Battery Pack Charger Connection

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esbro
Posts: 34
Joined: Tue Jan 25, 2011 6:21 pm

Battery Pack Charger Connection

Postby esbro » Sun Feb 17, 2019 9:37 am

Hi everyone, Sorry if this a really dim question, but I don't know how the system works.
I am considering buying an on-board charger for my (just started) conversion - with, hopefully, a 40kwh battery pack. I have a wall mounted evse (7kw max ?) at home, but want to use motorway service ones (3 phase) en route. Do I need to use 3 chargers (one for each phase) on-board, or will my home evse limit the current automatically, to 1 larger obc ?
Many thanks ...... Steve

Grumpy-b
Posts: 987
Joined: Sat Dec 01, 2007 12:06 pm

Re: Battery Pack Charger Connection

Postby Grumpy-b » Fri Mar 01, 2019 2:20 pm

Its depending on the charger.
The 3 phase and single phase units used in the Allieds, have to have completely different wiring for 3 an 1 phase use. Single phase type 2 power outlets use Live on ph1 and neutral. The allied uses live Ph1 and another phase neutral. so it cant use one standard connection, as it doesnt use neutral for 1 phase.
So you have to know what the charger is you intend to use.And if it has neutral as well. Few Three phase will do single as well.
There are very few aftermarket chargers that will do both 3 and single phase.

esbro
Posts: 34
Joined: Tue Jan 25, 2011 6:21 pm

Re: Battery Pack Charger Connection

Postby esbro » Sat Mar 02, 2019 10:13 am

Hi Grumpy, Thanks for your reply.
So.... from this I get that it's difficult to get an OBC that will will accommodate the available range of evse points. If I have an OBC that will use my 1ph evse at home, I'm stuck with only that ? I've been looking at chinese OBCs, but not quite sure what I'm getting.
Should I, then, use 3 single phase chargers in parallel (1 for each phase of a charge point) so that I can use whatever evse is available ? Surely there is a way around this.
Cheers ..... Steve

Grumpy-b
Posts: 987
Joined: Sat Dec 01, 2007 12:06 pm

Re: Battery Pack Charger Connection

Postby Grumpy-b » Sat Mar 02, 2019 6:28 pm

OBC?

esbro
Posts: 34
Joined: Tue Jan 25, 2011 6:21 pm

Re: Battery Pack Charger Connection

Postby esbro » Sun Mar 03, 2019 10:46 am

On Board Charger as opposed to EVSE :D .... Steve

Grumpy-b
Posts: 987
Joined: Sat Dec 01, 2007 12:06 pm

Re: Battery Pack Charger Connection

Postby Grumpy-b » Sun Mar 03, 2019 6:30 pm

In connection with a conversion having its own charger built in, what do you mean by an EVSE as opposed to an OBC.
You cant use Chademo / CCS unless you have a high voltage pack, presumably you dont have that.

esbro
Posts: 34
Joined: Tue Jan 25, 2011 6:21 pm

Re: Battery Pack Charger Connection

Postby esbro » Mon Mar 04, 2019 10:25 am

Hi Grumpy-b, I'm sorry if I wasn't clear, it was lazy using abbreviations.

EVSE - the charge point attached to my house or the ones at service stations etc. (electric vehicle supply equipment).
OBC - the battery pack charger fitted on-board my vehicle, connected to the battery pack at one end and to the inlet socket at the other.

My query was to find out-
a) if I need 1 charger per inlet socket phase to give me a range of charging options when travelling about. That is, using 1ph domestic supply at either 3.3kw or 6.6kw (depending on what is available) or
b) using all three input phases of say, a motorway services electric charging point.
c) If my home (Rolec) 1ph supply unit is connected to a 6.6kw on-board charger in my car, does the Rolec unit limit current to the available supply, say, 3.3kw ? or does it just blow fuses ?

Hope you can help.

Cheers ...... Steve

Grumpy-b
Posts: 987
Joined: Sat Dec 01, 2007 12:06 pm

Re: Battery Pack Charger Connection

Postby Grumpy-b » Mon Mar 04, 2019 4:32 pm

The point I was trying to make was that you dont appear to understand whats does what, unfortunately an awful lot of people think Charge points (evse) actually charge the car. They dont they just provide mains power to the vehicle. So when someone goes off using lots of abbreviations and asking questions, often its because they really dont understand the question or the problem.

Three phase is not simply a question of having three chargers. Single phase is 240v and uses a Neutral line . Some three phase charges just use the three phase ( results in a balanced current flow) which three separate phases and neutral would not have. I dont believe that the std charge point cabling is built for such use, as the neutral line is normally the same as any individual phase, ie all cables have say 4mm2 cable.
Very few charge outets can deliver three phase. Normally these are associated with Rapid charge locations, where a large three phase supply is situated.
But the point of three phase is the ability to pass high power with relatively small cables as the phases use each other on the negative part of the cycle as the return path. Not the neutral line.
A charger of the type used in conversions (the actual device that takes AC mains and turns it into controlled DC) is normally built to work at a given power output, ie 3kw. You can normally parallel these up to give higher outputs.
On a production vehicle. The charge outlet makes a link to the car. It then detects what the vehicle is looking to take, and act accordingly. Ie you have a 3kw charge outlet, and your car is 3kw, all is good and the charge outlet will turn on. If you have a 3kw charge outlet and your car tells it its got a 6kw charge, the outlet will not turn on.
Most modern cars with a 6+kw charger will use the handshake to establish what the charge outlet can deliver, then cut the chareg rate back to suit. So if you have a car with a 22kw capable three phase charger and you plug it onto a 3kw Charge outlet, the car will cut back its capability to match the 3kw.
That is actually hard to achieve in a conversion, unless you have all of the charge system (and its control)from a suitable car, or a lot of logic control to do this using std chargers.
One option is just to have two 3kw single phase chargers and some simple switch arrangements to allow the charge outlet to get the appropriate signal to know what you wish to use, ie you plug in and its just 3kw, or push an additional button and get 6kw and give the different signal to the charge outlet if 6kw is available.
Trying to do this on three phase is getting really complex.
With a 3kw charge costing about £600 to £2500 new it can get costly.
Charge outlets are just a device that turns on a contactor if certain conditions are met. Exceed the capabilities of the device ie spoof a 3kw outlet to turn on with a 6kw charger and you will simply blow the trips or do more serious damage to the unit and the supply.
Too many people think their 3.3kw early leaf will charge faster on a 7kw charge outlet. Because they call the mains outlet a charger.

esbro
Posts: 34
Joined: Tue Jan 25, 2011 6:21 pm

Re: Battery Pack Charger Connection

Postby esbro » Thu Mar 07, 2019 1:08 pm

Hi Grumpy-b, Thank you for your almost comprehensive reply.
I have been a Mechanical Engineer, man and boy for over 55 years and, yes, I do understand 3ph distribution, balanced and rotating fields and so on... and yes, I do know the difference between an OBC and EVSE. However, I was not sure of the method of sensing the output of an EVSE or that of the input to the OBC. I was also not sure of how/when to parallel the chargers. Referencing your remarks, I now know the "how" and, from further research, what resistor values on pin PP to earth are for which current supply.
I was under the impression that, like the 3ph supply in the street I could use all three phases - splitting them (as if to different houses) using a common neutral. I did not bargain for the added complication of Control Pilot and Proximity Pilot pin functions.
Thank you again for your input.
Best regards ..... Steve

Grumpy-b
Posts: 987
Joined: Sat Dec 01, 2007 12:06 pm

Re: Battery Pack Charger Connection

Postby Grumpy-b » Thu Mar 07, 2019 4:07 pm

Dont forget the Charge outlet has all conductors of the same size. If pure three phase then there is no return path required, if you use all three phases to neutral, then the shared neutral will be taking the return for all three phases, and the cable is really only sized for the max of the charge outlet ie you will find 4mm2 at 16amp possibly 6mm2 at 32amp,But thats just the supply. If you put all three phases through the single neutral at 11kw you would need an enormous cable to the vehicle, and none of the available plugs will do that, and neither are any of the inlets made for vehicle made for cable of greater than provision for 32amp.
Its always worth going back to basics, as its likely its not just you looking at this. And if others pick up on stuff thats taking them down a bad route, however unintentional, it s worth taking the time to explain the issues.
As I commented, too many people think the Mains outlet on the wall is the charger, and a higher capacity one will charge their car quicker. They just dont get that its simply a mains connection.


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