Spare Mobile Connector a waste?

[doug]

Actually, (with a little help from Martin's blog) you can make really nice 24A NEMA 14-50 charger:

[noparse]

[/noparse]

Hmm... seem to have lost an image there.

Does the small enclosure in the center do anything besides generate the pilot signal? Is it adjustable?

 

[scott451]

Hmm... seem to have lost an image there.

Fixed.

Does the small enclosure in the center do anything besides generate the pilot signal?

No.

Is it adjustable?

No. It is set for the maximum current the cable can handle. I use the VDS or tattler to lower the current to what the outlet can support.

[EDIT: ***** bad info below ****]
Last night I tried modifying one of the cables to signal (pilot) 30A while connected to 120V. The roadster would not allow any current above 15A. So it looks like 15A is the max for 120V regardless of what is signaled by the EVSE.
[EDIT: ***** corrected info *****]
Switching one of the hot leads on on a 14-50 to neutral allows the car to charge off of 120V at currents higher than 15A (e.g. 40A) as signalled by the EVSE (pilot). As Don points out, you must set the "higher" current limit on the VDS before plugging in the cable.

 

[S-2000 Roadster]

Last night I tried modifying one of the cables to signal (pilot) 30A while connected to 120V. The roadster would not allow any current above 15A. So it looks like 15A is the max for 120V regardless of what is signaled by the EVSE.

Thanks for testing that.

Did you try setting the charging screen to a higher current limit? I seem to recall that you can set it higher somehow - but I've lost those notes.

In case it makes you feel any better, the J1772 standard from SAE doesn't specify any EV or PHEV charging level for more than 16A at 120V. Apart from RV lots, you should never find a 120V source that is rated above 20A (16A actual), at least not anything intended for electric vehicle charging. That is, until SAE changes the specifications again. 15A is still shy of the 16A you should be able to pull from a NEMA 5-20.

To clarify with more detail: J1772 specifies AC Level 1 charging as 120V at 12A (15A breaker) or 16A (20A breaker) and AC Level 2 charging as 208V to 240V at any current up to 80A (breaker per NEC 625). I'm not suggesting that J1772 is the be-all, end-all of specifications, but reading this does sort of make me not blame Tesla for staying away from anything over 16A when connected to 120V.

 

[donauker]

I am definitely also in the market for a Spare Mobile Connector. So anyone with a neglected one that is just taking up space send me a PM with your desired price.

 

[S-2000 Roadster]

I recall that the HPC was included with the original Roadster, but now the SMC is included with new Roadsters - does anyone remember when the transition occurred?

 

[vfx]

I recall that the HPC was included with the original Roadster, but now the SMC is included with new Roadsters - does anyone remember when the transition occurred?

At car number 214- even though it was paid for in advance

 

[donauker]

Last night I tried modifying one of the cables to signal (pilot) 30A while connected to 120V. The roadster would not allow any current above 15A. So it looks like 15A is the max for 120V regardless of what is signaled by the EVSE.

Interestingly enough I am currently charging my Roadster at 40A 120V. I modified my RFMC 14-50 connector by moving one pin to neutral and am able to charge. VDS is showing 40A 119V and TED Monitor shows 4.778 KW usage. But if I try to use the VDS to set a lower charge level while connected it only shows 12 and 15 as available but I can cancel and set other levels when the thumb switch is opened.

 

[scott451]

Interestingly enough I am currently charging my Roadster at 40A 120V. I modified my RFMC 14-50 connector by moving one pin to neutral and am able to charge.

That's exactly what I did on my 24A SMC.

VDS is showing 40A 119V and TED Monitor shows 4.778 KW usage. But if I try to use the VDS to set a lower charge level while connected it only shows 12A and 15A.

That Explains it... My last charge was 240V@13A (tattler cooldown). So when I plugged in the 30A charge cable, rigged to work on 120V, the VDS went to 13A. I used the "current limit" button, but I was only able to select 12A or 15A. Based on your post, I tried it again but I first set the current limit to 70A before sliding the switch. As you described, the charge went to 116V @30A. Nice find! I tried setting the current to 20A using the Tattler and it worked! It looks like the 12/15A current limit for 120V is enforced by the VDS not the PEM, so the Tattler can override it.

This is a great find because it seems like some restaurants use NEMA L5-30. And a lot of the computer rooms and lab benches use NEMA L5-30 too.

 

[doug]

I recall that the HPC was included with the original Roadster, but now the SMC is included with new Roadsters - does anyone remember when the transition occurred?

January 2009.

 

[donauker]

This is a great find because it seems like some restaurants use NEMA L5-30. And a lot of the computer rooms and lab benches use NEMA L5-30 too.

This also opens up 10's of thousands of TT-30's at all those smaller campgrounds which may not have 50 amps sites.

Not the fastest charge but certainly better then 15A. Of course with a simple adapter for the UMC/RFMC and the Tattler it also allows you to turn the same blind eye to the NEC that all those 50A RV's do when they use their adapter to plug in to that same TT-30.

But since those 50A RV's are not 240V but actually dual 120V the very common adapter for them will not work for the UMC/RFMC.

 

[Lloyd]

Here is an adapter also.

 

[donauker]

Any adapter specifying a RV 14-50 will not work. These adapters take the same hot input to both of the hot connectors on the 14-50 and tie the neutral to the center pin. This results in no power between the two hot pins.

 

[smorgasbord]

So when I plugged in the 30A charge cable, rigged to work on 120V, the VDS went to 13A. I used the "current limit" button, but I was only able to select 12A or 15A. Based on your post, I tried it again but I first set the current limit to 70A before sliding the switch. As you described, the charge went to 116V @30A.

I've noticed this behavior with the stock UMC with stock 14-50 adapter when the car's timer is waiting to charge. It's weird:

1) With charge port door closed, set the timer to midnight. Set the current limit to 30 amps on VDS.
2) Plug in UMC w/ 14-50 and engage switch.
3) Go to VDS and try to change the current limit to 40 amps or 24 amps. You can't do it. Matter of fact, you can only select something like 12 or 15 amps (I'll double check that part tonight).
4) Disengage the connector thumb lock and you can change the current limit.

This mirrors the behavior donauker and scott451 are reporting with their shopmade connectors, but I'm getting it on a stock connector, so it's not something they're doing. Any ideas?

 

[smorgasbord]

Actually, (with a little help from Martin's blog you can make really nice 24A NEMA 14-50 charger...

That's a bit too much circuitry and soldering for me. Is there a simple way to "hard-wire" the cable to a specific amperage and then rely on me remembering to dial down the limit via the VDS?

 

[vfx]

So what is the MPHc (charge) at 30 or 40 amps /120V?

 

[S-2000 Roadster]

Here is an adapter also

Ha! That product claims to be "Made with UL Listed components" but they would never get a UL Listing for the product itself. It allows you to plug a 50A device into a 30A circuit, and that is against code. GenTran risks some serious liability with this one.

 

[S-2000 Roadster]

That's a bit too much circuitry and soldering for me.

I haven't read Martin's blog because it's gone, but most of the wiring that people are discussing in this thread involves no circuitry and no soldering. Most plug and receptacle wiring is done with a screwdriver. On the one hand, I wouldn't want to encourage you to work with 240V or even 120V because you can kill yourself, but on the other hand this stuff is very simple.

 

[hcsharp]

Home made UMC

This is my homemade UMC solution. I find it much more practical than Tesla's UMC or any others that I've seen because I can select whatever current draw I want right from the control with just one button. It's much easier than using the VDS. There's no self-limiting based on which adapter so you have to know what you're doing, and therefore not recommended for just anybody. But the flexibility is really handy. Total cost was about $100.

Today as an experiment I set it for 48Amp on my NEMA 14-50 outlet. I monitored it constantly as it was only 2A shy of the breaker. The cable is rated for 55 amp and the plug for 50. I won't normally do this but it's nice to know it works. After about 15 min the breaker got a little warm but never hot. After 45 min I got tired of baby sitting it and changed it back to 40A by pressing one button - never got in the car. I'll remove the 60 and 70A options next time I update the firmware... I had them there just to test the signal. My next project will be a homemade HPC but it will cost about 4x as much money.

.

 

[scott451]

Today as an experiment I set it for 48Amp on my NEMA 14-50 outlet. I monitored it constantly as it was only 2A shy of the breaker. The cable is rated for 55 amp and the plug for 50. I won't normally do this but it's nice to know it works. After about 15 min the breaker got a little warm but never hot.

Nice work!!!

I've be using 48A for about a year (16K miles) on my modified MC240 cable, without problems. The key issue is not only the breaker, but the connection to the NEMA 14-50 plug. It needs to be really low impedance or else heat will build up in the plug contacts. I crimped, soldered and clear shrink wraped #6 AWG lugs and then connected them to the NEMA 14-50 plug. This creates a very low impedance connection to the plug.

In martin's RFMC design, he put a 90C temp cutoff switch in the plug to protect it from bad (old RV) sockets.

...I'll remove the 60 and 70A options next time I update the firmware... I had them there just to test the signal.

You might want to add 30A so if you use a J1772->NEMA 14-50 adapter on a blink/charge point charger, you can draw the full 30A.

...My next project will be a homemade HPC

You might want to consider using a RECON sealed 100-240V -> +5V converter as the main power supply. They are very small, cheap ($18) and if you seal the line-in connections, any water ingress will do minimal damage. An $8 +5V to +/-12 DC to DC converter provides the other voltages. (The tolerance on the regulator isn't that great, so you might want to convert to +/- 15V and then for another $1 linear regulate down to +/- 12V. Overall cost was $40 (add another $5 if you want the LEDs and a switch)

 

[TEG]

You guys might enjoy this topic too:
My Nissan Leaf Forum View topic - Weekend Project - J1772 Control Pilot