A li-ion that - DOESN'T NEED BALANCING --- the 18650V ---

[Doctorbass]

You must remember that cell... the 18650V

I just want to confirm you guys that the famous cell i've been talking about on many post here that are in the Makita cordless tool and bionx PL350 ebike kit DOES NOT NEED BALANCING ! and that the imbalance after 300 cycles is only 0.2%

I've been looking for data over the internet about the sony 18650V cell and that's what i found.

In my case, instead of discharging them to 2.5V, i prefer 3.0V cutoff. that preserve the cell for 100+ more cycles, and you only sool e like 50mah.

Even though, i would recommand to use a LVC circuit to detect the first to reach the 3.0V. it's not recommanded in the specs, but i'm sure it would help to preserve them!

I also learned that they have theirt own heat protection inside that cut the current if the tab temp get too hot.. like if you solder directly on the tabs for too much time, you will hear a "tic".. and the cell will measure 0.00V (the thermal fuse would have blow)... that's a great news cause that indicate they are safer.. but you can anyway draw 16A or 19A pulse even if they reach 60 degree C max.



here is the list of all post about that great cell.

http://endless-sphere.com/forums/viewtopic.php?f=14&t=2764&p=52947&hilit=18650v#p52947

http://endless-sphere.com/forums/viewtopic.php?f=14&t=2638&hilit=18650v

http://endless-sphere.com/forums/viewtopic.php?f=14&t=4058&p=60146&hilit=konion#p60146

http://endless-sphere.com/forums/viewtopic.php?f=14&t=2764&hilit=+konion

http://endless-sphere.com/forums/viewtopic.php?f=14&t=2619&hilit=+konion



Doc

 

[TylerDurden]

Wish I needed batteries...

 

[docnjoj]

Is that thermosensor very likely to pop during soldering, cause these are little cells, so U need a lot of them (soldered) together!??????
otherDoc

 

[vanilla ice]

And what do you do to fix em once it pops?

In case I find some spare money in the couch cushions, where do I buy these? I remember looking at the spec pdf, but I couldn't find them for cheap any where. And I've tried calling around to tool shops, but no go.

 

[Doctorbass]

And what do you do to fix em once it pops?

In case I find some spare money in the couch cushions, where do I buy these? I remember looking at the spec pdf, but I couldn't find them for cheap any where. And I've tried calling around to tool shops, but no go.

This is one place where they sale them. http://www.cnc-modellsport.de/index.php?cPath=41_82 but i'm searching to find a place like batteryspace where they a re availlable

But when i'll get more "defective pack" i will sale them here for good price.
when they pop, there is no way to revover them.. but i've never had problem with any of my 500+ cells :wink:
I solder on the the nickel strip that is already spot welded on the tab st the heat thansfet is minimal.

But i already had to solder directly on the negative tab and i had no problem.. just be carefull to heat it just enough but not more to solder your wire on it.

Doc



Doc

 

[Doctorbass]

Is that thermosensor very likely to pop during soldering, cause these are little cells, so U need a lot of them (soldered) together!??????
otherDoc

Yes, this is a kind of thermosensor inside the cell.. probably between the positive tab and the internal cell electrode.

if you need to solder many cell together, simply use conductive strip. each cell can deliver 16A but i recommand to draw 5Amax to preserve their cycle life.. so linking many parallel cells together that eachone draw 5A would need a very small amount of heat for every strip.. so no problem would happen.

i've made 24s 18p pack with those.. without problem.

 

[Iron Yeti]

Is there a spec sheet on the size of the cells?

 

[Doctorbass]

Is there a spec sheet on the size of the cells?

size:

18650

or read d = 18mm and lenght=65.0mm

(18 650)

for the rest of the specs search here on that forum i posted them in pdf already.

doc

 

[Iron Yeti]

Sweet, thanks. I think I am going to go with these for my build.