Samsung 25R/LG 18650HE2/ Sony VTC5 high power 18650 battery

[andreym]

These welders are too low power - my friend tested one and he succeed to weld only 0.1 nickel strip max.
So I decided to get more powerfull one DN-10 means 10kw I believe. 35AC barker is barely usable at 240V AC, 25a hits immediately when you try.
btw wires are 50mm2 and they become quite warm..
Check this out:

Got couple of batteries welded already.
used 0.3mm x7mm pure nickel stip

and more on the way

 

[madin88]

wow, 20p is insane for ebike. Is this the battery from Ivanov new chaika frame?
very good job!

 

[parabellum]

Andreym.

Is this resistive welder? Double pulse?
Please give more info about.

 

[dbaker]

Very interested. What thickness tabs were you able to weld? What calculations did you use to size the tabs?

What vendor did you use for the DN10? Link? Cost?

 

[riba2233]

Yeah, where can we buy that and for how much?

 

[Hillhater]

This also available at Amazon for $72.48:
http://www.amazon.com/Pro-Grade-Ultra-Portable-100-Amp-Electric-Welder/dp/B000V663G8
... seems to be highly rated. Would be interested in opinion. Thanks.

Looking for a cheap solution to spot welding a pack. This would work but what would you use for the two elements?

You do realise that is an arc welder ?
..and you know the differences between an arc welders and a spot welder ???

 

[parabellum]

You do realise that is an arc welder ?
..and you know the differences between an arc welders and a spot welder ???

You need to ad a button with timer? :lol:

 

[andreym]

Very interested. What thickness tabs were you able to weld? What calculations did you use to size the tabs?
What vendor did you use for the DN10? Link? Cost?

I have not tried more than 0.3mm thick, But manufacture tells it is able to weld up top 2.6mm (what i doubt)
but up to 1mm thick I believe it would not be a problem, as i use only ~1,5 setting from max 10 available
here is the link if you can talk Chinese http://item.taobao.com/item.htm?spm=2013.1.0.0.X4fW1i&scm=1007.10011.531.0&id=1029910039&pvid=ad49c28b-b749-439d-996a-84806110b424

as for calculations....,
I checked Ni compared to cooper resistance, it is ~5\1 so for nickel you need at least 5x gauge,
than, 0.3*7=2.1mm2 what almost = 0.4-0.5mm2 cooper. you can use 10a per 1mm2 cooper wire with almost no heat continuous and ~20a per 1mm2 peak. So I Assumed 2.1mm2 of nickel would handle 10a no problem,
checked it with icharger - indeed nickel strip 0.3mm x 7mm at 10amps would become luke warm after couple minutes.
So for the pack to handle 100amps we need ~10nickel strips. On those green batteries you can see these 10 strips from the negative to positive. and one long parallel strip for balancing.
I calculated the resistance, all interconnections would be less than 2% of actual cell IR in the pack what I assumed acceptable

 

[ecruz]

These welders are too low power - my friend tested one and he succeed to weld only 0.1 nickel strip max.

I have not had a problem welding .2 strips whatsoever on the cheaper one.

 

[andreym]

I have not had a problem welding .2 strips whatsoever on the cheaper one.

It could be different welder. But looked similar.
The other disadvantage is you cannot use it for the large pack.

 

[cwah]

how much for the DN10 shipped here?

Is it the best spot welder you can find?

 

[ecruz]

I have not had a problem welding .2 strips whatsoever on the cheaper one.

It could be different welder. But looked similar.
The other disadvantage is you cannot use it for the large pack.

I am using it on a large pack. I weld rows then attach ends and middle after insert in holding brackets. Just think welding a row at a time then attaching the rows together. You would want to solder the series either way not spot weld. The series connections are soldered to the strips not the at the battery spot weld.

 

[zener]

Cycle life testing simulation of 25R cells.

I have choosen to take 1.3A (0,5C) to charge and 5A (2C) discharge (about 80% in average about 1850mAh 4.13V is charge end i set in iCharger).
1 of 10 cycles is a fast charge 5A and fast discharge 12A( also about 1850mAh). I stop discharge@12A when the cell hits 40*C (thats about after 600mAh) and wait for cool down. (2 times i have forgoten to stop and it gone to about 55*C and 40 times i did charge with 2.5A so the results are a little worse)

Ambient testroom temperature is from 22*C to 27*C still air.
Wait between charge and discharge i set to 2 minutes.

I do all 50 cycles a mesurement discharge of nearly full capacity (4.2V to 3V set on iCharger) with 0.5C/1C and resistance(funktion from the iCharger not accurate!).

Results are:

1 2360mAh 55mOhm
52 2331mAh 55mOhm
103 2280mAh 56mOhm
154 2261mAh 57mOhm

After these 154 maximum offroad simulation.
I start now with new other cell an 'eco' simulation with 70% usage about average 1650mAh (70% from the full initial capacity @ 2A discharge not from the rated 2500mAh.).
6 times @3A
4 times @6A
Charge 1.2A no fast charge. I stop charge @ 4.07V set on iCharger.

1 2360mAh 55mOhm
52 2323mAh 55mOhm
103 2305mAh 55mOhm
154 2296mAh 55mOhm


I see there some inaccurate in the messurements. Maybe this is about +-1or2% unprecise.

 

[Ebikebert]

Hey guys I have been trying to test these batteries for you but I just screwed up my E-bike hub motor! I really need your help guys so I can finally test the power of these cells.

http://endless-sphere.com/forums/viewtopic.php?f=2&t=60368

 

[hochdorf]

What glue is between them?

 

[ridethelightning]

in th vid i saw of them making packs.. they were going crazy with the hotglue gun....

 

[Allex]

Video:
https://www.youtube.com/watch?v=UrKvoZ-oyxQ#t=53

 

[Ebikebert]

wow! this video makes my pack build look like a joke. Haha, job well done to my friends in Russia!!

 

[cal3thousand]

Video:
https://www.youtube.com/watch?v=UrKvoZ-oyxQ#t=53

Awesome!!

 

[sflorlando]

any updates guys?

 

[Schlafmutze]

Why would you want to use these cells in a pack?
300 cycles, might as well go with lipo from hobby king.

 

[circuit]

Why would you want to use these cells in a pack?
300 cycles, might as well go with lipo from hobby king.

Energy density, safety, quality, flexible dimensions..

How many HC lipo packs you know that run without problems for at least one year?

 

[riba2233]

Would you buy tesla S if it had hobbyking lipo packs? Guess not

300 cycles is like worst case scenario, you can get more cycles, even up to 1500 with some measures, like charging to lower voltage, lower charging current, lower discharge, lower discharge rates, not keeping the cell at full voltage for a longer period of time.

 

[silviasol]

Why would you want to use these cells in a pack?
300 cycles, might as well go with lipo from hobby king.

Lipo is 25% larger, 25% heavier and the small cylinders make a nicer pack. You could quote any lithium cell at 300 if you drain it to 2.5v every time. Drain it to 3.7v resting every time I would think 18650 would still have more cycles and no puff of course. Honestly I still don't think it is worth the extra price though, you will get more with lipo from what I have seen with my build.

 

[parabellum]

HK LiPo is not to compare to 18650. I could do things with most HK 5A lipos I could not with 50A 18650 cells, heroes of this topic.