Hi,
I'm new to the forum and have a question related to chargers for Lipo battery modules. I recently built an EV that has a total of 6x67v battery modules, each with its own 120/240v charger onboard.
I have wired up a J1772 socket and charge from my 240 outlet in my house. This has worked great. The chargers are all in plastic housings so don't have a ground, therefore I only have two of the contacts wired up on the socket for the 240. I am guessing that EV charging stations search for a ground when plugging in and if there isn't one, nothing happens (tried it and this is what happened). Is it possible to add a ground to my configuration for this use? Would I wire a ground to the chassis? Hopefully this isn't a dumb question :0 Thanks for any help or suggestions on this.

 

No such thing as a dumb question, just dumb people that don't ask. And Welcome to AAC!

There may be some safety issues involved, others here will know. A big reason is to avoid running all the grounding leads from the batteries to all the "Other" vehicle electrical devices. Which are designed for the "12V (13.8V)" standard. In particular all the signal and lighting bulbs, gauges, and now LEDs.

 

There is a signaling protocol required for compatibility with charging stations, have you implemented that?

 

No such thing as a dumb question, just dumb people that don't ask. And Welcome to AAC!

There may be some safety issues involved, others here will know. A big reason is to avoid running all the grounding leads from the batteries to all the "Other" vehicle electrical devices. Which are designed for the "12V (13.8V)" standard. In particular all the signal and lighting bulbs, gauges, and now LEDs.

Thanks for the response! I don’t intend to ground any of the battery modules to the chassis. Was just wondering about the 240v being grounded only while charging. My chargers are at the module level and don’t charge through the 400v hv circuit like dedicated onboard ev chargers do.

 

There is a signaling protocol required for compatibility with charging stations, have you implemented that?

Thanks for responding! I’m not sure about that. I did a quick search but didn’t come up with anything.

 

Chargers have both + and - leads as do batteries... But...

 

Thanks for responding! I’m not sure about that. I did a quick search but didn’t come up with anything.

SAE J1772 standard

Scroll down to signalling.

 

SAE J1772 standard

Scroll down to signalling.

Ok thanks for the link! Looks like it won’t work for me. I’ll just need to stick to standard 120/240 outlets with my system.

 

My suggestion is connect that "ground" terminal to the vehicle chassis. If that is not accepted, then connect it to the AC power "common" side thru a one ohm resistor.
If that does not satisfy the stupid safety computer in the charging system, there are other things to try. I followed the link and never saw "signaling" or anything remotely close.
As is often the case, features intended to improve safety often prevent any possibly useful operation.Perhaps a small value capacitor in parallel with a 10Kresistor between the "ground" sense and the 240 volt neutral would satisfy the sensor circuit.