Using EV Chargers

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methods   10 GW

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Joined: Aug 08 2008 12:08pm
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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:

J1772:
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.


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


CCS1/CCS2:
You need special goodies for this.... but a quick search of the web can point you in the right direction.


Tesla:
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.
REMEMBER THAT.

With CCS... you can set bounds and limits similar to a CV/CC... like... Max Voltage, Max Current.
Trip limits
BUT DO NOT DEPEND ON THOSE OR ASSUME YOU CAN HOOK UP WILLY NILLY
THE CHARGER WILL DO WHAT YOU TELL THE CHARGER TO DO... SO... DONT TELL IT TO DO ANYTHING STUPID!

So...

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:

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

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