BIG 18650 battery pack

[alpg88]

Please, explained better.
Are you recommending me to use a holder as this?
http://www.turboferret.co.uk/Index.htm

that is one way of doing it, or you can build one yourself that fits your needs better, use your imagination,

 

[SilverFox]

Hello Lupino.86,

There are limits on the balancer circuit. Your charger is fine. The charger will charge up to 5 amps. The question is what can the balance circuit handle?

A 2S2P pack should be no problem. You can even parallel 2 of those packs for extra run time. When charging you can charge each 2S2P pack individually and there will be no problems. If you try to parallel packs for charging you can run into problems if the balance circuit is unable to keep up with the charge rate. This is why you have to review the specification for the balance circuit.

Tom

 

[Lupino.86]

It is not about insults but about practicality and safety.

Strange... with Silver he is finding a solution, really strange!
I don't want to reach the moon afoot, I want only to connect together some batteries! :laughing:

No one needs that much light for road or dirt.

I possess these torches:
1x Romisen RC-T6 (500-1000-1500lm triple position)
1x 900lm
2x 270lm
I don't obligatorily have to turn on her all however if I have more need light I don't see because doesn't have to have it!
Perhaps to make a pleasure to you or to Linger?

By wanting excessive light, you are lead to needing huge battery capacity, which can be unsafe and impractically large and heavy.

If there is a dog to the or of the holes on the road do I want to see them to hundreds of meters, something in contrary?

Thousands including me do rides like Paris-Brest-Paris with much less light and we can carry sufficient battery and/or generating capacity for three or four nights in a row.
I have not said that I have to use 20 batteries or I kill all, I have since the said beginning that I don't have problems if the batteries are less or more. I have exposed only my proper problem in this proper forum to find together a solution.
Cannot I use 20 batteries because it is dangerous? No problem! It doesn't do anything, tell me how much I can use of it and as I have to connect her without risks... this is synonymous of civilization (I take another time as example the competent one, kind and always polite SilverFox), not as certain people that bark to the first thing that he doesn't like!

I may be preaching but I have the luxury of being right!

For me you absolutely are not correct because you don't respect the others in to express his/her ideas.:thumbsdow

 

[Lupino.86]

that is one way of doing it, or you can build one yourself that fits your needs better, use your imagination,

Here is thing misses me...
Do you have some practical homemade holder example?

 

[Lupino.86]

Hello Lupino.86,

Hello competent, kind and always polite SilverFox :thumbsup:

There are limits on the balancer circuit. Your charger is fine. The charger will charge up to 5 amps. The question is what can the balance circuit handle?

I don't understand the question. :thinking:

A 2S2P pack should be no problem. You can even parallel 2 of those packs for extra run time.

Can I connect maximum two 2s2p battery packages to the torches? Have I understood well? Do you confirm it to me?
Did I have intention to connect together five 2s2p battery packages , cannot I absolutely do it?

When charging you can charge each 2S2P pack individually and there will be no problems.

Yes Yes, not do make you problems, has thought never about loading all the united packages, not to worry you... I know the dangerousness

If you try to parallel packs for charging you can run into problems if the balance circuit is unable to keep up with the charge rate.

I don't have doesn't even want to try us!

This is why you have to review the specification for the balance circuit.

Tom

Here is the manual of my balancer.

 

[LuxLuthor]

Hello Lupino.86,

There are limits on the balancer circuit. Your charger is fine. The charger will charge up to 5 amps. The question is what can the balance circuit handle?

A 2S2P pack should be no problem. You can even parallel 2 of those packs for extra run time. When charging you can charge each 2S2P pack individually and there will be no problems. If you try to parallel packs for charging you can run into problems if the balance circuit is unable to keep up with the charge rate. This is why you have to review the specification for the balance circuit.

Tom

Tom, having read your comments and those of OP, and perceived level of expertise--given your stature here--are you comfortable implicitly endorsing soldering Lithium Cobalt cells into packs?

Without a way to verify possible thermal damage to underlying structures by each individual hand soldering event, that worries me more than anything else being discussed in this thread--way more than debating the number of cells put safely in parallel.

As you know, it only takes one solder-compromised cell pushed to the edge of safety which when put under sufficient charge/discharge, roadbike trauma stress tipping into a runaway explosion/fire to cause a disaster.

I don't see the significance of a 8, 10, 15, 20, 40, or 60 cell disaster once a runaway 1,400° F fire with extrememly toxic fumes starts.

The various pack scenarios whether connected in smaller parallel packs or one large pack is equally prone to spontaneous involvement of all cells if located within reasonable proximity to first runaway event.

 

[alpg88]

Here is thing misses me...
Do you have some practical homemade holder example?

that slow uh???

 

[SilverFox]

Hello Lupino.86,

Your balancer is rated for a maximum of 6 amps charging. When charging your battery packs, you must keep the charging rate below 6 amps in order for the balancer to work properly.

As far as paralleling packs, I would suggest starting with 2 packs and going up only if you find that you actually need more capacity.

OK, now that we have figured out the theory of how to do this and the safety issues involved, the next issue, as LuxLuthor has pointed out, is how are you going to connect these cells together to make the packs?

Soldering Li-Ion cells is not safe, nor is it a good idea. Spot welding is a better idea, but it still is easy to burn through the cell and cause problems. The best bet would be to have cells with leads attached. Then you would only have to solder connectors to the leads, and solder the leads together. It sounds like you are harvesting cells from battery packs so they should have leads attached to them. Be careful when you disassemble the packs to make sure you can hook things back up again without having to solder to the cells.

Tom

 

[SilverFox]

Hello LuxLuthor,

Patience my dear battery enthusiast...

When I jumped into this discussion the main concern was charging and discharging large parallel strings of cells. I believe it is important to understand the theory behind parallel cells in order to properly assess the safety issues. Once we communicate the theory behind this, we can move on to the practicability of actually connecting some cells into a pack, and what is needed to connect packs together.

I think we can now appreciate the dangers associated with charging and using large battery packs and can now move on to the dangers of actually building a large pack.

Perhaps you can share the amount of skill required to spot weld cells together, and the special concerns associated with Li-Ion cobalt cells.

Tom

 

[timberwolf]

Perhaps you can share the amount of skill required to spot weld cells together, and the special concerns associated with Li-Ion cobalt cells.

Full ack, thats what's of interesst to me too. I have used a spot-welders some time ago, but I can't think of any way for soldering the positive pole of any cell without pushing a hundred amps through it...

 

[LuxLuthor]

Hello LuxLuthor,

Patience my dear battery enthusiast...

When I jumped into this discussion the main concern was charging and discharging large parallel strings of cells. I believe it is important to understand the theory behind parallel cells in order to properly assess the safety issues. Once we communicate the theory behind this, we can move on to the practicability of actually connecting some cells into a pack, and what is needed to connect packs together.

I think we can now appreciate the dangers associated with charging and using large battery packs and can now move on to the dangers of actually building a large pack.

Perhaps you can share the amount of skill required to spot weld cells together, and the special concerns associated with Li-Ion cobalt cells.

Tom

Tom,

I was reacting to post #6 & OP's response #9 which seemed to confirm solder, but then put the soldering issue out of further discussions.

I know from taking apart battery packs, that it is extremely difficult to keep an adequate length of original nickel tab to avoid solder heat transfer damage of underlying cell structures. Those that have done it on this forum, have not taken their soldered cells apart to see what safety protection components may have been compromised.

In this thread, post #6 shows Lithium Cobalt cell without tabs with soldering iron next to it, and in the 2nd photo, bus-bar connectors soldered Trinity VIS ex-tra Nickel Metal Hydride cells which unlike Lithium Cobalt, can be soldered carefully.

Before going into details of spot welding Lithium Cobalt cells, I think the first question is whether the OP has access to a battery spot welder, or undamaged tabs still attached to cells. If not, the rest of the discussion is academically interesting, but none-the-less moot.

 

[Lupino.86]

LuxLuthor, thanks of the precise statement, but I have have ever said that I will directly soldering on the poles of the batteries! :thumbsdow
My batteries have long tabs and I would not even dream me to soldering on big quantities of ampere!!! :thumbsup: