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Esperanto

Battery cells with removable cases instead soldering

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I'm trying a new way to change the cells of my wheel. I bought these cases for 18650 because I do not have a soldering machine. Remove the cells and raise another possibility, which is charge them separately or for easy health check up.

The first test without BMS: it works but low power, does not go up hills. Three of the cells are of poor quality, so maybe that's why.

Next tests I intend to connect the BMS in the cases.

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@Esperanto

Hell, yeah! Chriull said it very "nicely " ....what you are doing there can get real dangerous and result in batterie venting/explosion/fire!

you can NOT just pack some different 18650 together and even NOT by that lousy 4-piece plug thing!

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2 hours ago, Esperanto said:

I'm trying a new way to change the cells of my wheel. I bought these cases for 18650 because I do not have a soldering machine. Remove the cells and raise another possibility, which is charge them separately or for easy health check up.

The first test without BMS: it works but low power, does not go up hills. Three of the cells are of poor quality, so maybe that's why.

Next tests I intend to connect the BMS in the cases.

3.jpg

2.jpg

1.jpg

 

No need for harsh responses. :efef2e0fff:

I have used these holders in the past for hobby projects and temporary household applications (after replacing the wires) and can see the appeal of your idea, but agree that it's just not feasible nor safe for EUCs. Here are two (of several) major reasons:

1. The metal contacts and wires are not robust and cannot handle the demands placed on the batteries. The wires are very thin aluminium (28-30 gauge?), and the contacts are similarly of poor quality.

2. The holders, despite appearing snug, cannot hold the batteries secure enough to prevent momentary loss of contact or even displacement of the batteries. There are very good reasons why EUC battery packs are soldered together and tightly bound in 'shrink wrap', not least of which is to keep the cells connected under very harsh conditions. 

I think there is a solution to this problem, and hope you reattempt the project carefully while asking for input from the community. There are many bright and knowledgeable members with a lot of hard-earned experience who may help you along the way.

Good luck. :)

Edited by litewave

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4 hours ago, Chriull said:

Whats the wattage of yours?

My wheel is 350w.

4 hours ago, KingSong69 said:

@Esperanto

Hell, yeah! Chriull said it very "nicely " ....what you are doing there can get real dangerous and result in batterie venting/explosion/fire!

you can NOT just pack some different 18650 together and even NOT by that lousy 4-piece plug thing!

@KingSong69

Thanks for the warning. I appreciate it.

2 hours ago, litewave said:

I think there is a solution to this problem, and hope you reattempt the project carefully while asking for input from the community. There are many bright and knowledgeable members with a lot of hard-earned experience who may help you along the way.

Good luck. :)

@litewave

Thank you very much. I will 'reshape' my project. I clearly have a lot to learn here. :P

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1 hour ago, zlymex said:

I don't use that cell cases for current over 1A, the reasons have been best described above. I got some of those cases as well which I use for testing 18650 cells at not over 2A current after I modified the wires.

I don't use spot welder neither when I build battery packs, even one of my friends got one readily accessible by me. Most of the common spot welders are low current rated thus cannot weld thick nickel strip.

Thick nickel strip is necessary because nickel is less conductive than copper(only about 25%), let alone there are nickel plated steel strips widely available with even less conductivity.

 Even professionals like Gotway(is it?) has not done this correctly, only about 0.1mm thickness is used for their EUCs, and I don't know the type(of nickel or nickel plated steel).

Here is the ACM(820Wh, two packs of 410Wh each) of one of my friends, the nickel strip was once(or several times) becoming so hot that burned the shrink wrap through a fish paper layer.
596445a6de6f4_webwxgetmsgimg(24)sp.jpg.d5bc8b326a4ef41777c0d6ce6383532c.jpg

Guys check your batteries if you are hill lovers, that is another hazard apart from motor wires and motor connectors

 So what and why do I use when I build my own battery pack? I won't talk about it this time because I don't recommend to others.

Just amazing!  It looks like putting pieces of technology together is too easy and creates dangerous innovations. Frustrating! One would thing low cost of entry is a good thing but then non-engineers think they can just use it with no consequences .

I love innovation but people getting hurt should not be part of it specially for things like design margins, heat,power, efficiency. 

We train all engineers in the USA the fundamentals, these Chinese hackers should at least be engineers. They are just putting things together, having us test it and getting hurt. Then they try something else using the same methods and other problems show up. 

RIDICULOUS. 

If my firmware had failed after production realease, I would be fired.

Edited by Carlos E Rodriguez

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On 10/07/2017 at 5:29 PM, Slaughthammer said:

Do you really want to put those in your EUC?

Not really. I intended to make it easier to change the batteries. I could not imagine the dangers.

.

So once again thanks everybody for the advice and sorry for the inconvenience.

Let's try again!! 

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On ‎11‎.‎07‎.‎2017 at 5:35 AM, zlymex said:

Here is the ACM(820Wh, two packs of 410Wh each) of one of my friends, the nickel strip was once(or several times) becoming so hot that burned the shrink wrap through a fish paper layer.
596445a6de6f4_webwxgetmsgimg(24)sp.jpg.d5bc8b326a4ef41777c0d6ce6383532c.jpg

Guys check your batteries if you are hill lovers, that is another hazard apart from motor wires and motor connectors

Wow....

Thats crazy, never have seen that on another batteriepack before! And that's only because of a lot of stressfull hillriding?

I would be VERY interested how much Amps a ACM/V3 draw in those high current situations "on batterieside"(not Motor).....

Perhaps you have some numbers here also, @zlymex ?

 

@Esperanto If my answer has sounded "harsh"...i would like to say Sorry! I just want to -clearly- warn of the danger....

 

Edited by KingSong69

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7 minutes ago, zlymex said:

The strip is 8mm * 0.1mm which only equivalent to 0.1mm^2 copper(if it is nickel plated steel).

And that's why I used 0,3*10mm nickel strips for my custom battery extension. just shy of 4 times bigger cross section, and my wheel is not a particularly powerful one...

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Unbelievable!!

i will directly check on my (upgraded) v3 67 volt! (1160wh)

good that i a added an extra pack , so the amperage is more shared....

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