Charge Cables

[Hunda67]

Hi, new here but got my first question so here goes:

Took a phev for a test drive this weekend and probably going to go back to the dealer this week and order one. Is it possible to get a charging cable that can switch between different charge rates e.g. 6A or 16A? The reason I ask is I have a wind turbine at the house and if I could stretch the charging time to 10 hours with a 6A charge then more of the electricity used would be free from the wind turbine than if I charged the car in 4 hours at 16A. Would still like the option of a 4 hour charge if need be but overnight (most days) it would be better to charge it slowly and make use of the wasted wind generated electricity.

 

[jdsx]

Are you in the UK? If so, you could try this one.....but it is expensive...
https://evconnectors.com/portable-e...-16a-J1772-EVSE-13A-Domestic-Plug-With-Sensor

 

[maby]

Are you in the UK? If so, you could try this one.....but it is expensive...
https://evconnectors.com/portable-e...-16a-J1772-EVSE-13A-Domestic-Plug-With-Sensor

That does look like it would do the job, but it is wickedly expensive! If there were any significant market for these things, I would be in the wrong business - there is not very much inside one!

 

[jdsx]

There has also been some discussion of this on speakEV.com, relating to solar charging. It's worth a look if you understand such things (which I don't). https://speakev.com/threads/adapting-mainpine-evse-for-smart-solar-charging.2082//[url]

 

[Ozukus]

Have you considered using a power reducer.

Sibert have one at the following link. It's designed for Immersion heaters, however if you look at the description below it says immersion tank or other resistive load.

http://www.sibert.co.uk/products/elios4you-power-reducer

"The new Power Reducer (Immersion Controller) from 4-Noks is their very own proportional controller designed to divert ANY surplus energy to the immersion tank or other resistive load up to 3kW."

The way I read the above is any of your excessive could be directed to a dedicated circuit that you could plug your car into.

 

[maby]

Have you considered using a power reducer.

Sibert have one at the following link. It's designed for Immersion heaters, however if you look at the description below it says immersion tank or other resistive load.

http://www.sibert.co.uk/products/elios4you-power-reducer

"The new Power Reducer (Immersion Controller) from 4-Noks is their very own proportional controller designed to divert ANY surplus energy to the immersion tank or other resistive load up to 3kW."

The way I read the above is any of your excessive could be directed to a dedicated circuit that you could plug your car into.

Those only really work for resistive loads providing heating - they can operate at reduced output either by dropping the voltage or fiddling with the duty cycle. The Outlander battery charger is not going to like this at all, I think. There is already provision to control the power drain in the interface. One of the five wires going into the charging port carries a signal indicating the current level available to the car. It can be varied from 6A up to 32 A (if I remember correctly). This is the maximum current that the power socket is offering - the car is then free to draw however much it wants up to that advertised figure.

It is well documented in the specifications for the charging point interface. The control signal is a square wave at a relatively low DC voltage. The available current is encoded in the duty cycle of this square wave - any reasonably competent amateur electronics enthusiast would be able to build the circuit board to subvert the signal and control the current drawn by the car.

 

[Hunda67]

Thanks for the replys. Yes I'm in the UK - Shetland to be precise. I'm also happy to fiddle with electronics / electrics although I am not a qualified electrician.

The cable suggested does look as it will do what I want but as you say it's horrendously expensive considering probably what is inside it. I also agree that the power reducer - I already use something similar for heating hot water and it works but chopping bits out of the sine wave of the supplied voltage and as Maby says the car will not like this - to the best of my knowledge it will either refuse to charge or (possibly much worse) seriously reduce the lifespan of the car batteries.

Maby - do you know where I could find the spec of the square wave control signal? I haven't found any company that will install my free home charging point up here yet. Actually I'd be happy to install one myself but would need to get it signed off by a qualified electrician to stay legal.

 

[Hunda67]

Also meant to say although it looks like the cable does what I want with selectable charge currents from 6 to 16A it is fitted with a 13A plug - doesn't seem if that can be quite legal to my mind here in the UK.

 

[maby]

Thanks for the replys. ....

Maby - do you know where I could find the spec of the square wave control signal? I haven't found any company that will install my free home charging point up here yet. Actually I'd be happy to install one myself but would need to get it signed off by a qualified electrician to stay legal.

See half way down the Wikipedia article : http://en.m.wikipedia.org/wiki/SAE_J1772

 

[Hunda67]

Thanks. Like you say no reason why the cables should be so expensive if that's all that's in them. The most difficult thing would be making one nice and waterproof yourself but maybe the charge level electronics could be built into the charging station.

 

[maby]

If you have a wall mounted charging station, then the electronics is in it. The 13a charging cable supplied with the car has it built into that box in the middle of the cable. It's the special case where you want to reduce the current drawn that we are talking about here - building a controller to go in line with the cable and tell the car to olny draw 6a.

 

[Hunda67]

The idea is to have a selectable charging unit on the wall - say 6A, 10A or 16A. One question is what will the car accept - I see on the Mitsubishi website 16A is the max but is there a minimum below which it will not charge and what steps could be used i.e. could you go all the way from say 6A to 16A in 1A steps? Next trick would then be to monitor the excess power and then automatically change the charge rate.

 

[maby]

The idea is to have a selectable charging unit on the wall - say 6A, 10A or 16A. One question is what will the car accept - I see on the Mitsubishi website 16A is the max but is there a minimum below which it will not charge and what steps could be used i.e. could you go all the way from say 6A to 16A in 1A steps? Next trick would then be to monitor the excess power and then automatically change the charge rate.

The lowest rate supported in the interface specification is 6A. I guess you could try fiddling with the duty cycle of the signalling line to see if you could get it to go lower, but there is no documentation regarding what effect that will have. I've not seen any mention of dynamically adjusting the rate - I guess the designers of the car electronics would be perfectly compliant with the specification if they just read the rate signal once when the charging started and assumed that figure would remain constant throughout. Since it is effectively an analogue signal (OK - I know that it is encoded on a square wave, but it is the duty cycle that is the signal), I don't think it is against the rules to make it continually variable, but the specification only talks in terms of discrete values at 16A, 10A and 6A. Again, I think the car designers are at liberty to take this literally if they please and round down to the nearest published value.

I guess that the bottom line is that if it matters to you, you'll need to experiment. The electronics is not complex and you can buy the J1772 plugs and sockets quite easily - build a little box that plugs between your Mitsubishi supplied 13A charging cable and the car and replaces the charge rate signal. Then try winding it up and down, keeping an eye on the current drain via your electricity meter.

 

[Hunda67]

Thanks for the info. It started me googling around a bit more in depth and I found the Open EVSE website in the states (https://code.google.com/p/open-evse/).

There seems to be everything available there along with J1772 specifications. It looks like the lower limit is 6A (in the specification but maybe the car would work with less - however, I think it would be best to stick to the specification as there would be the slim potential to do some damage to the car). The also have a home charge point system where you can adjust the charge current. It is something I will look into further - I am sure there are folks out there that have either solar panels or a wind turbine and would like to charge their car at a lower power to make more use of the free electricity.

I'm not sure if I'm correct on the following but I get the impression the free charging station from a government grant seems to need a GPRS signal as part of the conditions to log energy usage. I live in Shetland and my nearest mobile signal is 5 miles from my home so I don't know until I get some response to my enquiries to charging station suppliers / fitters if I can get a free home charge point.

In the meantime ordered by Outlander Phev today - told delivery will take place sometime in December