# Convert from Lead to Lithium



## dcb (Dec 5, 2009)

fwiw, it is at the point where you can with a little effort find a nissan leaf battery at the boneyard with plenty of life left in it for a couple grand. the modules are 7.5v (8.1 charged) 60ah, and there's 48 modules in a leaf pack, and they weigh ~8 pounds per module. They go for ~100 individually.

So if you scrapped up a whole pack you would have a ~120v, 180ah pack that weighs ~400lbs, for ~$2k and performs a lot better all-around. 

http://car-part.com/


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## Duncan (Dec 8, 2008)

Hi
If you can't find a Leaf pack there seem to be lots of Chevy Volt packs out there as well 

A volt pack is 14Kwhrs - mine was seven 2Kwhr modules and two 1Kwhr modules for $1800
Which is more actual available power than your old pack when brand new!

The Leaf batteries don't like high temperatures - which seem to reduce their life
The Volt packs have a very sophisticated temperature control and don't seem to deteriorate the way the Leaf ones do


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## dcb (Dec 5, 2009)

Duncan said:


> The Leaf batteries don't like high temperatures - which seem to reduce their life


FWIW, mostly a problem in hot climates, if you leave it fully charged in the heat for long periods of time.



Duncan said:


> The Volt packs have a very sophisticated temperature control and don't seem to deteriorate the way the Leaf ones do


This implies adding a liquid cooling system to your vehicle for the battery, FYI. A good idea certainly, but not strictly necessary (obviously), especially with your 400 amp controller, 3p leaf cells will not be severely taxed..


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## piotrsko (Dec 9, 2007)

volt packs are rated 16 kwh, 18 kwh if you go to 4.15 v per cell. 12-14 KWH usable so at pick up efficiencies of 400 wh/mi you get 35 ish miles depending on how daringly low you take them.

last year people wrecked a lot of volts so they are common, but the wreckers learned the packs are worth $2000 more or less to solar powered people. a damaged pack could be cheaper, but worth it if the front of the case only got damaged. the systems are mostly bullet proof. Cooling so far isn't an issue, keeping them warm is harder. I haven't seen a reliable system to run the installed BMS, and I don't use a automated BMS system mostly because mine don't drift all that much over 3 years they have been installed.

Obviously I'm a volt battery fancier. I could be convinced to do a leaf pack for more capacity. Tesla salvage is too expensive for me and currently too many problems.

MY $0.02 YMMV


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## dcb (Dec 5, 2009)

also fwiw, the leafs are nice in terms of molecularity. Since they aren't water cooled it is trivial to re-arrange them to suit. Since OP leads in with "I want to reuse my elcon", it is important to identify suggestions that do not minimize change the scope of the project.

Of course volt cells don't have to be water cooled, but they aren't as compact with the built in plumbing, and they are essentially misshapen lower capacity leaf cells at that point, and they have much larger units which are harder to break into smaller units to get them to fit in an existing space.


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## piotrsko (Dec 9, 2007)

yes but no matter the pack choice,  the ELCON needs a $75.00 reprogram because lead stops charging at 2.42v a cell and the profile is wrong.


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## dcb (Dec 5, 2009)

yup. There's a few folks here working on elcons too, with custom logic.

here's OP's equipment
http://www.elohmbre.com/evconversiondetails.html

I would suggest a leaf pack plus sourcing 9 additional modules for a bump to 144v as long as you are tweaking the elcon (it should still be in the output range of the elcon, and in range of your curtis, double check pls). 19S 3P ,should be good for 20% more range and top speed than the leaf pack alone.

plus you should monitor balance, if not actively control it. Theres a few solutions there, but at a MINIMUM at least keep an eye on it from a high level (like watching two fuel gauges and ensuring neither one EVER runs out) with a couple voltmeters watching the top and bottom halves of the pack. i.e. http://www.diyelectriccar.com/forum...-pack-balance-monitor-batt-bridge-165953.html , it will set you back maybe $5.00 in parts, and give you some measure of confidence in the charger/controller cutoffs. 

You can kill lithium batteries if they get out of balance, and you can start a fire if you ignore it. Typically they seem to get damaged on over-discharge then left to charge, never reaching the cutoff voltage, until it ignites, so a charge timer as a backup is good too (or something to say "it should be charged by now, I'm shutting it down"), at lest that is my understanding. So any indication of imbalance is cause to stop and investigate.


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## kennybobby (Aug 10, 2012)

Or you can reprogram it yourself, if you are somewhat handy with building some small electronic circuits and using an Arduino. Coulomb wrote the software to reprogram them--there may be a separate thread on just that subject.


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## el ohmbre (May 28, 2009)

Thank you everyone for the quick responses.

It sounds like a Leaf (or Volt) pack is the way to go. I found an entire Leaf pack near where I live with only 24K miles on it.

Will I need a battery management system to use these batteries or is it build into the modules?

Thanks again.
Tom


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## dcb (Dec 5, 2009)

I wouldn't count on using the leaf battery management system, they aren't built into the modules themselves, which you will have to re-arrange substantially. If you had a ~400v motor and controller and the entire pack fit as-is, maybe.


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## el ohmbre (May 28, 2009)

Well that brings up a new twist to this question. If I use the Leaf batteries, what do I have to do for a battery management system?

If I used all the modules, could I use the Leaf BMS even if I reconfigured the modules to fit my existing battery boxes? My boxes are pretty big since they held the Trojan batteries so they should fit nicely but the boxes are probably not the right shape for the entire Leaf pack unchanged.

Thanks


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## pdove (Jan 9, 2012)

There are people reusing the leaf bms. Search the leaf forums.


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## dcb (Dec 5, 2009)

el ohmbre said:


> If I used all the modules, could I use the Leaf BMS even if I reconfigured the modules to fit my existing battery boxes?


The thing is a "real" bms monitors at each distinct voltage level, i.e. every ~3.75V. With your existing motor/controller/charger you are going to be rearranging the leaf pack from 48S (S=Series) (96 really, each module has 4 cells, 2 in parallel and those 2 in series with another 2 in parallel).

So it originally had 96 voltage points to monitor @ ~360V+, and you are looking at maybe 38 (144v), or 32 (~120v) if you don't add additional modules. Such that you should wind up with 3 modules in parallel, and 16 in series (or 19 if you want to bump to 144), but 3x16 is 48, the number of modules in a leaf pack, so you would need to source 9 additional modules for 144v.

I don't know anyone who is using a leaf BMS to measure a partial stack of voltages, or even if it will work.

I don't know much about aftermarket BMS's for that matter, orionBMS comes to mind, but that isn't a recommendation. I just keep it simple with the system I described in post 8, http://www.diyelectriccar.com/forum...-pack-balance-monitor-batt-bridge-165953.html, some people don't use one at all, but hopefully they keep a voltmeter handy and do lots of checking, and/or use a wide margin of safety on charge and discharge cutoffs. There are so many nuances and opinions on BMS's, and even then they are not foolproof (indeed the occasional tesla still catches on fire). You are kinda on your own there. You have to really understand what you expect your BMS to do, and how it does it, at which point you almost don't need one, or don't have any guarantees what you buy does what you expect.

Sorry, it is a long tedious subject with lots of misconceptions. I'm gonna beg off of that.


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## dtbaker (Jan 5, 2008)

el ohmbre said:


> Hi. I did an S-10 conversion several years ago. I used 20 Trojan T145 batteries.
> 
> The batteries are long past their useful life and I would like to replace them with Lithium batteries.
> 
> ...


The large format prismatic cells (CALB are probably the 'best') are almost a drop-in for existing Pb battery racks. You can see what I've done with both mine was start with lead, and convert to Li.

I am a believer in simplicity, and would hesitate using the Leaf, Volt, or Tesla packs because of complexity. Managing hundreds of cells in parallel and series sounds like a nightmare compared to 38 cells in series.


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## el ohmbre (May 28, 2009)

OK, the Leaf pack has 48 modules with 96 "cells" for a total of 360v or about 7.5v per module.

Assuming I'm OK with 120v is there any reason I can't make 3 sets of 16 modules each? 7.5v x 16 = 120v and then wire the three groups in parallel?

Could I do 6 sets of 8 modules each?

I'm just thinking of what would be easiest to fit them in the exiting battery boxes.

Is my math correct? Are there any technical reasons preventing either of these configurations?

Thanks,
Tom


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## dcb (Dec 5, 2009)

el ohmbre said:


> OK, the Leaf pack has 48 modules with 96 "cells" for a total of 360v or about 7.5v per module.


essentially, technically it has 4 cells per module, but they are already 2P (parallel) so it acts like 2 cells.




el ohmbre said:


> Assuming I'm OK with 120v is there any reason I can't make 3 sets of 16 modules each? 7.5v x 16 = 120v and then wire the three groups in parallel?


Yah, that is what I'm suggesting, paralleling them is easy, just make sure they are the same voltage first, then bolt the connectors together.
Module wise a 48 module pack will make a 16S3P pack. at the actual cell pouch level it will be 32S6P. They are 60ah modules, so 3p would give you 180ah.



el ohmbre said:


> Could I do 6 sets of 8 modules each?


Yah but it would be silly, higher voltage is better, even 1P can keep up with your current demands, 3P is plenty stiff for your setup, you need the 16S to get the voltage up there so you can make some RPM (which is a component of power), plus losses are generally smaller with higher voltage systems.



el ohmbre said:


> I'm just thinking of what would be easiest to fit them in the exiting battery boxes.


series or parallel combinations will take the same space with the leaf modules, you just use a different busbar configuration.

Here is 5S3P leaf modules in my tractor (with my simple "BMS" hookups shown)











el ohmbre said:


> Is my math correct? Are there any technical reasons preventing either of these configurations?


Math, correct, reasons yes. Your setup is for ~120v, you might be able to push it to 144v. If you went 8s6p, it would be a 60v battery (though with 360 amp hours), the motor would only spin 1/2 as fast and develop 1/2 the power it does now. Plus you might need a new controller if it doesn't like that low of an input voltage, and if your elcon can handle it, it will lose 1/2 its power, like a 1.5kw unit.


edit: re space, you are not gonna have a problem. I replaced 6 forklift batteries with this setup, and it left the front battery box completely empty and didn't fill the rear. Shaved off probably 400 lbs also.


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## Duncan (Dec 8, 2008)

Hi
Volt packs
The 2013 Volt Battery consists of - 7 12S Units and 2 6S Units - It is dead easy to take apart to that level and reconfigure
That is 7 off 48v units and two off 24v units
If you want to split it up any more you have to start cutting welded parts - much much dodgier!


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## raphen (Jan 11, 2017)

Hi there. TBH a lot of this stuff is over my head but able to understand some basic stuff. After reading this a couple times this is what I have figured out. Please let me know if any of it is incorrect.

My current (12=8+4) lead acid batteries can be 
replaced with up to 18 leaf batteries because Open ReVolt 144 volt, 500 amp controller. 144/7.6=18. They could all probably fit in the current battery box if not I will figure that out when I get there. Given my climate (northwest california coast) I wouldnt need to supplement cooling of batteries or heating them although it could be done.

these are all the specs of the vehicle

Motor: Netgain Impulse 9" motor 
http://evolveelectrics.com/motors/ngm-impulse-9/

Controller: Open ReVolt 144 volt, 500 amp 
http://www.paulandsabrinasevstuff.com/onlinestore.html#!/Paul-&-Sabrinas-144v-500amp-DC-EV-Motor-Controller-Kit/p/59121625/category=16287308




System Voltage: 144 volts

Chargers(2): Quick Charge Octopus-AGM 10 Bank Charger
 Quick Charge 2 Bank
http://www.chargingchargers.com/quick-charge/octopus.html
http://www.chargingchargers.com/quick-charge/mb1210x2.html

DC/DC Converter: Kelly HWZ Series 144V TO 12V 300W
http://kellycontroller.com/hwz-series-dcdc-converter-144v-to-12v-300w-p-185.html

Instrumentation:

PakTrakr Battery Monitoring System, which monitors instantaneous
voltages of each battery in the pack.

Paktrakr Current Sensor, which monitors instantaneous
current delivered by the battery pack.

PakTrakr ES1R automatic logging serial interface for
recording instantaneous battery voltages and current.
The recorded data can be downloaded to a PC for detailed
analsys.

http://www.mightyboyev.com/PakTrakr%20800.htm


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## dcb (Dec 5, 2009)

fwiw, I would triple up the leaf modules. if you buy 18 individual modules it can cost you nearly as much as 48 modules out of a whole pack from car-part.

But you still need 6 more modules to get that to 3 parallel and 18 series (18s3p), that way.

I think 19 series modules *might* work too, and 2p is still ok for a 500 amp controller, so still a whole pack is a good bargain
19 series * 2 parallel (9s2p) = 38 modules, you would have 10 left over which you can sell or use for other stuff (they are very useful for trolling motors/ebikes/etc too, as long as your terminal charge voltage isn't anywhere near 100% you don't seem to need a very fancy charger, just a 16v laptop power supply for a couple cells).

You can watch the infamous Ben Nelson receive and dissect one here:
https://www.youtube.com/watch?v=h0dDHJKzX78

Note, he is using 18 modules on a glorified scooter, so you probably wanna up the ante on module count there. (heck I have 15 in a lawn tractor to replace 6 forklift batteries).

Don't know about packtracker, if I had one I might repurpose it to monitor various points in the pack to keep tabs on balance that way, if it were suitable, and I could figure out how to do it.


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