DIY Open Source EV Charger

[jackbauer]

Quick video on the mode 3 code running from a 16amp evse :

http://www.youtube.com/watch?v=dqn8jkrj3aE

[jackbauer]

I've made a few extra modifications to the charger. Installed a solid state relay in the ac line to the fans and coolant pump psu. Controlled directly from the arduino fan output pin. Fans and coolant pump cut in at 20C. Also purchased a 12v 7 day timer on ebay. This is a simple little device with a single NO contact that can be controlled by time or a manual override button on the front. I connected a 4v7 zener across the 10k pulldown resistor on the bms input pin and sent a 12v signal throught the timer and a 1k resistor to that pin. Reversed the logic in software so the charger idles if the pin is low waiting for it to go high to commence charge. Charging is terminated by the timer opening the contact and the pin reverting low.

Full mode 3 communication is now running stable with the charger reading the control pilot signal and calibrating power accordingly. When running in mode 3 the charger enables power by selecting state c but does not begin charging until the timer brings the bms pin high. This is so as to allow battery heaters to raise the pack temperature before commencement of charge. Another option for this would be pack termperature monitoring. That's on the to do list!

http://www.youtube.com/watch?v=HaeKXdtx_EM

[MPaulHolmes]

Whenver you don't hear from jack for a couple days, that's because crazy and awesome things have been happening. hahaha. YOu are the absolute man!

[dmills483]

Jack now that you've gotten the 10K charger up and running so beautifully would you consider documenting the schematic and bill of materials?

Also, I've never been able to locate the sketch that you have been using. Is there a wiki or location that you could share with me?

Is that Val's printed circuit board I see in the video? I bought 2 of his first generation boards but like the hardware you have come to use. Your wave forms are much cleaner and the heat generation and remediation is superb.

Have you considered a name? The Bauer M3 (mode3) 10K Intelligent charger.

A long time follower of yours, Dan

[sawickm]

Originally Posted by dmills483

Jack now that you've gotten the 10K charger up and running so beautifully would you consider documenting the schematic and bill of materials?

Also, I've never been able to locate the sketch that you have been using. Is there a wiki or location that you could share with me?

If Jack is interested, I could add his Bauer M3 10K Intelligent charger to the Open ReVot wiki ???

Just let me know.

-Mark

[jackbauer]

Well I finally got the new liquid cooled charger installed and running in the car.Charger has a few software issues I need to resolve around end of charge detection but boy is it fast! Took the pack from 48% to 95% in a half hour. Peak input power of 10.5kw. The fuseboard at home started making interesting popping and creaking sounds as it warmed up. It's so powerful compared to the pack capacity that it only spent a few minutes in CC phase!.Measured a total power factor of .982 for the vehicle. That includes main charger , aux battery charger (chennic) and two battery heaters.

[MPaulHolmes]

Holy crap!!! I thought this was a 10kw charger. What's all this 10.5kW talk here! haha. That is so stinking awesome I can hardly stand it. Do you just use 220v, or do you do a voltage doubler like I think I read on that EVWerks website? Was the power factor correction hard? What constant voltage is being put into each headway? When I did a basic charger for the thunderskys, the higher the current going in, the higher the voltage seemed to be for each battery, I guess because of the internal resistance of the batteries. And they say you shouldn't let them go over "x" volts, but I think its' not really over 'x' volts if you are charging with lots of current. Do you wait until the whole pack reaches a certain voltage threshold?

[jackbauer]

Mains voltage here is 230v so no need for a voltage doubler. Valery designed a pfc stage for the charger but i didn't bother with it figuring i'd add it later if the pf was really bad. To my surprise when i started testing the pf was very high and has remained so even when battery charging.

The voltage of a lifepo4 cell will vary depending on charge current. The important voltage is when the charge current has dropped to 0.05C. I charge to approx 3.44v per cell or about 165v total pack voltage.

[MPaulHolmes]

This is just absolutely awesome!!!!! What inductor value are you using?

[jackbauer]

The inductors were removed from the mains input filter of a 50kva 3 phase ups. They measured in at 1mH on my cheap $20 lcr meter. I used two in parallel for extra current handling capability and 0.5mH total inductance. They are bonded to the chill plate with thermally conductive epoxy that seems to do a very good job of thermal coupling. For the next version i'd mill out a solid block of aluminium to fit the inductors and totally incase them in epoxy. Liquid cooling channels could then be drilled through the block.