Max Current input

[magudaman]

Does anyone know what the max current is for the FFE input? Can I use a juice box on a 120v 30a circuit and get 3kw? Can I charge on a 208v circuit and get to 6.6kw if it was a 40 amp pilot signal?

 

[sefs]

It appears the max the car will draw (as measured with a clamp on current meter) is about 30 Arms. It will not draw more current at 208 Vrms to maintain constant power, which means your charging rate will be slower on 208 Vrms than 240 Vrms. The max the car will draw at the level I range of 120 Vrms is only 12 Arms no matter what pilot signal the car receives.

 

[magudaman]

Awesome exactly what I was looking for thank you! I went to a charge point where I first saw a focus pulling 6.6kw about 1.5 years ago and I could only muster 6.1kw. Bummer. I have yet to find anywhere to do the full rate. My house is only at 5kw.

I need to see if there is already a feature request for the dash to show the current charge wattage. It would be good to know if I'm at 6.6 verse 5.6kw.

 

[magudaman]

So I am seeing a steady 5.6-5.7 at chargepoints around the bay area. This is a bit disappointing since 208v * 30 = 6280 watts instead I am only seeing about 27 amps. Even with crazy voltage drop 5.6kw/200v= 28 amps. But it seems to me that the system could be actually dropping the current for lower input voltages. Frankly I am disappointed I can't pull the 6.6kw pretty much anywhere except my home outlet.

 

[michael]

How are you measuring the power?

 

[magudaman]

The charge station by chargepoint send out that info through their app.

 

[paw160]

Most 30A rated units are really 30A peak and continuously draw something less than that (27A sounds reasonable).

At home you probably have a 240V circuit so 240x27=6480W. Public charge stations with 208 will have 208x27=5616W.

What is your continuous current for home charging?

Your numbers are not surprising. It's more a function of the operating voltage and not the current.

 

[magudaman]

Well the units used at most charge points output a 30 amp pilot signal. The data sheet says you need to run 40 amp breaker and they claim them to be 7.2kw (240v or 30a). It is just looking like the focus is running about 3 amps under what it should be. My home system is actually only a 20 amp continuous system (240v 30a fuse circuit), I am limited by our electrical box specifications. When I measured that with a high quality fluke clamp meter it showed 19.1 amps. So maybe there is just some fudge room in the focus.

 

[WattsUp]

Most 30A rated units are really 30A peak and continuously draw something less than that (27A sounds reasonable).

Actually, 27A isn't reasonable. It is actually considered unsafe.

The NEC guidelines say that any device drawing power "continuously" should do so at no more than 80% of the rated maximum of the circuit it is on. 27A is 90% of 30A, which violates the NEC. To avoid violation, any device on a 30A circuit should be drawing no more than 24A (80% of 30A).

For EVSEs, this means the best charging rate possible (safely) on a 30A circuit is 5.76 kW. (240V * 24A) For something higher, such as 6.6 kW, you really should be using at least a 40A circuit.

 

[JohnGarland]

It appears the max the car will draw (as measured with a clamp on current meter) is about 30 Arms. It will not draw more current at 208 Vrms to maintain constant power, which means your charging rate will be slower on 208 Vrms than 240 Vrms. The max the car will draw at the level I range of 120 Vrms is only 12 Arms no matter what pilot signal the car receives.

Thanks for this info. Is it possible the 30 amps was limited by your EVSE, not the charger on the FFE?

I have a 50 amp / 208 volt circuit at work. I was hoping my 40 amp jukebox would go up to 32 amps when hooked to that circuit in order to get the most I could out of the 6.6 kWh charger on my FFE.

Thanks for the input

 

[magudaman]

I'm pretty positive the limit is 30 amps. On almost all the charge points in Bay Area they are running on 208v and I never have seen more than 6.1kw ( usually 5.8kw) . I did how ever find one that was 240v and showed something like 7.2 kW. So that computes to roughly 30a.