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Just a bit confused - Nissan Leaf Solar battery set up

Erzferz

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I have six Nissan Leaf second life batteries set up with 2 sets of 3 modules paralleled. And when I do connect this BMS from Overkill solar I will also connect a 40A solar charge controller and 200W of solar. If I'm right this should create a 12v system I could start running lights and other small 12v things with.20201202_124623.jpg

I don't have the components yet as I haven't decided what would work best. Though I intend to add DC to DC charging from the vehicle and an inverter to charge the system with as well as run higher voltage appliances here and there. Recommendations for these and how to incorporate them would be appreciated.
I have fuses, wires, a couple master power cut off switches. And determination to get myself some real running power!

The first thing I want to confirm is that the arrangement and setup of my wiring looks correct. (Please see edited photo of hypothetical wiring)
The BMS for the most part seems like it will be fine but C- being my main negative seems a little odd. Do I then connect it to a bus bar to evenly distribute the load, and then have that go to one wire that is my main negative for the charge controller?20201209_111639.jpg

Second, almost inline with my initial question I am unsure I understand where my main negative and positive posts are supposed to be, and do they connect directly to the solar charge controller? Another side question is what size wire you would recommend running from the batteries to carry the main current? ( 4.0AWG?)
So I was hoping to just get a little direction as well with how everything else comes together in this. I understand wiring up my lights, and switches but not exactly where to bring in my little fuse box and connect all these to the battery bank. 20201202_124646.jpg

This entire setup is going to live in a Chevy van that I happen to call home.
Any and all help and direction or tips are so very appreciated. Ill definitely keep this up to date with my progress.
Thanks so much.
 
Your wiring of the BMS looks correct. Those modules have 2 series cells in them. So you have 3p4s, will give you about 16.4v fully charged. If you custom set your charge controller to something just under 16v, you might be able to use a 12v inverter. Look up the inverter spec for max DC voltage and stay within that voltage.

The three black C- leads that is the negative to the inverter and charger. I would combine them and join to a heavy cable by whatever proper means you have available. A similar heavy cable goes where you have indicated on the photo.

Will has some diagrams on the web site. This one might help. https://www.mobile-solarpower.com/the-classic-400-watt-rvs-vans-buses.html
 
Thank you DThames, very helpful link there. I also greatly appreciate the confirmation on what I am doing because frankly I just am very new to a lot of electrical work.

I just ordered


to replace the 40A charge controller I had, somehow I stumbled on this through Will's videos. I realize the Solar charge controller I had would have likely worked fine but I wanted to incorporate vehicle DC charging as well and this seemed like a great 2 in 1 system. I think this would work well for me being that I drive quite a lot.
I am unsure of how I would have been able to custom set the charge controller but if the original setup seems more viable I can easily return to that for the time being.

Does this seem like a proper means of attaching a large battery cable for these C- cables? They would be bolted to a fabricated copper bus bar with room for a terminal on one side.
Or if it seems like it would distribute load better could join them all to a single terminal on a copper bar and have a large 4gauge cable come out right in front of them. ( I can draw this if it would describe it better.)20201212_181504.jpg

Thanks again for all of the help. Very Appreciated.
 
If you try to put 3 wires together into one terminal, there is risk the connection will not be ideal. If you solder them together first, you would have a better connection (most likely). I can see where 3 lugs, each attached to a copper bar and then your main lug to the copper bar would be a good way to connect. It might not be the best to look at but function is most important.

I have a couple of BMS to mount as well. Mine are similar but with two cables, where yours have three cables. When do you plan to hook yours up. I am still deciding how to connect mine....what type of lugs. I will most likely make something from copper tubing.
 
The Nissan Leaf modules aren't perfect for a 12 volt setup. As @DThames pointed out finding an Inverter that can go up to 16 or more volts will be the first challenge. It does look like that charge controller can handle 16 volts.
 
Not sure what type of inverter you are looking for but this one says up to 16v. You need a programmable charger to limit the max change to something inside your inverter range. That EPever shown in your first post is programmable. You can set the voltages exactly where you want them. Not sure about that Renogy one you mentioned. I don't see any "user" battery settings in the manual, but I might have missed it.
 
There's only one manufacturer (that I know of) that makes a 12 volt inverter that can accept a 16 volt input, the rest are limited to 15 volts.. The Sensata Dimensions inverter can go up to 19 or 20 volts DC input... I think they put these things on fire trucks and ambulances and stuff.. They are very heavy.

They are low frequency inverters.. Imagine that.. 12 volts and low freq.. Wow. And they have crazy surge ratings of like 400% or something like that.

Here's a link:

You can find them for sale on craigslist for around $300 to $400 quite frequently.. Almost bought one myself.
 
Such awesome feedback. Thank you all.

DThames, I may take your suggestion and solder the three C- wires. Ill take a look tomorrow. But either way your totally right function is most important.
Planning to set everything up as soon as a couple more parts come in, maybe a couple days ideally.
But ill be working on some things tomorrow.

Looking into this charge controller from renogy it does specify it goes up to 16v.DC from what I can tell Ampster.Screenshot (1).png
Though while your right on that DThames i noticed that as well and found a video from Will that indicated he reached out to renogy and found out about a small button that allows the user to set and reset the unit for different types of batteries. I don't know if this would be programmed enough or if the EPEVER would allow more.
Also funny you sent the link to the inverter you did as i was looking at one from the same company just in 2200W here.


MurphyGuy I appreciate the link, though new they are definitely out of my price range. While id like to keep my eyes peeled I do want to get this running ASAP for myself so if possible I may try to stick to the linked above one or something similar for now.


Thank you all so very much for the input! This has me feeling more and more confident in what I'm putting together. Even if those darn Nissan leaf batteries are not ideal everyone's help has me feeling optimistic!
 
"Though while your right on that DThames i noticed that as well and found a video from Will that indicated he reached out to renogy and found out about a small button that allows the user to set and reset the unit for different types of batteries. I don't know if this would be programmed enough or if the EPEVER would allow more."

While the type of battery is important, you are creating a very specific design need when you picked a 4s (4 in series) Lithium solution. A charger set for 4s lithium will take the pack up above 16v. Your inverter will shut off until that voltage is below a threshold, specific to that inverter. A USER battery type is what to look for in a charger. The EPEver has it, I use it. You need a computer interface or a remote LCD interface to get to the settings. Will also talks about this in one of his videos. This USER type is important for cases where you want precise control of your charging profile, cut off voltages, etc.

Charger-user.PNG
 
I see, I believe that was originally one of the reasons id gotten the EPEVER unit. So my Solar Charge Controller will be EPEVER and I will try to program it before I hook it up or when I am hooking it up. And the Inverter like the one you show here has to be programmable as well- I was looking originally at the renogy inverter you show actually.
Do you think it would be wise to still use the DCtoDC Charger function of the renogy unit for just that. Many others at similar price points don't have voltage sensing for when the vehicle actually is running and I liked the protections built into this.

I also know that my BMS from Overkill Solar is supposed to be very configurable and programmable on the computer. Would it be possible to adjust battery output voltage directly?
 
I see, I believe that was originally one of the reasons id gotten the EPEVER unit. So my Solar Charge Controller will be EPEVER and I will try to program it before I hook it up or when I am hooking it up. And the Inverter like the one you show here has to be programmable as well- I was looking originally at the renogy inverter you show actually.
Do you think it would be wise to still use the DCtoDC Charger function of the renogy unit for just that. Many others at similar price points don't have voltage sensing for when the vehicle actually is running and I liked the protections built into this.

I also know that my BMS from Overkill Solar is supposed to be very configurable and programmable on the computer. Would it be possible to adjust battery output voltage directly?
If you can get the Renogy unit with the USER type battery option and the alternator option you want, that would seem to be a good solution. As far as programming the EPever, if you want to do it with a PC, you need the RS485 to USB adapter cable. Also the program needed was not clear and how to use it was not clear. I should be able to help you if you go down the EPEver road.
 
Looks like I am going to try that route.
I appreciate the help. The inverter is currently on the way.
And I was looking at the RS485 to USB I happen to notice they also have an Elog- and Ebox one for logging data, one for adjusting parameters and everything else from their mobile app. I was wondering if you had any experience with either of those add on parts or the mobile app. Just trying to figure out if either of those would be of help down the road or if the mobile app is any more or less clear than the computer program.
 
It seems like with Circuit breakers people often size up, I believe so they are not tripped constantly.

For the 40A EPEver charge controller I have a 50A breaker and I am assuming I then would need a 60A breaker between my 50A DCtoDC charger and the rest of my system.

I am also wondering about the inverter, I realize fuses and breakers are put in place as protections, just not sure how many I should have and where fuses or breakers are more appropriate. It seems with an inverter of this (2000W) size I would want a 400A fuse. Or a 250A breaker, though it seems like a fuse in line would be more clean looking and be sufficient protection.
Screenshot (3).png
 
Looks like I am going to try that route.
I appreciate the help. The inverter is currently on the way.
And I was looking at the RS485 to USB I happen to notice they also have an Elog- and Ebox one for logging data, one for adjusting parameters and everything else from their mobile app. I was wondering if you had any experience with either of those add on parts or the mobile app. Just trying to figure out if either of those would be of help down the road or if the mobile app is any more or less clear than the computer program.
That Ebox might be an easier solution than the USB to PC. I am not familiar with it.
 
Realized I wouldn't be able to have it delivered for quite a while with anything but the cord. That's coming Thursday though.
Should have the inverter here tonight. Ill start working on my setup of everything tomorrow.
 
Got the inverter today, was kind of concerned about how beat up the packaging was. But the inverter looks to be in good sorts. Still took photos and will see how it works out when hooked up.

Out of curiosity do both of these hypothetical connections offer the same functionality?
Option one - Copper Bus bar that ill drill a couple extra holes into to bolt the part onto a wood platform. With three terminals and the main battery terminal wire coming from the center point.
20201215_173133.jpg

Option two
Like recommended before, soldering the three wires, using a single terminal to connect them to a copper bus bar that ill also add a hole or two to screw it in.
20201215_173045.jpg
Maybe ill just add three terminals and run them all to a single bolt on the board- and run my main negative lead off there.

Watching some of Will's videos It definitely seems like I could have a central circuit breaker to connect my system. Or like here I am seeing him use less breakers and fuses. I am becoming more lost with all the fuses and breakers an where they are all needed or where they are not.
In the above linked video this looks closer to what I am at. Instead of my system going to a breaker and spreading out across the system, it would go directly to the solar charge controller- and i suppose once i plug in i should be able to program the EPEVER controller/ as well as my BMS.
I started making a panel to bolt all my electronics and will post some photos tomorrow.
 
The second image has less bulk. You could even solder the wires to the copper and put heat shrink around them for a pretty neat solution. DIY, means your way is....your way.
 
Alright well, I attempted your idea of soldering the three wires to a busbar directly though my cheap soldering gun couldn't manage to get hot enough or stay hot enough, to bond the wires correctly to the copper. So I soldered the three C- wires, and crimped them to a terminal together.
Their all running to a 1/4" bolt. I drew in my anticipated main negative and positive cable that I will send directly to my 40A EPever Solar Charge controller.
I would appreciate confirmation that I can just plug it all in.
Two main questions I am hung up on.
One - Can I just plug the whole system in now and run it to the Solar Charge Controller without damaging anything? ( And then program the EPever after its all plugged in? or Before?)
Two- Should I, have these two wires going to a 40A or 50A Circut breaker before the Solar Charge Controller? Or should I be using a ANL fuse in line?
I have cut out a Wood board for my other components to go around my rear wheel well. Ill be mounting the Inverter and other components as I can starting Tomorrow.

Thanks again for help, and hope everyone has had enjoyable holidays!

bms wiring to charge controller.jpg
 
When you connect your black wire on that bolt, make the lugs touch one another without a washer between them, for best contact (what I would do).

You can connect the EPEver to the battery, which will power up the EPEver (without the solar connected) and you can do all of the programing like that. Connect the solar when you are ready to charge or test charging. I actually made a tiny pack from 7s 18650 cells (only 7), to power up and program a 24v setup.

I would fuse one wire normally. If you put a fuse right at the battery and then connect the yellow wire, all wiring will be fuse protected. If you have a two pole DC circuit breaker, I guess yes to 2 wires.

Looks good. Yes, soldering that that large of a copper mass would need a LOT of heat. I was thinking way smaller when I mentioned that before.
 
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