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One more no “solder”, no tools, no skills, 18650 pack build.

Posted: Jan 31 2015 12:57pm
by parabellum
The Idea of such low tech, low skill build was born after seeing post of friendly1uk and following to it discussion , criticized as ever but idea with improvement potential.
http://endless-sphere.com/forums/viewto ... 18#p989001

Why?
I lately have lost the access to any professional equipment and machinery, ass well to material supplies, time only on weekends where stores nearby are closed, battery of my moped is getting older and 18650 batteries cheaper and energy denser.

Goals (more will be added or over lined in process):
-Minimize electric tools and eliminate machining.
-Limit tool count used
-Use materials from easily accessible (for me) sources, Amazon and Supermarket, added Hobbyking 14/02/15
-Pack must be easily reparable and cells replaceable
-Cell protection level (final trade off consists in lowering serial connection resistance but still 1 cell not damaging others kicking out whole serie in the block)
-Most parts reusable if disassembling
-Shape variable
-Easy to inspect and detect failed cell

Cons (more will be added in process):
-It gets bigger
-It gets heavier

Tools used (more will be added in process):
-Scissors (I have large format guillotine in the office, for nice copper strips, but its optional)
-Pliers
-Carpet knife
-Soldering Iron
-Laptop (To make orders)
-Coffee


Materials and prices for 1kWh pack using NCR18650PF 2.9Ah cells 4P24S (more will be added in process) :

25x 4P 18650 holders 55.65US$ (1 holder in reserve)
Source: http://www.amazon.com/gp/product/B00NPZ ... UTF8&psc=1

1x Cooper foil roll 36Ga 12”x5' 30US$ (less thet 1' or 1/5 of the roll will be used)
Source: http://www.amazon.com/gp/product/B0042S ... UTF8&psc=1

2x Roll of double sided foam tape 1.50US$
Source: Local supermarket.

1x Vinyl floor tile ???
Source: Materials junk box

1x #3 Abro Synthetic Lithium Grease ~5US$ (454gr(1lb)Lifetime supply :lol: ) added 14/02/15
Source: Local supermarket

Progress:
IMG_20150124_194547.resized.jpg
4P 18650 holder and its weight
Springs should not conduct any current and just act as springs.
IMG_20150124_200209.resized.jpg
Need to remove/bend the pins.Lower original, upper with bent pins.
Using double side foam tape for serial holder connection
IMG_20150124_201706.resized.jpg
Holders taped together in series
IMG_20150124_201910.resized.jpg
3S4P
IMG_20150124_203239.resized.jpg
Floor tile used as spacer and structural reinforcement between 2x3S
Note the balancing wire channels between 2 halves
IMG_20150124_203409.resized.jpg
4P6S blocks assembled
Note the tinny balance strip, will be used as fuse.
IMG_20150130_202312.resized.jpg
Series connector
Notice the connector hooked up and centered with the folds on positive end
IMG_20150130_202407.resized.jpg
Connector in the holder
IMG_20150130_202712.resized.jpg
Old Konions used as models =)
IMG_20150130_204633.resized.jpg
Fused balancing strip and its rating for 3 sec.
Principe of my fusing is as following:
Those fuse balance strips of 1P will be interconnected with wider strip and to balance wire
If one cell shorts, current from others in P brakes the fuse then the current of 2S in next interconnection goes brakes next fuse (V difference) trying to run current in to 1S (1 good + 1 failed cell) and so on all 6 fuses of the serie are broken. Every 6S is connected to the bus negative with automotive 40A mini fuse, it brakes as well when other 3 series are trying to pump current in due to 3.0-4.1V differential. Now, failed 1P6S is isolated.
After that.
a)BMS shuts down after 1 of those remaining 6S reaches LVC and user notices the missing 2.9Ah and visually inspects fuses.
b)One of my 4 battery medics shows way lower and saggy now 3P6S group and I visually inspect the fuses of the block.
Note. Battery medics are permanently attached to the battery with firs negative wire interrupted by relay at moped switch off. For draining lower cell reasons they only operate at system ON condition.

That was my plan and now...

Any ideas, critics and suggestions welcome! :D

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Jan 31 2015 12:59pm
by parabellum
There is a problem in fuse blowing I believe. Taking 0.045Ohm per cell resistance, there will be 200A on first and only 9.5A on last fuse at 3V per cell (worst case scenario). Is my calc right?

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 01 2015 7:53am
by spinningmagnets
DIY 18650 battery packs are time consuming, that is true. But experiments are fun sometimes, and I like doing experiments, even when they are unlikely to succeed. I guess if the outcome was certain, they would be called "verifications"?

I am looking forward to how these turn out. I know Tesla adds fuses to each individual cell, but I suppose it wouldn't be horrible if there was one fuse wire for two cells...or even each parallel group? Any fusing is better than no fusing.

I was just on an electric bike yesterday. I gave my co-workers test-rides on a recent build (rear hub, 48V, 1000W) and there were smiles all around. I am 55 so I guess I don't have much time left (* a tear slowly runs down spinningmagnets' cheek, as he contemplates changing his user-name to "stationarymagnets")

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 01 2015 8:01am
by parabellum
Kiriakos GR wrote:I wish to you to have also the nerve and energy to post the failure rate of this project too.

If free time is all that you have? Then do not forget that you have 30 years of time so to experiment.
People over 60 years old does not ride bicycles.
Sure I will post my failures, after all it is not for a bicycle and I will need at least 3kWh to come forward. There is still long way to go. Any constructive observations? :D

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 01 2015 8:03am
by parabellum
spinningmagnets wrote:
I am looking forward to how these turn out. I know Tesla adds fuses to each individual cell, but I suppose it wouldn't be horrible if there was one fuse wire for two cells...or even each parallel group? Any fusing is better than no fusing.
I will simulate few failure mods with real cells. At the end of the day, if fusing fails, I will skip it and have something where whole 1S fails. There is no fun without experimentation and failure. :twisted:

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 01 2015 9:05am
by SlowCo
Kiriakos GR wrote:People over 60 years old does not ride bicycles.
Glad I came across this post so I can tell my parents (71 & 72yrs) to stop riding their bicycles... :lol:

I'm afraid I live in a country where many people keep riding bicycles as long as they can. Not strange for a flat country that has more bicycles than inhabitants. The pedelecs have made it possible for a lot of "elderly" to keep riding longer or even start riding again. It's quite amusing to see younger people being past by granny's and grandpa's.

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 01 2015 10:38am
by spinningmagnets
Here's a recent pic of me (a worn out dilapidated 55-year old grandpa), when I was shopping for a rocking chair to rest my poor old bones on...

Good thing I'm writing about E-bikes now...no telling for how much longer I'll still have the energy to twist a thottle (*silently weeps for his lost youth)

Image

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 01 2015 11:19am
by SlowCo
Although I'm a lot younger at 42 I still rode a (hand)bike until I got severe shoulder problems. Then I rode a normal sports bicycle until the only knee I have left began giving in. It was quite amusing trying to set of and come to a halt with one clip on pedal....(I only fell 3 times!)

Here's proof of better times with the most precious cargo in the back... 8)
SlowCo.jpg
Sorry parabellum for the off topic. I just discovered ES and am reading as much tech info as I can to use later in my build. That's how I came across this thread and will try to follow it so I might be able to build my own battery pack at a later stage. back on topic: Succes :!:

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 01 2015 2:56pm
by Punx0r
I see a chap occasionally about my home town or in the local supermarket with a similar chair setup, except he's got a Crystalyte 9C in the front wheel :D

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 01 2015 5:32pm
by Ch00paKabrA
Around here, a lot of people are just getting into cycling after 60 when they retire. Lots of beach cruisers and lycra for the over 60 crowd as well as the custom builders.

I have a feeling that Kiriakos does not speak English and is using a translate program so we are not getting his full meaning. Either that or he should be using a translate program so that we can get a better idea of what he is trying to say. :lol:

There have got to be people in Greece over 60 riding bikes.

PS. Spinning Magnets, I think those magnets are going to be spinning for a long time to come.

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 02 2015 9:46am
by parabellum
Contact grease. If I am not mistaken its function is,
1)keep oxygen and watter and other contaminants out of contact area (preventing oxidation under others),
2)have high dropping temp point to not flow away if connection gets hot,
3)be not flammable and not expose flammable vapors if used in power connection and sparking environment,
4)it should be chemically neutral to materials in contact,
5)it should be dielectric but can present conducting particles(in some applications).
Please correct me if I am wrong.
Have observed some silicon greases on amazon but, they are costly and take some time to get here. I went to supermarket on Sunday with my family and not being part of the purchase ritual, used the time to look what greases they have to offer. I found this.
IMG_20150201_183703.resized.jpg
ABRO #3
http://www.abro.com/products/automotive ... oduct=7806
It costs under 5US$ for 545gr (1 pound)
I believe it has real potential as contact grease.
1)OK by specs. How can I test real world the“excellent water resistance”?
2-3)”Typical droop point of 550F(288C)” (Silicon grease is usually 200C) Have heated it up on round polished SS pipe on open kitchen stove flame and it starts smoking and hardens with only 1 small droop running out of this mess, droop, vapor and smoke seems not flammable. Result was a chewing gum like moderately sticky jelly.
4)Can not find any specs or data sheet on this grease. Does it have some aggressive to copper, nickel, iron or gaskets in 18650, chemicals inside?
5)It is dielectric with no conductive particles.

I will ad this grease to materials list for now, until its use is proved unappropriated.

P.S. I would rather chose to be 80 years young cyclist, then crunchy 40-50 years old know it all "helping professionals to avoid such mistakes". :lol:

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 02 2015 1:54pm
by parabellum
Did few cuts in recess.
IMG_20150202_134415.resized.jpg
Strips 12"
IMG_20150202_140127.resized.jpg
Strips 1x4cm and 1x8,5cm

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 02 2015 6:43pm
by tomjasz
Kiriakos GR wrote:
People over 60 years old does not ride bicycles.
I'll try to remember that tomorrow morning when I ride my bike. Well past 60 and riding nearly everyday in 0C/32F

I'm trying, like others to sort out your meaning. You've been very helpful to me. And I usually understand you humor. I'm missing this one... :lol:

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 02 2015 7:06pm
by dnmun
you should have used that copper sheet to make your little serial connection links so it could be soldered together for reliability.

if you had made little short links, 1-1.2mm thick, 4-6mm wide and about 16mm long then you could use them to connect each of the cans together in series by soldering them.

if you solder to the edge of the case on bottom and hit the solder as soon as it reflows with the wet sponge i think the damage is minimal.

pretin the spot on the edge of the bottom of the case so it can be reflowed really fast and then when you hit it with the sponge all the heat will be soaked up.

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 02 2015 7:28pm
by parabellum
dnmun wrote:you should have used that copper sheet to make your little serial connection links so it could be soldered together for reliability.

if you had made little short links, 1-1.2mm thick, 4-6mm wide and about 16mm long then you could use them to connect each of the cans together in series by soldering them.

if you solder to the edge of the case on bottom and hit the solder as soon as it reflows with the wet sponge i think the damage is minimal.

pretin the spot on the edge of the bottom of the case so it can be reflowed really fast and then when you hit it with the sponge all the heat will be soaked up.
Yes, but it defeats the purpose. Idea behind all that is, make it once and easy to repair or replace cells and not worry about overheating the cells and probably shortening their life or killing them at the scene. What do you think about my fusion solution? :D

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 02 2015 10:57pm
by dnmun
as i said, i think soldering to only the edge of the bottom and cooling immediately with the sponge is not damaging. soldering to the anode is not damaging since the anode is separated from the cell anyway.

using the large wires soldered onto the bottom is damaging imo. spot welding in the middle of the bottom is damaging imo.

but it is all pointless since you are gonna put grease on it.

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 03 2015 12:37am
by TheBeastie
Cool to see a new 18650 pack.
Overall I enjoyed making my nib 18650 pack, sometimes it reminded me of doing arts n craft or something of that nature back when I was in 3rd grade.
I think my pack is still less of a fire risk then a lipo pack which was half the reason I made it, I hate the crappy feeling of having to worry about fire.

I think those 18650s holders are the way to go if you can make it work as theres nothing more easy of convenient removal of cells then with holders like that.

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 03 2015 12:09pm
by parabellum
Could occupy the kitchen table briefly after all went to sleep. Here is the result. Those are old Konions to be used for failure simulation. All current is caried by copper links/tabs. Hi resistance springs do not participate in the conduction.
Image
Image
Those are 4 separate 1p6s for now.

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 03 2015 1:37pm
by cwah
It does look bulky and taking lot of space for nothing however

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 03 2015 2:32pm
by friendly1uk
Apportioning blame in the first line hay lol

It's not 'that' bulky. Perhaps 20% bigger than the cells alone.

I like it. For people that want a few cells here and their, rather than one big pack, It could be a great option. Something one can piece together at home. And having built it yourself, you can add lots of fusing here n their that a fully built pack lacks. If you feel the need.

What sort of current will you be trying to pull?


I wouldn't use any grease. Especially insulating grease. Even a car battery clamp don't have the clamping action required to displace the stuff. Oxygen free copper is worth consideration though. I would also look at the silver solder plating idea, to see if that would stay clean longer.


I'm looking forward to seeing how this goes. If the connection method is successful then we can look at other holders that limit their number. Grouping basically.

Good luck with it.

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 03 2015 3:26pm
by parabellum
friendly1uk wrote:What sort of current will you be trying to pull?


I wouldn't use any grease. Especially insulating grease.
If I go for PFs, they can deliver 20A peeks and 10A continouse, so under 40A for 4P. If I go LG MG1 route then under 20A for 4P, but will double capacity.

The pack above is assembled with grease already, but it is for testing purposes. I have pulled 2 cells out and copper presents, noticeable metal to metal mechanical abrasion and deformation despite the grease, those springs are very strong, the underside of the bow is supported by the plastic guide when you push the cell in, so you practically straitening the bow to get them in, not just bending the upper link.

I told you, I am working on your idea. :wink:

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 04 2015 8:41am
by parabellum
Little update.
IMG_20150203_211137.resized.jpg
Parallel links
IMG_20150203_213121.resized.jpg
Strips of double sided tape between links and batts.
IMG_20150203_214036.resized.jpg
Balancing wires added.
IMG_20150203_221324.resized.jpg
Positive terminal
IMG_20150203_232405.resized.jpg
1P is lower by 0.08V then the rest (knew that)
Forgot to make picture of negative terminal with 35A fuses on every series. Will post them tomorrow. :roll:

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 04 2015 11:27am
by TheBeastie
Looking good, so are you planing to put it in a EM3 battery frame bag? or something more fancy? I was thinking frame bag would be pretty practical for it.

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 04 2015 12:08pm
by mistercrash
This is cool, if the cells can be held in place so they don't pop out or move too much it is pretty sweet and soooo simple. Can you please post the exact measurements of one 4P holder with the cells and copper installed? I'm curious to figure out how big a 20S16P battery made like that would be.

Thanks
Ray

Re: One more no “solder”, no tools, no skills, 18650 pack bu

Posted: Feb 04 2015 12:18pm
by www.recumbents.com
Any thoughts about using gold leaf between the battery and the (cleaned!) copper tab to prevent oxidation and improve the conductivity in these no-weld/no-solder packs? I think gold leaf is pretty inexpensive at the hobby store.

-Warren