DIY Open Source EV Charger

[teraamper]

Hello to everybody
I'm new her, and I have to say. Excellent work here!

JackBauer
Can we get the full shematic and the program for the charger.

[jackbauer]

yeh i'll do a full write up on it asap. Just real busy these days!

[jackbauer]

Ok schematic attached. Not pritty best i can manage for now. The "CON" contacts are a large 50amp contactor controlled but the small relay onboard the sparkfun board. This takes care of switching and precharge in one package. Also in this revision the power is totally off until a charge cycle is engaged.

The 12v psu is a power brick from a scrap portable tv. Also included is an inhibit relay to stop the car from turning on while on charge. The 15mH main inductor is the hf transformer from a scrap 50amp inverter plasma cutter with its primary and secondary in series and in phase. The choke is a laminated unit from the same plasma cutter. Diodes are 150amp fast recovery modules from a scrap inverter welder.

IGBT is a 150amp fuji 2mbi150 module. A miller clamp circuit is used on the driver to improve switching tails. Both diodes and igbt are mounted on a heatsink and fan cooled using parts from the plasma. No noticable heat is generated since igbt drive upgrade. Not on the power section battery output diagram are two mkp caps. one is a 1uf 1000v part the other a 500v 50uf.

[MD2000]

Just ran into this thread,
great work guys, and I can really appreciate the fun of rolling your own.

I have been playing with grid chargers for hybrid battery packs lately and have come up with a modular approach that has a lot of possibilities.
We all have seen the small efficient switcher power supplies from China.
I got some isolated universal input 48V units that will run from 85-250 VAC.
They are short circuit and over temp protected with 1500V isolation. They are available with a wide range of output currents.
With the gradual appearance of high power LEDS, another type of high efficiency power supplys have started to show up. The LED power supplies have true constant current outputs and will adjust the output voltage to maintain the current from 3-48V.
By putting the isolated 48V switchers in series, one can get any base voltage that you want. Add an isolated constant current LED supply to the series string, and you have an adjustable max constant voltage(the 48V switchers can each be adjusted to between 40-54V output) And a constant current range of ~40V.
The LED supplies can be paralleled and will share load perfectly throughout the 40V CC range.
I started with a 350ma combination for charging my honda Insight 144V batteries, ( Schematic http://www.99mpg.com/Data/resources/...balancer_2.pdf) and will be finishing a dual rate system that will output a bit over 1 A. The dual rate system has bypass diodes on the four 48V supplies, and the supplies can be turned on or off in any combination. This yields a constant current charger that can charge a battery anywhere between 7.2V to 256V, with a limit that is only limited by the 1500V isolation.
The led and switchers to make this supply were just a bit over $120 total.
Bigger 48V supplies with paralleled LED constant current supplies, and you can pretty much build any charger you want with well designed and protected off the shelf building blocks.
Some photos and the information is here, about half way down the page:
MIMA Pack Whack and rebalancing the battery - MIMA Honda Insight Modified Integrated Motor Assist
A simple max voltage detect,circuit will allow the 700ma to be shut off when nearly finished with the charge, which will drop the output current to a safe constant 350ma trickle charge which will safely top off the pack.

[jackbauer]

Whats the max charge current you can pull? I need at least 30amps for my application.

[williamson]

Is this site talking about a home charger to charge a typical 144 volt pack, or an on-board charger, to keep the on-board SLI battery charged, as you drive? Kindest regards to all

[williamson]

Does anyone know of a thread to open-source design an on board SLI charger?

[adamj12b]

This is about a charger capable of charging a traction pack. It can be onboard or homebound. It can be made as big or as small as you want. It can be a simple 1kw or as big as you can find inductors for. Im am working on a 17Kw one. This will obviously need to be fed by a large AC circuit at home, but away, i will be able to be turned down to accommodate for smaller, less capable circuits.

The only problem right now is 11 cell (12V cells) lead battery pack is about all you can charge off a 120V outlet. You might be able to get 12 cells, but you are getting to the rectified voltage of the outlet and will get a slower charge.

A PFC/Boost circuit is in the works to improve this range and allow high voltage packs such as my 90 TS Cells (288V) to be charged from a 120V outlet.


-Adam

[dcb]

you can also turn a transformer around.

if you have a 60 volt transformer you can connect 120 to the secondary side and get 240 out.


also a voltage doubler on 120 (170 peak to peak) will make plenty of volts too.

[adamj12b]

Originally Posted by dcb

you can also turn a transformer around.

if you have a 60 volt transformer you can connect 120 to the secondary side and get 240 out.


also a voltage doubler on 120 (170 peak to peak) will make plenty of volts too.

Both of these are a possibility with exceptions.

The transformer would work for small loads. But for a substancial load, you will need a very large and heavy transformer. I have one that can convert 190-240 to 120V @ 18A which I was thinking of using, But I would not want it in the car...It weighs almost 80lbs!!

A voltage doubler is a boost circuit really, The boost circuit is just controlled a bit better. The power factor correction is needed for high power charging also because without it, you will be loosing a considerable amount of power that you could be putting into the batteries.

-Adam