Home Wall Connector Installation - Circuit Breaker Size?

[Rocky_H]

When talking about a 90amp vs 100amp circuit for two chargers, I'm talking about the fact that the "max" for one car will be limited to 64 amps (72 amps - 8amps) if the other car is attached yet idle (given that idle car still grabs 8 amps, I've read). Going up to 100 amp circuit (i.e. 80% = 80 amps available) would solve this, as the max 72 amps would still be available for the car that needs it.

I do remember having heard about that--I thought it was 6 amps, but whatever. It still doesn't seem very relevant whether it's 64 or 72 amps. Even at 64A, for some period of time, it will still easily be able to refill over 200 miles. I still don't see any problem with 90A, but sure, 100A is more, and so is 150A.

 

[BluePhoton]

Here's what I found about moving from a 90 amp to 100 amp circuit for 2 HPWCs:
In my locality, changing to 100 amp circuit requires moving up to a 2 gauge wire = much thicker and harder to bend.
My electrician said #2 wire almost doesn't fit into HPWC.

So, since this is such an edge use case (Both connected: Model 3 idle, Model X needing extra-fast charge rate), I decided to just go with the 90 amp circuit.

BTW: Installation of both HPWCs with wires in wall and drywall repair = ~$1,300 (includes required local permit)
Better than next-best price by ~$500. = Pays to shop around!

 

[Krazaak]

Here's my planned scenario:
Two HPWCs for one Model X (72A max) and one Model 3 (lower max)

My question:
Is a shared 90 amp circuit sufficient or should I go with 100 amps?

Reasoning:
While the 90 amp is fine for just the Model X = 80% of 90amps = 72amps = Model X max.
Having another vehicle connected and idle reportedly takes 8 amps of current.
So, with a 90 amp circuit, it would seem I'm reducing my Model X charging by 8amps if the Model 3 is also connected and idle...

Moving up to a 100 amp circuit (providing 80 amps total available = 72 full to Model X, 8 amp idle to Model 3), would solve that issue, no?

Thanks!

Does an idle charger really draw 8A with a car plugged in or is the load sharing just holding it in reserve for the idle charger? Drawing nearly 2kW constantly while idle would be consuming more power than I actually use charging my Model X driving 2000 miles per month.

 

[elasalle]

Installing Wall Connector is gonna cost me like 1500. Not bad, but is it worth it for current Model 3 charging? (I already have a quote and have ordered the Connector.)

 

[davewill]

Does an idle charger really draw 8A with a car plugged in or is the load sharing just holding it in reserve for the idle charger? Drawing nearly 2kW constantly while idle would be consuming more power than I actually use charging my Model X driving 2000 miles per month.

Just holding it in reserve in case the car tries to energize the connector. I would have thought they'd have time to lower the other car down before honoring the signal to energize, but apparently not.

 

[Krazaak]

Just holding it in reserve in case the car tries to energize the connector. I would have thought they'd have time to lower the other car down before honoring the signal to energize, but apparently not.

Interesting, thanks. Will keep that in mind once I add the 2nd charger for the Model 3. If I need to charge at the full 48A, I'll unplug one or the other.

 

[Klaus]

Does an idle charger really draw 8A with a car plugged in or is the load sharing just holding it in reserve for the idle charger? Drawing nearly 2kW constantly while idle would be consuming more power than I actually use charging my Model X driving 2000 miles per month.

It’s not so much about idle charger power. When the car is done charging, opening the door or otherwise turning on A/C will draw power about that much.

 

[jtdiddy]

Yes, it really depends on your house. If you have plenty of capacity and a breaker box in your garage, that is going to be the cheapest install. In my situation the breaker boxes were in the basement, and I was already over capacity on my 200 amp service, so I ended up spending just under $10,000 to have the service to my house upgraded to 400 amps and a 100 amp circuit run to my garage from the basement including the required local disconnect and installation of the Tesla HPWC.

ouch, $10k??

 

[MerkinT3]

If i have a two-pole 50 circuit hooked up for the charger that came with the model 3 how fast should it be charging? i'm currently only getting a charge value of 7 miles for an hour of charge. Is there something in the charger box that needed to be changed? I read people are getting 37 miles value for an hour of charge. My 7 mi/hr 240v 8/8a is what shows in my tesla app. Was this some place in the manual and i need a RTFM cue?
Thanks,
Ralph

 

[P85_DA]

If i have a two-pole 50 circuit hooked up for the charger that came with the model 3 how fast should it be charging? i'm currently only getting a charge value of 7 miles for an hour of charge. Is there something in the charger box that needed to be changed? I read people are getting 37 miles value for an hour of charge. My 7 mi/hr 240v 8/8a is what shows in my tesla app. Was this some place in the manual and i need a RTFM cue?
Thanks,
Ralph

32amps max with that setup using gen2 umc...14-50 plug ...check setting in car what u have for amperage

 

[davewill]

If i have a two-pole 50 circuit hooked up for the charger that came with the model 3 how fast should it be charging? i'm currently only getting a charge value of 7 miles for an hour of charge. Is there something in the charger box that needed to be changed? I read people are getting 37 miles value for an hour of charge. My 7 mi/hr 240v 8/8a is what shows in my tesla app. Was this some place in the manual and i need a RTFM cue?
Thanks,
Ralph

Something is wrong, probably with the UMC. Try reseating the 14-50 adapter on the cable. If that doesn't fix it, you need to test with another UMC or another car...or take it in for service.

 

[Rocky_H]

My 7 mi/hr 240v 8/8a is what shows in my tesla app. Was this some place in the manual and i need a RTFM cue?

Heh, no, you get off without a RTFM, because there really does seem to be something wrong. The 8 amps used out of 8 available isn't a setting that should ever be showing there.