Use of Nissan Leaf battery in Solar installation.

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offpist

Active member
Joined
Mar 16, 2014
Messages
34
Hello everybody.
I currently drive an Nissan Leaf, and I am also very interested in Solar systems.
So I started thinking an battery from Nissan Leaf would make a good storage for solar power I normally export to the grid.

So, I got a hold of a battery pack from an wrecked Leaf, and started building.
First of all i had to make it about 48V, and to do that i have to put 14 Cells in series.
Each module has two cells, so its only 7 modules in series and 6 in paralell.
Then I can use 42 of the 48 modules from the battery pack.
This may be expanded with more modules later, we will see.

For battery management i am using this unit:
http://www.rec-bms.com/BMS9R.html" onclick="window.open(this.href);return false;

BMS.


Fuse, contactor and pre-charge unit.


Some of the connections.


Shunt.


LCD panel.


Comming together.


From the back.


Thermostatic controlled fans on top.


4 pcs M10 bolts on each bank.
 


Here is a picture how it is connected.



This video also shows the system well.
Could only find it in german, but the video is self explaning.

https://www.youtube.com/watch?v=9mIDjdnJDwE" onclick="window.open(this.href);return false;

Even more info her:
http://www.tritec-energy.com/images/content/D_264_SMA_SI6H_BRO_enu.pdf" onclick="window.open(this.href);return false;

When connected i should be able to see the status of the battery in Sma Home Manager.


 
Very cool. Please continue to update.

What SMA inverters are you using? I just found out about the "Sunny Boy" units that can provide 1.5 kW when the grid is down. I wonder how this could work alongside that system.
 
I will be using the SMA Sunny Island 6.0
http://www.sma.de/en/products/battery-inverters/sunny-island-60h-80h.html" onclick="window.open(this.href);return false;

Ordered it two weeks ago from Germany, but still have not arrived.
(I live in Norway btw)

The BMS has allready been programmed to work on CAN bus with the sunny Island.
So it should be just plug and play when it arrives.

I allready have the SMA Home Manager running with two SB4000TL inverters for two years now.

For now I am using a cheap 6000W China 48V inverter I borrowed from a friend.
It can only work off-grid ofcourse so i am running it on our hot water tank.

Today I charged the battery from 3,4V to 4,12V, About 10%SOC to 100%SOC.

Everything seems to work just fine, and very stable.
 
Very nice! I wondered who would do this first. Will this become a product?
offpist said:
The BMS has allready been programmed to work on CAN bus with the sunny Island.
So it should be just plug and play when it arrives.
CANbus? Why does Sunny Island support CANbus?
 
I have no plans of making more of these for selling.
The CAN bus is simply for communicating with the BMS.
BMS reports SOC, Cell voltage and also error message to the inverter if needed.
BMS controls the relay, so if there is something outside the parameters it will turn the power off.
I am by no means an expert on this, but its all done over this CAN bus.
Safety, and long lifespan if the battery is important.

The Sunny Island supports Lithium batteries, but ONLY if it receives signal from the BMS.
I used a lot of time asking different manufacturers if they made support for SMA, and this one did.

I do have the whole CAN protocol if anyone is interested, pm me.

Everything should be automatic, charging when surplus power is available and discharge when sun has gone down.

Usually i have an self consumption rate at about 50%, but with this system i should reach at least 80%, maybe more.

Not doing it for saving money, electricity is really cheap here.
Just really like the idea. And when i have an idea, i usually go thru with it ;)
 
CAN bus was developed for cars but it's made its way into industrial uses. PM sent about this "BMS CAN info" which I'm assuming is not the car's original BMS!
 
I have a xantrex xw6048 and 3000w of panels with a 350a 48v bank. What kind of voltage does it swing from on the low and high side? I would assume it takes big loads nicely given that is what it was intended to do.
 
The CAN bus protocol is designed by SMA (i think) for communicating With the BMS.

I plan on cycle the battery from 3,2V to 4,12V (44,8 to 57,68V).
The Sunny Island operates between 41 and 63V, so this should be just fine.
 
Very nice looking install, offpist - very professional!

How much energy are you getting out of the pack and are you able to provide an estimate for project costs? It looks like the modules cost around $125/ea here in the USA, so the batteries alone would cost over $5,000.

If it were me, I would probably opt to charge to a lower voltage (perhaps 4.05-4.08V / cell) in an effort to prolong battery life, but being in Norway you may not be very concerned about battery life with your cool temperatures depending on how long the pack will sit at max voltage. It may not sit at fully charged for very long since you will tend to pull from the pack shortly after the sun goes down?
 
I use Leaf Spy pro in my car, so I can follow the SOC compared to volt on each cell.
And it seems to match the SOC calculated by the BMS at home also.

I should be getting around 21KWH out of this setup, but I am very happy if I end up at 18KWH.

As you say, the battery pack will only be at 100% SOC for a few hours in the afternoon.. as soon as the sun goes down it will start to drain.
Or even earlier as we come home from work at 16:00 and start cooking and using TV/PC etc.

The system in my house already control 7 items in my house.
Meaning it turns on the units when surpluss power is available.
Hot water, dishwasher, washing machine etc. All comes on automatic during the day.

 
I usually buy 10-20 KWH everyday, the rest is covered by solar.
At the same time we usually export 10-20KWH pr day.

So i think this battery setup at about 20 KWH is just what we need.

I may add that EVERYTHING is run on electricity in my house.
We use no gas or oil for heating the house, or making food.

 
Cool setup!
We're doing this now with used MiniE modules from EVGrid. I've had 7 of the modules (also 2S like the Leaf although ~100Ah) running with my prehistoric Trace/Xantrex 4048 inverter for a few months now. The original 48V lead acid pack croaked earlier this summer after 12 years of use. I've developed a small circuit that talks to the AC Propulsion LOM BMS circuits on the modules (via fiber optics) to handle balancing and read voltages and temps. The circuit can control a contactor as well as displaying battery stats on a small 128x64 pixel graphic LCD. Optional RS232 and CAN connections available as well.

An entire 48V pack replacement including 7 or 14 EVGrid modules and the control circuit and contactor will soon be available in California directly from Sustainable Solutions Partners.
http://sustainsp.com/solar.php" onclick="window.open(this.href);return false;
 
I have nothing to add other than to say I'm really jealous and you've done a very professional job putting it together. Thanks for sharing! I do think solar + battery storage = the future. Especially when net metering goes away.
 
Thanks for the kind words.

Today I added some better ventilation.
The shed where all this is installed in is kind of small and we all know Lithium batteries don't like heat.

It is also isolated, so it will keep the batteries from freezing in the winter but with all this electronics giving off heat I needed to do something to control the temperature.

I wanted the inlet to be low, and close to the bottom of the cabinet.
But, having a hole in the wall close to the ground is not good here as we do get snow in the winter.
So I made a duct inside the wall, and the outside air is now coming out right where I want it.


Inlet, can be closed completely during winter.


This is the fan sucking out the hot air high up in the ceiling over the inverters.
It is controlled by an thermostat and only runs when needed.
Currently it runs at 50% speed, more than enough and very silent.
 
It has been running for some days now.
Works great ;)

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offpist said:
I usually buy 10-20 KWH everyday, the rest is covered by solar.
At the same time we usually export 10-20KWH pr day.

So i think this battery setup at about 20 KWH is just what we need.

I may add that EVERYTHING is run on electricity in my house.
We use no gas or oil for heating the house, or making food.
This is a very slick set up. I'd imagine several will start doing something similar. I hope Nissan doesn't jack up the price on their pack, to slow such projects down.
:(
.
 
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