Solar battery and V2L

[jack74]

I am curious to know if its possible to charge Givenergy solar battery from MG4. Any advice would be greatly appreciated.
I saw this video too and learnt about automatic transfer switch (ATS).
If possible definitely a job for MCS qualified electrician.

 

[gdog]

Sounds interesting but technically difficult.

 

[T1 Terry]

I am curious to know if its possible to charge Givenergy solar battery from MG4. Any advice would be greatly appreciated.
I saw this video too and learnt about automatic transfer switch (ATS).
If possible definitely a job for MCS qualified electrician.

What voltage comes down from your solar to the inverter/charger/grid energy gifting device? Maybe possible to feed DC into there, with a suitable diode on the panel side to avoid back feeding and turning the solar panels into heaters, and powering the house and charging the battery that way .... be sure there is an auto cut to the grid gifting before the battery reaches 100% and use that signal to stop the DC transfer out of the MG battery .......

What voltage is the house battery? Maybe a suitable voltage charger connected to the V2L would be easier ......

T1 Terry

 

[jack74]

Thanks Terry
From solar to inverter - difficult to say there is 12 panels.
I believe discharge from car is AC right ? not DC ??

Battery specs

Inverter specs

 

[Barrie]

It's simple. Just connect a suitable 48V battery charger to your V2L connection to your battery. Set the battery charger that suits the charging voltage for your battery. If you have charged your car via solar during the day it's an ideal solution to back up your home battery during the night. Can't quote on a Givenergy battery set up but this works with my home DIY set up.

 

[Everest]

Just connect a suitable 48v battery charger to your V2L connection to your battery.

That is what I intend to do too. Inspired by others on here that have done the same (@Bricktop X PWR and @wattmatters, IIRC).

Something like a Chargeverter or similar would work well, though probably an overkill with the MG4's limited V2L output of 2.2kW. There are some DIY options too.

Edited to add.... unless your inverter has an additional 'generator' input, in which case you can connect directly to the inverter from the V2L output and avoid the cost/complexity of an additional battery charger.

 

[Bam Bam]

Thanks Terry
From solar to inverter - difficult to say there is 12 panels.
I believe discharge from car is AC right ? not DC ??

Battery specs

Yes, you are right the car will output AC.

I would imagine that the Givenergy battery only works with a givenergy inverter (at least not easily)

What is it that you are looking to do, here? Use the car to store excess solar during the day and then discharge back in the evening?

Why does the power need to go back into the house battery rather than being used directly for something?

 

[Everest]

I would imagine that the Givenergy battery only works with a givenergy inverter

From the specification on the label image above, the Givenergy battery is an industry standard LFP in 16s configuration (rather than a proprietary high-voltage battery).

The battery and inverter will therefore be agnostic as to where the supply power comes from. So no different to having multiple solar charge controllers powering the same battery pack - i.e. basic Kirchoff's Current Law comes into play.

The key considerations to charging the battery from a V2L output will be:-

a) Maximum charge current of the battery. If the battery is not rated to charge at a greater rate than the inverter can supply, then you will need to limit inverter's charge so that the total charge will not exceed the battery's capacity. In the images above we can see that the battery supports up to 80A and the inverter has a max charge of 65A. So there is 15A to play with, without restricting the inverter, which, at 48V is 720W.

b) That the charger is fully isolated from its ground connection. This would normally be the case, but would be best to check / verify first. The battery voltages on a typical HF inverter are floating wrt the internal HV DC Bus of the inverter and must not be grounded. Doing so will damage the inverter.

c) The charger should be configured to output the required voltage to maintain the minimum battery SOC that you require. Typically 53 - 54v would suit a 16S LiFePO4 battery system.

What is it that you are looking to do, here? Use the car to store excess solar during the day and then discharge back in the evening?

That would be the most useful case in the UK, plus have the ability to power the house during a power-outage, assuming you have a critical loads circuit wired up to your inverter. But it would be good to know the OP's intended use.

Using the car to store cheap electricity overnight and use that to power the house in the day is less attractive due to the very high conversion losses going from AC->DC->AC->DC->AC combined with the quiescent consumption of the vehicle during charge and discharge periods.

 

[Bricktop X PWR]

In the very simplest of terms....

In the winter, I plug the car into a 48v battery charger (ex forklift)

This charges my 48v battery bank.

This is connected to my 240v 5000w inverter.

Depending on the amount of Sun received in the day time (winter) I might need to do this every couple of days.

The car discharges 10% per session overnight to my off grid battery bank which easily powers my home all day.(24hrs)

 

[wattmatters]

From the specification on the label image above, the Givenergy battery is an industry standard LFP in 16s configuration (rather than a proprietary high-voltage battery).

If it's a bog standard 16S LFP battery, then it's not difficult - just need to connect the battery's terminals to a compatible battery charger designed for use with regular AC power input. Ensure the connection has a suitably rated fuse/DC breaker to protect the circuit components/wiring.

I've used V2L to occasionally supply supplemental charge energy to our home battery using a spare all-in-one inverter/charge controller, but it can be any AC powered charge controller designed for use with a 16S LFP battery.

My main use case is to provide supplemental charge for when we have extra long grid outages. Car can supply a steady charge to the home battery, which is already powering our homes via an 8 kW off-grid inverter. Most I've discharged from the car in one session was 22 kWh, during and following a long daytime outage.

 

[Cowton jb]

Have you managed to acquire a suitable 240v lfp battery charger?
I'm hoping to do the same ideally with a plug to fit the pictured socket

 

[Tig170]

By far the easiest is to get on Intelligent Octopus Go, plug in the car charger and 99% of the time it will give you an immediate charge slot (i.e. charging at 7p), and just manually switch-on the Giv Energy device to charge, I never plug in at night, but when we get home ~ 3pm, and unplug at 11:30, but from 25p to 7p for all electric could work in ones favour. e.g. I used 1600kWh in Jan 25, but it only cost:

There is a post on this forum in recent times, which has shown bi-directional V2G with the MG4, but I cant find the link.

Also see this

 

[Rolfe]

I am curious to know if its possible to charge Givenergy solar battery from MG4. Any advice would be greatly appreciated.
I saw this video too and learnt about automatic transfer switch (ATS).
If possible definitely a job for MCS qualified electrician.

I just asked my installer about this and he said no.

 

[Everest]

I just asked my installer about this and he said no.

Did he give a reason?

 

[Rolfe]

He said that there was nothing in the GivEnergy specs about any other way to charge the battery, other than the mains.

 

[Cowton jb]

By far the easiest is to get on Intelligent Octopus Go, plug in the car charger and 99% of the time it will give you an immediate charge slot (i.e. charging at 7p), and just manually switch-on the Giv Energy device to charge, I never plug in at night, but when we get home ~ 3pm, and unplug at 11:30, but from 25p to 7p for all electric could work in ones favour. e.g. I used 1600kWh in Jan 25, but it only cost:

View attachment 34624


There is a post on this forum in recent times, which has shown bi-directional V2G with the MG4, but I cant find the link.

Also see this

Already do the intelligent cheat. Rarely get a charge slot during the day unless very windy or sunny. Get enough solar in the good months just need some help on those grey days.
Looking at a mains charger to assist from the V2L but not sure whether it should be 16S 58.4v or 13S 54.6v both output 588w?

 

[wattmatters]

Looking at a mains charger to assist from the V2L but not sure whether it should be 16S 58.4v or 13S 54.6v both output 588w?

What are the specs of the battery you wish to charge?

Note that the small All In One inverter/charge controller I use enables me to set charge voltages in 0.1V increments anywhere from 48.0 to 64.0 V.

Also enables charge current to be set in 10 A increments (which is roughly 500 W increments).

 

[hojnikb]

Does the inverter have a separate AC input? If that's the case, you can use that to supply power to it via the V2L system of the car.

You can then set the grid charging (grid being the car) at night or when theres no solar.

If that's not possible on this particular inverter, then a separate AC battery charger could do the trick, but it might interfere with the way your main inverter works and charges the battery.
In this case, it might even be cheaper to just buy another seperate hybrid inverter, that only acts as a charger, because purpose built charger can be more expensive for the sort of power than your inverter.

 

[Cowton jb]

What are the specs of the battery you wish to charge?

Note that the small All In One inverter/charge controller I use enables me to set charge voltages in 0.1V increments anywhere from 48.0 to 64.0 V.

Also enables charge current to be set in 10 A increments (which is roughly 500 W increments).

Battery is a 9.5kWh Givenergy, same as pictured in previous posts.

 

[Tig170]

... not quite the original question, as its not really possible, but this may be of use - i.e. to stop your ESS discharging during those extra IOG slots - I'm also a beginner to home assistant - you dont need such a fancy set up - I got a PI 4, poweved by my home router (USB), used the SD card from my dashcam, and plugged it directly into the back of the network secket in the router, and I'm almost up and running