# Li-tec batteries from 2013 smart car



## tenthousandclowns (Jun 21, 2012)

Is anyone using salvage smart car cells from Li-tec? I just got some on ebay and will be learning about them...

I found this test that seems to show min/max cell voltages of 3 and 4.2:
http://energy.gov/sites/prod/files/2015/02/f19/batterySmart5544.pdf

It looks like the low-voltage knee is at 310v or 3.333 volts per cell.

and their graph starts at about 385v or 4.14 volts per cell.

Any more/better/different information out there?


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## akseminole (Jan 5, 2014)

Hello, I have also acquired some Smart Fortwo Li-Tec battery modules.

I've done a bit of searching and I hope that the information that I found is helpful or even useful to this conversation as I am still trying to ascertain what charger and what kind of charge parameters I will need myself. 

I searched primarily for Li-Tec related information, some of the links look like they were multimedia presentations for whatever purposes. (The engineers talking to the pointy haired boss perhaps?)

I hope that these links will be useful as many of them are simply touting the technology in the batteries. However there are nuggets of (seemingly) useful information in all the links that I am providing.

In no particular order:

http://www.trolleymotion.eu/www/uploads/tx_sbdownloader/Herr_Hennige__Vortrag_.pdf

http://corporate.evonik.de/sites/dc...ortrait/Portraet_Lithium-Ionen_-_englisch.pdf

https://www.drive-e.org/wp-content/uploads/vortraege_2010/3_Di_Zschech_LiTec_CERIO.pdf

http://s1b677a343c55ff35.jimcontent...i-ionbatteries Davos 21012011 proceedings.pdf


http://www.maynards.com/media/components/ams/events/AAKRR101315/LiTec-Expose_compressed.pdf

http://energy.gov/sites/prod/files/2015/02/f19/batterySmart5544.pdf

http://ma.ecsdl.org/content/MA2010-03/1/699.full.pdf

http://litarion.com/content/pdf/Brochure_LITACELL-Lithium-Ion-Cell.pdf

http://www.evs24.org/wevajournal/php/download.php?f=vol3/WEVJ3-1130258.pdf

http://www.tec.ch.tum.de/uploads/me...ures_-_Battery__Michele_P._for_Hubert_G._.pdf


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## akseminole (Jan 5, 2014)

I'm not sure if these add anything useful to this, but it is more information about the batteries (or at least the BS that marketing tells the public about the batteries) as from Li-Tec's perspective.


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## akseminole (Jan 5, 2014)

It is my hope to wire my modules in parallel to create a 114v 150 ah battery pack.

From the information that the seller provided, it seems as though 125 amps continuous(per module) may be acceptable. Some information that I got from another eBay seller who briefly had some of these packs leads me to believe that 170 amps would also be acceptable from each module.

If true, then I am hoping that 375 amps continuous in parallel will work as well as at least 500 amps peak.

If the 40 ah cell is similar enough to the 52 ah cell, perhaps that 10c Max discharge statement would also apply. My application currently only requires 400 amps peak and my future plans only bump up to around 550 amps.

When possible I prefer to make conservative plans while simultaneously hedging on the side of overkill when applicable.


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## tenthousandclowns (Jun 21, 2012)

I have four of the 31-cell blocks... I was also going to put them in parallel for around 200ah. I am leaving three in the original box and making another box for the fourth.


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## tenthousandclowns (Jun 21, 2012)

are you going to try to use the BMS? I ripped mine off. I can send them to you if you want to try to figure them out.


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## akseminole (Jan 5, 2014)

I have no idea how to make that work. Does removing the bms reveal how to tap the cells to apply a bms of your own or could you partially remove the bms and reuse those attachment points?

I still haven't unwrapped my three and poked around in the original case yet.

I feel as though I should purchase some minimum level of PPE when attempting to disconnect the series connections, but I am uncertain what I should do. I've seen some electrical PPE on eBay, they look like rubber gloves inside leather gloves. Am I overthinking this?

What type of fastener holds down the (what looks like laminated copper strips with light blue insulation) that they use to connect the batteries? (I'm assuming a metric fastener, but like Hex or Star or?)


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## tenthousandclowns (Jun 21, 2012)

i think there are three or four sizes of the six-pointed star nuts in there...

each cell's bms connection was a pinpoint solder or weld onto an exposed plate... no screw holes or tabs or anything. I didn't see a great way to attach my own wire onto there.

If I recall correctly, the contactors in the pack were rated for 250A and the fuse was a 225A so I would definitely not go over that (per block)... the ebay ad I got them from said 100A continuous and 125 peak I think.. it was from greentecautohybridspecialist in connecticut.


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## tenthousandclowns (Jun 21, 2012)

I don't know what a PPE is but I just took out the two flatbars between the blocks first and put tape over the contact points before i did anything else. Only touch one thing at a time. The flatbars are a totally straight shot so no awkward wrenching.

Also when you poke a knife or scraper or whatever into the gap to separate the halves of the case, make sure you don't poke it in very far, not much more than the depth of the flange. .. whoever opened mine poked into one of the contactors.


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## akseminole (Jan 5, 2014)

PPE= personal protective equipment (I was an EMT/Hazmat tech for a time.)

Basically it just means I wonder if I should insulate myself from the tools that I use or will using only one hand do the same trick?

I would be interested to see a writeup of how you took apart your batteries (with pictures) if that were possible? As well as your build up with adding in the 4th battery.

I am still uncertain how I want to integrate my batteries into my build.


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## onegreenev (May 18, 2012)

akseminole said:


> PPE= personal protective equipment (I was an EMT/Hazmat tech for a time.)
> 
> Basically it just means I wonder if I should insulate myself from the tools that I use or will using only one hand do the same trick?
> 
> ...


When working with batteries it is wise to cover your tools, not because it insulates you from shock but from plasma balls if the tool touches both a positive and negative terminal. Trust us when we say a plasma ball is very dangerous. It will blow off hot molten metal and burns and ruins batteries and tools. Instantly.


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## palmer_md (Jul 22, 2011)

onegreenev said:


> .... Trust us when we say a plasma ball is very dangerous. It will blow off hot molten metal and burns and ruins batteries and tools. Instantly.


I'm not so worried about someones tools, but it can ruin lives, Instantly!


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## tenthousandclowns (Jun 21, 2012)

here is somebody selling 14-cell blocks of these on ebay:
http://www.ebay.com/itm/Lithium-Li-...029084?hash=item3d1ae2149c:g:RDkAAOSwAahXPPEm


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## akseminole (Jan 5, 2014)

It is hybrid auto centers eBay arm:
http://www.hybridautocenter.com/HAC...6kwh-lithium-battery-pack-50v-53ah&Itemid=605

What I like is that they have shown me how to attach a bms to my cells.


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## akseminole (Jan 5, 2014)

What I don't quite understand, is how they attached the cable to the cells.

I know where the cable attachment point is on the specific cell that is used for connection in the battery pack, but it seems like that would limit how much current you could pull.


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## Yabert (Feb 7, 2010)

akseminole said:


> What I don't quite understand, is how they attached the cable to the cells.


They seem to have fix/weld at different points the wire on the cell terminal and add silicone.
Good to pull a lot of Amps (relatively!!).


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## akseminole (Jan 5, 2014)

Yes, I see what they did. Though I'm at a loss for how to replicate it myself.


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## akseminole (Jan 5, 2014)

I'm curious how your project is coming along, specifically in regards to the batteries?


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## tenthousandclowns (Jun 21, 2012)

I welded up a battery rack and then left town... haven't done anything with them electrically yet.


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## akseminole (Jan 5, 2014)

It's been awhile, checking back in to see how your build is coming along with these batteries?


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## tenthousandclowns (Jun 21, 2012)

I have a couple photos of the cells mounted at evalbum.com/5187. I ended up using a third of the original bottom tray to set one block under the front seat, and welding a custom tray for the three blocks in the middle of the van.. then I will trim the original top cover to make an opening hatch cover for those blocks. I will make a separate cover for the front one too.
When I got the cells the blocks were around 112v i think. a while back they were down to 108 or 109 so I charged them at about 10A back to about 115v. so not much news electrically.
ebay seller ev-hv-battery seems to have half-blocks for sale now with or without BMS... here is the specs they list for a 14-cell unit with BMS:
Specifications:

Average voltage: 3.6V per cell, 14 cells in series - 50.4V average

Capacity - Rated 52Ah, Measured 53Ah - 

Minimum voltage: 42V

Maximum voltage: 58.8V

Size 8" (9.5" with the side brackets) x 14" x 7" 

Total weight: approx. 55lb

Installed BMS for balancing and overcharge protection
To connect to the golf cart you need a Andersen connector 175A red with 2AWG wires - we can add that for $35.
Chargers available - $168 for a 10A charger


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## tenthousandclowns (Jun 21, 2012)

further reading about running parallel strings:
http://elithion.com/pdf/BPC2012Elithion.pdf

makes me think I should break up the four blocks and make bricks of 4 cells in parallel and wire those in series.... I already mounted the 31 cell blocks though. dang. Also the tubes for the coolant are set up so nice for the blocks already. So I am considering going with a higher voltage drivetrain and using the three blocks in series, like in the original smart car, and maybe eventually getting two more blocks to have a second pack to use on long trips.


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## Markas (Feb 11, 2017)

Hello, I am looking for this sensor from Smart electric traction battery pack. If someone can help me, please write me: [email protected]. Thanks.


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## tenthousandclowns (Jun 21, 2012)

just sent you an email


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## tenthousandclowns (Jun 21, 2012)

I have been toodling around town a bit with this van... I have had the four 31-cell blocks up to 123v and drained them down to 112v or so.


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## akseminole (Jan 5, 2014)

Did you end up wiring them in series or did you make do with the parallel series strings?

How has their performance been?


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## tenthousandclowns (Jun 21, 2012)

They are in the series blocks of 31, then the blocks in paralel.

They sag a couple of volts under acceleration, not much.

It seems like the voltage goes down faster than I'd like. I haven't explored any of the range to be had at less than 112v.

What about you akseminole?


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## GreenTecAuto (Jun 14, 2017)

How are these working out?
I remember your username from ebay, not an easy one to forget.


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## tenthousandclowns (Jun 21, 2012)

they are doing well but i am using them very lightly... i am starting to feel like i am not the best at building electric cars... i charge them up to 124v and use them down til about 113 and i guess that is 20 miles or so so it seems like the voltage drops too fast.... not sure if it hits a plateau somewhere maybe around 113, that would be nice, i was hoping for a range of about 60 for a 20kwh pack but im not ready to push it... i also always check if yall are selling more of these because i could easily stick another 3 pack in there for longer trips...


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## GreenTecAuto (Jun 14, 2017)

You need to consider that the tiny little car only got 58 miles per charge.
How much bigger is your van?
I dont know if you know the back story to these, so here goes.
Li-tec messed up. They made great batteries, but the cases they put them in sometimes didnt do their job.
The cells would sometimes not fit perfectly in the case. 
I have 6 packs with one bad cell in each. I took one apart, the corner of the bad cell was dented in. 
From what i can tell, it looks like it was a short inside after that damage, but it didnt look like it caught fire or exploded, maybe more like a slow drain on the cell.
Since then, Li-tec has gone out of business, and all the warranties of the Smart car owners have been canceled. 
They dont offer any replacement options.
I was told this by someone looking for a battery for their Smart Car after you bought the ones you have. 
So, back to the ones I have, it is possible to replace the one bad cell. Would require a bit of work and would need to figure out how to make sure the BusBar connection was as good as when new.
I dont have the time to do that. I took the one apart for parts, and decided i didnt want to get too involved.
Still have the one for parts, most of the bus bars are still together.
The question is, do you have any interest in *doing it yourself*?


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## tenthousandclowns (Jun 21, 2012)

i haven't taken apart any of the 31 cell blocks.... but from what i have read it is much better to put individual cells in parallel and then series those than to use parallel blocks... im not sure i want to dig into the blocks but if i did then i could use more cells yes....

i have a few cells in each block that are slightly lower voltage but not much... haven't checked them in a while.


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## GreenTecAuto (Jun 14, 2017)

Here is the discharge curve of one Li-tec cell.
Tested from 4.2V to 3V at 20A. Got 48.8Ah
If you are only going from 124V to 113V, your voltage range is only 4V to 3.64V per cell. Not a whole lot of usage of the battery.
I programmed your voltage limits for the next test, but dont plan on waiting around for them. Interesting to see What capacity percent of the pack you are actually using.
As for the pack configuration, you are right. First parallel, then series.
However, i would like to point out that Honda Fit EV and the Prius prime both have a set up similar to yours. 3 strings of series paralleled together. 
They however have a relay unit for every string of series to be able to turn them on and off individually. Im not sure, but they might only use one at a time, instead of all 3 at once.
Better? Probably. 
Necessary? Maybe not.


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## tenthousandclowns (Jun 21, 2012)

i haven't tried to explore the whole range of them... still working on car in general


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## GreenTecAuto (Jun 14, 2017)

Here is the same cell discharged in your voltage range.
From 3.96V to 3.61V at 20A.
Got 11.2Ah. 
You are only using %20 of your batteries. 
You could probably get 100 mile range if you utilize the whole pack.


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## tenthousandclowns (Jun 21, 2012)

If you can get me there i will give you money.


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## jimmyaz (Oct 9, 2017)

tenthousandclowns said:


> If you can get me there i will give you money.


I have acquired a pack... if anyone need more to add to their set up... let me know. 

http://www.diyelectriccar.com/forums/showthread.php?p=944650&posted=1#post944650


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