Another No Solder/Weld 18650 Build (Updated 03/09/2014)

[Gregb]

I've heard closed-cell foam doesn't lose its "sponginess" over time (for at least the 3 years that I would imagine is the life of a pack like this). What is a good supplier and what is the best type of closed-cell foam to make the compression blanket?

Most builders suppliers altho it is in strips about 6 cms wide. I made a flotation vest from it.

[999zip999]

A#1 Thanks. Clean.

[liveforphysics]

The air in closed cell diffuses out over time.

I have covered foam choice in his previous thread throughly. Browse it.
_______________________________________

Moderator edit to add the quote mentioned:

Here are some examples of types of foam that are able to supply more than adquate pressure for at least decades.

http://www.silicone-sponge-supply.com/S ... icone.html

This page gives a pretty good overview of various materials set properties.

http://www.dkirubber.com/materials.asp

[Gregb]

I don't doubt it does but my vest is over ten tears old and still works well. I thinkit will last the life of a battery.

[Gregb]

This is truly a magnificent job. Have you given consideration to hinging the two plates and replacing the holes and punch with fixed length circular "mounds" ,for want of a better description, made from cut down rod.
Fitted with a longish handle you could do 4 at a time just by squeezing it shut or even put it in a vice....

has anyone ever tried putting a small hole in the strip and block welding it with the touch of a mig?? I have been toying with the idea but have been too busy with other things to try it.

[liveforphysics]

I don't doubt it does but my vest is over ten tears old and still works well. I thinkit will last the life of a battery.

There are so many closed cell foams with terrible compression-set. You can not use it as a foam choice metric.

If your vest was being kept compressed, then the air pressures in each cell would be equalized to atmospheric pressure pretty quickly and no longer be helping provide any clamp load beyond what the modulus of the material composing the foam offered.

Hence why the foam material/design is what matters.

[cwah]

nice one, now it's time to create a new solderless battery kit in which there is less empty space between cells

[snath]

nice one, now it's time to create a new solderless battery kit in which there is less empty space between cells

Already done. But it was a lot more work.

See my previous post. Link at the beginning of this one.

[mrfeelgooddrag26]

would love too see these come up for sale would totally want to buy one if they could be mass produced for reasonable price i would totally buy one in my eyes i see them being worth 120$ each because your giving the person buying it the chance to simplify battery making for there ebike in all honesty i think the thing that keeps most people away from ebikes it trying to get a decent battery for a good price without buying one pre made or building your own this is a great design simple yet brilliant my only question is how you charge it up???

[r3volved]

I bet the box alone would sell really well (sans cells).
It would be so easy to diagnose cell problems and swap cells in a jiffy. And the ability to customize the pack v & ah.

[waynebergman]

I really like the idea of being able to peek inside the battery casing with out taking things all apart like in your design. I have recently had two 18650 14.3 ah packs that have met an early demise because of moisture getting inside the pack. I foolishly left the bikes parked outside in a campsite and they got wet with an overnight water sprinkler. I now know to keep my packs away from moisture and have seen how after the inside of a pack gets wet, the damage can spread quickly. With the clear covers it may be reassuring to peek inside from time to time and if there is any moisture in there you could open the pack up and dry things out and also it looks easy to plug and play new cells with out the trouble of all the spot welding and soldering. If I knew then what I know now I would have cut open the pack enclosure right away to let things dry out but I had no idea the water could cause so much grief.

After seeing the inside of my packs after taking them apart and seeing all the work that was involved in wiring everything up and the foam packing and everything I had an appreciation for the work that went into the packs original construction but trying to repair it was nasty. ......Long story short after taking 3/4's of the best packs cells and trying to marry that up with the other cells needed from the worst pack things went terribly sour. Actually a small fire started in the back of my crew cab on a trip to the city transporting this half repaired battery to a shop to do a spot weld for me to finalize the repair. By the time I got it out of the back of the crew cab and I threw it on the ground is was into full on fireworks.

It looks to me that with your design a person could monitor moisture in the system and jump on things at first sign of moisture, and worst case scenario of things got damaged you could swap out bad cells for good fairly easily. I hope this design takes off and works for you. It would be cool if you could buy a pack like this with a BMS etc all ready to go and get a few spare cells at the time of purchase for maintenance as needed.

Wayne

[snath]

I really like the idea of being able to peek inside the battery casing with out taking things all apart like in your design. I have recently had two 18650 14.3 ah packs that have met an early demise because of moisture getting inside the pack. I foolishly left the bikes parked outside in a campsite and they got wet with an overnight water sprinkler. I now know to keep my packs away from moisture and have seen how after the inside of a pack gets wet, the damage can spread quickly. With the clear covers it may be reassuring to peek inside from time to time and if there is any moisture in there you could open the pack up and dry things out and also it looks easy to plug and play new cells with out the trouble of all the spot welding and soldering. If I knew then what I know now I would have cut open the pack enclosure right away to let things dry out but I had no idea the water could cause so much grief.

After seeing the inside of my packs after taking them apart and seeing all the work that was involved in wiring everything up and the foam packing and everything I had an appreciation for the work that went into the packs original construction but trying to repair it was nasty. ......Long story short after taking 3/4's of the best packs cells and trying to marry that up with the other cells needed from the worst pack things went terribly sour. Actually a small fire started in the back of my crew cab on a trip to the city transporting this half repaired battery to a shop to do a spot weld for me to finalize the repair. By the time I got it out of the back of the crew cab and I threw it on the ground is was into full on fireworks.

It looks to me that with your design a person could monitor moisture in the system and jump on things at first sign of moisture, and worst case scenario of things got damaged you could swap out bad cells for good fairly easily. I hope this design takes off and works for you. It would be cool if you could buy a pack like this with a BMS etc all ready to go and get a few spare cells at the time of purchase for maintenance as needed.

Wayne

Your experience is exactly why I shared this design. I have noticed that a lot of self and commercial builds do not take into consideration vibration, bumps, moisture, and general abuse that these packs take. This build attempts to compensate for that.

[kiwipete]

I really like this design and want to have a go at this for my first battery pack build.

I'm looking to build a 14S5P pack but it has to fit into a specific size bag with dimensions of a bit over 220mm x 150mm. Since the battery spacer blocks are 20mm x 20mm it makes sense to go to a config of 10 batteries/blocks wide and 7 deep.

Given that size requirement, I've come up with the configuration as per the attached picture and would like to know if that would work OK??

For clarification: in the picture the red circles are obviously the pluses of the cells, the grey ones are the negative. The solid black bars are the copper strips that would run over the top of the pack, and the grey dotted ones are the ones underneath.

BattPack.JPG (171.07 KiB) Viewed 1271 times

[snath]

I really like this design and want to have a go at this for my first battery pack build.

I'm looking to build a 14S5P pack but it has to fit into a specific size bag with dimensions of a bit over 220mm x 150mm. Since the battery spacer blocks are 20mm x 20mm it makes sense to go to a config of 10 batteries/blocks wide and 7 deep.

Given that size requirement, I've come up with the configuration as per the attached picture and would like to know if that would work OK??

For clarification: in the picture the red circles are obviously the pluses of the cells, the grey ones are the negative. The solid black bars are the copper strips that would run over the top of the pack, and the grey dotted ones are the ones underneath.

BattPack.JPG

Might make it on the 220mm side if you face the connections, bend the tabs over, and use a, very narrow, spacer. Probably not gonna have enough room on the 150mm side after you add in the thickness of the case.

Not sure about your connection diagram.

[Gregb]

Are u sure u know what 14S5P means? Draw it up as 14 rows of 5 parallel connected cells hooked up in series. The positive lead would come from the positive connection of the first row of 5 cells and the negative from the negative connection of the last row. I can't see that in your diagram...

[Spicerack]

This is a bloody great idea- but where on earth can you buy the 18650 spacer blocks? Seems down under they are not easily available (or I'm too thick to search properly?)

[snath]

This is a bloody great idea- but where on earth can you buy the 18650 spacer blocks? Seems down under they are not easily available (or I'm too thick to search properly?)

I got mine from this place: http://stores.ebay.com/SuPower-Battery/ ... 34.c0.m322

[agniusm]

Are u sure u know what 14S5P means? Draw it up as 14 rows of 5 parallel connected cells hooked up in series. The positive lead would come from the positive connection of the first row of 5 cells and the negative from the negative connection of the last row. I can't see that in your diagram...

R u sure? His diagram is perfectly fine not taking into consideration black line. The underside should be different thou.
Spacer blocka on ebay, alibaba, aliexpress, 18650 holder I think they r called

[Spicerack]

This is a bloody great idea- but where on earth can you buy the 18650 spacer blocks? Seems down under they are not easily available (or I'm too thick to search properly?)

I got mine from this place: http://stores.ebay.com/SuPower-Battery/ ... 34.c0.m322

The weird thing is I do a search and those products still don't come up. Thanks for the direct link.

[Hyena]

The weird thing is I do a search and those products still don't come up. Thanks for the direct link

Same. Supower told me a while back they won't ship any more than a few cells to Australia. If you search through ebay.com they'll show up but not if you search from ebay.com.au - even if you click world wide.

[Spicerack]

The weird thing is I do a search and those products still don't come up. Thanks for the direct link

Same. Supower told me a while back they won't ship any more than a few cells to Australia. If you search through ebay.com they'll show up but not if you search from ebay.com.au - even if you click world wide.

Aah I see. Thanks for that Jay!

[Gregb]

Same. Supower told me a while back they won't ship any more than a few cells to Australia. If you search through ebay.com they'll show up but not if you search from ebay.com.au - even if you click world wide.

Did they say why??? and how many is a few??

[Hyena]

I think it was around 1kg limit so you'd need to break a decent battery into multiple shipments which would cost a heap in air freight. Apparently they've changed their tune now so it might have been just temporary crackdowns on the parts of the courier companies.

[Gregb]

OK thanks. I appear to have a cell mucking up so may need a replacement. will check them out

[Hyena]

If it's just a few cells it's no dramas either way. Even locally. I noticed there's a guy on ebay Au selling local stock of 20R cells for ~$6ea