# Junkyard rollers



## Lionstrike (Oct 29, 2011)

So I was lazily driving home today using another route and I discovered a junkyard not too far from my front door. I must have driven past it 1000 times, but never once did it strike me that is a place where I could possibly find a donor, and possibly save a vehicle from becoming scrap metal. This is relevant to my interests...

So, anybody get a junkyard roller before? Anything to look out for? 

I am just considering my options. I still haven't sourced all my EV parts yet. It's nice to have options though.


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## evmetro (Apr 9, 2012)

That is how I got the Cadillac Eldorado that I am converting right now,


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## nimblemotors (Oct 1, 2010)

The car itself is usually the cheapest part of an EV, which most people don't understand at all. 
Having a car to convert gets you about 1% of the way to a working EV.

For this reason, converting a cheap car to an EV is just foolish.


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## evmetro (Apr 9, 2012)

nimblemotors said:


> The car itself is usually the cheapest part of an EV, which most people don't understand at all.
> Having a car to convert gets you about 1% of the way to a working EV.
> 
> For this reason, converting a cheap car to an EV is just foolish.


There is a lot of merit to this. If you are going to buy a junkyard roller for the purpose of saving money, it may cost you more in the long run. When I picked up the Eldorado from the junk yard, I already knew that I was going to re engineer far more than the average guy who just wants a basic EV conversion would. An EV conversion can be much simpler on a car that is already in good running condition. What Nimblemotors is saying about the 1% of the final value is about in the ballpark. None of the conversions that I have done have a Kelley Blue Book value of over $1000, and they are simply platforms for the real assets, which are all the components. If you know what you are looking at, a junker may be the way to go, but if you are looking for the easiest way to convert a car, get one that is in the best shape that you can afford.


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## favguy (May 2, 2008)

I would second what has been said above. Also, cars get handled badly and beat up quickly once in a scrapyard, even if you find one that's just arrived at the gate, it's probably sustained damage in the pick up handling by the breakers...

A much better option is to buy someone's pride and joy that's suffered a blown engine, an older car such as this will often cost barely more than scrap due to the economies of replacing the ICE engine and can be like new bodywise


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## Lionstrike (Oct 29, 2011)

evmetro said:


> There is a lot of merit to this. If you are going to buy a junkyard roller for the purpose of saving money, it may cost you more in the long run. When I picked up the Eldorado from the junk yard, I already knew that I was going to re engineer far more than the average guy who just wants a basic EV conversion would. An EV conversion can be much simpler on a car that is already in good running condition. What Nimblemotors is saying about the 1% of the final value is about in the ballpark. None of the conversions that I have done have a Kelley Blue Book value of over $1000, and they are simply platforms for the real assets, which are all the components. If you know what you are looking at, a junker may be the way to go, but if you are looking for the easiest way to convert a car, get one that is in the best shape that you can afford.


Good points. 

I don't want to deal with rust, suspension issues or transmission problems. Now, while I am sure that there are rollers in that lot that have been essentially wasted by their former owners for having a blown motor, it seems to me to be more likely that they've got more than one problem with them that caused them to discard them.

I don't want a headache that's waiting for a new head.


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## nimblemotors (Oct 1, 2010)

Let me also add that in fact you are better off to buy a perfect good running car, and then you can sell the ICE parts for the same or even more than you paid for the entire car.


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## Lionstrike (Oct 29, 2011)

nimblemotors said:


> Let me also add that in fact you are better off to buy a perfect good running car, and then you can sell the ICE parts for the same or even more than you paid for the entire car.


Another good point.

I have to take care to avoid delusional sellers as well. What's wrong with some of these people on Ebay and Craigslist? I am seeing 90' Ford Rangers that people want $3000 for.

Kbb.... $650. I don't get it.


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## Duncan (Dec 8, 2008)

Lionstrike said:


> Another good point.
> 
> I have to take care to avoid delusional sellers as well. What's wrong with some of these people on Ebay and Craigslist? I am seeing 90' Ford Rangers that people want $3000 for.
> 
> Kbb.... $650. I don't get it.


KBB might be $650 - but that is for "average" condition on a 24 year old car
In other words - rough!

Any vehicle in good mechanical order with a tidy body - is probably worth $3000

As far as age goes - that is important when a car is relatively new - say up to ten years old
After that - the age becomes less important 

After that - its all about condition - 10 years, 15 years, 20 years??? - is it important??

For your EV
Its handy to select a common car - bits are more readily available
But common cars are like - common

Something a bit more exotic - more fun!

Maybe something that has been chopped or channeled and not finished


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## Lionstrike (Oct 29, 2011)

Oh yeah.... 

I am keeping a lookout... I'll know what I'll see it. But the branching overall point here is quite valid. It is possible that I'll find a diamond in the rough in a junkyard, but not likely. Far more likely that I'll find a rusted old ride with mouse habitation.


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## Duncan (Dec 8, 2008)

Lionstrike said:


> Oh yeah....
> 
> I am keeping a lookout... I'll know what I'll see it. But the branching overall point here is quite valid. It is possible that I'll find a diamond in the rough in a junkyard, but not likely. Far more likely that I'll find a rusted old ride with mouse habitation.


 _Far more likely that I'll find a rusted old ride with mouse habitation_

But if that mouse house is the car that you go - YES!!! - ???

Actually even then you should probably note it down or buy it for parts and keep looking for a nice example


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## Lionstrike (Oct 29, 2011)

Duncan said:


> _Far more likely that I'll find a rusted old ride with mouse habitation_
> 
> But if that mouse house is the car that you go - YES!!! - ???
> 
> Actually even then you should probably note it down or buy it for parts and keep looking for a nice example


There is a chance that I could strike gold in that field... but I am going to guess that I just end up with a handful of sand.

Maybe I'll have a look sometime when I am ready, but I am still missing a few conversion parts like batteries, an adapter plate and an appropriate charger.

Oddly, I'll probably get the chassis last.


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## Duncan (Dec 8, 2008)

Lionstrike said:


> There is a chance that I could strike gold in that field... but I am going to guess that I just end up with a handful of sand.
> 
> Maybe I'll have a look sometime when I am ready, but I am still missing a few conversion parts like batteries, an adapter plate and an appropriate charger.
> 
> Oddly, I'll probably get the chassis last.


I was told to get the batteries last
And that was good advice - 
they are the parts most likely (possible) to go down in price and up in performance if you wait


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## Lionstrike (Oct 29, 2011)

Duncan said:


> I was told to get the batteries last
> And that was good advice -
> they are the parts most likely (possible) to go down in price and up in performance if you wait


That's solid advice.

I am however, putting away a couple of dollars a month... so that I can get the good stuff when I am ready.

I really do not know if I want to roll with lead acid at all until it's very, very low cost. It seems to me to be a vital part of the conversion and that's an understatement.


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## Duncan (Dec 8, 2008)

Lionstrike said:


> That's solid advice.
> 
> I am however, putting away a couple of dollars a month... so that I can get the good stuff when I am ready.
> 
> I really do not know if I want to roll with lead acid at all until it's very, very low cost. It seems to me to be a vital part of the conversion and that's an understatement.


I got hold of a pile of old car batteries (free) and I was going to use these for some initial testing

Never happened!

It was just so much (wasted) work to try and get a testing pack together - I tested my controller and motor using a couple of car batteries,
Just a 12v spin test for the motor
and running a starter motor for the controller 

Then it was onto the Lithium


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## Lionstrike (Oct 29, 2011)

Some folks that I know ended up replacing their lead batteries after a single year. UNACCEPTABLE. 

I am considering Nissan Leaf cells, but something plagues me...

http://www.hybridautocenter.com/HAC4/media/com_hikashop/upload/img_0970.jpg

What the devil is that middle terminal? I get the positive and negative leads, and I am guessing that the middle terminal is for a BMS... but if that's true isn't it just an auxiliary positive connection?


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## favguy (May 2, 2008)

Hi,
The Nissan modules aren't a single cell, they are made up of 2 cells in parallel and 2 in series, thus the third terminal between the 2 cells. If you are using a cell level BMS, it would be connected to all the terminals making up the battery.


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## lithiumlogic (Aug 24, 2011)

favguy said:


> Hi,
> The Nissan modules aren't a single cell, they are made up of 2 cells in parallel and 2 in series, thus the third terminal between the 2 cells. If you are using a cell level BMS, it would be connected to all the terminals making up the battery.


In the OEM product, you've got 48 of those 7.2V modules and they are all connected in series to feed the 400V controller.

If you are using this on something like an AC-50, you might reconfigure that pack, grouping three modules together in a parallel "brick" , resulting in 16 "bricks" connected in series for a 130V or so system voltage.

If you're not using a BMS, I take it you could connect the middle terminals of all three batteries within the "brick" to keep them balanced with respect to each other. The middle terminal is small and is not designed to handle discharge currents, but tiny balancing flows should be ok....


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## Lionstrike (Oct 29, 2011)

I don't mean to be dense, but I think that I am still a bit foggy.

So if the pack is composed of four cells, two in series and two in parallel... how is balancing even possible on a single cell level? It contains four cells that would need to be balanced off of a single terminal lead.

I can understand some part of that series parallel connection... but that third terminal still strikes me as weird.


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## favguy (May 2, 2008)

Lithiumlogic, 

If you check out my build thread, you'll see an example of buddy triplets, with the centre terminals also linked as you suggest 

Lionstrike,

The centre terminal is joined to both of the cell terminals shown in your drawing:


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## MitchJi (Dec 14, 2007)

Hi,



> really do not know if I want to roll with lead acid at all until it's very, very low cost.


Don't even thing about it! Used OEM Lithium packs from Wrecked EV's are the best and cheapest solution.


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## Lionstrike (Oct 29, 2011)

So Favguy... I see how it's wired up now and forgive my lack of understanding of BMS technology, but what charge is on that center terminal?

My understanding is that terminal was for wiring up a BMS. Now as I understand it, the first cell on the BMS gets a negative lead and a positive lead, with every consecutive cell thereafter getting the positive lead to monitor individual cell voltages. I am really foggy on how to wire up a BMS to 40 leaf cells with a center terminal.

Also... back to the idea of rollers... I am finding that there's really no hurry. After about 3 weeks of hawking my local classifieds, I find just today about four that would actually work. Go figure. When it rains, it pours. I guess rollers are easier to obtain than I thought.


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## favguy (May 2, 2008)

The centre terminal exists to connect a BMS to. I'm not sure what you mean by what "charge" is on it? it will read the current voltage of the cell if you connect a multimeter between it and one of the other terminals, so around 4v or so.

Wiring your BMS to a series string of Leaf cells is no different to connecting one to, say, a string of CALB's. The leaf module is just like 2 CALB's already linked.


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## Lionstrike (Oct 29, 2011)

favguy said:


> The centre terminal exists to connect a BMS to. I'm not sure what you mean by what "charge" is on it? it will read the current voltage of the cell if you connect a multimeter between it and one of the other terminals, so around 4v or so.
> 
> Wiring your BMS to a series string of Leaf cells is no different to connecting one to, say, a string of CALB's. The leaf module is just like 2 CALB's already linked.



I can clarify my statement, and forgive me, my understanding of BMS technology is fairly rudimentary. This is my understanding of the wiring.

In this example of a BMS connector, there can be wiring like this for two cells connected in series:
http://www.batterysupports.com/images/2S Balance Connector.jpg

In this example, there are 2 cells, and the black wire goes to the negative of the first cell. The first red wire goes to the positive of the first cell. The second red wire goes to the positive of the second cell. My understanding is that this method is how individual cell voltage readings are obtained.

Because of this, the "charge" or whether it is positive or negative on the third terminal screws up my life. So if I had to wire these leaf cells to a BMS... let's say to a 2s BMS... how does that work? 

I could put a negative on the first leaf cell in the pack. And then a positive to (now I am lost)... the positive terminal on the first pack?... or the center terminal? What about the next block of cells and the one after that? 

What I mean by "charge" is this... if I were to take a volt-ohm meter and set it to DC volts... and put the negative lead on the negative terminal of the cell, and take the positive lead on that middle terminal that's frying my brain... what would the meter read?

Now, I've actually never used a BMS before, (I self manage my lifepo4 with my ebikes) but I understand that they are pivotal or lithium builds. That's why I want to solidify my understanding of these things as those leaf cells look like a likely candidate for my future build.


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## favguy (May 2, 2008)

OK, 

I think I understand your confusion, but you are getting too hung up on negative and positive terminals, in any string of cells, the point where two cells join, weather joined by a copper link, cable between the two separate terminals, or as you see in the case of the Leaf modules, just the one terminal (the two cell terminals being connected internally), can be both be both negative or positive in relation to the cells either side of it. 

So if using a BMS, just follow the instructions regarding connecting the wiring exactly as you would with any string of cells, imagining the Leaf module as two separate cells side by side with the centre terminal the link between them.


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## Lionstrike (Oct 29, 2011)

favguy said:


> OK,
> 
> I think I understand your confusion, but you are getting too hung up on negative and positive terminals, in any string of cells, the point where two cells join, weather joined by a copper link, cable between the two separate terminals, or as you see in the case of the Leaf modules, just the one terminal (the two cell terminals being connected internally), can be both be both negative or positive in relation to the cells either side of it.
> 
> So if using a BMS, just follow the instructions regarding connecting the wiring exactly as you would with any string of cells, imagining the Leaf module as two separate cells side by side with the centre terminal the link between them.


I think that I understand. I might just have to inquire later what kind of BMS' folks have been using with those leaf cells and how it's all wired up. Like I mentioned, I am an absolute BMS newbie and I don't understand much about it beyond a BMS as a concept.

Seeing as the center terminal has a "line of sight" with a positive connection in series, my understanding of how it could possibly wire up could be like this:


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