Skip to main content

J1772 - Type 1 'Charger'/Wallbox

 The wall boxes for charging EV's aren't actually chargers, they are just a fancy 240v (some can also be 3 phase) outlets. 

The protocol is pretty simple, and can be found on Wikipedia. https://en.wikipedia.org/wiki/SAE_J1772

There's basically 2 signal lines, Pilot Proximity and Control Pilot, the control pilot is a 1 khz PWM signal, where the duty cycle represents the maximum current the car is allowed to draw. The proximity pilot is a fix resistance, one of 2 values. On denotes the plug is connected, another that the release button is pressed so the charger can immediately stop drawing current and so stops arcing.

Inside the wall boxes are simply a EVSE protocol controller, an RCD, possibly a GFI and a relay/contactor. They are insanely expensive for what they are, so I've designed a simple circuit board that makes use of an Arduino Pro Nano, a cheap and widely available micro controller and a simple program that implements the bare minimum of the protocol. 

The code and board design files are here should you want to take a look https://github.com/jamiejones85/BigPieEVSE

I take no responsibility for anything you choose to do with the design for the board or the code.




Comments

Post a Comment

Popular posts from this blog

Instrument cluster and CAN Bus

 The car has quite a simple instrument cluster, and a single CAN Bus network.  The instrument cluster is mostly simple signals but a few are required to keep it happy. The cluster has a dynamic oil pressure warning, meaning that over ~800rpm the oil pressure pin needs pulling to ground otherwise the cluster shows an error and beeps. The RPM signal is on the CAN Bus, ID 0x280 where Bytes 2 and 3: RPM*4, I'll have my custom ECU replacement send out this signal. 2 Other CAN BUS messages appear to be required:  0x 488, this contains a counter,  Byte 0: Counter 0-F << 4 + 8, Byte 1-4: 21, 21, 7E, A6, Byte 5-6: 0, Byte 7: Counter 0-F << 4 0x580, this also contains the counter and some static data,  Byte 0: 0x80 + counter 0-F,  Byte 1, 2: 0, Byte 3: sequence 0x0f, 0x28, 0x7f, 0x28, Byte 4: sequence 0x1e, 0x10, 0x00, 0x10, Byte 5: sequence 0x70, 0x56, 0xf0, 0x56, Byte 6: sequence 0x0c, 0x48, 0xa7, 0x48, Byte 7: sequence 0x46, 0x90, 0x28, ...
Post a Comment
Read more

DVLA Refusal to Update V5

 Now with over a 1000 miles done on electric, and over 6 months of to and fro, the DVLA are still refusing to update my V5 to electric and change the tax classification. Their reasoning in the VERA act, below, they have taken this to mean that on post 2001 vehicles the fuel type and tax classification cannot be changed. This is despite the DVLA website (https://www.gov.uk/change-vehicle-details-registration-certificate) making no reference to been unable to make the changes. LPG conversions, changes to disabled classification and conversions to a camper-van are all possible. Here's another part of the VERA act. The purpose of this post is to document my experience with the DVLA, so back in August 2021, the 2nd to be exact, I filled out my V5 to change the fuel type to electric and tax class to electric. On the 14th of October I was asked to provide more details, receipts, photos etc.  I was also asked to fill out a V627/1 built up vehicle report. Below is the first letter I re...
2 comments
Read more

Golf GTE Battery Disassembly

Having deliberated over battery pack options, I was convinced I would go for a pack from a BMW plug in hybrid or the Outlander PHEV, but a pack from a Golf GTE popped up on eBay for £500 delivered, which was too good to let pass by, at 8.8kwh it works out at £57 per kilowatt hour, a bargain. Tearing it down wasn't the easiest task, and with 350v - 400v under there, a little nerve wracking. The lid was glued down with some serious adhesive. The pack consists of 4 modules, each module is 2 strings of 12 cells, with a cooling plate between them for liquid cooling. Each of the 12 cells has a BMS slave board, which reports the voltage of cell cell to the BMS master, along with the temperature of the string. Each module can store just over 2 kwhs. The modules communicate with the master via a CAN Bus network that's internal to the battery. I've put up a GitHub repo with a DBC file for interpreting the reported frames https://github.com/jamiejones85/DBC-files if you are looking at...
Post a Comment
Read more