Using a campground plug

[mikeva]

I've tried to search on this question but I could not find anything specific.

If I am using a campground plug (14-50) and am concerned about the car drawing too much power for the fragile system, I've heard that I need to reduce the draw down to 30 amps or so. My question is how do I do that? Is that something I can control from the car?

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[tigerbalm]

I do it by using a specialised travel charger (https://www.mobilityhouse.com/int_en/juice-booster-2-master-traveller.html) which allows me to control what amps to draw - depending on the plug used.

I know of no way to control this from the car – unless it just knows what to do automatically.

 

[schad]

You should just be able to plug in your portable EVSE. RVs can and will draw a sustained 40A @240V (though they will do it as two separate 120V circuits) so the circuit should support an EV just as well.

But with that said, the electrical service at many campgrounds is dangerously substandard, so it would not at all be a bad idea to turn it down as low as you can tolerate.

Unless the electrical service is metered at your specific site (rare unless you're seasonal), be sure to talk to the campground owner or host before charging your EV there. They might ask you to do it for only a certain amount of time or at certain times of day. It's just common courtesy.

 

[benver]

If you use the Porsche mobile charger connect, you can configure the number of amps it draws from the mains. I also think the PMCC limits the maximum itself, depending on the quality of the mains.

 

[NC_Taycan]

But with that said, the electrical service at many campgrounds is dangerously substandard, so it would not at all be a bad idea to turn it down as low as you can tolerate.

This is exactly the problem.

The PMCC allows you to configure the charging current from the touch screen. I expect most other portable EVSE systems allow this as well. I would not travel with one that did not.

With the PMCC, the errors you will encounter at a campground (or track paddock) NEMA 14-15 outlet include unexpected shut-down, to ground fault, to poor mechanical connection (resulting in a very hot plug). Reducing the charging current helps in all cases. At the VIR paddock for example, I've never consistently been able to charge above 32A, but 28A seems reliable.

 

[mikeva]

My problem is that based on a number of positions taken on this forum --- I did not buy the PMCC but only have the PMC+ and the only option I see on it is 50% or 100%. while I will guess that 50% would probably handle the questionable 'flow' it will really increase the time.....

 

[kort]

FWIW: there is an app from www.rvparky.com that list camps that will let you charge. I haven't looked at it in years because these days there are so many places to charge that using a 14-50 and evse isn't worth the bother.

pro tip: most camp grounds have no idea what 14-50 means, just ask for 50 amp service.

 

[Jhenson29]

Is that something I can control from the car?

I know of no way to control this from the car – unless it just knows what to do automatically.

There is no way to control it from the car (only because Porsche didn’t provide one. Not because of any technical difficulties with it.).

I did not buy the PMCC but only have the PMC+ and the only option I see on it is 50% or 100%. while I will guess that 50% would probably handle the questionable 'flow' it will really increase the time.....

That’s correct. The only option for less current on the PMC+ with a 14-50 is to use the 50% setting.

 

[NC_Taycan]

There is no way to control it from the car (only because Porsche didn’t provide one. Not because of any technical difficulties with it.).

Not quite - the way the J1772 protocol works is that the EVSE advertises the current it can supply and the car controls starting/stopping the charging process. The car can't change the current consumed. This does not apply to the CCS port where the car can and does change the charging current.

Anyone with a Mustart or other recommended portable charger - can you change the charge current on those? From what I recall of the picture, there are no controls.

So perhaps there is a bit of guidance here - if planning to use a campground, track paddock, or other questionable quality grid, you want an EVSE that allows you to adjust the charging current. I wonder what would be the best recommended EVSE with this feature...

 

[Jhenson29]

Not quite - the way the J1772 protocol works is that the EVSE advertises the current it can supply and the car controls starting/stopping the charging process. The car can't change the current consumed.

My original statement is correct.

I’m aware the EVSE signals it’s max current to the car. Then the car limits it’s current draw based on that limit. If it didn’t, there would be no reason for the EVSE to send the signal in the first place.

And it must be this way. The EVSE cannot directly control the current. All it can do is send it’s limit to the car via the control pilot.

For a fixed voltage (EVSE) the load (car) will determine the current.

So, since the car can respond and adjust from the EVSE signal, it can also control and adjust from a user settable maximum.

*other than on/off via contactor

 

[NC_Taycan]

Still sends us back to this point though - we need a good portable EVSE with the capability to change the advertised maximum current to handle lower-quality grids.

 

[Klepper]

Not quite - the way the J1772 protocol works is that the EVSE advertises the current it can supply and the car controls starting/stopping the charging process. The car can't change the current consumed. This does not apply to the CCS port where the car can and does change the charging current.

Anyone with a Mustart or other recommended portable charger - can you change the charge current on those? From what I recall of the picture, there are no controls.

So perhaps there is a bit of guidance here - if planning to use a campground, track paddock, or other questionable quality grid, you want an EVSE that allows you to adjust the charging current. I wonder what would be the best recommended EVSE with this feature...

I have the Mustart Travelmaster charger. It has a maximum charger amps of 32. It will reduce the output based on which pigtail is plugged in. For example, if you plug the 14-50p pigtail in, it sends the max of 32amps. If you plug the 14-30p pigtail in, it sends a max of 25amps. If you plug in the 6-20p pigtail, it limits the output to 15amps.

So it’s the pigtail thats plugged in that signals the EVSE which amps to output. That’s the only way to limit the output.

 

[whitex]

For a fixed voltage (EVSE) the load (car) will determine the current.

The voltage does not have to be fixed. The EVSE advertises the available current (through the Control Pilot pin of the J1772) so the load (car) doesn't have to figure anything out, just draw less than or equal the advertised current, regardless of voltage.

 

[whitex]

There is no way to control it from the car (only because Porsche didn’t provide one. Not because of any technical difficulties with it.).
That’s correct. The only option for less current on the PMC+ with a 14-50 is to use the 50% setting.

Wow, Porsche really is new to EV's, or they are trying to milk it by encouraging people to buy the PMCC, or they are outsourcing their charger software and paying per feature and amperage adjustment feature on PMC+ was more expensive than 50%/100% setting. This is really surprising, since the car must always adhere to the EVSE advertised current, including changing it during the charging session, so the hardware capability to control the current is obviously already in the car.

 

[whitex]

I do it by using a specialised travel charger (https://www.mobilityhouse.com/int_en/juice-booster-2-master-traveller.html) which allows me to control what amps to draw - depending on the plug used.

I know of no way to control this from the car – unless it just knows what to do automatically.

A more affordable option (though with only Nema 14-50 cable):
https://store.openevse.com/collections/all-products/products/advanced-station
It's open source software and hardware too, in case you are inclined to tinker with it (you don't have to though).

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