DIY Tesla battery for $300 USD

Van Living Forum

Help Support Van Living Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Richard

Well-known member
Joined
May 3, 2016
Messages
274
Reaction score
2
Hey, Everyone...

Apparently I used the incorrect URL in the first link, but the correct one in the 2nd link, in the post above. I tried to edit it but the edit didn't take. Now, I can't re-edit my post so, the correct URL is the one ending in "44512"

https://www.minds.com/blog/view/583978659530944512

Sorry for any confusion.
 
That was certainly interesting...but I don't think I could ever feel safe leaving something like that unattended.
 
BradKW said:
I don't think I could ever feel safe leaving something like that unattended.

I know very little about this subject. What is it that feels unsafe to you?
 
So here's the guy's video on testing the cells after you've bought and disassembled your collection of ebay purchased 'dead' laptop batteries:


A boatload of time consumed, no mention of a small battery spot welder for connecting the buss bars (I for one would not heat the end of a lithium cell with a soldering iron, nor trust a soldered joint in a vehicle), no way to know how many cycles the cells have done b4 ending up on ebay, a maintenance nitemare considering 600 'used' cells....even after his 'tests' there's no way to know how much life left in the cells....your 'pack' of 600 cells will only be as good as the weakest cells in the batch.

Four 3.2V cells @ 2 amps in series gives 12.8 volts @ 2 amps. Parallel the 150 groups to get 12.8 volts @ 300 amps (600 cells).

Way too much time and effort to end up with a 'used' 300 aH battery....oh yeah, with no warranty. (Plus our standard '20 hr' rating of deep cycle batteries may not equate here, so not sure just how much battery this thing ends up as)?

Plus these are the cells that overheat and cause fires....Tesla cars use them, but they are 'new' and there's a cooling system...i.e. a radiator, water pump, and antifreeze. Replay the part where he's testing the cells--if it gets HOT while charging at low rate, throw it out.

THANKS, BUT NO THANKS.

Cheap = Golf Cart Batteries
Mid Range = AGM
High Dollar = LifePo4 (Long term cost brings to mid range)
 
I never clicked the link, but johnny Bs mention of 18650s made me realize what was atttempted.


18650 lithium cells are indeed used in tesla battery packs, as well as many laptop battery packs.

Their quality ranges from horrid and dangerous, to quite good, the best cells being SAmsung, Sanyo, Panasonic and LG.  It seems their capacity and ability to deliver hige currents are still not available in the same cell, ie a high capacity cell is not able to maintain high currents, a High current cell cannot have a high capacity.

I have about 2 dozen 18650 cells I have extracted from failed laptop batteries.

Their remaining capacity is almost a joke, in comparison to the panasonic NCR 18650 cells I outright bought.

I have a USB power source which uses a single 18650 cell, and a USB power meter.  The Panasonic NCR 18650s will wind up producing 3 to 8 times as much usable capacity as the laptop extractions when powering my bluetooth speaker or recharging my phone.

There is so much absolute crap on Youtube in terms of DIY stuff.  Far too many halfwitted self important people giving dangerous advice and acting as authorities.  I would never ever in a million years trust a conglomeration of  laptop 18650 batteries in series parallel to form a  high capacity ~12 volt battery.  This is a fire waiting to happen the same as a open  bucket of gasoline in a hot shed, next to a fireworks convention.

I have a hard time trusting my laptop extracted 18650s.  Anytime one of them heats to 110f when recharging, It gets put into a fireproof bucket for recycling.  These cells still have usable capacity, but are simply not worth the risk. I mainly use them in a powerful LED headlamp, and they cannot maintain the higher light levels of 'high' or 'turbo' whereas the panasonic cells, which are not high current cells, easily can maintain these rather absurd light levels for a while before the light gets too hot and throttles back output.

The Panasonic NCR18650b cells have now dropped in price as they are no longer the highest capacity cells available at 3400mah,  the newest cells are 3600mah.

Do not believe ANY claim of 18650 capacity over 3600mah at this point in time.  Many cells on amazon and Ebay will claim higher capacities, but all they really are are used rewrapped laptop cells, already compromised, and dangerous.

These batteries should not be treated like Alkaline/Nicad or NiMH batteries, but their cylindrical shapes will have many people doing exactly that, and the ignorance could easily cost them, greatly.

Beware of DIY stuff on Youtube posted by self important yet highly ignorant nimrods, and especially where lithium batteries are concerned.

Making a huge DIY batterypack of used 18650 cells is criminally negligent
 
Thanks for the additional information in your comments, Everyone. Made me want to understand more about lithium batteries so I've been doing some reading.

This article discusses the chemistry of various lithium battery cathode types. It confirms what others have said, that laptop batteries are lithium cobalt oxide, and that these are the most dangerous of the bunch.
 

Latest posts

Top