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Re: automatically ajusting EVSE for off-grid/current sensing

Posted: Mon Apr 29, 2019 10:23 pm
by Oilpan4
48v at 410ah is a very impressive battery bank. Are you sure you don't want to go off grid?

I only have a little 24v 255ah warehouse tug battery for powering my water well setup.

Re: automatically ajusting EVSE for off-grid/current sensing

Posted: Tue Apr 30, 2019 4:46 am
by BrockWI
I would like to, but I would need a LOT more solar (and not much more space) and a lot more batteries. Most of our useage is the geothermal heat pump that pulls 5 kw running :)

Re: automatically ajusting EVSE for off-grid/current sensing

Posted: Mon May 13, 2019 11:47 am
by ripple4
The EVSE control box came in and opened it it up to find tie points on the board and documented where i got the signals. LED 2 did not have a test point, so i jumped on the current limiting resistor but it broke off, so i put in a through hole resistor to repair it, it was ugly, then i used black RTV to stick the wires to the board and that was mess too. I got a used j1772 handle and 20' cord off ebay and will connect it in to test it on the car. I don't have 240v at my soldering station, but i did have a 480/240 --> 120 .1KVA control transformer, I connected it backwards to power up the 240v only evse. if it works it works.

working on the code now, the flashing LEDs is a tricky angle i didn't expect, looks like i'll have to read the input twice, 1/2 second delayed, and see if its different between each reading. i'll put the code up once its done.

https://ibb.co/BcJQPWL
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Re: automatically ajusting EVSE for off-grid/current sensing

Posted: Thu May 30, 2019 11:15 am
by ripple4
It works! today i plugged it in and it charges the car OK, so it functions as a EVSE which is the first requirement. the time delay between when the current is changed and the car changes its draw is between an instant and about 2 seconds, so very responsive to changes. the 6 interface pins are pulled into a round connector on the side so it can be disconnected.

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here is a youtube video of the controller adjusting the current up to the maximum. not all of the features have been tested. the clamp-over current sensor is giving me trouble, its a learning process.



https://youtu.be/bjBkcHM5C0w

Re: automatically ajusting EVSE for off-grid/current sensing

Posted: Tue Jul 09, 2019 10:24 am
by ripple4
the code is pretty well sorted out, getting the hall effect current sensor to read well was very tricky, had to use someone else's RMS calculations, but it reads very accurately now. the controller increases and decreases EVSE pilot signal commanded current to maximum available supply or the maximum EVSE current of 16a which ever is lower. in the code I have it setup for a 18 amp max, and if the current gets close to 18a it sets the current to 6amps, and then auto increases to 16 amps on the EVSE or until it reaches the maximum allowed current without going over.

https://github.com/ripple4/auto-ajustab ... ontrol.ino

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I have to simulate an AC current draw using a 10a variac and a load bank, but at least i am demonstrating getting the system to increase, decrease and hold a EVSE charge current.

https://youtu.be/QjijG0nJKng