EVs and MPPTs

[Darren Orange]

I have an idea that in theory a DC based house battery could easily be assisted when needed from a EV with a simple MPPT charge controller. Most EVs run a battery voltage that is less than 500V, so my theory is there would be no reason you could not connect a 500V Mppt charge controller to the car battery to charge the house battery which might be 48V.

I know that there are some other elements to consider to get this to work, but in theory all you really need is a MPPT charge controller that can handle the voltage which there are quite a few that can. This would greatly simplify all these processes out there and could allow for a more universal solution across multiple EVs.

To me this solution sounds extremely inexpensive so I doubt they will be doing this any time soon consider the lighting costs some 9 grand plus install but in theory this to me would be the quickest solution to take advantage of the EV battery.

 

[Solar Guppy]

Mppts are not design to track off of fixed voltage sources and are also do not come with current protection. Also how would one actually connect to the EV battery? The Charge port DC pins require protocol handshake to have the vehicle enable the DC pins, they are not just live 24/7

 

[Darren Orange]

I've tested tons of MPPTs using a bench power supply so I doubt it would work any different. Current protection you would simply put a standard Solar fuse inline I would think. Getting access to the power making the pins hot is a issue but assuming that worked, I would think a MPPT would be a cheap solution vs these very expensive custom setups that are currently being sold.

 

[yabert]

Most EVs run a battery voltage that is less than 500V, so my theory is there would be no reason you could not connect a 500V Mppt charge controller to the car battery to charge the house battery which might be 48V.

Done here: https://diysolarforum.com/threads/360v-dc-input-split-phase-120v-240v-ac-inverter.15036/page-6
Chevy Bolt 360V battery connect to AIO charging 7S NMC battery (24V)
Still the real thing should be to have a CCS gun connect to the car and allow the charge station to take of give energy (like Ford Lightning).
The missing link is the CCS controller...

 

[timselectric]

Yes, it works just fine.

 

[zanydroid]

The missing like is the CCS controller...

Someone can potentially try to reverse engineer the ChargeStation Pro or whatever it’s called. It breaks the CCS out into RS485 and HVDC. But it’s not clear whether it can be made to work with non Lightning EVs, so probably not that many people interested in hacking on it.

 

[pollenface]

A simple solution would be a Vehicle2Load cable with a battery charger plugged into it, then connected to your house battery.

My MG ZS EV has a V2L output capability of 2200w.

 

[zanydroid]

Yes, that is something I have in one of the designs I'm considering for my next system.

They might also be used with generator assist mode (AC coupled) for a little more efficiency.

Best we have in the US is Hyundai/KIA's ~1800W V2L. Which actually is theoretically good enough to run my minisplit by itself for many of the heating/cooling hours