EV battery output connected to inverter solar input

[Vigo]

I did the abs module on this one. Its not a terrible job, not much worse than an abs module on a bunch of other cars. My assumption about why they fail is having to do with the extent to which they use the pump motor vs conventional vehicles. An abs hydraulic unit for many cars is $1000 new so thats not out of line either. I think i got a used one for $250 on ebay. I also repaired the combo meter with a capacitor i stole out of an old radio. ?

I just watched a seminar about the Solterra master cylinder which essentially has the abs hydraulic unit and ecm built onto it, as well as the ‘stroke simulator’ for force feedback on the pedal, etc. If those became a common failure point i can imagine the expense..

 

[goingbush]

Hi, New member here. I saw this thread & thought I should add my experience.
I have DIY converted my 4x4 to EV , its my daily driver now for 6 years , it has 45 x 200Ah LiFePo4 prismatic so pushing about 144V @ 500Amp . I recently replaced solar inverter on my house so have a spare Sungrow 5kw Grid Tie inverter .

Just as a thought about how to use excess solar energy , ( I export a lot for very little FIT, only $0.049) I made an experiment & hooked my 144V EV battery up to MPPT solar input . I stood back with PPE incase of smoke / explosion .

The Inverter happily produces 240V but it has some weird algorithm . I'll attach screenshot of production graph over a few hours. The inverter starts with low current & builds up to 12A ( its maximum string input) then falls back to 2A & builds up again over about 2 minuites. It does not get hot.

I tried with another ABB Inverter I bought on marketplace for $100 , it also works, pulls a constant 20 amps & makes about 2.5kwh , but old school inverter has no wifi so no graph.

(For experimental purposes only as its way off code)

 

[yabert]

Just as a thought about how to use excess solar energy, I made an experiment & hooked my 144V EV battery up to MPPT solar input .

Hi. What do you mean about excess solar energy?
When a battery is connect to the MPPT the battery can only discharge to the inverter and not the opposite.

 

[sunshine_eggo]

I suspect it's the MPPT algorithm continuously searching for the sweet spot. Since it's a battery, it's always going to produce peak output at peak current.

It could also be heat related. If the MPPT is hitting max temperature, it may fall back to a lower power, rinse and repeat.

 

[goingbush]

I suspect it's the MPPT algorithm continuously searching for the sweet spot. Since it's a battery, it's always going to produce peak output at peak current.

It could also be heat related. If the MPPT is hitting max temperature, it may fall back to a lower power, rinse and repeat.

Yes correct. The battery is capable of 500Amp , The Max MPPT inverter input is 12.5Amp , so it can't pull any more than that. But its definetly not heat related . If I watch the BMS Display in the car when I hook the battery to the Solar input the weird algorithm shows from the beginning. Even after a few hours running the Inverter is no warmer than it would get on a sunny day .

When the inverter was on the house PV system it would clip at 12.5Amps and show a similar output . ( I replaced the original panels with newer 15Amp panels)

 

[goingbush]

Hi. What do you mean about excess solar energy?
When a battery is connect to the MPPT the battery can only discharge to the inverter and not the opposite.

During the day I export more solar to the grid than I can use (in summer) even after charging the car, and only earn $0.049 FIT . , that is excess .
I won't comment on you thinking I might expect to charge a battery via MPPT input.

At the end of the day I have a fully charged car battery via its 3.3kwh onboard charger which I plug into a 20A outlet, my idea was to use some of that in the evening rather than pay for power from the grid at $0.26kwh.

OK Ideally I get a Hybrid inverter and buy batteries for $6000 for a questionable ROI ,
but I have 28kwh of battery sitting right there in my car.

 

[yabert]

... that is excess .
I won't comment on you thinking I might expect to charge a battery via MPPT input.

Haha! sorry if this has offended you.
English is not my first language and I didn't know how to ask detail with few words write in a discussion forum.

There is many peoples here who have or are interest to have their EV part of the solar/battery system and there is few challenge with current technology.
Myself, I connect my EV conversion with his 64 kWh battery to charge the house battery sometime.
It work, but it's far from plug and play
So, thanks to share you experiment.
Do you share details about you conversion somewhere? EV conversions are always interesting to see.

 

[goingbush]

Haha! sorry if this has offended you.
English is not my first language and I didn't know how to ask detail with few words write in a discussion forum.

There is many peoples here who have or are interest to have their EV part of the solar/battery system and there is few challenge with current technology.
Myself, I connect my EV conversion with his 64 kWh battery to charge the house battery sometime.
It work, but it's far from plug and play
So, thanks to share you experiment.
Do you share details about you conversion somewhere? EV conversions are always interesting to see.

Vigo, no problems, I struggle with English too and it is my first language
I converted my 1973 LandRover , Old school conversion before it was easy to buy salvage EV parts . i enjoy it so much its my daily driver . Here is my build
http://goingbush.com/ptev.html . I really need to update as its a long time ago now . The prismatic cells are still performing well.

 

[Vigo]

That's an excellent conversion writeup, thanks for sharing! Very cool vehicle!!

 

[goingbush]

I just recieve PowMr inverter today $300 , I intend to use it to run my 240V fish pond pump from solar & a backup battery but first I tried to make magic smoke by connecting MPPT to my EV battery. This is so cool, Im going to mount one in a pelican case with some safe connectors to use as a Power source to keep fridge running when the grid goes down (it happens a lot here) . At the moment i only have GTI inverters.

 

[yabert]

I just recieve PowMr inverter today $300 ... This is so cool

Yes, it's clearly unbelievable to have such features for 200-300$.
My PowMr 2400W still run a part of the house since near 2 years now. Solar panel always hook to the MPPT and 2-3 time a year I connect my Vanabolt (360Vdc) to the MPPT in order to charge the home battery when grid is down.

 

[sunshine_eggo]

I got the PowMr 24/3000 120VAC as an early x-mas present... still gnawing on bunch of used cells to get the LFP battery up and running. Looking forward to finally seeing what it can do.

 

[AussieDave]

Apologies for reviving an older thread but this is the closest thing I've seen to something I've been brainstorming.
I currently have a 5kW solar array feeding two strings connected to a 6kW Grid Tied Inverter.
Also have an AC Coupled 5kW Alpha ESS.

I'm about to purchase an EV with V2L capability. Unfortunately being V2L rather than V2G means it can't sync 50Hz AC with the grid. Hence my idea.

Attach the 220v AC output from the vehicle to a high output AC-DC rectifier which puts out 220vDC @ 3 amps (already seen a version I think will work)

Attach this to an input string of my grid tied inverter via a DC-DC Auto Changeover Switch.
So when that string reaches 0VDC (as the sun goes down), the Changeover switch swaps the input to the now DC output from the vehicle.
This DC from the vehicle is then used seamlessly with the grid as the inverter should treat it as if the Solar panels are producing power and therefore feed the entire house. If the output from the vehicle isn't enough, the grid tied inverter should then supplement from the grid.

Thoughts????

 

[Vigo]

Rectifying 220vac will give you something more like 350vdc so your components have to be designed around that.

I dont know anything about an auto changeover switch but i do know that the timing of dark hours is highly predictable so you could simply run it off a programmable timer switch.

You would need to be able to set your MPPT to only draw as much as the vehicle's onboard inverter can support. That's IF your mppt is 'larger' than the vehicle inverter.

 

[AussieDave]

Rectifying 220vac will give you something more like 350vdc so your components have to be designed around that.

Yeah a direct rectified current would provide 350VDC, I was thinking of using this VARIABLE unit to provide 220-240VDC at 3A to match the Voltage and current from that PV string input.
Wouldn't need to change the existing grid tied inverter this way.

https://www.aliexpress.com/item/1005003714947164.html