General warning to all who make custom packs.

I made a custom pack, 14ah, using Panasonic cells. Nickel strip, soldered cells.

Well, I ran the bike for a while, and no problems, then one day, it cut out, and wouldn't turn on.

So, I said, I intended to dismantle the battery, check balance of non BMS pack. Better the build with fine strand copper with heavy jacket.

I used nickel strip to attach cells. Due to it being a custom pack, there were many cell connections, that weren't convenient.

So, the nickel strip, was attached to the cell, and left long, to solder to wires, to carry power. Well, they are pos and neg wires, and some of them would short, if they broke thru the case plastic covering of cells.

So, in my upgrade rebuild, I used the KAPTON tape I had sent for. I cut small patches of tape, and placed two, or even three thicknesses of tape, UPSIDE DOWN, so that, when you kapton taped the pack together, those patches, stick to that wrap, and affix all those nickel strips. Stop them from wiggling, containing them if they desoldered.

Relying on the thin plastic casing on cells, is nutz. they split. They just do. So, two or three kapton layers, affixed by the wrap of kapton, makes my custom pack as safe as many other designs.

Got pictures?

Pack safety is no joke for sure. Peoples' lives may depend on it. Depending only on the sleeve around cells is an accident waiting to happen.

fechter said:

Got pictures?

Pack safety is no joke for sure. Peoples' lives may depend on it. Depending only on the sleeve around cells is an accident waiting to happen.

Click to expand...

It is packed into my battery tube, but, the nickel strip, was used, to solder wire to. The nickel strip, was on the outside of battery cells that were hot glued together.

So, the nickel strip was soldered to, then bent over, so that the heat would not affect cells. This soldered, nickel strip, had sharp stuff on it. that would tear the cell shrink wrap. Then, the POSITIVE wires, would short on the outside of cells. This would lead to meltdown.

SO, I cut pieces of Kapton, big enough to protect the bent over nickel strip from touching the cell. I put this on upside down, so that the stickum was towards the stickum of the wrap of kapton. So, these pieces would adhere to the wrap layer, and affix the bent over nickel strip. As wiggling could desolder the strip from batt end.

If you want to double, triple, quad or quint, you can. It is cheap insurance.

Oh, I would not trust anything less than kapton.

Im using special insulating paper 0.3mm for that.
Between series cells too.

DVDRW said:

Im using special insulating paper for that.
Between series cells too.

Click to expand...

YES !..very important.

That self-adhesive insulating paper sheet is a useful link, thank you for posting it.

Does anybody have a favorite link for Kapton tape? I can just order some from a random seller, but I usually end up buying stuff from three different vendors to finally find something I'm actually happy with.

I'm not looking to save pennies. I want a reliable vendor, arrives within a week, and is high quality/strength...Where is the "good stuff"?

DVDRW said:

Im using special insulating paper 0.3mm for that.
Between series cells too.

Click to expand...

A very fine solution. Is that hotglue between cells? I used little, and depended on the kapton wrap. Looks like you encapsulated. Nice.

The very important washer on the pos.end before the assembly.

Plastic? An insulative washer? That would HELP, but not solve the problem. I figure the ends, are rather rigid, not ductile. With the kapton somewhat reaching around, so I didn't go to that measure, it wouldn't hurt.

DVDRW said:

Im using special insulating paper 0.3mm for that.
Between series cells too.

Click to expand...

That is nice looking stuff. Thanks for posting the link.

What I've seen happen before is the cells heat up for whatever reason and the heat shrink wrap around the cell will split apart. If you have cells from different series groups next to each other and they make contact, you have a massive short, which will make a huge fiery mess. The fish paper can withstand much higher temperatures, as well as abrasion, so makes a short between sections far less likely.

Banggood hs it for a couple bucks less, my last order, and supower direct has free shipping to.

Cant find it on Banggood and if i try buy directly then it is 79$ shipping to my country.

What do you think about ceramic paper? Seems good isolation and fireproof.

I wouldn't personally recommend trusting Kapton more than you trust the shrink on the cells, and I trust the shrink on the cells so little I only build with bare cells.

Nomex Fiber paper washers and cell insulation spacers would be a place to start, and if you do a very good job in potting it may last for a bit in weather.