Another DIY Battery - Makita 18V Drill Packs (Konion Cells)

[jerrysimon]

I know I am a big fan of building A123 DIY packs but surfing over at Endless-sphere I came across these which some there have been using and building huge packs out of for a while. So the other good thing is they seem well tried and tested!

Makita 18v, 3.0Ah power pack.

The cell inside a Konion 18650V 3.7v, 1.5-1.6 Ah, 65.0mm long * 18mm diam.

These actually seem to have been around a while and I am surprised I over looked them. Full details on this endless-spere post.

Each Konion 18650V cell does not have as much capacity as my A123 26650 cells. They do however have a slightly higher nominal voltage (3.7v) and are usually paired and then give a higher 3.0Ah capacity. They are claimed to be very safe (use LiMn chemistry), not need balancing and have a high cycle life (1200 cycles typical).

Anyway I have purchased 3 faulty 18v drill packs (can be had on ebay for around £10 each if you are patient) and plan to scavage at least 20 good cells from the total of 30 to make up a 10s2p pack. This should give me a 37v, 3.0Ah battery.

I am hoping that this will give me a slighlty lighter/higher capacity battery than my A123 12s1p packs. Mainly though I am doing it for fun

*** WARNING/DISCLAIMER *** Just like my DIY A123 thread I want to make it clear that these packs can carry and discharge high currents, so I in no way condone or recommend anyone to build them even after reading this post. If you do its your choice and you are completely responsible. Not sure if this is the correct legal jargon but you get my drift RIGHT

Regards

Jerry

 

[cwah]

Hello,

Have you tried the konion cells? Is it better than A123? what's the best value?

 

[morphix]

Jerry you're always on the frontiers of battery and folding ultra portability I have a friend on YouTube who is into model airplanes and got interested in e-bike building after seeing one of my vids, he wants to have a go at building a Lipo battery pack for his first build after seeing your posts.

 

[Deleted member 4366]

Those cells are the same as you find in most laptop batteries, which are a lot more readily available to reclaim.

 

[cwah]

D8v3h, are you talking about the Konions or the A123?

If these cells are standard on laptop, then in the ebike (battery) industry we have a lot of progress to do. Konion seems to have good C rating and lifecycle. They seem to be better than standard Lifepo4?
And A123 are the lifepo4 with high C rate.

Both of them seem quite good actually. (cheap) Konion seems to be difficult to find

 

[Deleted member 4366]

I'm referring to the green ones in the photo, which I believe are Sony 18650 cells. The G08 marking means 2550mAH and I think I heard 8A max. It's a bit of a lottery which cells you get out of the laptops, but most are like this and you have to look up the designation or, if they're Sony, the "G" rating. G2 is about 1.2aH and the higher the number, the more amp-hours so you have to match cell groups to get a balanced capacity between the cell groups. I guess it would be the same with Makita packs - that the older ones will be G2s and the later ones G8s .
I'm guessing that the Makita pack in the photo has 10 cells with a marking of G3 or G5 at 1.5aH each to make 5S2P to make 18V 3.0aH.

 

[jerrysimon]

I abandoned this project in the end having purchased a couple of dead packs which subsequently had few usuable cells in them.

Buying new A123 cells is a more cost effective alternative, unless you can find a reliable source of the Konion cells from Makita packs or as you state maybe from laptop batteries. Not all 18650 cells are the same though, these Konion ones in Makita packs are very safe in a simlar way to the A123 cells are. Note the Konions are pobably better if you can find them as they require less (ten) to make up a 36v pack and are lighter/smaller/slightly higher (if paired) capacity than the equivalent 12s packs required when using A123 (3.3v) ones.

Regards

Jerry

 

[cwah]

I may have a silly question, but if the Konion cells are better than A123 (and therefore Lifepo4), why don't we already have mass production of these type of battery for eBike?

 

[jerrysimon]

I have no idea and it is a good question BTW!

They can be built without balancers and remain in better balance than A123 cells even though they are also renowned for remaining in balance and can be abused.

Over on the Endless-Sphere forum there is a guy in the USA that has good access to old Makita Packs and runs a thriving trade in selling them on to ebikers to make up DIY ebike packs.

Regards

Jerry

 

[flecc]

I may have a silly question, but if the Konion cells are better than A123 (and therefore Lifepo4), why don't we already have mass production of these type of battery for eBike?

The new for 2012 Kalkhoff Impulse systems e-bikes have new Kalkhoff-BMZ batteries populated with 18650 cells, 11 Ah using 50 cells (10s, 5p) of 2250 mAh, and the 15 Ah using the same number and formation with 3100 mAh cells. Cells green in colour, I haven't seen the markings on them, could be Sony but I suspect they may be Panasonic sourced.

 

[jerrysimon]

So are these the same as the Konion cells flecc in terms of, physical size, their chemistry and ability to remain in balance without a balancing circuit ?

I don't think I have ever seen single cells of this type ever listed ?

Regards

Jerry

 

[flecc]

I don't know Jerry, other than the 3100 mAh being Li Ni Co Al O2 and the 2250 being Li Ni Co Mn, only have outline information on these new batteries. Having never used any, I thought 18650 cells would be only one physical size.
.

 

[Deleted member 4366]

I may have a silly question, but if the Konion cells are better than A123 (and therefore Lifepo4), why don't we already have mass production of these type of battery for eBike?

Many ebike batteries are made of these cells.

 

[cwah]

Thanks D8veh. Can you be more precise? Do you know where I can get them for good price?

 

[jerrysimon]

I don't know Jerry, other than the 3100 mAh being Li Ni Co Al O2 and the 2250 being Li Ni Co Mn, only have outline information on these new batteries. Having never used any, I thought 18650 cells would be only one physical size.
.

Thanks. I have to admit that these cells defeated me and it is just easier to stick with my A123s.

Regards

Jerry

 

[Haku]

Has anyone bought laptop battery packs purely to salvage the cells for rebuilding into an ebike battery?

I'm talking about new battery packs instead of used/faulty ones. My ebike batteries are all over 3 years old and hold little energy compared to when they were new which makes riding a chore rather than a pleasure.
Searching for individual 18650 cells has taught me that they're either very expensive (even in bulk) for the decent ones or very cheap and nasty (used, random manufacturers, false mAh claims) if bought from China - yet laptop batteries have high Ah packs with cells from the same batch/manufacturer, meaning I should be able to get 28 new, high capacity (over 2000mAh) cells for under £100.

 

[jerrysimon]

Its really worth taking a look and doing some searches on Endless Sphere as there are many different approaches to DIY batteries over there.

Be sure to report back if you find any answers/ideas.

I have now purchased and built my third spare DIY A123 pack (I and my daughter run a pack each) and will be sticking with them for now. My current one is about 30 months old, has nearly 3000 miles on it and apart from changing two failed cells (one from each 6s1p pack) a few months ago has performed flawlessly and still retain near enough their full 2.3Ah charge. I abused them for a couple of years but fully discharging them but now charge at work every day so they are never any less than 60% discharged.


Regards

Jerry

 

[cwah]

Jerry, I'm a interested now lol. Have few questions for you if you don't mind:
Do they have 1000+ cycle and good calendar life when you use them at 2-3C? How many % did the max capacity dropped from the new one in 30 months? And ultimately where do you buy your battery? I'm sure you know good value shop lol

 

[Deleted member 4366]

Thanks D8veh. Can you be more precise? Do you know where I can get them for good price?

I don't know a supplier. I got mine out of laptop batteries, but you need a lot of them to make an ebike battery, which means lots of soldering and lots of chance for solder to break when going over bumps. Plus you need a BMS and charging system too.
Have a look at my new post:
http://www.pedelecs.co.uk/forum/electric-bicycles/10520-new-batteries-lightweight-9ah-about-40-a.html#post125989

 

[wurly]

Jerry, can i ask where did you buy your A123 cells? they are lifepo4? you aren't using a BMS are you? were you not worried about cells degrading and causing problems in your pack without your knowledge. With a BMS you get a prior warning at least. I have seen the thread on ES (darkangel) is the one i think you refer to.
It seems like a lot of effort and results are sketchy, i just wonder if it is best to get larger Headways from BMS Battery and have done with it.
I was thinking of buying these.
38120S 10Ah 10C LiFePO4 Cylindrical Battery Cell with Screw - BMSBATTERY