Voltage, amps and charging at 7.2 Kwh.

[JoulesThief]

If one has a Juice Box 40 Pro, I know if I plug in to residential 240V with the unit set at 40 amps on a 2015 SEL with the 7.2 kwh charger pack on board, I will get the full 7.2kwh with 240V at 30 amps.

My question is this: If i plug into a commercial receptacle that is running 208V, and still have the JuiceBox set at 40 amps, will I get 208V at 34.6 Amps, for the full 7.2kwh charge rate? Anybody know with certainty?

 

[phr00t]

I'd e-mail or call JuiceBox & ask what their device will do at that voltage. However, you also need to know what the outlet's amperage is rated... you don't want it pulling ~35A if it is only rated to 30A or worse.

 

[JoulesThief]

I'd e-mail or call JuiceBox & ask what their device will do at that voltage. However, you also need to know what the outlet's amperage is rated... you don't want it pulling ~35A if it is only rated to 30A or worse.

The plug is a 14-50 NEMA RV plug. That is rated for 50 amps peak, 40 amps continuous. No way to plug it into an outlet rated for less, unless I do some stupid math with some pigtail adapters.

What I don't know is if all NEMA 14-50 outlets are 240V, or are they also 208V commercial? An electrical Contractor would know.

 

[phr00t]

I thought your usual 14-50 RV outlet provides ~240v-250v... atypical for a 14-50 208v outlet... so, I'd be worried the amperage rating would be atypical as well. Here are some plugs for 208v with amperage ratings:

http://www.stayonline.com/reference-nema-straight-blade.aspx

18-50 & 18-60 are rated >= 50A.

 

[JoulesThief]

I thought your usual 14-50 RV outlet provides ~240v-250v... atypical for a 14-50 208v outlet... so, I'd be worried the amperage rating would be atypical as well. Here are some plugs for 208v with amperage ratings:

http://www.stayonline.com/reference-nema-straight-blade.aspx

18-50 & 18-60 are rated >= 50A.

That pretty much answers it... If I plug in a 14-50 at an RV park, I am almost guaranteed to get a full 7.2kwh charge rate with a Juicebox 40. If I am driving and getting 5.5 miles per kwh and putting in at 7.2kwh, and the batteries can take it at that rate, I wonder how many miles per hour I am really adding at?

 

[miimura]

The e-Golf will only pull 30 amps. If you plug into a source that is only 208 volts, maybe sagging down to 200 volts, you may get as little as 6kW. With on-board charger efficiency of about 85% (worst case) you will put only 5.1kW into the battery. With a driving efficiency of 4.5mi/kWh, you will get about 23 miles of range per hour in these conditions.

There is nothing that says a 14-50 outlet has to have 240VAC nominal. If the facility is on 208Y120V power, it will only have 208V available. However, most RV parks are on split phase power, not three phase, so they are usually 240V. With a driving efficiency of 5.5mi/kWh, you would get 240*30/1000*85%*5.5=33.6 mi/hr charging.

By the way, the calcs above (23mph) apply to public charging stations too. Most of those are on 208V and are on long circuits, so voltage sag to 200VAC is common.

 

[JoulesThief]

I don't think 208v in a RV campground, with voltage sag , would do a 15 btu AC unit on a motor home any good.

 

[phr00t]

I don't think 208v in a RV campground, with voltage sag , would do a 15 btu AC unit on a motor home any good.

15,000 BTU AC units are generally rated 115v @ 12 amps...

 

[JoulesThief]

I don't think 208v in a RV campground, with voltage sag , would do a 15 btu AC unit on a motor home any good.

15,000 BTU AC units are generally rated 115v @ 12 amps...

Yes, but compressor rotor lock up amps is what is needed to be known, as in under a full head of pressure at 100F ambient temperatures, after being cycled recently, and that will generally pull 60 to 65 amps at start up, and that is with a start up capacitor taking a big brunt of the start up load. I know of folks in RV's with a paired set of Honda EU2000i's, and 26.6 amps available at 128V that won't start an already run 15k BTU Dometic AC unit in hot weather. The RV crowd can tell you all about it.