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Bi-directional EV charging

Posted: Thu May 22, 2025 11:31 am
by Stinsy
Looks like Sigenergy have something ready for market. First one I've heard about. Jordan has a video about it up, I'd be very interested to hear about it from a credible source...

https://www.sigenergy.com/en/products/dc-charger

Re: Bi-directional EV charging

Posted: Thu May 22, 2025 11:33 am
by Yuff
I have literally had an electrician around to price up adding storage as bi-directional seems a long way off

Re: Bi-directional EV charging

Posted: Thu May 22, 2025 11:42 am
by Stinsy
Yuff wrote: Thu May 22, 2025 11:33 am I have literally had an electrician around to price up adding storage as bi-directional seems a long way off
I don't understand the delay.

Inverters that can take a 400V DC feed from solar and inject it in your house or the grid are cheap, reliable, and plentiful. Why do we have no inverters that can take 400V from an EV battery and inject it into the grid? The problem seems to be a software one that could be fixed by lunchtime given the correct motivation!

Re: Bi-directional EV charging

Posted: Thu May 22, 2025 12:31 pm
by SimonSays
Some cars' BMS don't like seeing power flowing out the CCS2 DC connectors.
I know some Teslas will tolerate it for a few seconds and then the BMS will shut down.

Re: Bi-directional EV charging

Posted: Thu May 22, 2025 12:51 pm
by Adokforme
I don't understand the delay.

Inverters that can take a 400V DC feed from solar and inject it in your house or the grid are cheap, reliable, and plentiful. Why do we have no inverters that can take 400V from an EV battery and inject it into the grid? The problem seems to be a software one that could be fixed by lunchtime given the correct motivation!
According to one of the speakers at the recent EE show at Excel Arena the hold up is purely down to the OEM's who won't release the software info until they can secure a cut of every transaction that takes place as a result and this is only likely to be resolved by regulation!

Re: Bi-directional EV charging

Posted: Thu May 22, 2025 1:13 pm
by Stinsy
Adokforme wrote: Thu May 22, 2025 12:51 pm
I don't understand the delay.

Inverters that can take a 400V DC feed from solar and inject it in your house or the grid are cheap, reliable, and plentiful. Why do we have no inverters that can take 400V from an EV battery and inject it into the grid? The problem seems to be a software one that could be fixed by lunchtime given the correct motivation!
According to one of the speakers at the recent EE show at Excel Arena the hold up is purely down to the OEM's who won't release the software info until they can secure a cut of every transaction that takes place as a result and this is only likely to be resolved by regulation!
Yeah, I've heard that VW and Tesla want to present themselves as a "distributed power station". They've forgotten that the EVs and the energy stored within is the property of the EV-owner!

Re: Bi-directional EV charging

Posted: Thu May 22, 2025 5:00 pm
by dan_b
Historically the car manufacturers have been wary of enabling V2L (bidirectional charging) due to concerns over battery lifespan - the worry being that allowing the customer to do multiple extra discharge cycles would prematurely age the battery and subject the OEM to additional battery warranty claims - as battery warranties are (at the moment) measured either by age or total mileage.

Also back in the early days, all Teslas were sold with unlimited lifetime free Supercharging - and Tesla was concerned about people basically filling up their batteries for free and then driving home and getting paid to inject their free electricity back into the grid and abusing the system that way.

It doesn't seem that difficult technically speaking to enable 3 or even 7kW AC discharge via the Type 2 CCS connector, and the concerns about battery cycles has rather gone away, so why isn't it a thing in all new EVs now already?

Re: Bi-directional EV charging

Posted: Thu May 22, 2025 5:11 pm
by Stinsy
dan_b wrote: Thu May 22, 2025 5:00 pm Historically the car manufacturers have been wary of enabling V2L (bidirectional charging) due to concerns over battery lifespan - the worry being that allowing the customer to do multiple extra discharge cycles would prematurely age the battery and subject the OEM to additional battery warranty claims - as battery warranties are (at the moment) measured either by age or total mileage.

Also back in the early days, all Teslas were sold with unlimited lifetime free Supercharging - and Tesla was concerned about people basically filling up their batteries for free and then driving home and getting paid to inject their free electricity back into the grid and abusing the system that way.

It doesn't seem that difficult technically speaking to enable 3 or even 7kW AC discharge via the Type 2 CCS connector, and the concerns about battery cycles has rather gone away, so why isn't it a thing in all new EVs now already?
The obvious solution would have been to have the inverter in the car and it squirt out electric through the AC terminals of the Type-2. However the powers that be decided against that and went for the CCS DC terminals and an external inverter being the only way that AC could be exported. The cars that use the Type-2 for V2L applications are ignoring the official spec.

My iD4 is advertised as being V2G enabled and it has a counter for the number of hours and a hard limit thereof.