Making a Charge Controller for the LEAF Battery Modules

During this week I stared building a Charge Controller for my AESC / LEAF Battery Modules
I have had this idea since last summer: build a simple, effective and safe Charge Controller for LiFePO4 cells, which is in fact a sub-system of my DIY ESS, taking care of the Battery pack charge and discharge functionality

Since the AESC Modules behave like LiFePO4, except for the voltage limits, this kind of controller ill work fine

It is composed of a Programmable Dual Relay Voltmeter, and 2 Tyco Kilovac Contactors, wires, and that's pretty much it !

I even had to read again the DIY ESS Kit documentation to see the wiring of the Voltmeter


and go through their manual to set up some additional values like the decimal point here



and I decided to set up the low voltage limit to : 3.6V x 6 half modules = 21.6V
and the high voltage limit to : 4.15V x 6 half modules = 24.9V (slightly under charge is always safer, since 4.2V is the target voltage on these Lithium Manganese cells)


Higher limit reached => the upper LED is lit and the high relay is open, which will open remove the power from the Charge Tyco Kilovac and stop the Charge .... so simple and effective


Tyco Kilovac not wired yet, but will be done later


and it should stay open until the value I entred is reached, I think it is 23.5V

More Diodes and Digital Programmable Voltmeter arrive in the mail

More components arrived in the mail yestedray: Diodes and Dual Relay Programmable Voltmeter for my new DIY project : LiFePO4 Charge Controller

New : LiFePO4 DIY ESS Technical Diagram

Just added this diagram to the newly created 'How does it Work ?' page on my DIY ESS Kit blog, after a French person requested a technical overview of the system; Good suggestion, thanks !

Electric VW Transporter, Episode 6

Richard Van Wyhe from EV4U Now, EV Custom Conversions continues the rare VW Transporter  Electric Conversion, and does a very job



"In this episode we install the charger, fuses, safety interlock, shunt, main disconnect, battery rack, and more. Plus we discuss what's in store for future episodes."
www.EV4Unow.com

DIY ESS - AC Charger terminals modification for Water Heater

Before moving all the ESS components to the metal cabinet, I decided to make a last modification to the charger side relay and AC terminals; Instead of having 6 relays for 6 chargers, I removed the 6th one AC wires and left the relay terminal free for my water heater command line (220V, 2A max) that activates the coil of a 220V 20A line that feed the water heater at night during off-peak hours. A signal sent by the utility closes a relay in my utility meter at night and opens it in the morning, and this is how the water heater runs only on low rate electricity. Closing the 6th relay on the same command line, I will be able to switch ON or OFF the water heater as a "6th charger" in a way, meaning, when all the chargers from 1 to 5 will have been switched ON already

If you get my kit, have no water heater - or a gas one, like many in the USA - , use the 6th relay for a charger - like I used too all this time - continuing the AC charger line up to relay 6, the behaviour of the 6th relay has not been changed at all, it is still the 6th charger from teh Arduino point of view !

Then I add to move two chargers on the same AC terminal/ relay twice, like you can see on the photo since I have 7 chargers

I also changed the program so that when the 5th charger comes ON, and the arduino sees that it uses too much power compared to the net power, instead of switching it back OFF, it switches the 1st charger OFF instead, making it more precise (so always install several chargers on the same line towards the end: 4th, 5th)

PWM Kit received for the Tyco Kilovac EV200A1ANA

Look what came in the mail yesterday :-)

A small PWM kit I ordered few days ago to replace the resistor & capacitor used as an economizer for the Tyco Kilovac EV200A1ANA that requires one

This resistor & capacitor have been doing the job, except that the resistor is burning some energy in heat  and this is maybe no the best way to handle this problem

Now, I just have to switch on my soldering iron and put all this components together on the PCB ...

Link to this item: http://boutique.rhaaa.fr/49-kit-r%C3%A9gulateur-pwm.html