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Charging two Teslas at once?

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We have an S and X and I found a 14-50 splitter that allows me to plug our 2 chargers into the one plug, then we just set the charge current to 18-19A on each car and charge overnight. For our normal weekly commutes that is more than enough charge rate to keep both charged. Rare occurrence of a big trip taking the charge on one to under 50A may take it a few days to catch back up to the 85% mark for the daily charge. Works for us as our daily commutes are only 70-80 miles. Was going to do the dual HPMC, but why spend $1k+ when I got the splitter for like $100 I think it was...
 
We have an S and X and I found a 14-50 splitter that allows me to plug our 2 chargers into the one plug, then we just set the charge current to 18-19A on each car and charge overnight. For our normal weekly commutes that is more than enough charge rate to keep both charged. Rare occurrence of a big trip taking the charge on one to under 50A may take it a few days to catch back up to the 85% mark for the daily charge. Works for us as our daily commutes are only 70-80 miles. Was going to do the dual HPMC, but why spend $1k+ when I got the splitter for like $100 I think it was...

What are you getting for miles per hour with this solution?
 
What are you getting for miles per hour with this solution?

Roughly half of the regular UMC at full power 40A from a 50A breaker. So what is that like ~14MPH.

I think the link below is the one that I bought, definitely beefy and well built, leads me to believe they used full size cables throughout even though you can't pull 50A off either split if both are in use...cheap solution as long as you don't need to charge more than half rate each night on each car. We have just left one unplugged and charged full rate on the other if we needed to, but that was like once in the last 2-2.5 years.
https://www.amazon.com/RV-Female-Li...qid=1549903935&sr=8-3&keywords=14-50+splitter
 
2018-01-05 14.30.56.jpg
Two HPWC's is the proper answer. If you have the proper #6 wire to the 14-50, you can go 60 amps (breaker) load share between the two HPWC's at 48 amps continuous. This is plenty for two cars to charge overnight. I charge our model 3 and S daily this way with no issues.
 
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View attachment 376302 Two HPWC's is the proper answer. If you have the proper #6 wire to the 14-50, you can go 60 amps (breaker) load share between the two HPWC's at 48 amps continuous. This is plenty for two cars to charge overnight. I charge our model 3 and S daily this way with no issues.
Are you trolling ?
#6 is just enough for 14-50 with 50A breaker, and #4 is recommended for in-wall wiring or longer runs. HPWC should never go below #4 due to 80A potential.
And then, 2 x HPWCs for $1K vs 2 x NEMAs for $50 to get roughly same charging rate ? OK...
 
Are you trolling ?
#6 is just enough for 14-50 with 50A breaker, and #4 is recommended for in-wall wiring or longer runs. HPWC should never go below #4 due to 80A potential.
And then, 2 x HPWCs for $1K vs 2 x NEMAs for $50 to get roughly same charging rate ? OK...
You seem confused. My Tesla-certified electrician used #6 for a 90’ run in ¾” conduit, with 2-place 60 amp breaker. This is standard for HPWC.

The Mobile Chargers max out at 32 amps, HPWCs are 48. That’s 50% faster not “roughly the same”.
 
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I just use the mobile connector from my S (gen1, so it charges at 40A not 32A) plugged into a NEMA 14-50 outlet and use that for both cars -- alternating them when they (rarely) both need to be charged at the same time.
 
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You seem confused. My Tesla-certified electrician used #6 for a 90’ run in ¾” conduit, with 2-place 60 amp breaker. This is standard for HPWC.
I can't comment on Tesla's standards, but given that their UMC adapters are massively overheating, I wouldn't rely on them.
If you're happy with the installation, that's only thing which matters. Just don't look into current rating tables, it may make you upset.
The Mobile Chargers max out at 32 amps, HPWCs are 48. That’s 50% faster not “roughly the same”.
Actually I should take it back. Lloyd is load sharing from 60 A breaker so momentary current is 48A only no matter how the HPWCs operate. NEMAs sitting on individual breakers doing 32A (40A on Gen1) each would total 64A (80A) which is 35% (65%) FASTER than his setup.
 
As much as I like our HPWC (we have only one Tesla) it is still a failure point that is without a quick fix. It would be prudent to install a 14-50 on the same line and placed next to the HPWC but only use one or the other. A visiting EV of a different brand would then have a charging option available too.

Just an observation when I see the neat double HPWC installations and consider the risk of them becoming bricks. Home charging needs to have high availability and hence a form of backup/recovery, in my opinion.
 
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If a wall connector bricks you can still plug the UMC into a 120volt outlet or something.

A 14-50 on the same circuit as a wall connector isn't legal even if only 50amps, unless maybe you have some sort of one at a time lockout.

What is more likely to fail a UMC running at Max 32_40amps all the time with an adapter connection and plug connection, or an 80amp capable wall connector running at half capacity or less with fewer connections?

14-50 takes an extra conductor, the "good" outlet is $70.
I really believe the prevalent fixation with UMC and 14-50 is false economy.
 
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The UMC with 14-50 is a backup plan and if it is on the same fused line as the HPWC there is nothing illegal. Overloading the wiring will trip the breaker as it should. It's no different than ten 15 amp receptacles on a single breaker. The user plugs in for convenience and if they overload the wiring the breaker releases.

My suggestion is simply to provide higher availability to charge should a HPWC fail. I need the Tesla to be ready to go every morning.
 
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Phase 1, Phase 2, Ground - 3 conductors like in HPWC.
50A industrial-grade NEMA 14-50 - $13 at Lowes.
All my setup with multimeter and 4' of #4 is probably within $70 you claim.
But this is not the point.
Both solutions have strengths and weaknesses. There's no "one size fits all".
For the people who only charge overnight, but appreciate more versatility, 14-50 is way to go.
 
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I can't comment on Tesla's standards, but given that their UMC adapters are massively overheating, I wouldn't rely on them.
If you're happy with the installation, that's only thing which matters. Just don't look into current rating tables, it may make you upset.
Not to belabor this, but the NEC rating table I see says:
#6 THHN Copper wire: rated at 75 amps.

So, no I’m not upset (yes THHN copper is what was used).
 
Very good you gentlemen have found the table. Now, how about reading it carefully.
#6 copper @ 75A will be generating 90 C / 194 F which is almost boiling water temperature. And it's for single wire in open air at normal conditions of 20 C / 68 F. Higher ambient temperature will directly translate into more overheating, and you're running two phase wires in tight conduit or jacket, basically doubling heat dissipation in almost same tight volume with much less air flow. Not even saying that you're wasting kilowatts of energy, it's sort of dangerous so you know.
And if you ever try your HPWC at 80A, with good chance overheating can cause avalanche effect with wire melting.
Of course you can always pay another $500 to the Tesla certified electrician to redo everything right with #4 when you finally need 80A.
 
Very good you gentlemen have found the table. Now, how about reading it carefully.
#6 copper @ 75A will be generating 90 C / 194 F which is almost boiling water temperature. And it's for single wire in open air at normal conditions of 20 C / 68 F. Higher ambient temperature will directly translate into more overheating, and you're running two phase wires in tight conduit or jacket, basically doubling heat dissipation in almost same tight volume with much less air flow. Not even saying that you're wasting kilowatts of energy, it's sort of dangerous so you know.
And if you ever try your HPWC at 80A, with good chance overheating can cause avalanche effect with wire melting.
Of course you can always pay another $500 to the Tesla certified electrician to redo everything right with #4 when you finally need 80A.
Who the H is talking about running at 80 amps? 48 amps with 60 amp breaker! Jeez I don’t know what your agenda is. The table says “”Raceway, Cable or Earth (Directly Buried). If you know better than Tesla, you should apply for a job with them

Signing off.