Speak EV - Electric Car Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
30 Posts
Discussion Starter · #1 ·
We had a Rolec EV charger installed around 2 years ago when we bought a Mercedes B250e.

Today I've had a second charger installed as we now have a Jaguar i-Pace as well. The NewMotion engineer told us that he has had to cap the current available to the new charger to 20A max as the total load on our electricity feed may exceed 100A if both chargers were being used simultaneously with other consumers.

The B250e has quite a small capacity battery, 28KWh, whereas the i-Pace is 90KWh. We've had the new charger installed where it's best located to suit where our i-Pace is parked, with the Mercedes continuing to be charged buy the Rolec unit.

Obviously if one of the chargers has to be de-rated we'd prefer it to be the Rolec unit that charges the Mercedes, rather than the NewMotion charger connected to the i-Pace.

The engineer explained that if the Rolec unit is de-rated to less than 20A (I guess 16A), then NewMotion can remotely remove the 20A cap, allowing the i-Pace to be changed with the full beans at 7Kw

Does anyone know how to safely do this, as I'd need to send a photo of the changed Rolec installation to NewMotion before they would lift the cap.
 

·
Registered
Joined
·
4,662 Posts
Yes. First off, is your Rolec tethered? If so you can adjust the apparent current limit of the cable by adding an extra resistor in. The cable ratings can be 32A, 20A, or 13A. It's anyone's guess if, when Rolec sees the 20A value, whether it offers 20A to car, or whether it offers 16A as that's a commonly known value. But the 13A value will defo offer 13 or a whisker less.
If untethered, this resistor is in the detachable cable, so cable swaps will defeat this approach. I assume your Rolec is the original dumb type? Like mine that's 5 years old. If so, these do not meet present safety specs. There's a video in here of one happily charging a car with the Earth wire detached and loose in the air!
A better solution that works with tethered or not is in a post by me somewhere here about a month ago. Spend £250, fit a Viridian controller from ecoharmony.co.uk plus their PEN loss detector option (£180 for this) . This can be set with dip switch to 16 or 32A. You can instead use an external tiny resistor to set to anything between 6A and 32A. Could fit a rotary switch and have a load of values, eg 6A for solar use etc. Send me a msg, am on useless tablet at the mo.
 

·
Registered
Joined
·
239 Posts
In the tethered version of the Rolec, the resistor goes between PX and PE on the unit. In the untethered version, those terminals are wired out to the type 2 socket to pick up the resistor value in the cable.

I've upgraded the firmware in my Rolec unit to OpenEVSE to make it controllable over the serial link. I put a wifi to serial device in the box and I can now enable and disable it remotely as well as issue a $SC command with any value from 6A to 32A. Cheaper than replacing the controller as long as you don't mind taking the front off it to change the firmware.

That said, it sounds like you need a permanent limit so changing the resistor is probably a more appropriate solution.
 

·
Registered
Joined
·
4,662 Posts
@barneyd does the modifying the code inside the Rolec apply to the ancient dumb Rolec controllers? Have Rolec upgraded theirs to a newer version to suit their smart ones, and that's the one you've been playing with? Just curious really. I think the OP needs something he can photograph as proof. At least with the Viridian latest controller, you just unclip the lid on top, set the dip switches for 16A, take a picture, & one of that page in the instruction PDF all about this, and clip the lid back on. There is then, of course, no visible proof of whether it's 16 or 32 inside, and you can flip the unit any time you want! :)
 

·
Registered
Joined
·
4,662 Posts
Here's the link to my recent upgrade to ancient Rolec. I think the OP should maybe consider doing similar. And if by chance the original blue-lettering Rolec RCBO is still in there, than that item needs to go in the bin asap & get a decent Garo or other good-quality make in asap!
Rolec Dumb Charger upgraded with DC Leakage Protection...

Here's a pic of the utterly cr*p original Rolec RCBO, and the way these fail, and the damage caused. These things must be binned, frankly.
137929
 
  • Like
Reactions: cah197

·
Registered
Joined
·
30 Posts
Discussion Starter · #6 ·
Thanks very much for your replies.

My wall box is a dumb tethered unit. I'm interested in the additional resistor, but NewMotion have said they want me to sent an image showing that the Rolec has been de-rated to less than 20A. Would sending a picture of the resistor in-situ be sufficient, or would it look like a 'dodgy hack'? I got the impression from the engineer that it would be, and I'm paraphrasing here, a simple case of removing one part (which has 32A somewhere on it) and replacing it with one that said 20A, or 16A. Is that not the case?

Thanks for the advice and link to your upgraded box Andy, but I'm not going to invest much cash on this as I'm happy for the Rolec to be dumb and permanently cranked back to 16A (I will add a note on the wall box saying so, so any future owners of my house will understand why their EV isn't charging very quickly).

I'll open up the box to see where PX and PE terminals are, but I'll need some guidance regarding the correct type and resistor value. While I'm in there I'll also check the RCBO type too!
 

·
Registered
Nissan LEAF30
Joined
·
6,727 Posts
Thanks very much for your replies.

My wall box is a dumb tethered unit. I'm interested in the additional resistor, but NewMotion have said they want me to sent an image showing that the Rolec has been de-rated to less than 20A. Would sending a picture of the resistor in-situ be sufficient, or would it look like a 'dodgy hack'? I got the impression from the engineer that it would be, and I'm paraphrasing here, a simple case of removing one part (which has 32A somewhere on it) and replacing it with one that said 20A, or 16A. Is that not the case?
It is the correct way of limiting the current that the device will output, but may not meet the requirements of the "engineer". They may require you to downrate the RCBO to 20 Amps as well - check with them as it is their rules that you have to satisfy.

Speaking out of turn, whilst I understand the purpose of the rules it all seems very much "worst case scenario" and if the NewMotion people want to avoid their installation causing an issue in the future they should include a CT clamp to restrict their product at that time.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #8 ·
Changing the RCBO sounds like it's the solution I'm after, but how does that work. If the car asks for more than 20A, then won't the fuse trip? Or is it the other way round, and the RCBO actually limits the max current that can be drawn by the car?
 

·
Registered
Nissan LEAF30
Joined
·
6,727 Posts
Changing the RCBO sounds like it's the solution I'm after, but how does that work. If the car asks for more than 20A, then won't the fuse trip? Or is it the other way round, and the RCBO actually limits the max current that can be drawn by the car?
No, the "fuse" will trip - but it might be the item that convinces the "engineer" that you have made the other changes. You still need the resistor suggested by @HandyAndy or to change the EPC to one that produces 16A maximum - but that is a very expensive component to replace. Is your unit tethered or untethered?
Edited - you mentioned tethered earlier on. You need a total resistance of 348 Ohms, but somewhere there must be a 732 Ohm resistance that you need to reduce by either replacing or adding another 660 Ohm resistor in parallel. Hopefully @HandyAndy will know as he has done this before on his.
 

·
Registered
Joined
·
4,662 Posts
@Milnei is yours a tethered unit? If so, you can fit the correct value for a 20A cable rating.
Technically this is not "Less than 20A", it's "Less than or Equal to 20A", but I think you'll get away with this 0.000001A difference! The (cable) resistor values are:
220 Ohms for 32A
680 Ohms for 20A
1500 Ohms for 13A
What you're looking for is this. Colours (right to left, sorry, should have turned them over!) are
Blue Grey Black Black and it's a 1% accuracy one, = far more accurate than the standard calls for (5%).
137932


Ping me a msg with yr address, I'll chuck you one on the post.
I like the idea of putting a 20A RCBO in, that's indisputably going to limit the current drawn! Excellent evidence.
Hard to see how you prove the ECU itself is 16A (the common value they'll expect to see), unless that's on the label itself outside. Which means buying an OEM Rolec 16A one (can't see any on eBay), and that's throwing good money after bad in my book. But they may be happy with 32A ECU plus 20A RCBO!
 

·
Registered
Joined
·
4,662 Posts
And providing you have this 20A resistor value in, the car will never ask for more than 20A from the EVSE, so the 20A RCBO will never trip. That's the theory.

In practice it won't work quite like this! I had 32A breaker in my CU, and EV charging at 31.5A. Fine for 20 mins, then the Breaker tripped for overcurrent, charging stopped instantly. Reason is, these RCDs (& I assume RCBOs as well) de-rate as bit as they warm up above 30C! And they do warm up, as they use a bimetallic strip to do the high current test, or maybe it's an over-temperature test. Whatever, mine derated to say 31A from the nominal 32A, and cut the charge. Solution was fit a 40A breaker (to match 40A RCBO already inside the Rolec) so everything that checked currents is rated 40A.

You could fit the 13A resistor, 1500 Ohms again a standard value, can send you one of those as well if you like. This will definitely not trip due to warming up at the limits of the current allowed! Sadly, there aren't any in-between values of cable resistances, I really wish there had been!
 

·
Registered
Joined
·
4,662 Posts
They've both got the Rolec name on it. Avoid. Period. No matter how cheap the price. At this point you need a proper sparky in here.

That said, I trust Viridian, they make & use good quality stuff. See page 2 of ecoharmony.co.uk "Components" sub-page. They show a Garo 16A RCBO 1P+N Type A Char C 30ma made by Garo, a reputable quality brand. Rolec buy cheapo from far east as far as we can determine.

My Rolec has a recommended-on-here Garo RCBO 1+N, 40A, char B.
So I don't know which of char B or char C is better, or what the difference is.

So you're after a Garo (or other reputable make, ask a sparky not me) 20A 1+N 2 Pole RCBO of some flavour. Try the search widget, search on RCBO should get discussions as I'm sure this detail has been answered recently in last month somewhere.
 
  • Like
Reactions: Milnei

·
Registered
Joined
·
239 Posts
@barneyd does the modifying the code inside the Rolec apply to the ancient dumb Rolec controllers?
Yes, mine was an original dumb one from 2014. I asked Rolec about upgrading to their smart version and they told me to buy a whole new chargerpoint. I was not prepared to replace all the perfectly working bits.

The Rolec smart unit is the same controller with new software and the addition of a Quasar GPRS modem. As I wanted to be able to connect to WiFi rather than pay for a mobile connection, that was another reason to turn down Rolec’s less than generous offer. Last reason was that I wanted to be able to remote control the charging current so I can enable solar diversion, which the so called smart unit cannot do.

I can’t claim full credit for the software, it is OpenEVSE. What I have done is port it so it runs on the Rolec hardware in place of their software.

Mine is connected to WiFi using an Elfin EW10 so I haven’t tested any other solutions but it should be possible to use an OpenEVSE based device to connect to WiFi, in which case you can use the OpenEVSE app or control solar diversion from Open Energy Monitor.
 
1 - 15 of 15 Posts
Top