Headway 38120S condoms

[webfootguy]

To avoid overtighting and physical stresses on the joint between cells and to maintain contact, I would highly recommend use of "spring washers" between cells that are joined end to end. Also known as "Belleville Washers" or "Belleville Springs" or "Disc Springs". The idea is a washer that is curved so it attempts to flatten out as you tighten it down. It tries to return to its curved shape thus maintaining tension. If there is physical stressing of a cell (vibration or hitting a bump) it goes into compressing the spring more rather than breaking something. I suppose if your cell holders are rigid enough, this is unnecessary.
--phil

 

[voicecoils]

It's wonderful to see the idea in action! The pack looks great

Perhaps the bigger pack could be held together/compressed with PET/polyester strapping eg:

The heatshrink should mechanically and electrically isolate each cell from it's neighbours while minimising packing density.

 

[voicecoils]

To avoid overtighting and physical stresses on the joint between cells and to maintain contact, I would highly recommend use of "spring washers" between cells that are joined end to end. Also known as "Belleville Washers" or "Belleville Springs" or "Disc Springs". The idea is a washer that is curved so it attempts to flatten out as you tighten it down.

The cells come with split washers as part of the original hardware which perform that function

 

[scoot]

It's wonderful to see the idea in action! The pack looks great

Perhaps the bigger pack could be held together/compressed with PET/polyester strapping eg:

.

That is so cool... i wish I knew someone with one of those strapping guns at work. I think it would be puurrrrrfect 8) . Once those cells get tightly bundled with that poly olefin or rubber interface contact, they won't be moving anywhere.

 

[olaf-lampe]

To avoid overtighting and physical stresses on the joint between cells and to maintain contact, I would highly recommend use of "spring washers" between cells that are joined end to end. Also known as "Belleville Washers" or "Belleville Springs" or "Disc Springs". The idea is a washer that is curved so it attempts to flatten out as you tighten it down. It tries to return to its curved shape thus maintaining tension. If there is physical stressing of a cell (vibration or hitting a bump) it goes into compressing the spring more rather than breaking something. I suppose if your cell holders are rigid enough, this is unnecessary.
--phil

These springs are not very well conducting, they are stainless steel.

Just my 2 Cents
-Olaf

 

[crashnfool]

Ok so I just tried my first one on the pos terminal and not fun at all...

It sure takes alot of heat to get this to shrink down properly but I think its just gonna take some practice...I'll post pics once I have some sort of success with this one then they will be for sale.....the heat shrink not the batteries..

 

[v_tach]

These springs are not very well conducting, they are stainless steel.

Just my 2 Cents
-Olaf

I've seen beryllium copper Belleville washers used in the aircraft industry. Wouldn't know where to begin to source them though.

 

[scoot]

Ok so I just tried my first one on the pos terminal and not fun at all...

It sure takes alot of heat to get this to shrink down properly but I think its just gonna take some practice...I'll post pics once I have some sort of success with this one then they will be for sale.....the heat shrink not the batteries..

I used this cheapee heat gun from Harbor Freight Tools. Do you have 1000 or 1500 watt hair dryer... that would probably work pretty swell too 8). and yes, I blundered a few times myself
View attachment IMG_0821.JPG

 

[Lapwing]

To avoid overtighting and physical stresses on the joint between cells and to maintain contact, I would highly recommend use of "spring washers" between cells that are joined end to end. Also known as "Belleville Washers" or "Belleville Springs" or "Disc Springs". The idea is a washer that is curved so it attempts to flatten out as you tighten it down.

The cells come with split washers as part of the original hardware which perform that function

Because the split washer is steel or worse, stainless steel, there will be a significant resistance. Normally split washers are no biggy because they are not in the current path, but here sandwiched between two cells they would be. Get beryllium copper or phosphor bronze beleville washers from Mc Master Carr. Edit: looks like they no longer stock them! Possibly these might work.
http://www.mcmaster.com/#bronze-tooth-lock-washers/=4r0uwq

better solution -- http://www.amazon.com/Beryllium-Copper-Wave-Washer-Thick/dp/B000FMWVLO
http://www.smallparts.com/b/1641082...tbin,availability,review-rating,date,is_prime

http://bokers.com/belleville_washers.asp
https://sdp-si.com/estore/Direct.asp?Exp1=71698&GroupID=1000#40447
http://www.springmasters.com/sp/wave-spring-washers-4.html

http://ecmweb.com/mag/electric_belleville_washers_correctly/

 

[olaf-lampe]

I like the idea of the retaining shaped washer:
http://bokers.com/images/washers/specialty_flat/Retaining.jpg

Would be perfect to have a belleville/retaining washer combo for BMS connection. 8)

-Olaf