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Discussion Starter #1 (Edited)
Had a couple of people quote for the OLEV subsidised home charger installs , (£470 and £270) but they would only install them where I didn't really want it (ok didn't want it at all where I couldn't get my car to it etc) I would like to either buy a used one and install it myself (only 16A required anyway) or build one. The installers were unable to give me any info as to the ability of turning down the max charging rate to 10 amps or under. They didn't seem to know what kind of contoller they had in side (anyone know?) I heard of some of the controller modules (Viridian etc) being able to instruct a Leaf to only draw up to 7 amps, (230v) maybe someone can confirm this. This would be ideal for me as a: I don't have the 3 pin charger b: I only use a car about 2 or 3 times a week and under 50 miles a week generally. c: I have solar PV but only 2000W peak (so generally a LOT less than 2000w available.)

So at least if i build my own I know i can tweak the charge rates. (IF anyone can tell me how many different charge rates the leaf onboard 3.3kw charger is capable of that would be great) I understand you swap the resistors around on the controller to tell it to send different pulse width on the signal going to the car which then tells the car charger what current to draw.

Any help or spare components would be greatly appreciated. Anyone got an old type1 (J1772) plug/cable for example or a broken brick charger or charge point? Cheers.
Will
Sussex
 

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I am basing this on my Charge master EVSE. There is no control module per-se. So to change the max current , would require changing components which you would need to trace and calculate. I believe the current draw signal is very coarse so big steps. Good luck.
 

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Isn't there a resistor in the type 2 to type 1 cable that I use on my Rolec 32 amp untethered charger? I actually ordered a 16A cable as that's all my Ampera can draw, but was given a 32A one! But if I'd got a 16A cable, how would the Rolec know not to pump 32A through it into a Leaf? I'm sure I've read about a resistor in these cables somewhere in these threads.

What I've thought about doing is fitting 3 resistors internally, than add 2 reed-switches ( switch closes when strong magnet brought near) fyi) internally spaced say 120 degrees round the central axis; add a small neodymium magnet in a rotary collar mounted outside the cable-handle where the resistors live, so I don't upset the water-sealing properties in any way. The internal resistors would be chosen so that when both reed switches are off, there's the highest resistance value (whatever current that selects for); the other 2 positions of rotary collar would switch-in one of the other 2 resistors in parallel with the high-value one, so I'd have a total of 3 resistance values selectable. I'd set my cable for 16, 10 and 6 amps, as Ampera can use all these, and the 10 and 6A especially would be a great fit for my east-facing 4kW panels which max-out at 3 kW for an hour at the moment, but on a good day give me a solid 2.4kW for hours, and on a bright-but-hazy day give me 1.5 kW for hours.

If someone can point me to the specs for these untethered cables, I'll happily mod mine! Got the bits (somewhere) already!
 

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Hi, If you have a 32A charger and 32A cable then 32Amps will be offered to your Ampera but as the ampera only draws 16A then it won't go over that. So there is now reason for a 16A cable.
For solar charging (6A) you could fit a switch that switches between the PX wire from the cable(to allow upto the cable rating) and a fixed resistor of 3.3k ohms to the PX pin on the mode3 controller(that will restrict the max output to 6A).
 

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Sorry that should say 'no reason for a 16A cable'. As in the charging station checks the resistor in the cable to determine the max amps. As opposed to the switch you could put 3.3k in a seperate cable which would do the same thing.
 

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Thanks for that. I've looked into the specs - and there's a resistor in the Rolec-end of the Type2->Type 1 cables which tells the Rolec the max current capability of the cable. There are 4 values relevant to me, 6A, 13A, 20A, 32A which have resistances of infinity, 1.5K, 680, 220 ohms respectively. Where mine has the 220 ohms shrink-wrapped, I'm making as we speak a 3D-printed assembly to hold 3 reed-switches + resistors, and this will fit internally to replace the 220R with no mods to the existing handle. Exterrnally I'm making a sort of collar thing with a 4-position rotary-clicking selector, and a tiny neodymium magnet is going into this to select which if 4 currents I fancy. So the Ampera will negotiate with Rolec & use 6/10/16/16A, other cars might be more/less flexible.
 

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Hi the rolec units can only do certain amp selections which is 220 ohm for 32A, 680 ohm for 16A, 1.5k ohm for 13A and 3.3k ohm for 6A (this requires a later mode3 controller as the earlier ones didn't have the 6A feature).
Hope this helps!
 

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Thanks for the thread above. Very interesting (I've just joined).

I'm waiting for a couple of Rolec 32 amp untethered units to be installed at home, for a Leaf and an Audi A3 e-tron (am I the only person in the UK who is buying an e-tron??!!).

The installer is fitting "solar switches" to the Rolec units. These rotary switches switch in extra resistance to the PP (pin 5) to kid the system that the charging cable has a low rating, so charge rate is reduced (as described above).

What I'm wanting to do is move the switches into the house. Question is, what cable should I use? The cables will be 35m long, so I will probably need to compensate for the resistance of the cables. Has anyone done this? Any advice on type of cable (35m, half in duct below ground and half above ground)? Armoured Cat6, or simple multi-core? I also need to be thinking about how to detect the charge rate (A) and state of charge (%) of the car - any ideas?

What I'm heading towards is using a controller (probably z-wave system) to control the distribution of power from my 7.5kW PV system to the two Rolec units and to an immersion heater (currently controlled using an Immersun unit, brilliant device!). But one step at a time.....
 

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Hi, Ok the distance of 35m should be ok but I haven't tested it.
if you used 18AWG cable (approx 1mm diameter) you would get a voltage drop of 0.015volts at 35 meters.
I think this loss is so low it wouldn't effect the operation.
You would need a core for each resistor plus a core for GND. So something like alarm cable would be sufficient (I would recommend screened cable if possible to reduce interference that could be picked up).
Detecting the charge rate is a bit of challenge, maybe a simple solution would be to use a clamp meter with rs232 output?
 

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I heard of some of the controller modules (Viridian etc) being able to instruct a Leaf to only draw up to 7 amps, (230v) maybe someone can confirm this.
The Viridian-Mainpine EPC does have a feature (IC terminal, controlled by a small voltage or a resistor) that permits you to adjust the solicited current from 6A to 80A adjustable in 1A increments.
 

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Any help or spare components would be greatly appreciated.
I built my own EVSE around the Mainline EPC. I bought most of the parts from RS and eBay.

I'm happy to answer questions.






Disclaimer -- This photo should not be used as a wiring diagram!!!!

 

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Thanks for the great replies. I've certainly found the best forum for this subject!

Building my own EVSE is an interesting idea, using a “Mainpine 32A EPC Electronic Protocol Controller EVSE”, but I'm already committed to having 2 Rolex units installed. So I wonder if you might have some advice on the best way to proceed with regard to detecting the charge rate (A) and state of charge (%) of the car, for (1) manual remote control of the units and (2) automation (integration with my PV system)?

I’m sure there are many others out there looking for similar capability. That is, detecting and controlling what is going on without interfering with the power electrics.
 

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Discussion Starter #14 (Edited)
Thankyou Lee and Andrew. I bought a Viridian/Mainpine EPC but I also picked up a chargemaster complete tethered unit. First thing I did was dismantle it to see if i could figure out how to mess with the charge rates, but it isn't obvious. Strangely one of the small wires that goes to the plug isn't even connected, it is just looped back on itself and heat shrinked. I took some photos of the circuits (including the modem board with the sim card in it - think i will be junking that!) I can post the pics up here if anyone woud like to see the guts of one of these units.
 

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strangely one of the small wires that goes to the plug isn't even connected, it is just looped back on itself and heat shrinked.
A lot of the cable used is 8-conductor... 5 - 12AWG - 2 20AWG - 1 18AWG. That leaves you with unused wires.

 

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Discussion Starter #16
Thanks but the cable definitely doesn't look like that, it has L N and E and 2 small wires, one seems to be the pilot (i think it goes to a pin called that on the board) and its the other one that loops behind the circuit board. Very strange, its like it has been done on purpose rather than just cut off at short as possible.
 

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The ABL EVSE uses their EVCC controller and supports an RS485 serial connection. The PWM current signal to the car can be varied dynamically from 6A up to 32A in well known steps and the pulse width can be varied in 1% steps for even finer control.

I now have a USB to RS485 adapter and I intend to wire this in soon as part of my Solar PV to EVSE project.

English starts on Page 8: http://www.abl-sursum.com/global/downloads/bedienungsanleitungen/EVCC.pdf

Default and available charging current can be set via the RS485 serial interface. The available charging current can be changed while charging, limited by the default current and the rated current of the charging cable (type 2 socket outlet only).
 

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Discussion Starter #19
This ABL thing looks like it works in a similar way to the Viridian. I guess one charger could be made by ripping out the circuitry from the chargemaster and fitting one of those EPC modules. (and a contactor etc)
 

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Rolec units now up and running, complete with their "solar switches" to regulate the charge current (the rotary switch is fitted into the side wall of the Rolec case). It's worth noting that the charge current doesn't change when you rotate the switches during charging. Pretty obvious, with hindsight, because the resistor in the cable which is there to indicate the capability of the cable (which the rotary switch is mimicking), is only "measured" during the initiation sequence. So, to change the charge rate during charging it is necessary to pull the plug, choose the required switch setting, then plug in again ... or electronic equivalent.
 
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