring down the coolant temperature if there isn't air passing through it.
f1geek said:
DCFC generates a LOT more pack heat than L2 or L1 charging, so I am skeptical that the car would interrupt a charging session at home.

Hi, to be clear, I'm charging in morning on a Blink charger in the sun. Maybe it's the Blink L2 equipment (EVSE) now that I read how you charge in heat much faster than a mere 6kW
I'm an engineer and I like to know how mechanisms work. I routinely repair my cars myself and have been taking apart machines and repairing machines since I was a child (a long time ago....). If you visit a VW parts website, you can find schematics of the cooling system and you will see there is no connection to battery pack. Again, if you lift the hood and look for all the coolant pipe routing, you will see no coolant connection to battery pack, confirming the parts schematics.

I agree the removal of heat from the coolant is assisted by moving air over the radiator, but if there was only a temperature differential of 10 degrees F, it is possible the car computer decided it was not necessary. The e-Golf is a very efficient car, and it is possible the radiator still works very well without fan assist. It is also possible there is a problem with the radiator fan (though I suspect you would see an error code if that were true).

I have read that the early Blink charging stations are not very reliable. If the station was in the sun, it could have overheated. Maybe you should direct a fan at your Blink station. ;-)

I have Clipper Creek charging stations (LCS30-P and LCS40-P) in my garage and they have never overheated even in my hot garage, though as I mentioned before, the included TE L1 10 amp charging station did overheat in afternoon sun.