I will be interested to see the replies, but since that 8A/12A choice is made in the EV and not the EVSE, I think it will govern all AC Level 1 charging.

 

Okay, here's the post I found that mentions a 120V/12A limit.

EDIT: And here's a second one. Guess I'm just looking for confirmation (as the Tesla/UMC clearly has no such limit).

 

Correct on the 8 or 12A limit for 120V charging. Those are your only 2 options. To use this receptacle, you will need a TT-30 to 5-15 adapter.

On 240V, it's the minimum of the EVSE or 32A. I wish I could adjust the rate, like on a Model S.

 

I wish it would charge faster than 12A on 120V, but it just won't. As others mentioned, the car will limit you. Heck, 5-20 outlets are pretty common (120V / 20A, look almost like a standard 3-prong, but with the left hand port looking like a sideways T). It may not seem like a lot, but 16A is still 33% faster than 12A (more once you factor in overhead).

 

GM being GM really decided to play it safe with the Bolt, as I am sure they do with lots of their other vehicles in other ways. This is the same reason we have such an aggressive taper and low overall DCFC speeds. I wouldn't expect Tesla-speed charging in any GM EV ever.

 

Thanks everybody for the confirmation. A pity. I've gotten a simple adapter from TT-30 to NEMA 5-15 and added it to my travel kit.

 

I have an EVSE that has a programmable current. It is 240V nominally but I have tested at 120V via adapter. My 2017 Bolt only ever pulls up to 12A at 120V.

 

OK, that's the first time I have seen an actual confirmation of that. OpenEVSE by any chance?

Slight chance it might be worth trying in a 2020, but sounds unlikely. Once lockdown ends I may try a TT-30 to 6-20R adapter and an EVSE with a 6-20 plug that reports 16A.

 

The OEM EVSE has a 5-15 plug. So they assume you are going to plug in a 5-15 receptacle, which is 15A max. It is quite reasonable to limit the current to 12A for prolonged period of operation. I don't think you can get anything more than that, try as you can.

The only way one can get more juice out of the charger is to double the voltage. TT-30 won't do it as it is still 120V. It is no different from 5-15 in this regard.

Low-power as it may sound, a 5-15 or a TT-30 is still way better than nothing. Plugging in over night can give you up to 30kwh, or over 100 miles. Probably enough to get you to the next stop.

-TL

Sent from my SM-N960U using Tapatalk

 

The OEM EVSE has a 5-15 plug. So they assume you are going to plug in a 5-15 receptacle, which is 15A max. It is quite reasonable to limit the current to 12A for prolonged period of operation. I don't think you can get anything more than that, try as you can.

The OEM EVSE is in no way relevant, and its limitations are not relevant to this discussion.

By your logic of applying the OEM EVSE's limitations, the vehicle should never be able to charge at more than 12A from any source regardless of the capability reported by that source over PWM on the J1772 CP line.

Sadly, Chevy made the choice of ignoring the reported capability of the attached EVSE if it sees 120 volts, for no legitimate reason.

The only way one can get more juice out of the charger is to double the voltage. TT-30 won't do it as it is still 120V. It is no different from 5-15 in this regard.

Wrong. Watts = Volts * Amps

J1772 supports amperages significantly greater than 12 amps. This is obvious given that 12 amps corresponds to only 20% duty cycle on the CP line, and the fact that the car will charge up to 32 amps when it's not making boneheaded decisions to ignore the EVSE's reported capability via the duty cycle on the CP line.

Every component in the Bolt, and every component in the J1772 connector, is capable of 32 amps sustained operation.

Not crippling the entire system because someone made an EVSE with a 5-15 plug is the whole point of why a J1772 EVSE is required to report its continuous current delivery capability to the vehicle.

 

Let's hope someone comes up with a hack eventually...

 

This is the EVSE I have (although I didn't get it for this cheap!):

DUOSIDA 25 Ft Level 2 EV Electric Vehicle Portable Car Charger - 32-AMP 220-240V 7.68 kW, NEMA 14-50P - Includes Storage Case [E63G58P4] - $94.99 : elishops.com

elishops.com DUOSIDA 25 Ft Level 2 EV Electric Vehicle Portable Car Charger - 32-AMP 220-240V 7.68 kW, NEMA 14-50P - Includes Storage Case [E63G58P4] - Easy-To-Use - Simply plug into your NEMA 14-50 outlet to charge your electric vehicle. Can charge at 10, 13, 16, and 32 AMP. It can charge your...

www.elishops.com

It is programmable to advertise 10, 13, 16, or 32A. It comes with a 14-50 plug. The car obeys the advertised current limit when plugged into a 14-50 outlet.

I built a very simple 14-50 receptacle - to - 5-15 plug adapter. I simply left the "common" open, and connected one of the hot pins to common on the 5-15 side. So what would normally be 240V was only 120V.

So with the adapter, I tried setting the current limit to 10, 13, and 16A. The car obeyed 10A, but self-limited to 12 when given 13 or 16A.

I have never tried this on a TT-30, or a 5-20 for that matter. I haven't (yet) had reason to build the appropriate adapter.

NOTE TO THE CASUAL READER: I know what I am doing, and keep tight control of this adapter. It is dangerous in the wrong hands, since normally something plugging into a 14-50 expects to safely draw up to 50A, but it's really on a 15A circuit!

 

OK, so there's a slight possibility an EVSE reporting 24A from a TT-30 might see different results, but very unlikely.

There's also a slight possibility the 2020 might behave differently, but very unlikely.

It's enough that once I can get to a TT-30 (harder right now, I'm not sure if the CVSP ranger would be OK with someone requesting temporary 20 minute access to a campsite for an electrical test when the campgrounds are completely closed) it might be worth building a TT-30 to 10-30R adapter, but probably not worth bothering with an interim TT-30 to 6-20R adapter.



This is the first time I've seen concrete test methodology regarding this issue though, thanks!

Edit: For reference, I currently have a Mustart Travelmaster. It switches its reported current based on the plug attached (the only EVSE other than Tesla UMCs to do this to my knowledge?). For a 10-30, it does unfortunately choose 25A when it should be choosing 24... I am considering upgrading to a Tesla UMC as evseadapters can provide plug modules for the more esoteric plugs out there. I'm going to attempt to see what happens if a 25A current capability is reported to a 2020 whenever I can get to a TT-30 again.

 

In addition to that, for a long time, RV parks and electrified campgrounds were the best places for an EV owner on a long trip to get a charge.

Things have improved as DCFS rolls out, but back when Chevy made this decision in 2017, topping off at a campsite was still a widely known use case.

While 14-50 outlets are pretty common, there are LOTS of situations where the 14-50 sites are all booked up and you can only get a campsite with 30A service - which happens to also mean 120v.

Probably the best example of a "long roadtrip" report of a Bolt owner going to Canada had at least two examples where being able to charge at 24A from a TT-30 would've made a massive difference. (Also, it would be better if it were easier to find TT-30 adapters usable for EVs - RV TT-30 to 14-50 adapters won't work.)

(Side note: I wish Chevy had a better solution for "camping mode" than putting the vehicle in neutral and engaging the parking brake. Having the AC running while getting power from a TT-30 would be great at a campsite with one of those SUV tents.)

 

"For transformers like that, you want a pretty serious amount of over-rating of the equipment - even more than the 80% rule for connectors. I'd feel nervous even with a 5 kW unit given how bad their reviews are... And those are heavy. "
In another thread it was determined that a transformer capable of converting the output of a TT-30 to 240V/15A would weigh around 60 pounds!

 

Yeah, I use hospital-grade plugs in areas that have a lot of plug/unplug cycles (the kitchen!) and commercial grade everywhere else, whenever I change something, I upgrade it. Sure it's more expensive, but how much is your life worth? Or all the memories stored in boxes in your house? I spend more in heating in one month in the winter than I have upgrading the electrical sockets in my house over the past 25 years.

 

If I often used TT-30 plugs, I'd maybe consider something like this 10kW portable CCS charger: 10kw CCS Combo Portable Charger - EV Fast Charger - ShenZhen SETEC Power Co., Ltd.

In theory, you can use this to take in 120V@30A and then "DCFC" with that. Here's a demo of this thing (turn on auto-translate subtitles from German->English):

It looks like they're in the ballpark of a few thousand dollars, but could also be handy if you want to hack up a connection from a Tesla HPWC over DCFC, though might be worth getting the 20kW one if you're going to do that on an 80A one, which may or may not be possible with existing adapters.

 

TT-30 (120V 30A) can only deliver 120 * 30=3.6kW. In actual use it is probably 3kW max for prolonged use. You need a NEMA 14-50 at the least to make use of the charger's full capability.

Second thought. Is DCFC at 10kw worth that much trouble?

-TL

Sent from my SM-N960U using Tapatalk

 

The spec sheet says the maximum output is 20 amps. In my garage, even on 240 VAC, that would yield 400 V x 20 A = 8 kW max. I already get 7.6 kW into, and 7.2 kW out from my onboard charger. The Bolt gets its DC fast charge rates from high amperage, not high voltage.

 

The input and output specs are quite confusing. I pulled up the 20 kW unit:

20kw CCS Combo Portable Charger - EV Fast Charger - ShenZhen SETEC Power Co., Ltd.

For single phase it says that the input current is max 40 A and that the output current is max 40 A too. While the unit does meet the nominal 20 kW charging speed for DCFC, which is current measured at 500V: 40A x 500V = 20kW, A 240V input at 40A maxes out at 9.6kW. The maximum amperage needs to be at least 80A input, which is 19.2 kW @ 240V to make any sense.

ga2500ev

 

I see the point. You will need to go DCFC for that.

You properly have checked into a RV park for the night. The difference between 3kw and 1.2kw in 10 hours is 18kwh, or 70 miles ish. That makes difference.

-TL

Sent from my SM-N960U using Tapatalk

 

Second second thought. That unit costs $2500, weighs about 45lb, and comes from China. No thank you! The day I carry that thing around will be the day where Satan lives has frozen over several times.

-TL

Sent from my SM-N960U using Tapatalk

 

Second second thought. That unit costs $2500, weighs about 45lb, and comes from China. No thank you! The day I carry that thing around will be the day where Satan lives has frozen over several times.

It's certainly a very specialized piece of gear. Personally, I'd probably try to find places that have real 208/240V service over buying a big chunk of hardware like this, but I'll point out that they make gear that's designed to handle 200kW and have been in business for 15 years, so my expectation would be that they can handle the smaller designs. A UL listing would be ideal, but it's cheap for the price.

 

Last weekend, I finally had occasion to use a TT-30 outlet at an old campground. Operating at 120V, 12A, I got barely 20% charge in 9 hours, or ~1.3kW. I got more charge in 15 minutes the next morning at the DCFC... Are there any other EVs limited to 12A at 120V? Seems like an awfully stupid limitation.

 

What EVSE did you plug into it? I doesn't matter if the input has 1000 amps of current available if the EVSE advertises a max of 12A.

The maximum current is the minimum of the following 3 components:

1. The available input current of the circuit, at a 80% continuous power level.
2. The advertised maximum current of the EVSE.
3. The maximum accepting current of the EV.

For the TT-30 we have:

1. 24A, which is 80% of the maximum 30A of the TT-30
2. Unknown. It completely depends on the EVSE and its settings.
3. 12A @ 120V for the Bolt. No one has yet proven that the Bolt will accept 120V at any higher than 12A even if the EVSE advertises more.

All this to say that it likely isn't the TT-30's fault for the slow charging. My belief is that GM thought it was more important to not create a potentially dangerous situation by allowing more 120V current that what can by pulled out of an ordinary 120V wall socket. Personally, I think it's a mistake. At the minimum they should have allowed for a setting on the Bolt with a red "Are you sure" popup to set the max charge setting to 24A @ 120V. The car should not be the bottleneck here.

ga2500ev

 

i got one from a company called AEFA which have a specific TT-30 EV charger. Working well so far. It is not Tesla but works with all other EVs. I have not gotten it to work above 20 amps so maybe some kind of limiter but still better than using adapters etc.

 

I have not gotten it to work above 20 amps so maybe some kind of limiter but still better than using adapters etc.

If you've ever gotten above 12, GM must have changed behaviors in newer Bolts. On a 2020 or older, (do not know about '21 or '22 models...) you are stuck at 12A or less on 120v no matter what the EVSE reports.