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Bidirectional storage with EV.

JBDurocher

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Aug 3, 2022
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I would love to buy a huge battery and go 100% off grid, but the cost, especially for batteries is too much right now. I do have an EV that supports bi-directional charging. Anyone have success or ideas for using heir EV for battery to store excess power for use in the house?

The way our tariff works is that we can offset our use, but we do not get to keep our excess generation. I have a 4.6kW grid-tied system.

I inquired with a company called wall box, and they said they would email me when they have a product to go to market in my area. I’m not aware of an available commercial product.

It kinda seems like a no-brainer to use the 40kWh bidirectional battery I already have, especially because I don’t drive much. But my brain does not know where to start.
 
Google V2H for info on vehicle to home charging. Plus find out what your particular car can do.
 
I was planning to build V2L cable as soon as I get the new car(Kia EV6) This would be used mostly off-site or in emergencies.

Kia V2L cable was nothing more than connector, switch or two and and one resistor, rubber cable and type2 connector being the most expensive parts.
 
I was planning to build V2L cable as soon as I get the new car(Kia EV6) This would be used mostly off-site or in emergencies.
Tell me more what V2L is? I am familiar with Vehicle to Home and Vehicle to Grid. I presume you are going to tap the high voltage battery. The question is what are you going to do with the voltage and current from the car and what are you going to convert it to, AC or DC?
 
Tell me more what V2L is? I am familiar with Vehicle to Home and Vehicle to Grid. I presume you are going to tap the high voltage battery. The question is what are you going to do with the voltage and current from the car and what are you going to convert it to, AC or DC?
If it is within voltage range, could you feed it to MPPT input of a hybrid inverter like it is a string of solar panels and power your home from it ?
:cool:
 
There are a lot of 'entanglements' that can have negative effects.

First is dealing with high current capable, high battery voltage. Screw up and you can die.

Second is bypassing EV battery management systems. If you take out battery power that is not captured by EV coulomb counter the EV can think it has more capacity left than it actually does. At the least it can leave you with depleted battery on the highway, at the worse it can damage the EV battery from over discharging. Getting the EV computer tracking and EV battery back in sync can be complicated sometimes requiring a trip to service center. The EV computer may declare the battery as defective needing service attention.

There are some newer EV's that allow their use for a backup power source. Their battery management system keeps track of external consumption and provides safeguard limits on its use. They also have the physical interface and its activation management to make it safe.
 
Tell me more what V2L is? I am familiar with Vehicle to Home and Vehicle to Grid. I presume you are going to tap the high voltage battery. The question is what are you going to do with the voltage and current from the car and what are you going to convert it to, AC or DC?
V2L = vehicle to load. Quite similar to Vehicle to Home or Vehicle to Grid.

Kia EV6 and Hyndai Ioniq come with 230V 3.7kW 1-phase V2L inverter as standard package at least here in Europe.
You need type2 connector, one resistor and couple of switches to make your own DIY V2L adapter for the these Koreans.

RCinFLA's approach is bit too intrusive for leasing car :LOL:

 
It kinda seems like a no-brainer to use the 40kWh bidirectional battery I already have, especially because I don’t drive much. But my brain does not know where to start.
The simplest approach for small loads is to use the 12 volt battery terminals and a 1000-1500 Watt sine wave inverter. In EVs the 12 volt battery is charged from the pack with a DC to DC converter. The only issues are where to access the 12 volts and to know when the DC to DC converter is active. In my EV, the DC to DC converter is active all the time and the internal electronics monitor that load so the BMS and Coulomb counter provide accurate data. Other EVs only charge the 12 volt battery when the car is turned on which creates other overhead. I have used this approach to charge power tool batteries when working on a project at a relatives home during a power outage. We also ran the refrigerator from an extension cord when the same relative was getting a main service panel replaced. To use low Wattage inverters to run refrigerators requires that the refrigerator be a soft start inverter driven model.
If one wants to use this scheme with an inverter you should know the specs of your particular EV and the capacity of the DC to DC converter. 1500 Watts from a 12 volt source is 125 Amps and the DC to DC converter in my EV has a capacity of 150 Amps but many are a lot less so one needs to be careful.
 
Hopefully this thread will stay alive and be updated as developments emerge. Side note: I'm chuckling as this appears to be another thread with an OP that might never return.

I'm helping some friends design a modest off grid system. They will ultimately have an EV (make and model TBD) and it seems like a shame to size the battery for today ignoring the potential for so much energy storage parked in their garage.
 
I'm chuckling as this appears to be another thread with an OP that might never return.
Perhaps he realized that the technology is not there yet. I too would like to see this thread continue but the pace of development of any of thV2Grid, V2Load or V2Home technologies seems to be slow. Some of that is the techbologiy in the car and some in the bidirectional hardware needed at home.
 
V2G, (Vehicle-to-Grid Webinar) Link to Presentation.
This might be very specific to California, but I thought it is interesting in general.

Be sure to watch/listen to Jose Torre-Bueno's presentation which starts at 48:00.
And his remarks about the CPUC (California Public Utility Commission) at 1:01:00.
 
That plus the stuff is very pricy so far and no clear standard has emerged. Everyone agrees it's the cool coming thing but who wants to pay a premium for it? It's early days yet.
 
The video was good and the benefit to a stressed grid like in California, I had not considered. Tesla is doing something similar to help the grid with Powerwalls but not likely with any vehicles. They aggregate and sell back power from Powerwalls during peak demand times. They call it VPP or Virtual Power Plant. It is completely voluntary among participating Powerwall owners.
 
In my EV, the DC to DC converter is active all the time
I didn't know any EVs operated like this. What car is this?

The video was good and the benefit to a stressed grid like in California, I had not considered. Tesla is doing something similar to help the grid with Powerwalls but not likely with any vehicles. They aggregate and sell back power from Powerwalls during peak demand times. They call it VPP or Virtual Power Plant. It is completely voluntary among participating Powerwall owners.
The VPP concept with a powerwall is pretty great both for the grid and those that have spent big money on a real deal powerwall.
I've been doing something similar with a company called ohmconnect. They've been paying me over $1/kWh for each event where they activate the VPP. This summer there have been one or two events per week that last about an hour each. I don't know how that compares to the Tesla VPP as far as pay out or frequency. But, mine is far more manual. I've got to go and change settings in my inverter to push power to PGE for that hour. And the Tesla version is seamless, just get a check/deposit after they do all the programming and take their cut of the profits.
 
I didn't know any EVs operated like this. What car is this?
Tesla automatically charges the 12 volt battery all the time. Other manufacturers follow an artifact of how an ICE alternator operates and only charges the 12 volt battery when the vehicle is operating. Before my Tesla I actually ran down my 12 volt battery in two different EVs. It was at least six years ago and I don't remember the details except I was able to jump them to boot the electronics which got the car running and charging the 22 Volt battery.
 
I've been doing something similar with a company called ohmconnect. They've been paying me over $1/kWh for each event where they activate the VPP.
Some people refer to Ohmconnect as a VPP and it does operate in the framework of resources designed to relieve pressure on the grid. I think the concept is also called Distributed Energy Resources. OhmConnect tracks your usage and then when there is an Ohm hour they pay you for reducing your consumption below your previous average during that period. I used them for a few years but since I had a hybrid inverter I never had any usage during times when an Ohm hour was declared.
 
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