Battery cooling fan running while AC charging?

[jallen]

Hey all!

Admittedly only had my Lightning during winter-ish months so far, so I’m not used to warm batteries. However, today is the first time ever I’ve plugged my truck in at home, in my garage, and it sounds like cooling fans are running while charging.
What’s weird is the truck had not been driven for 5 hours, it was a high of 58 degrees today, and only AC charging at 32 amps. I’m not necessarily worried at all, just curious what “noises” and fans you all in warmer climates experience on a daily basis. Hard to believe my batteries needed “cooled” while charging today! Thanks everyone!

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[RickLightning]

Totally normal. Pumps, fans.

 

[Crilly]

Good

 

[TaxmanHog]

The first noise you may hear is the circulator pump, then as needed during warmer weather the chiller compressor and related condenser fan up front under the frunk will cycle as needed, more so at DCFC charging than home charging, at least that has been my experiences the last 8 months, all normal.

 

[jallen]

Thanks all. Figured it was all normal, just never heard it so far since owning. Interesting that a 58 degree day would need cooling. I bet some of you in warm climates hear it ripping away constantly!

 

[Calvin H-C]

Thanks all. Figured it was all normal, just never heard it so far since owning. Interesting that a 58 degree day would need cooling. I bet some of you in warm climates hear it ripping away constantly!

It can catch you off guard the first time you hear it. As a driver of a Ford Focus Electric for over five years, the AC charger on board the vehicle (I believe Lightnings have two to allow a higher AC charging rate than is practical for one - they make use of the single charge port) can require cooling at temperatures lower than one might expect. We've joked about how the car can be louder when it is charging than when it is actually being driven.

It's not hard to understand why. Our FFE can draw a maximum AC charging current of 30 amps. To change it to direct current, that 30 amps must pass through two diodes, each having a forward voltage of about 0.7 volts. 30 amps passing through a drop of 1.4 volts is 42 watts that has to be dissipated somewhere.

42 watts may not sound like much, but that power level has the capability of heating about 10 mL of water by 1 degree Celsius per second - that's about a third of a US fluid ounce about 1.8 degrees Fahrenheit per second. If the ambient temperature is low enough, the this heat gain will be balanced out with an equal heat loss without any further help.

At some point the ambient temperature is warm enough that the cooling pump must run to help remove that heat. A bit warmer, and that isn't enough, so a cooling fan may be needed as well. Any warmer and the chiller compressor is necessary to achieve the needed cooling.

 

[jallen]

It can catch you off guard the first time you hear it. As a driver of a Ford Focus Electric for over five years, the AC charger on board the vehicle (I believe Lightnings have two to allow a higher AC charging rate than is practical for one - they make use of the single charge port) can require cooling at temperatures lower than one might expect. We've joked about how the car can be louder when it is charging than when it is actually being driven.

It's not hard to understand why. Our FFE can draw a maximum AC charging current of 30 amps. To change it to direct current, that 30 amps must pass through two diodes, each having a forward voltage of about 0.7 volts. 30 amps passing through a drop of 1.4 volts is 42 watts that has to be dissipated somewhere.

42 watts may not sound like much, but that power level has the capability of heating about 10 mL of water by 1 degree Celsius per second - that's about a third of a US fluid ounce about 1.8 degrees Fahrenheit per second. If the ambient temperature is low enough, the this heat gain will be balanced out with an equal heat loss without any further help.

At some point the ambient temperature is warm enough that the cooling pump must run to help remove that heat. A bit warmer, and that isn't enough, so a cooling fan may be needed as well. Any warmer and the chiller compressor is necessary to achieve the needed cooling.

Thanks for the great explanation…I really appreciate it!

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