Hi Everyone, I wanted to share my Leaf conversion with you just to demonstrate how simple it can be in its most basic form. I'm no engineer and will never understand the intricacies of voltage information, discharge rates, current draw, etc - I will leave that to people who know better than me and I will always bow to their superior knowledge. All I wanted was a quick battery replacement, plug in and go ! This is what I did - (1) Removed the old NiMH battery pack, plenum fans & temperature sensors (none of it is needed), (2) Lined the battery housing with 2mm & 4mm rubber sheet to hold the cells in place (no nuts & bolts), (3) Slid in 19 leaf cells and linked them together using the old NiMH interlinks, fitted a positive & negative lead with an anderson connector, (4) Changed the charger software. Plugged it in to charge and then drove it ! The safe riding range is 156v to 140v with an impressive 90+ miles range (My max range 104 miles). There are a couple of caveats with this simple conversion - (1) I have to manually check each cells voltage to make sure everything is running as it should, and (2) there is no BMS yet. I am more than happy to talk about it and I will happily supply more pictures and share my spreadsheet with detailed battery voltages with anyone who wants that information. I have been running this configuration for 4 months now and the battery voltage is VERY slowly creeping up to its maximum of (hopefully) 158v. I manually balanced the cells after the first month and they are now 'self balancing' the remaining slight cell imbalances themselves. I wish I could have done it years ago !
My 'simple' Leaf cell conversion
Fri, 11/28/2014 - 13:07
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My 'simple' Leaf cell conversion
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Unfortunately I don't know how to link up and image in its original size (the upload feature reduces the image and makes it unreadable,) so if you want a copy of my most recent battery data that I have collected, please PM me and I'll send you the original JPEG image.
PS- would the admin please remove the duplicate entry for this topic, I'm not sure why that happened).
Electric traction is the future.
HI ALLEN,nice job on the leaf batterys conversion. these leaf cell are going like hotcakes here in the us and everwhere else I belive, when I first started looking at the cells on the (HYBRIDAUTOCENTER.COM) he had three 24 cell moduels and plenty of all the other bacthes that he sells but now he can't stock up ahead any more.I am still working on my conversion project since I am old and don't need to be in a hurry, but this is the best thing that came along since (sliced bread)was invented, keep posting. AND ABOUT THE DOUBLE POSTS WHAT HAPPENS IS YOU PRESS ON SAVE AND NOTHING HAPPENS SO YOU PRESS AGAIN AND AGAIN AND STILL NOTHING CHANGES BUT EACH TIME YOU HIT SAVE IT POSTS AGAIN,THIS IS NOT THE BEST SETUP IT SHOULD READ (SEND REPLY). HOPE THIS HELPS.
Hi Allan,
Great job! I send you a PM. I have to start a Leaf conversion and use your tips. I am waiting for 19 new LEAF cells delivery today :-)
You said: "they are now 'self balancing' the remaining slight cell imbalances themselves" What do you mean by 'self balancing'? (without BMS?)
I searched for a BMS solution. Emus seems great, but expensive. In a early project i used the Foundingpower BMS. it can handle 24 cells en all voltages can be set by PC software. No BMS boards for each cell, but wires. I think i buy 2 units for each 19 cells. Most important for me is overcharge protection and the possibility to watch seperate cell voltage. Foundingpower is currently working on a master-slave option.
http://www.foundingpower.com/en/Products/Smart_BMS/2012081492.html
'Self balancing' - Not really sure that is the correct term but this is what happened - After the the installation I had no way to make all the cells exactly the same voltage and I had to rely on the bikes charger to do the best it could, that meant that the cell voltages were out of balance by 0.01~0.03 volts. I eventually bought a charger for the job and spent several days balancing the cells to 6.472v(3.236v + 3.236v) but even then they were out by 0.001~0.006. Over the next few charges this minor imbalance disappeared and all the cells now hold exactly the same voltage (currently 8.2v). Also,the maximum voltage reached by a full battery pack is slowly creeping up now that they are balanced (154.1v, 154.7v and the latest is 155.6). I don't know why this is happening but I assume the batteries are settling down and slowly reaching their optimum levels themselves. All this with no BMS !
Electric traction is the future.
You can view my Vectrix photos here - https://www.dropbox.com/sh/2vy2e9rra1mtrbr/AAC-42-em61I4A56eTbuV4hma?dl=0
Electric traction is the future.
I think this is the best show of pictures I have ever seen, can you explain about the burnt controller board and how you fixed it.THANKS COOPER
Congrats Allan, that looks great! Two questions:
1. Are the Leaf modules from a new or used battery pack?
2. To manually balance the cells, does that mean taking apart the whole pack, or could you do it with the whole thing sittin in the well?
I'm hoping to do this conversion within the next year or two, if I can get a hold of the modules.
Hi Josh (Nice Volt, my friend has one), (1) The cells were new/never used and boxed up but they are from the Gen1 era, (2) You don't have to remove the battery pack but I did separate the cells just to make sure nothing went wrong.
As you can see I just disconnected the interlinks and moved them out of the way.
Electric traction is the future.
Hi Cooper, That is an old story on a separate thread from a couple of years ago. Simple story is this - incorrectly tightened terminal (at the factory) eventually became loose, eventually it arc'd and blew the board. Luckily I was able to get a replacement repairable board and I fitted that. My old board was given to Antiscab for repair or experiments - that way nothing gets wasted or thrown away.
Electric traction is the future.
HI ALLEN,Ithought that might be the problem a loose connection. I am not an electrictian but I have seen a lot of burnt items before like this and it's usually a loose connection. I will check mine at this point. thanks for the infomation. COOPER.
Nicely done.
I have a black Nissan Leaf and a blue Vectrix VX-1 too.
Did you use the threaded rods and/or compress/secure the cells together in some way? I would be worried if they move too much. Granted, there is some inherent flexibility at the cells connectors, which will nicely absorb small movements. But I would be worried about connectors coming lose over time due to motion of the cells within the pack if they are not secured to each other and compressed together a bit.
Also, I think charging 19 modules beyond 156V often, will likely reduce the life of the pack for very little added range gained. And is a bit risky without a BMS if a cell is potentially off balance. That's because above 4.1V per half module (above 156V for your 19 module pack) you get in the rather steep end of the charge curve, near "full", where even a little extra charge gets the voltage go up/overcharge an already full cell quickly, without you noticing by just monitoring the whole pack.
I'd be interested to follow your measurements over time about the "self-balancing". From a short discussion on this in my other Leaf thread, I understood that the cells can be balanced (like you did) at some voltage and they tend to remain balanced there, but they could be somewhat unbalanced at other voltages. And that they do not self-balance. However, your measurements appear to support the idea that they do self-balance (or by pure luck, they simply broke-in after a few charges to settle at the same voltages). It'd be interesting to follow more as you use them more. It's now too cold for me to ride here in the US, so I won't have my own data until Spring comes next year...
For charging in series without a BMS it seems the wiser option is to top-balance them. Like you have done. Mine are top-balanced to at least 0.01V (I can't measure more precisely). At the same time, they do show slight imbalance of as much as 0.1V when discharged to somewhat near empty, which is fine, as long as I don't push the limits towards empty. I only charge mine to 4.07V per half module (146.5V for my 18 module pack) rather than to the 4.16/150V that I safely could. I have not balanced my cells - I am using them as they came, being balanced "enough" out of the box seemingly. Maybe I will buy a balance charger and spend the time next year to balance them even better, but it does not seem to be necessary right now for me...
Yes, you can charge individual cells or half cells or any sub-string of cells in series without disconnecting the bus bars between individual cells. That's how BMS does it.
For convenience, and to not have to open the bike in order to check the voltages, I think it is worth it to wire the Leaf BMS wire leads even without a BMS connected (just make sure they don't short-circuit by chance, for example by something getting across the terminals at the end of the wires or by a wire insulation going bad somewhere along the path of the wires). This way also, if you have a powerful enough multi-cell balancing charger, you could hook-up several cells to it at once, saving time compared to balancing them one by one.
Kocho, thanks, that's good to know! Does anyone have a list of the best Multi cell chargers to do this?
HI KOCHO, you can put a strip of 3/4in x 2in. wood on top on each side of the cells and the top cover will hold them down real tight. I used the rods and spacers that came with the pack and used those spacers that have a bolt stud sticking up to bolt the wood strips down to.I also I did what you did and used the balance harness and ran them back to the rear trunk to monitor and balance charge the cells with. sorry that I don't have a camera and don't know how to put them on the computer anyway.now that I have a complete spare bike without damage for parts I think my bike will outlast me.
Hi Kocho (and everyone else),
I'll do my best to answer the questions and please rest assured that all my information is done from real world usage, testing, riding, charging, etc - no guess work, just the facts ! (1) Threaded bolts - I did not need them, the cells are so tightly packed that they are never going to move and I think that bolting them all together is a bit of extra work I didn't need. Also, If I have to remove a cell I can pull it out - if the cells are bolted together then I would need to remove the whole pack ! (2) As I understand it, using the battery spec sheet I have for my cells, the maximum they can hold is 8.4v (4.2v + 4.2v), times by 19 gives me a theoretical max voltage of 159.6v. The updated charging software cuts out at 158v (if it ever gets that high) so I believe I am well under the safe battery top voltage limit. As It stands at the moment, the pack is only reaching 155.6v so I have lots of safe room. I believe the safe maximum charge for this configuration is 158v - BUT - I will carefully test it and report back. (3) I agree that the 'top' and 'bottom' range is not usable - IE, generally speaking I get an easy 4+ miles per volt. Below the usable range (135v) this drops to less than 1/2 mile range per volt ! - I found this out when I accidentally dropped below 130 volts while testing. (4) I intend to fit a 'remote' testing point so I don't have to strip the bike down every time I need to measure the cells. This is a new year project :-) (5) Although the rubber lined compartment holds the batteries in situ, it doesn't stop the 'up/down' movement. I have added some wooden strips to hold them in place and this low-tech solution works very well indeed. I will take some pictures next time I strip the bike. (6) Range, currently I get 94 miles (using 21v) easily. If the pack eventually reaches 158v maximum I hope to get 103 miles (using 23v). Either way, it is close to my personal goal of a 100 mile range Vectrix - I'm a happy bunny. (7) I bought my cells from a friend, I do not know if he has any more, or if he can get any more. I can't give out his details but I will contact him for further clarification on the matter and report back as soon as I have more information.
I appreciate all the advice that is being offered and I take it all on board. I will continue to push my batteries to a safe maximum in the quest for some answers. If I think I am pushing too hard I will stop but at the moment the pack is safe and operating very well so I will push to the 158v goal and see what happens. Remember, I am doing this so that you don't have to and I will keep everyone informed. Wish me luck.
Electric traction is the future.
All the best people do have a black Leaf & a blue Vectrix ;-)
Electric traction is the future.
If I ever sell my (1966 IMPALA SS IT'S ONE OF A HIND AND I BELIVE IT HAS EVER OPTION THAT GM MADE IN 1966) it's blue inside and out and if it sells I will buy a blue or silver leaf to match my 2 bikes.
The idea of bolting the cells together is to keep them from buldging. If they do that you will never be able to remove even just one cell from within the pack because the forces generated by buldging can be enormous. People have had to use crowbars and the like in such cases...
My rides:
2017 Zero S ZF6.5 11kW, erider Thunder 5kW
I have never seen a "bulged" nissan leaf cell! Got a picture?
Lithium pouch cells only bulge noticably if excessively overcharged or over-discharged. I do not have a picture of a bulged Leaf cell. However, potential bulging is the reason for the "dent" in the middle of each cell can. It also applies some pressure on the pouch cell stack inside the can to reduce mechanical deformation of the cells. Lithium ion cells move mass from one electrode into the other during charge and discharge, and the electrodes do not have exactly the same volumetric behaviour when intercalating Li-ions, so the active electrode surfaces are always expanding and contracting during charge or discharge. If such pouch cells are left to their own devices their active surfaces suffer premature mechanical degradation by cracking.
Thus a ceratin amount of external compression can actually enhance cell life.
My rides:
2017 Zero S ZF6.5 11kW, erider Thunder 5kW
Regarding bolting the cells together : I wasn't aware that they bulged. As we are not using the cells to anywhere near their full capacity, I am confident that they will be okay - but - as a precaution I will removed all the cells after 12 months and see if I have any problems. Thanks for the information.
Electric traction is the future.
Hi Allan, very nice job!!
Can you tell us how you updated the charger software? We are thinking on making a similar conversion too....
Thanks,
Sirming.
You may want to read through some of the existing threads on the subject of updating the charger software. Many other questions on the Leaf conversion are answered here: http://visforvoltage.org/forum/13767-nissan-leaf-modules-li-conversion-questions
In essence, you need the right firmware (for your charger version/battery size/temp sensors in or out), properly installed Vectrix diagnostics software, and a CAN Bus adapter and cable that can talk to your bike. Then it's a matter of uploading the software to the bike... It is actually a very simple process that can be daunting at first and always has a potential for errors :)
Hi, this topic has been covered many times but here is a quick run through - You will need a Windows PC/laptop, a canbus lead, the original Vectrix diagnostic software & the updated files for the charger (I am using TheLairds excellent files). Then it is simply a matter of connecting it all together (in the right order - instructions come with the software), select your upgrade file and hit send, wait about a minute or so and all should be well. The first time you do it can be quite unnerving but it is fairly simple to do - even I managed it !
Electric traction is the future.
Thanks for the answers, I have a Canbus lead and a laptop with Vectrix diagnostic software. But regarding the TheLiards charger files, I have been told that only work for old chargers, e.g. for NiMH Vectrixs, and mine is a Li+ with a newer charger....
Yes, you are correct about the Laird's software only working with the old ESD type chargers. I am using the new Runke type charger, revision 4 (latest) that originally came from a Li bike (it was loaded with the Li software when I got it off eBay after my ESD burned out). The custom software for that I now use comes from here: http://www.vectrixsupport.com
David made changes to the charger and controller software for me and it now works with my Leaf conversion. David can also make custom changes per your specific needs.
I hear there is another alternative from fuelfreemotors in Europe (but there you have to ship your charger, where with David's software you install it like the Laird's).
Thanks Kocho, I have been told about David's option. What I have clear now is that it depends on the charger I have, if ESD/Runke.
Are you sure it's not white and gold?
Sorry.
OK, the actual question about your pictures Allen is the one where you have a J1772 plugged into a public charger and you have the other end of the cord is just a power plug that you have your bike plugged into. What is that? Where did you get it? I had been thinking I needed to build a custom one, but that looks great!
-Randy
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I also own a 2018 Tesla Model 3 and a 2012 Mitsubishi iMiev
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