Using Gen 1 Tesla charger at 40amps

[HyFLYeR]

I just received my Rivian R1S last week and I’m looking to move my 14-50 NEMA to the other side of the garage to accommodate my 2015 tesla model S and R1S. I would like to use my Gen 1 tesla mobile charger to charge both. I purchased the Lectron adapter to be able to do this. So here is my question.

My current 14-50 NEMA plug is using a 40amp breaker with 8 gauge wire. When I move this box I am considering bumping up to a 50amp breaker with 6 gauge wire since this is acceptable for the 14-50 NEMA. I have a fairly new home with a 200a panel so I’m not concerned about the upgrade. What I am concerned about is the fact that I’ve heard of issues with running the Gen 1 tesla charger continuous at 40amps. Apparently it caused fires due to overheating. I just want to charge a bit faster if possible but not at the cost of causing damage to my home or vehicles. If it’s risky then I would just leave the 40 amp breaker and run 8 gauge wire to move my14-50 NEMA plug. Any insight on this would be truly appreciated. Thanks!

 

[ucmndd]

Use a high quality Hubbell/Bryant industrial outlet with properly torqued lugs and it’s just fine. There’s nothing wrong or flawed with the mobile connector itself.

 

[Cosmacelf]

Why not install a new J1772 EVSE for the Rivian? That way you don’t use an adapter.

 

[HyFLYeR]

Why not install a new J1772 EVSE for the Rivian? That way you don’t use an adapter.

I dont plan to charge both vehicles at the same time and it’s much more cost effective for me to just move the plug to the other side and possibly upgrade the breaker and wire. I have the charger for the rivian but it maxes out at 32amps. I don’t have a reason (and possibly space in my panel) for another charger. Just want to know if I can push the tesla Gen 1 charger to 40amps or not…

 

[Cosmacelf]

I dont plan to charge both vehicles at the same time and it’s much more cost effective for me to just move the plug to the other side and possibly upgrade the breaker and wire. I have the charger for the rivian but it maxes out at 32amps. I don’t have a reason (and possibly space in my panel) for another charger. Just want to know if I can push the tesla Gen 1 charger to 40amps or not…

So, yes, running the gen1 EVSE at 40A works fine (just change the dip switch settings). I just don’t like using adapters for a permanent charging setup if it is at all avoidable. Just one more connection to possibly heat up.

 

[ucmndd]

So, yes, running the gen1 EVSE at 40A works fine (just change the dip switch settings).

There are no dip switches in the gen 1 UMC.

 

[HyFLYeR]

So, yes, running the gen1 EVSE at 40A works fine (just change the dip switch settings). I just don’t like using adapters for a permanent charging setup if it is at all avoidable. Just one more connection to possibly heat up.

I agree. Not ideal. Realistically, if it’s a problem I can just use the Rivian mobile charger instead but I don’t like that it only charges at 32amps. 16 miles an hour is meh… I will have to live with it though if that’s the case.

 

[Cosmacelf]

There are no dip switches in the gen 1 UMC.

ugh, I had made edits after I realized we were talking about the mobile connector and not the wall connector, but the edits disappeared.

My edits would have said:

Be careful with the gen1 nema 14-50 adapter, as it was prone to heating up and melting (even the newer one with the non black face).

I don’t like using the portable EVSEs for permanent charging. They aren’t built as robust as wall connectors. And you’ve got that extra 50A receptacle that can be a failure point.

Also:

if you send us pics of your panel, chances are we can recommend a way to put in a new double breaker for a second EVSE.

 

[ucmndd]

Be careful with the gen1 nema 14-50 adapter, as it was prone to heating up and melting (even the newer one with the non black face).

I don’t think the UMC itself was ever a particular problem. The issue is that cheap outlets with poorly torqued lugs heat up and end up melting the UMC along with the outlet.

To be fair this happens because the gen1 UMC doesn’t have a heat sensor in the plug head like Gen2 does - but I’m not aware of any particular design flaw in the UMC itself that causes IT to melt in absence of another problem.

I don’t like using the portable EVSEs for permanent charging. They aren’t built as robust as wall connectors.

Meh, I guess. I’ve put many many megawatts through my Gen 1 UMC over the past 6 years and 170k miles and it works just as well as it did on day one.

 

[islandbayy]

I just received my Rivian R1S last week and I’m looking to move my 14-50 NEMA to the other side of the garage to accommodate my 2015 tesla model S and R1S. I would like to use my Gen 1 tesla mobile charger to charge both. I purchased the Lectron adapter to be able to do this. So here is my question.

My current 14-50 NEMA plug is using a 40amp breaker with 8 gauge wire. When I move this box I am considering bumping up to a 50amp breaker with 6 gauge wire since this is acceptable for the 14-50 NEMA. I have a fairly new home with a 200a panel so I’m not concerned about the upgrade. What I am concerned about is the fact that I’ve heard of issues with running the Gen 1 tesla charger continuous at 40amps. Apparently it caused fires due to overheating. I just want to charge a bit faster if possible but not at the cost of causing damage to my home or vehicles. If it’s risky then I would just leave the 40 amp breaker and run 8 gauge wire to move my14-50 NEMA plug. Any insight on this would be truly appreciated. Thanks!

Use the original Gen 1 UMC at 40 amp only when ABSLUTELY NECESSARY to get desired charge before needed. For all other times, keep it at or below 32 amps.

The reason Gen 2 is limited to 32 amps, is due to heat build up at 40 amps killing UMC's.

Some side notes, I went through about 15 UMC's (Under warranty). Always had them at 40 amp. Since lowering and maxing at 32 amps, I'm on the same one for 6 years now.

 

[ucmndd]

The reason Gen 2 is limited to 32 amps, is due to heat build up at 40 amps killing UMC's.

Proof? Authoritative statements like this should have some available documentation.

Some side notes, I went through about 15 UMC's (Under warranty). Always had them at 40 amp.

Something else would almost certainly have to be wrong for that to be true. I’ve used the same one every day for 6.5 years and more than 100,000 miles of charging.

 

[Rocky_H]

What I am concerned about is the fact that I’ve heard of issues with running the Gen 1 tesla charger continuous at 40amps. Apparently it caused fires due to overheating.

That is a real, legitimate concern. I rarely heard of actual fires with these, but several where the adapter plug melted onto the fitting part of the UMC. The pin/sleeve connectors they used in that were pretty small, and probably a bit undersized for heavy 40A usage. They had similar problems with the old wall connectors running at 80A continuous too.

There’s nothing wrong or flawed with the mobile connector itself.

I don’t think the UMC itself was ever a particular problem. The issue is that cheap outlets with poorly torqued lugs heat up and end up melting the UMC along with the outlet.

Yes, there really were some problems with it. Outlet problems were a common thing too, but that interface where the adapter attaches to the UMC was marginally built and kind of a weak point, and some people saw blackening and melting there before it became a fire.

Meh, I guess. I’ve put many many megawatts through my Gen 1 UMC over the past 6 years and 170k miles and it works just as well as it did on day one.

I'm still using my Gen1 UMC from over 9 years ago too, but I heard about these melting problems early on, so I have only very rarely run it at 40A. I have kept it at about 31A for most of its usage to keep it from being that hot and to extend its life. And now I am using it with a 14-30 adapter so it's running at 24A.

 

[dwbv]

I always thought the 80% rule applied for most, if not all, electrical throughput in the home? I got both a gen 1 and 2 mobile charger when my P85D was shipped to me. I keep the gen 2 with the car and the gen 1 is charging at 24amps X 240 volts max. I've tested 32amps and it warms up too much for my tolerance. I tested 40amps and quit after about 15 minutes when it got too warm for my comfort. 24 seems to be the sweet spot; yea, it doesn't charge as fast but my house will less likely burn down.

Everyone has their own unique scenario and needs. My work commute is only 20 miles round trip so being plugged in 24/7 affords me plenty of range plus I have ICE backups but it may be different for others.

My electrician told me that those extra time saved by charging faster is not worth the potential consequences. I took his advice to heart.

 

[beatle]

Use the original Gen 1 UMC at 40 amp only when ABSLUTELY NECESSARY to get desired charge before needed. For all other times, keep it at or below 32 amps.

I do the same thing now. I melted my original 14-50R after 26 months of use @ 40A. Receptacle was a cheap Leviton from Home Depot. I also found my breaker tripped from heat a few months later. Though I really reefed on the connectors in their original install, only unplugged the UMC 2 or 3 times in those 26 months, and mounted the UMC it to the wall in such a way to offer strain relief on the plug, I suspect the terminals loosened just a bit from the heat cycles. I've since replaced the receptacle with a Utilitech, replaced the 14-50P adapter on the UMC, retightened the screws at the breaker, and I only charge at 32A now unless I need the speed boost for some rare reason.

 

[OrbiterTI4]

Do we have any data on how long the charging sessions were for Gen 1 chargers @ 40A that led to melting?

I've been using my Gen 1 mobile connector w/ NEMA 14-50 adapter @ 40A as the primary charger the entire (nearly) 8 years of having the car, no signs of melting/heat, BUT my sessions tend to be 2-3 hrs every couple of days with a rare 4+ hr session here and there. Occasionally I'd check and feel warmth but never "ouch" levels of heat.

 

[dwbv]

Do we have any data on how long the charging sessions were for Gen 1 chargers @ 40A that led to melting?

I've been using my Gen 1 mobile connector w/ NEMA 14-50 adapter @ 40A as the primary charger the entire (nearly) 8 years of having the car, no signs of melting/heat, BUT my sessions tend to be 2-3 hrs every couple of days with a rare 4+ hr session here and there. Occasionally I'd check and feel warmth but never "ouch" levels of heat.

It was never "hot" but too warm for me after only 15 minutes or so at 40amps. For me it was a "nope". At 24amps, only suttle warmth after hours of charging.

My gen 1 charger is plugged in 24/7 set to 50% max so I don't even want to think about it therefore 24amps is fine with me.

I'm also curious about what other variables played a part in the melting: poor installation, undersized wiring, cheap receptacle, etc.