Making a 12v 4s battery pack from 18650

[msacco]

Hi, I have around 20 18650 battery just sitting around, so I thought of making a 4s 12v(well more like 12-16v battery depends on charge).

That should be fairly easy overall, just looking for some advices to make it as good as I can.
One thing I would like to try is avoiding soldering as much as I can, especially with the 18650 batteries themselves, I'm not sure where I've heard that, but if I remember correctly soldering straight onto a 18650 is not very healthy for the battery due to the heat(like here for example:

)

Now I believe that with the proper soldering skills and tools, soldering the 18650 batteries might not be an issue, but in my case both my soldering skills and soldering tools are fairly bad, and that's mainly why I'd like to avoid that if possible.

I thought about a solution for that, and thought about getting 5 of these 4 slots holder:
https://www.aliexpress.com/item/3282...chweb201603_52

The wires are very very thin, so I believe I'll replace that, but the general idea here is that I'll simply get 5 of these, and then wire them up in parallel, so each slot holder is going to be ~12v(more like 14-16), and when wiring them in parallel each cell will increase the amps.

What do you guys think? Will that do the job? Would that be a good idea?

I'm also plan on using a bms for that, I already own the following 4s bms:
https://www.aliexpress.com/item/3296...27424c4dbx6fs0

That's probably a bit of an overkill, but that seems like it should work just fine.

Are there any other recommendations? Something I'm not doing properly?
Thanks for the help! ?

 

[Dan]

Welcome aboard. What on earth are you soldering so many of those together for?!?!

If they're old and have varying degrees of life in them they're already losing discharge faster than they should. If you have a knock-on effect of not old soldering them but them each heating up quicker than designed and the life ending quickly in them anyway. There are better cells out there that have better temperature management build in them.

Is this for a eBike like he's got?
[automerge]1568685840[/automerge]
This kinda thing no good for you?

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m.aliexpress.com

 

[msacco]

Welcome aboard. What on earth are you soldering so many of those together for?!?!

If they're old and have varying degrees of life in them they're already losing discharge faster than they should. If you have a knock-on effect of not old soldering them but them each heating up quicker than designed and the life ending quickly in them anyway. There are better cells out there that have better temperature management build in them.

Is this for a eBike like he's got?
[automerge]1568685840[/automerge]
This kinda thing no good for you?

Fer à souder électrique JCD 220V 80W LCD 908S fer à souder à température réglable avec embouts et kits de fer à souder de qualité _ {categoryName} - AliExpress Mobile

Fer à souder électrique JCD 220V 80W LCD 908S fer à souder à température réglable avec embouts et kits de fer à souder de qualité de qualité sur AliExpress Mobile avec la livraison gratuite

m.aliexpress.com

Hi Dan, thanks for the reply
First of all, I'd like to use it as a portable 12v battery for one of my hobbies, so that's why I'm making this.

Now as for the batteries, I recieved them recently from a friend, they're brand new, so should be fairly good.

I'm not really interested in spending more money on batteries, if they work then that's great, but if not I don't think I'll buy something else.

There are no soldering attempts on the battery, but don't you think I should avoid this? I do have a solder, very similar to what you've sent, but it's just no very good.
Are solders so cheap? o:

What about the 4 slots battery holder? Should that work in theory?

Thanks!

 

[Dan]

Can't you get them battery housings already setup and you clip the batteries in. And they use springs to connect them up?

 

[Zerax]

It's a popular way to create battery packs... if you search on youtube you'll find lots and lots of helpful vids... If I was doing it, I'd probably want to use suitably sized wire to interconnect so that in effect, each cell is fused.... It's all on youtube though...

 

[Mike Johnson]

I have been using A123 LiIo batteries for about twelve years all soldered together and still going strong, the secret is solder quickly and charge slowly with a good quality balance charger.

 

[msacco]

Can't you get them battery housings already setup and you clip the batteries in. And they use springs to connect them up?

I'm not sure I understood the question :x Are you referring to the battery 4 pcs holder?

It's a popular way to create battery packs... if you search on youtube you'll find lots and lots of helpful vids... If I was doing it, I'd probably want to use suitably sized wire to interconnect so that in effect, each cell is fused.... It's all on youtube though...

I've searched for many youtube videos regarding 4s packs, but didn't find anyone using such battery holder, I've seen only people solder, so that's why I'm asking here to make sure that would work.

I have been using A123 LiIo batteries for about twelve years all soldered together and still going strong, the secret is solder quickly and charge slowly with a good quality balance charger.

As I said above, with proper soldering skills and tools that should probably be just fine, which is not correct in my case, that's why I'd rather avoid it to not ruin the batteries.
I thought about getting this charger:

15.86€ 60% de réduction|Htrc – Chargeur De Batterie Imax B6 80 W, Déchargeur Plus Adaptateur 15v Et 6 A, Li-ion Ni-cd Numérique Rc Imax - Chargeurs - AliExpress

Achetez malin, vivez mieux! Aliexpress.com

www.aliexpress.com

Are you familiar with it?
Thanks

 

[Dan]

Yeah with the little springs in them to become one pack of 4 batteries. Those are still in series aren't they?

 

[msacco]

Yeah with the little springs in them to become one pack of 4 batteries. Those are still in series aren't they?

Well that is what I'm asking here to make sure I'm correct, from what it seems to me, the 4 batteries pack holder is in series, so each pack is ~12v, then if I simply connect in parallel each 4 batteries pack, I should still have a 12v battery with bigger capacity.
Again, this is what I'd like to confirm here, as I'm not all that familiar with that

It seems like a fairly nice solution, and makes me able to avoid soldering into the battery itself.

 

[Zerax]

Well that is what I'm asking here to make sure I'm correct, from what it seems to me, the 4 batteries pack holder is in series, so each pack is ~12v, then if I simply connect in parallel each 4 batteries pack, I should still have a 12v battery with bigger capacity.
Again, this is what I'd like to confirm here, as I'm not all that familiar with that

It seems like a fairly nice solution, and makes me able to avoid soldering into the battery itself.

Yes... you're correct.

I think Tesla uses the 18650 cells too ?

 

[msacco]

Yes... you're correct.

I think Tesla uses the 18650 cells too ?

Awesome, are there any recommendations for "best practices" on how to do that?

 

[Zerax]

Awesome, are there any recommendations for "best practices" on how to do that?

As I said... youtube search... you'll find zillions of examples...

 

[msacco]

As I said... youtube search... you'll find zillions of examples...

I've already done that, just wanted to know if you have anything special that comes to mind.
Thanks.

 

[Mike Johnson]

If you solder your packs up, you will need to also solder on your own balance leads, these will depend on what charger you buy which obviously must have a matching balance connection and be of sufficient capacity to charge whatever size pack you make up.