Using EV Chargers

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methods   10 GW

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Posts: 4401
Joined: Aug 08 2008 12:08pm
Location: Santa Cruz CA

Using EV Chargers

Post by methods » Jan 02 2019 10:53am

This will be slow to roll out... but I now am familiar with how to do this.

From Easiest to Hardest:

Basically you take any charger with a 240V input and zip-tie it to your bike. Add a diode and a couple relays and you are set. You will of course need the correct inlet connector. I can help you with this.

All that is required here is CAN and good timing. More on this later.

You need special goodies for this.... but a quick search of the web can point you in the right direction.

Same as CHAdeMO but wrapped in more riddles.


I can get all of those to turn on and provide a charge.

Most EV's are in the 400V range. The DC Fast Chargers I work with only go down to about 200V. You can actually spoof this for a 50V pack pretty easy... but it is inefficient.

EV Chargers (and I have to be careful here...) do not necessarily work like a CV/CC Power Supply.

With CCS... you can set bounds and limits similar to a CV/CC... like... Max Voltage, Max Current.
Trip limits


If you want to charge a 50V EV battery off of a 200V charger... AND I DO NOT SUGGEST YOU DO UNLESS YOU REALLY KNOW WHAT THE FRUCK YOU ARE DOING... you will need to run at less than 25% efficiency.

Lets say you want a 50A charge.
So... you request 200V @ 50A

Requesting 50V will just be rejected (most of the time)

So... You need to provide "back-pressure" that meets spec

200V / 50A = 4ohms

So... hooking up a 4ohm toaster capable of 10KW would do it
(Thats 10KW... not 1KW... pay attention!)

So in that case, if you have ~about~ a 50V pack you could calculate the following:

(200V - 50V)/50A = 3ohms

This is just ohms law and has to do with sum voltages.
If you have 50 pushing back on 200 then there is 150 to drop... and you gotta drop it somewhere...

So that would be 7.5KW of waste for a 2.5KW charge
Fine by me... Especially if it is cold out.
That is about what an average EV heater burns and if you are sitting in the car waiting for a charge... eh...

Hey - its cold out!
Get used to the idea that Electricity gets burnt for heat!

What would make more sense is to configure your pack to be 200V


Just remember...
That your ID is being logged...
So if you screw up and damage a charger...
I may end up coming to your garage to take away your tools.


If you are pretty hardcore you can contact me directly and I will help you to make good decisions around leveraging Charge Infrastructure.

If you are nOoB status... dont even think about it.
I mean it.
Fire... BIG FIRE... your stuff broken quick :cry:

Increasing battery voltage and controller current limit will result in a non linear experience

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methods   10 GW

10 GW
Posts: 4401
Joined: Aug 08 2008 12:08pm
Location: Santa Cruz CA

Re: Using EV Chargers

Post by methods » Feb 02 2019 2:01pm

Now hopefully we have dispelled any myths. . . The type held and propagated by folks who have no practical sense of Power and Electricity.

... NO ...

You can not practically "grab a charge" from a DC Fast Charge Station with a couple resistors and some jumper cables. :lol:


What you can do tho. . .
And what I have demonstrated against a Zero Motorcycle. . .
Is run a proper DC-DC converter.


To succeed I suggest you do your testing up to 420VDC.

Do NOT aim at 200VDC.
Aim higher

We make Power with Voltage and anyone who says different (Eh HEM... LFP...) is not being practical in any way.


Nearly any AC-DC converter out there which is Wold Compatible will accept something like a 380V DC input. Swap a few caps and diodes and very quickly. . . you will have a DC-DC converter which takes 420V at its input and produce 50.2V at its output.

... Have I done it? ...


Since when have you seen me NOT blowing shit up thru experimental proofs??

We are rolling this out R E A L S L O W

If you are in a big rush, go someplace else.
This aint the post for you


What we want to do is make a compact DC-DC for your Ebike which will accept CCS1, CCS2, CHAdeMO, or Tesla DC Fast Charge.

... Why?

Because we can.


While you are being patient please get rigged up with some J1772
Just 3D print the inlet

Wire only the following:


Those should be sufficient to carry 50A... so... 10AWG will work.

For comms you will need



Proximity is the easy part and you will quickly figure it out.

this is a bit more tricky...

Understand that it is NOT a DC stimulus
It is AC
And that is what the Diode is all about

You will need a DPDT relay, a few resistors, a mosfet, and an Arduino.
I now use PI... but an Arduino will suffice.


J1772 is everywhere
Roll by Google and check it out

Go download a 3D file and get to printing

Print one for me and I will do an article on setting it up for Arduino.


WHY do we need an Arduino?
Because I say so, thats why.

Anybody can flip switches to initiate a charge session.

What we are doing here is setting you up for DC Fast Charge. ... . which ... will take A LOT MORE... and this wont be any sort of plug-n-chug activity.


We are talking about sniffing packets, determining protocol, meeting electrical requirements, meeting timing requirements, properly interlocking, HiPot testing, and ...

Getting it to ACTUALLY WORK
Without undo risk or bullshit


Off to go do manual labor like Tesla did. . . when the masses just could not understand the basics. . . and time had to be lost to the machine.

Increasing battery voltage and controller current limit will result in a non linear experience

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