openinverter forum

Here I will try to give some information on the "perfect" marriage between Tesla battery and charger, Simp BMS , and the Inveter.
Have also made an "main" ecu with display, that will control/talk to inverter, charger, BMS and instrument cluster via CAN.

Will try to update this first post with documentation files and links.

With this new system, you can get rid of the old BCM, IOM, and contacor box.

So now is the time to buy an "dead" Ford Ranger EV, and give it new life.
This is a good solution for a EV build without the hassle of steel/hardware work.

If you are a electronics guy with a pickup truck need, this is for you.

Code main ECU:
https://github.com/jomy-tech/Teensy-CAN ... ller-in-EV
Modified tomb code for BMS and charger:
https://github.com/jomy-tech/My_TeslaBMS
https://github.com/jomy-tech/My_Tesla_Charger

Instrument cluster modified to CAN bus:
viewtopic.php?f=16&t=433


Complete diagram with Simp BMS, inverter, Tesla charger, battery, IAA and more.... updated 11-May-20:
NEW Battery box BMS connector diagram updated 11-feb-20:
Also updated picture of BMS connections/box:
viewtopic.php?f=16&t=187&start=10#p2338

Why run the contactors via the inverter?

Do you not want to charge when the car is turned off?

I would suggest taking the output from the charger into the AC input on the BMS to bring the contactors in when charging (believe you need a relay to make the signal 12V).

Having a vehicle turn on when plugging in the charging plug is just something so nice everyone takes for granted on a 'OEM' vehicle.

Hello Tom.
This is my setup for now.
I use the pos contactor and precharge ouput from your BMS to engange the AUX high volt (DC/DC, battery heat/cool)
The charger engage the pos charge contactor.
And the inverter engage the precharge and contactor for inverter.
When I open charge door and plug in, the BMS and charger start. The AC input (IN2) will go high 12V

There may be some faults in my diagram, will revise it again.

NB! the AC relays are not functional yet, they are for strange 230VAC tree phase (RL7) and one phase to all modules in the charger (RL8)
RL11 is for feeding AC to the battery heater/cooler. Can also run from DC (main battery) but have not found a relay that can do both AC and DC.

Would really like to have lowest and highest bat temp on the CAN bus....

Hi Tom.
Have checked my connections and diagram, and cannot find anything wrong.

I was just thinking it was a good idea to have charger controlling the charge contactor. And the inverter controlling the inverter contactor.

It works, just plug in and charging starts. (and stops)

This setup does not precharge the charger

The tesla charger has an input capacity I believe on the HV side, so this would mean quite a big impact on you HV contactor on the positive side (if this is last to close).

Why would having the charger in command if it gets HV be a good idea? Just trying to play devils advocate here, please do not take offence.

The charger has no idea what the battery is doing, temperature or voltage wise. Since the bms has control of the negative contactor and the Charger enable the chargers own contactor is redundant.

Looking at when you want to charge and what else you want to be turned on it makes sense to have an AUX circuit including the charger, cooling/heating and DCDC. Just trying to reduce component count and failure possibilities.

Btw, you got a very nice setup going there wish my test setups were as neat.

No offence taken, negative feedback is the the most positive feedback.....

On charger DC side, I only get 0.3A @300V at PSU power on.
Have not tested with scope, maybe I should, to get faster measurement.

I had precharge on the DC side, but Damien wrote "charger has built in precharge, no need to precharge"
Maybe that is wrong, or I remember wrong?

I also was of the impression that the OUT1 on charger was for the charge contactor. And it was timed to close/open at the right time?
So you suggest that I use OUT3 on BMS to start both charger and charge contactor? But wouldn't this open contactor at full charge power, before charger is commanded zero amp?

Actually I don't have a neg. contactor in my test setup, yet.
Shouldn't the neg. conatctor be closed first at power on and open last at power down? Else always close, except for emergencies?

I have not looked at the DC section of the charger that closely, so if Damien said so id believe it true. My mistake for thinking it was direct coupled.

I do not know what the open source code does in terms of timing the outputs. Out 1 has been used to indicate the charger sees the Control Pilot signal, thus the car is plugged in and ready to take charge.

There is very little capacitance on the output of the charger. Part of the startup sequence where you hear clicks is the dc precharge for the modules taking place.

Have added a small display that will show CAN data from inverter, Simp BMS and Tesla charger.
It connects to main ECU via I2C.

Button press will change between; Battery, Energy and Motor screen.
Showing: SOC, actul Wh/km, Wh/km for hole trip, km/h, motor/inverter temp, battery volt/temp and more......

Hi Tom and Johannes H.

The Simp BMS and inverter is playing nicely together!!
But I just mounted my neg. contactor, and then I get "error precharge" from the Inverter.

This is probably because the inverter is not waiting long enough and give "error precharge" before Simp BMS has engaged the neg. contactor.

Scratched my head for a while, so if someone have this problem, just connect the neg. contactor to run/start power.

Luckily you can change the precharge time on the SimpBMS.

Yes I know, have tried to lower that, but anyway Johannes H. is to fast for you.....

The inverter is using voltage reading for closing POS contactor. Dont know how much time there is added.

Is the BMS continually powered?
As that is the way it is intended, it has quite a few 'checks' and settling time allowed during first boot.

No it's not powered all time.
Have tried to avoid that, it works this way, so I will keep it this way for now.
It can't be worse than not having NEG contactor?

The original Ranger electronics was a terrible 12V battery drainer. And almost all errors was related to low 12V battery.

Joromy,

Keep in mind this then screws up the SOC monitoring as it loses its last known spot.

On power on it uses cell voltage to determine SOC, this then gets corrected with charge and discharge cycles.

Can you see how much power it draws without any thing else on, so no contactors? I can always look at creating a sleep mode for there is no canbus activity.

Good point, I didn't think about that.
But I can easily connect back on all time power. Without opening the battery coffin.
I guess it's not using much power, but all battery BMB modules are also powered by the BMS.

Maybe I go for a small HV/LV dc/dc to keep things running...?

Have made a diagram of connections going in and out of batterybox C1939.
There are about 10 wires spare, for some extra. (I will use it for the battery heat/cool system)
Included connections for Tesla Charger, Inverter, Simp BMS, IAA, CAN, Contactors and relays.
NEW BMS: (right click and "open/save link" to get big picture)


Original Ranger battery box cable, with new connectors:

Edited 17-feb-20
This info is not relevant for new design any more! (for reference only)

Have charged my pack with the Tesla charger and the key in "RUN" pos.
This works OK, but a lot of unnecessary modules are powered. And it's inconvenient to use the key.

If you cut 295 LB/PK wire going to the IAA C1945 pin 97 (12V RUN/START)
and connect it to J4-13 OUT3 on Simp BMS (charge enable) that also goes to charger A3 IN1.
Then only the IAA, BMS and charger is powered, water pump starts and radiator fan starts if coolant temp is over 40C.
You will need two small diodes. The IAA "RUN START" input only draw 27mA.

If you connect power to CAN display from IAA pin 97, it will power up in drive and charge mode.