Car Charger Voltage

Status
Not open for further replies.
L

Lizzy's Power Play

Member
Hello everyone.
Customer purchased high end electric car. Every time they plug the car into the 240v. 50 amp receptacle in the garage to charge the car, the voltage level begins to drop. The voltage at the breaker and receptacle is a steady 240v., until you plug in the car and the voltage drops and fluctuates to about 229v. within 10 seconds. This causes the built in car charger to stop working.
Circuit is fed from a 100 amp sub-panel in detached garage. Detached garage service is not new, its fed overhead from the house panel with tri-plex. Ground rod may or may not exist.
Power Company checked voltage at meter and its 240v., until you plug in the car and it drops there also to 230v.
Car company techs are there and they can't find a problem with the car.
Any ideas. Thank-you.
 
Sounds like the POCO transformer and/or the service entrance cables are too small to handle the large load from the car charger.

Power companies tend to size their transformers and conductors much smaller than we in NEC land would be allowed to do, and for the most part it works just fine. However, when somebody adds a large load like this it can cause excessive voltage drop. In that case, the only remedy is for the POCO to increase the size of the equipment supplying that service.

Who is responsible for paying for that increase in equipment size may vary by local policy. I would expect, though, that if the customer didn't increase the size of their service, the POCO would have to pick up the tab -- after all, the customer was already paying for 200 Amps (or whatever size the service is); he just wasn't using them all until now. :D But that's just a guess on my part.

P.S. Welcome to the forum. :)
 
Unless there is something else going on too, the charger cutting out based on 229 volts at its input does not seem right to me.
By something else, I mean for example a line voltage asymmetry with respect to neutral or ground, even if the unit does not draw power through the neutral.
Or a severe flat topping of the voltage waveform (as in third and higher harmonics). That could reduce the voltage available to the rectifier by a larger increment than the change in RMS voltage.
The car manufacturer should be able to give you more information about what can cause the shutdown. It is also possible that the charger goes through a set of current draw values before selling on the one that drops the voltage to 229, and the car then decides that is just not enough current.
In any case, the problem would be on the POCO side in some combination of undersized transformer and service wires.
With the open circuit (or low losd) voltage being 240, I doubt that POCO would be willing to just change voltage taps to increase the voltage.
The HO might be able to have a boost transformer installed at the charger, but the voltage drop seen by other loads would still be an annoyance.

Tapatalk!
 
GoldDigger said:
Unless there is something else going on too, the charger cutting out based on 229 volts at its input does not seem right to me.
Click to expand...
I agree. If the charger is rated for a 240V supply you might expect that it ought to be able to operate within at least a ?5% tolerance.
 
There is two separate issues going on.

1. Is plain ole voltage drop under heavy load. However don't chase that ghost as 240 to 229 is not much of an issue and well within +/- 10% that all equipment should be able to work with.

2. The real issue IMO is the charger itself. It appears it is tripping off line from under voltage. The charger should be designed to work on both 208 and 240 volt circuits. 229 volts should be no problem for it. In fact its range should be as low as 190 up to 270 volts for the simple fact it uses a Switch Mode Power Converter. Switch mode supplies if designed correctly can operate with a wide range of voltages of say 190 to 270 volt input.

One thing you might check is the operating manual for the charger as it might have a switch or switches to work on various voltages like 208, 220, 240......
 
Last edited:
dereckbc said:
There is two separate issues going on.

1. Is plain ole voltage drop under heavy load. However don't chase that ghost as 240 to 229 is not much of an issue and well within +/- 10% that all equipment should be able to work with.

2. The real issue IMO is the charger itself. It appears it is tripping off line from under voltage. The charger should be designed to work on both 208 and 240 volt circuits. 229 volts should be no problem for it. In fact its range should be as low as 190 up to 270 volts for the simple fact it uses a Switch Mode Power Converter. Switch mode supplies if designed correctly can operate with a wide range of voltages of say 190 to 270 volt input.

One thing you might check is the operating manual for the charger as it might have a switch or switches to work on various voltages like 208, 220, 240......
Click to expand...

I was thinking along the same lines. We have some rectifiers for communication sites that have selector switches for 208 or 240 built in. Or it could be a bad charger.
 
As others state, voltage drop from 240 off load to 229 under heavy load is nothing remarkable and should be expected.

I suspect that the charger may be defective, or wrongly set up or programmed.
Remember that the nominal 240 volts supplied from the utility could be as low as 228 volts at the service (95% of 240)
I would expect the charger to work correctly on a utility voltage at the lower end of the normal range, and with 3% voltage drop in the branch circuit to which the charger is connected. That would be about 220 volts.

If the charger is designed for the international market then it should work down to under 200 volts (220 nominal service, less several % drop in the branch circuit)

A low peak voltage due to severe waveform distortion could be a problem, but again the equipment should tolerate an entirely forseeable situation.

Do double check that it is in fact a 240 volt charger ! and not 277 !
A nominal 277 volt charger might well work on a 240 volt supply, but only at a full 240 v and not at say 230 volts.

Also double check that the charger is in fact tripping out on low line volts and not on some other real or imagined fault.
Ground fault ?
Battery temperature?
Thinks that the battery is already full ?
Parking brake not applied ?
 
high end electric car

Care to share the make?

May be some folks here who have specific knowledge of the type charger used since a follow on post implies it is a factor model charger that came with the car.
 
Any kind of fault indication on the charging station? Some units are very picky about the ground connection.

I've got a Clipper Creek unit for my Chevy Volt, and it's tripped a handful of times due to an air compressor starting. I figure it's some kind of voltage imbalance rather than a voltage drop (charger on 240V, compressor on 120v, but charger has never tripped on 208V)
 
Status
Not open for further replies.
Top