# Possible 18650 candidates for battery



## IchibahnSLC (May 22, 2015)

I've been looking into possibly purchasing some 18650s to build a light-weight battery pack. I know the issue with these batteries is discharge ratings so here is what I've found:

*SAMSUNG INR18650-25R 2500mAh High-drain Battery - 12C, 30A $3.00
*

*SAMSUNG ICR18650-22P 2200mAh High-drain Battery - 5C, 10A - $5.50*

What do you guys think of these?


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## Hollie Maea (Dec 9, 2009)

IchibahnSLC said:


> I've been looking into possibly purchasing some 18650s to build a light-weight battery pack. I know the issue with these batteries is discharge ratings so here is what I've found:
> 
> *SAMSUNG INR18650-25R 2500mAh High-drain Battery - 12C, 30A $3.00
> *
> ...


I have used the 25Rs extensively. It's a great cell--probably the best high drain 18650 widely available today. I have run them at 45A for up to 30 seconds (they do get warm at that level...). It's Nickel Cobalt Aluminum, which is a great chemistry. You can run them at 20A continuous, but not without liquid cooling.

The 22P is a Cobalt Oxide chemistry, which isn't as good for power and is more volatile. Considering that it is less capacity, less power and more money, I wouldn't consider that one.


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## IchibahnSLC (May 22, 2015)

Hollie Maea said:


> I have used the 25Rs extensively. It's a great cell--probably the best high drain 18650 widely available today. I have run them at 45A for up to 30 seconds (they do get warm at that level...). It's Nickel Cobalt Aluminum, which is a great chemistry. You can run them at 20A continuous, but not without liquid cooling.
> 
> The 22P is a Cobalt Oxide chemistry, which isn't as good for power and is more volatile. Considering that it is less capacity, less power and more money, I wouldn't consider that one.


Great advice! Thank you for the info. Right now I'm looking into getting some of the 25Rs as I would have to run less for my project then the regular 18650s out there. What kind of project have you used them for?


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## IchibahnSLC (May 22, 2015)

Looks like with a 15s35p setup I can do 200a continues and 525a spikes at 144v.
Hm.
That means 525 batteries, which is about $2500 if bought in the US. 
That would only get me a range of maybe 20 miles. 

I'm still shopping around for better pricing. I've found some sellers on alibaba that will do 500 batteries for about $1700.

Also I'm still trying to find a mass supply of laptop batteries. Just ordered some to crack open for an equivalent of about $1 a cell for new old stock laptop batteries. Will see how that works out.


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## Karter2 (Nov 17, 2011)

You know there is a 3.0 Ahr version of that Samsung ..the 30Q... That will do 15 A continuous, and available for a similar $3 range price .
I here there will also soon be a higher drain 30R version also.
LG also have an equivalent cell .
Good luck with the laptop replacement packs, they are either an expensive source of genuine "protected" cells......or more often a cheap source of very poor ( often re-wrapped used) cells. There are a lot of con artists in that market !.


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## IchibahnSLC (May 22, 2015)

Karter2 said:


> You know there is a 3.0 Ahr version of that Samsung ..the 30Q... That will do 15 A continuous, and available for a similar $3 range price .
> I here there will also soon be a higher drain 30R version also.
> LG also have an equivalent cell .
> Good luck with the laptop replacement packs, they are either an expensive source of genuine "protected" cells......or more often a cheap source of very poor ( often re-wrapped used) cells. There are a lot of con artists in that market !.


Yeah, I know the con artist stuff. Not looking forward to trying to find a legit source from china. I'll see if digikey or mouser carries any. 
The laptop batteries I ordered are supposed to all be Genuine Dell new old stock.

I will look into those other batteries as well. It'll be a slow process as I only have 2 testers and 3 chargers.

Thanks for the info!


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## AntronX (Feb 23, 2009)

IchibahnSLC said:


> Looks like with a 15s35p setup I can do 200a continues and 525a spikes at 144v.
> Hm.
> That means 525 batteries, which is about $2500 if bought in the US.
> That would only get me a range of maybe 20 miles.


This is another one of your bad ideas, just like used AGM batteries one. You are assuming too many things here without experience. First, you must have meant 35s15p, since you expect 144V. Lithium-ion cells have nearly linear voltage curve and considerate voltage sag under load. I am testing NCA 18650 cells from Tesla model S (type A pack), and at 50% SOC or 3.57V resting voltage, they sag to 3.39V at 3A (1C) discharge rate within 10 seconds, and 3.2V at 6A (2C) rate. If you expect 200A with your proposed pack, then you are loading each cell to 13.3A continuous! Assuming voltage sag remains linear, that's 0.82V sag or only 2.75V per cell at 50% SOC. That makes your 35s15p pack output 96V at only half capacity. And these are automotive grade cells. Laptop cell on other hand, are not NCA but most likely old Cobalt Oxide type that are much more dangerous and have short cycle life. Also, they are made to be discharged at slow and steady 0.5C at most. Nowhere near acceptable for EV use (unless you can get 50KWh of them and keep them under 0.5C for cruising). Laptop cells are out. 

Next, how are you planning to wire them together? You need Capacitive spot welder. That's a lot of work. 

Your best bet for usable pack on the cheap is that Chevy Volt pack that you posted from ebay. Cells are already packaged with interconnects, housing and watercooling. The pack can be broken in half (i am assuming here) and two halves paralleled for about 170V average. And they won't sag as much under heavy load. Your main headache will be BMS for that pack. You will need to manage each half with separate BMS, since you can't parallel at the cell, but have to parallel at the pack half ends. But still not bad for $1800 (make offer first) you will get 51 miles of real world driving range from the pack that may last you 10 years or more, if you take care of it. 

But research the Volt option better first, ask advice from those who took those packs apart and adapted them to their EVs. I personally never dealt with those packs. For myself, I am hunting for Tesla model S modules.


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## IchibahnSLC (May 22, 2015)

AntronX said:


> This is another one of your bad ideas, just like used AGM batteries one. You are assuming too many things here without experience. First, you must have meant 35s15p, since you expect 144V. Lithium-ion cells have nearly linear voltage curve and considerate voltage sag under load. I am testing NCA 18650 cells from Tesla model S (type A pack), and at 50% SOC or 3.57V resting voltage, they sag to 3.39V at 3A (1C) discharge rate within 10 seconds, and 3.2V at 6A (2C) rate. If you expect 200A with your proposed pack, then you are loading each cell to 13.3A continuous! Assuming voltage sag remains linear, that's 0.82V sag or only 2.75V per cell at 50% SOC. That makes your 35s15p pack output 96V at only half capacity. And these are automotive grade cells. Laptop cell on other hand, are not NCA but most likely old Cobalt Oxide type that are much more dangerous and have short cycle life. Also, they are made to be discharged at slow and steady 0.5C at most. Nowhere near acceptable for EV use (unless you can get 50KWh of them and keep them under 0.5C for cruising). Laptop cells are out.
> 
> Next, how are you planning to wire them together? You need Capacitive spot welder. That's a lot of work.
> 
> ...


Yes 35s15p, my fault. I've been up for 25hrs or so and am starting to become delusional. As always I appreciate the information you have posted. I'm still looking into alternatives to both the 18650s and the AGMs. I have only purchased the motor and adapters so far and am saving for the MK2 Golf. The budget on this build will be tight and so I am looking at cheaper options than the Calb cells and the wrecked EV cells, unless I can find a really good deal on them. 
I'm thinking I'll see if I can sell the good cells I have of the 18650s on eBay, not really a ton of profit but something. 
The entire electrical side of things is rather new to me, even though I've done some PCB design, frankly that did not require much electrical knowledge. My mechanical knowledge is pretty extensive although I'll have to talk to my buddies about the VW since I don't know much about them. 

The volt cells can be broken up into pieces but I think they are either 48v or 24v sections. Really want to pull the trigger on it but just don't have those funds. Need them for the car first.


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## piotrsko (Dec 9, 2007)

Volt packs 1/2 ed are 192/200. Modules are 120, 70, 98 (ish)

I have 18 months, maybe 500 charges, NO bms everything good so far cells within .01 volt.

YMMV


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## wb9k (Apr 9, 2015)

AntronX said:


> This is another one of your bad ideas, just like used AGM batteries one. You are assuming too many things here without experience. First, you must have meant 35s15p, since you expect 144V. Lithium-ion cells have nearly linear voltage curve and considerate voltage sag under load. I am testing NCA 18650 cells from Tesla model S (type A pack), and at 50% SOC or 3.57V resting voltage, they sag to 3.39V at 3A (1C) discharge rate within 10 seconds, and 3.2V at 6A (2C) rate. If you expect 200A with your proposed pack, then you are loading each cell to 13.3A continuous! Assuming voltage sag remains linear, that's 0.82V sag or only 2.75V per cell at 50% SOC. That makes your 35s15p pack output 96V at only half capacity. And these are automotive grade cells. Laptop cell on other hand, are not NCA but most likely old Cobalt Oxide type that are much more dangerous and have short cycle life. Also, they are made to be discharged at slow and steady 0.5C at most. Nowhere near acceptable for EV use (unless you can get 50KWh of them and keep them under 0.5C for cruising). Laptop cells are out.
> 
> Next, how are you planning to wire them together? You need Capacitive spot welder. That's a lot of work.
> 
> ...


Good post. Connecting the 18650's with a homebrew welder in a pack that large would be a nightmare. Mixing a bunch of used cells of unknown provenance is a recipe for endless heartache, especially when you consider the amount of detective work required to find a bad cell in such a pack. 

To the OP, you're getting good advice here. I know it's hard to wait/spend the money, but it's not worth it to try to cheap out here. I don't know your experience...have you built anything smaller previously? A motorcycle? How about an ebike or lawn mower pack? I would strongly recommend a project like that before trying to jump in to building a car, which is an order of magnitude more difficult and involved than a bike, which is an order of magnitude more involved than a mower pack. It really takes years of experience with this stuff to competently assemble and manage a car-sized system, let alone try to assemble one out of hundreds of 18650 cells. In the time you would have to take to properly test and vet used cells, you could save up the money to buy proper modules. 

With the little info I have, I would recommend you slow down and concentrate on research or smaller scale projects before continuing with this car project.


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## Hollie Maea (Dec 9, 2009)

IchibahnSLC said:


> Also I'm still trying to find a mass supply of laptop batteries. Just ordered some to crack open for an equivalent of about $1 a cell for new old stock laptop batteries. Will see how that works out.


I wouldn't waste time with that unless I knew exactly what cells they were and researched them separately. The chances that a random cell will have the characteristics you need is pretty low.


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## IchibahnSLC (May 22, 2015)

Hollie Maea said:


> I wouldn't waste time with that unless I knew exactly what cells they were and researched them separately. The chances that a random cell will have the characteristics you need is pretty low.


Yeah I figure at this point that salvaging them would just be extra funds for the project. Most seem to sell at about $2/cell on ebay. It would take up a lot of my time though....


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## IchibahnSLC (May 22, 2015)

wb9k said:


> Good post. Connecting the 18650's with a homebrew welder in a pack that large would be a nightmare. Mixing a bunch of used cells of unknown provenance is a recipe for endless heartache, especially when you consider the amount of detective work required to find a bad cell in such a pack.
> 
> To the OP, you're getting good advice here. I know it's hard to wait/spend the money, but it's not worth it to try to cheap out here. I don't know your experience...have you built anything smaller previously? A motorcycle? How about an ebike or lawn mower pack? I would strongly recommend a project like that before trying to jump in to building a car, which is an order of magnitude more difficult and involved than a bike, which is an order of magnitude more involved than a mower pack. It really takes years of experience with this stuff to competently assemble and manage a car-sized system, let alone try to assemble one out of hundreds of 18650 cells. In the time you would have to take to properly test and vet used cells, you could save up the money to buy proper modules.
> 
> With the little info I have, I would recommend you slow down and concentrate on research or smaller scale projects before continuing with this car project.


Good advice here. This is my first electric build. Like I've said I've only ever worked on ICE engines, I've worked on plenty ICE cars. Maybe I'll see if I can utilize 18650s I get into my electric mower. 

I'm not nervous about building my first EV as I know it takes time, money, and learning along the way. Whenever I get into some sort of a project I like to join the forums to see what it's all about.

The extent of my electrical experience is really relatively small. I've built PCs since the age of 14 and started working on cars at the age of 15. I've done some pcb design from open source schematics and have even had some PCBs printed and stuffed, as the companies to do that here are plenty. Electrical on homes, working on Laptops, soldering some phone items, fixing cell phones, 3D printing, AutoCad, SolidWorks, Inventor, Pads. So it'll be fun to figure everything out as this will be just another step into tinkering for me.

This forum seems very helpful and I welcome any suggestions.

Thanks guys!


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## Hollie Maea (Dec 9, 2009)

Cylindrical cells are a pretty tough place to cut your teeth. If you don't have a welder, there simply aren't any good ways to assemble them. Even over at Endless Sphere, where their density is strongly coveted, a lot of veterans have trouble with them.


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## Zmazo (May 4, 2015)

What distributors were you looking at for the 18650s?


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## dpeter (Jun 9, 2014)

Hi!
You may want to take a look at this one:
http://lygte-info.dk/review/batteries2012/Sony US18650VTC5 2600mAh (Green) UK.html
I've ordered some from china (however i have some doubts they are original).
They were like $6 with shipping, but I only ordered 10pcs. I saw cheaper prices on aliexpress at larger quantities.
I will let you know about my test results if you are interested (as soon as they arrive).

Oh, and I will make a spot welder, like this one: http://www.avdweb.nl/tech-tips/spot-welder.html. I've salvaged some used laptop batteries too, and my experience is this cells are around 70-80%, but can't handle too high current.


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## hmincr (Jan 20, 2012)

Just a heads up for anyone needing a good spot welder. This guy has satisfied customers for a very simple design welder he sells.

http://endless-sphere.com/forums/viewtopic.php?f=31&t=68865[/URL


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## palmer_md (Jul 22, 2011)

hmincr said:


> Just a heads up for anyone needing a good spot welder. This guy has satisfied customers for a very simple design welder he sells.
> 
> http://endless-sphere.com/forums/viewtopic.php?f=31&t=68865


Wow, that is a fantastic little device.


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## tylerwatts (Feb 9, 2012)

Why not get second hand Tesla modules? Alot of battery for your money


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## Hollie Maea (Dec 9, 2009)

tylerwatts said:


> Why not get second hand Tesla modules? Alot of battery for your money


Not everyone wants 74 cells in parallel. That's about 230Ah. The Tesla modules don't look very reconfigurable, so unless you want a really low voltage or a really big battery, they might not be the best choice.


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## tylerwatts (Feb 9, 2012)

No idea about reconfiguration but if you have a welder it seemed feasible and they are affordable and without doubt in my mind the best chemistry. Only a suggestion


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## Siwastaja (Aug 1, 2012)

I'd recommend these, based on my testing, availability and price:

Samsung INR18650-25R for high power, between 2C-4C continuous
Samsung INR18650-29E, -32E, 35E for high energy, I'd recommend 1.5C continuous max. (I have only tested 29E, but I assume 32E and 35E are rather close, just higher capacity (new tech).)
LG MH1 (3.2 Ah), LG MJ1 (3.5 Ah), high energy. MH1 has comparable current capability to 29E.

Other brands seem to be too expensive. Samsung seems to have the best availability.

At least a year ago, Samsung 25R was clearly the best power cell, and although it's only specified up to 20A, it did have smaller DC resistance than some competitors specified to 30A (Sony VTC5, LG HE2), and it was also clearly the cheapest of the power cells.

But do you really need a power cell? Because the energy cells will be much cheaper. Just do a large enough pack and enjoy the range.

Don't care about the naysayers. You can construct a 18650 pack without high tech if you can spend a lot of time in manual work and if your brain works. Some people are knitting socks, which makes as little sense if you think about it that way. I'm working at automating the process, so that it would also make financial sense.


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## Johnny5 (Aug 11, 2015)

Hi, I should actually receive my first small batch of 18650 Samsung 25R today so I am looking fwd to test them. I am still trying to figure out lots of thing like bms and charging but im impressed no one seem to use the Tesla wire fuse style connection, that being said how do you think the wire itself is attached. So far I think that 480 cells would give me a nice light 72v 60ah 840a peak pack with 50 lbs of bare cell to configure but if I am wrong please feel free to correct me.


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## riba2233 (Apr 29, 2015)

These wires are attached with ultrasonic welding. You are probably better of with regular welding  

Samsung 25R are 10 A cont and 20 A peak per cell without active cooling. They are rated to 20 A cont, but they do get very hot and only have around 300-400 cycles in those conditions. But I doubt you'll be using them at such higg currents constantly.


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## Karter2 (Nov 17, 2011)

Johnny5 said:


> ..
> . So far I think that 480 cells would give me a nice light 72v 60ah 840a peak pack with 50 lbs of bare cell to configure but if I am wrong please feel free to correct me.


Wow.. That would be 35 Amps per cell !
Not a good plan if you want the cells to last !
( maybe you meant to say 840 cells ?)


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## Johnny5 (Aug 11, 2015)

Well the seller advertise them capable of 20A constant and 35A peak but so far the electric motor I plan to use is 600A at peak 20S24P configuration so 24 X 35A = 840 Amp out of those 480 cells and the motor seem to be 180 amp constant which is around 3C discharge on this battery. That being said I will be testing the 26 cells I got before I order 480 cells, I was curious if there would be a way to spot weld that wire fuse but even if it comes down to solder it im not too worried. If the battery can really handle the 35A peak I was thinking to use the 35A wire fuse and a 700 amp fuse at the battery pack for double the safety just like Tesla.



riba2233 said:


> They are rated to 20 A cont, but they do get very hot and only have around 300-400 cycles in those conditions.


That is the down side of these cells the cycle life I mean but for how compact and priced they are currently, 1500$ for 30000 miles aint too bad.


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## Karter2 (Nov 17, 2011)

Actually, Samsung state that cell can handle momentary pulses of 100A !
...But, above 20 A discharge and your "average" discharge voltage goes below 3.3volts ( lower beyond 50% SOC) so your 20S pack is going to sag to 60-65 volts.
If you solder to the cells , you risk internal damage and unpredictable cell life.
buy a cheap tab welder. ( or order your cells pre-assembled into pairs at least so you can solder to the links)


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## Johnny5 (Aug 11, 2015)

Yeah I also came across the 100A info today but Im not a using it for a e cig or vaping so no need here hehe. I doubt that a quick solder would do much to affect the cell but Id still rather a better way to get it done, guess Ill do some experimenting and see if I can come up with an easier way to weld/bound the wire fuse.


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## riba2233 (Apr 29, 2015)

You can pull 35 A from cell, but that should be in seconds, and you should temp. monitor them.


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## Johnny5 (Aug 11, 2015)

I was able to test the Samsung cells and although my small RC battery charger/tester is not the most high tech they seem to have the capacity advertised. I decided to convert my nephew's pocket bike with a small motor from hobby king and Ill be using these cells for it, Im just not sure if this motor could play along well with this controller with the lack of spec on the motor.
http://www.hobbyking.com/hobbyking/..._CA80_80_Brushless_Outrunner_50_80cc_Eq_.html

http://www.cloudelectric.com/product-p/kelly-kds72200e.htm


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## riba2233 (Apr 29, 2015)

You can't use brushed controller with brushless 3 phase motor. You need brushless controller. I wouldn't recommend that motor since it's too expensive (you can have same motor with halls for less money), doesn't have halls, and has way of mounting that is only good for RC planes. Also too high rpm (around 8000). You might want to look at something like big block alternative, search on ES


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## Tomdb (Jan 28, 2013)

NO.

Brushed dc controller with an brushless motor? Thats a no go for sure.


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## Johnny5 (Aug 11, 2015)

riba2233 said:


> You can't use brushed controller with brushless 3 phase motor. You need brushless controller. I wouldn't recommend that motor since it's too expensive (you can have same motor with halls for less money), doesn't have halls, and has way of mounting that is only good for RC planes. Also too high rpm (around 8000). You might want to look at something like big block alternative, search on ES


Well I assume there is a cheap brushless controller option and with at 5 to 1 ratio I would get a top speed of 70 kmh with a the 10 inch wheels of a pocket bike... I obviously overlooked the brushless to brushed part but I assume there would be an other option. thanks for your reply tho. I like the fact that the motor is so light and I thought maybe 20lbs on a battery, motor and controller could be feasible here.


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## riba2233 (Apr 29, 2015)

Ok, if you can handle the rpm (although I think that 70 kmh is too high and you wont get too good performance with this tiny motors), then you can have these motors which have hall sensors, and are cheaper:

http://alienpowersystem.com/shop/br...nsored-outrunner-brushless-motor-130kv-7000w/

http://alienpowersystem.com/shop/br...nsored-outrunner-brushless-motor-130kv-7000w/

http://alienpowersystem.com/shop/br...nsored-outrunner-brushless-motor-130kv-7000w/

http://alienpowersystem.com/shop/br...nsored-outrunner-brushless-motor-130kv-3200w/

http://alienpowersystem.com/shop/br...nsored-outrunner-brushless-motor-130kv-3000w/

And if you want lower rpm (bigger, but still small and light motor), you can buy revolt 100:

http://www.revolt.org.il/rv-100-with-hall-sensors/


Small block from es would probably also do the trick, but not for 70 kmh. You wold need big block alternative for that:

http://www.ebay.com/itm/KIT-ELECTRI...-CAR-E-BIKE-/191529528875?hash=item2c980cae2b

It's actually a 3 kw motor, and has much lower rpm.


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## Johnny5 (Aug 11, 2015)

Thanks for all the info Riba, I was thinking about my nephew here at 80lbs not me at like 220lbs but it would be neat if it did. I obviously still have a lot to learn but just like when I started rebuilding car engine I like learning as I go but what is a "big block" you keep referring to. I should start a thread or something I feel like im high jacking this one.

I made a new thread Riba if you feel like sharing your knowledge. 

http://www.diyelectriccar.com/forums/showthread.php?p=684554#post684554


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