HPWC wiring question

[CLLACAB]

I have a 2013 that came with the dual onboard chargers. I seem to remember that I should be able to charge up to 59 miles per hour with a HPWC. I just picked one up, which I think is a Gen 1 as it says use 3 gauge wire and I understand the newer one recommends 2 gauge. What size circuit do I need to put on my panel to get the maximum charging. I have a 200 amp panel and a subpanel in the garage.

Thanks,
Dave

 

[BrettS]

You need a 100amp circuit, which provides 80 amps to the car.

 

[bigdaddie]

I have a 2013 that came with the dual onboard chargers. I seem to remember that I should be able to charge up to 59 miles per hour with a HPWC. I just picked one up, which I think is a Gen 1 as it says use 3 gauge wire and I understand the newer one recommends 2 gauge. What size circuit do I need to put on my panel to get the maximum charging. I have a 200 amp panel and a subpanel in the garage.

Thanks,
Dave

You'll have to look at the instructions. I wired a Gen 2 HPWC with 3 gauge and a 100 amp breaker; however, a 80 amp breaker is adequate. Your 200 amp panel should be fine. I have a 2017 MS P100D with the dual chargers and the highest charge rate is 72 amps.

The question is what is the rating of your sub-panel? If it's 100 or more amps and it is the convenient place to tap the HPWC to, I would throw a 80 amp breaker and use 3 gauge wire from there, especially if it's a relatively short wire run. 3 gauge for 80 amps is still overkill. You can look here Ampacity Charts.

BD

 

[BrettS]

however, a 80 amp breaker is adequate. Your 200 amp panel should be fine. I have a 2017 MS P100D with the dual chargers and the highest charge rate is 72 amps.

The newer cars have a single charger. Either a smaller 48 amp or a larger 72 amp charger, like yours. In the case of the 72 amp charger you will need a 90 amp circuit to charge at the full 72 amps.

However, the OP has an older car with two 40 amp chargers and it can charge at 80 amps. For this you need a 100 amp circuit.

The electrical code allows for a continuous power draw of up to 80% of the circuit rating. For a 100 amp circuit 80% is 80 amps. For a 90 amp circuit 80% is 72 amps.

 

[CLLACAB]

When the subpanel was put in, the electrician ran 4 gauge for my Nema 14-50 and my L2 charger for my Volt. The good news is that he already ran all the conduit, so it is just a matter of pulling new wire through the conduit. The subpanel currently has the Tesla on a 50 amp circuit, the L2 on a 40 and my garage door opener on a 20. The Tesla and the Volt will overlap charging as they both are set to charge after midnight. So would a 100 amp from the main meet my needs ?

 

[bigdaddie]

When the subpanel was put in, the electrician ran 4 gauge for my Nema 14-50 and my L2 charger for my Volt. The good news is that he already ran all the conduit, so it is just a matter of pulling new wire through the conduit. The subpanel currently has the Tesla on a 50 amp circuit, the L2 on a 40 and my garage door opener on a 20. The Tesla and the Volt will overlap charging as they both are set to charge after midnight. So would a 100 amp from the main meet my needs ?

Yep, that's what I did. I had conduit running into my main from my garage for the solar. I had just enough space to stuff the 3 3 gauge wires through. Keep in mind the HPWC only uses 3 wires: L1, L2, and earth(ground). I had to buy an adapter to get the 3 gauge ground into the ground block. It does not use the neutral wire. Also make sure you tighten the lugs good. I had a charging cable error when I first tried my charger. It turned out one of the line wires was slightly under torqued. It didn't take much for the MS to pick up the errror.

 

[GSP]

@CLLACAB,

A 20 Amp breaker would be enough to charge your Volt at its 14 Amp max. This would allow an 80 amp breaker for your HPWC with only 100 Amp feed from the main panel.

With an 80 Amp breaker, the HPWC can charge at 64 Amps. This should be plenty fast enough for overnight charging.

You will need to change your L2 charger to not draw more than 16 Amps, or make sure you only use it for your Volt. Otherwise it will trip the 20 Amp breaker.

Whatever you decide you want to do, be sure to have a licensed electrician review your plan and do the work, or check your work if you do it.

GSP

 

[CLLACAB]

I am not adventurous when it comes to electricity. Licensed electrician all the way. So will the 80 amp circuit charging at 64 amps get me the 59 miles per hour charging level?

 

[GSP]

64 Amp charging will get about 47 mph. Not the full capability of the HPWC, but plenty fast enough for overnight charging.

My HPWC is on a 20 Amp circuit, charging at 16 Amps. More would be better, but given my limited daily use, it sill is enough to fill the car overnight.

GSP

 

[BrettS]

So will the 80 amp circuit charging at 64 amps get me the 59 miles per hour charging level?

No, you will need a full 100 amp circuit with 80 amps to the car for 59 miles per hour.

 

[CLLACAB]

Thanks to all for the information provided. All my questions were answered. One small correction: I believe that I have the newer HPWC as it says in the instructions that I have the ability to connect 4 chargers. I think this is only available on the newer model.

 

[gavine]

59MPH charge rate is overkill for home charging in my opinion. I’m sure there are edge cases where it comes in handy, but for the most part, 40A (29MPH) is plenty.

 

[Rocky_H]

Yeah, I don't get this beyond overkill attitude for overnight home charging. You sleep more than 1 or 2 hours a night, right? If you can't fit a 100A circuit in for the wall connector, a 60 or 80 would still be more than enough.