Finally built my monstrosity of a 14s10P pack!

[Klauts]

I finally got my pack fully built and running using those 10s2P batteryhookup modem batteries! Samsung 18650 26j cells

I used 4 layers of .15ml Nickel Strips for the series connections. The strips were wrapped in this self Adhesive Silicone Electrical Tape prior to spot welding to the packs.

It can handle 400V/mm so I went for a 3 mm wrap all the way along the lengths just to make them extra cut/tear resistant. (I don't want any exposed metal whatsoever on the outside of the hardcases, the goal is to prevent accidental shorts but also to keep the battery bag which is not fireproof from being I'm contact with any electrical contacts.)

For the ends of the nickel strips where they were spot welded to each pack in the series I used this liquid rubber electric tape that is rated for 1400V/mm to cover the actual contact points I went for a 6mm mound here to also add some stability to the welds (unnecessary but why not?)

Here's a picture of the opened pack showing my wonderful series and balancing connections

And one from the side

It's being controlled by a 40A Daly Smart Bluetooth BMS with active balancing, limited to 25 Amps via the BMS.

The pack should ever draw more than 12-15 amps though as it will be run in parallel with another 52v pack at all times using a parallel battery discharger to power my 25A system.

Any glaring problems? Things you liked?

This is my first ever pack aside from a 2s2p pack I made for some hand warmers to practice

The sides of the case are lined with closed cell foam as is the bottom, the top is only protected by the hardcases on the individual 2s10p packs.

The Bag I chose is waterproof but I will also be putting a waterproof battery cover on top of it to be safe.

 

[amberwolf]

Is the bag chewproof against the crate's resident?


I can't tell if you have the packs fastened to each other...but if it's possible, you could run two or four bag-length bolts thru the corners of the cases.


I recommend making sure all the small balance wires are secured down and insulated against contact with each other, so they can't vibrate and abrade and potentially short across cells.

 

[Klauts]

Is the bag chewproof against the crate's resident?

Hahahahah no it is not but she's a really good girl never even chewed furniture as a puppy. Although to be safe I always leaves anything poisonous or potentially explosive out of her reach when I'm not using it

 

[Klauts]

I can't tell if you have the packs fastened to each other...but if it's possible, you could run two or four bag-length bolts thru the corners of the cases.

They're only fastened to eachother using a strip of that silicon tape on each layer ATM, have to be careful lifting them out of the bag. I'll take a look and see if i can't figure out a way to get some bolts holding them together... They've already got screw holes in the hardcases to work with.

I recommend making sure all the small balance wires are secured down and insulated against contact with each other, so they can't vibrate and abrade and potentially short across cells.

I'll tape them down and isolate them right this moment, it should be ok if the balance wires touch my insulated series strips so long as I reinforce the balance wires at the point of contact? (Using liquid tape?)

All the packs are rated to be able to power my bike on their own and I've got the wiring set-up to easily switch which packs are powering the motor vs the 12v step-down and peripherals.

 

[amberwolf]

The two younger shorter-haired ones PeanutButter and JellyBean in these pics chewed on more things than almost any I've ever had (the older longer-haired ones Yogi and Kirin didn't really do that sort of thing, but they were grown when I got them like most of my dogs...but I've had a few that started out as puppies over the years)

 

[amberwolf]

I recommend making sure all the small balance wires are secured down and insulated against contact with each other, so they can't vibrate and abrade and potentially short across cells.

I'll tape them down and isolate them right this moment, it should be ok if the balance wires touch my insulated series strips so long as I reinforce the balance wires at the point of contact? (Using liquid tape?)

Whatever keeps any wiring with potential voltage differences from ever resolving those differences is good.


She's beautiful. Good thing she's really small, right? And probably totally relaxed and not boisterous or anything. :lol:

BTW, for some dogs (like PeanutButter), there is no "out of their reach"; he could've gotten to stuff on the top of the kitchen cabinets if he wanted to.

 

[Phasedout]

I finally got my pack fully built and running using those 10s2P batteryhookup modem batteries! Samsung 18650 26j cells

I used 4 layers of .15ml Nickel Strips for the series connections. The strips were wrapped in this self Adhesive Silicone Electrical Tape prior to spot welding to the packs.

It can handle 400V/mm so I went for a 3 mm wrap all the way along the lengths just to make them extra cut/tear resistant. (I don't want any exposed metal whatsoever on the outside of the hardcases, the goal is to prevent accidental shorts but also to keep the battery bag which is not fireproof from being I'm contact with any electrical contacts.)

For the ends of the nickel strips where they were spot welded to each pack in the series I used this liquid rubber electric tape that is rated for 1400V/mm to cover the actual contact points I went for a 6mm mound here to also add some stability to the welds (unnecessary but why not?)

Here's a picture of the opened pack showing my wonderful series and balancing connections

And one from the side

It's being controlled by a 40A Daly Smart Bluetooth BMS with active balancing, limited to 25 Amps via the BMS.

The pack should ever draw more than 12-15 amps though as it will be run in parallel with another 52v pack at all times using a parallel battery discharger to power my 25A system.

Any glaring problems? Things you liked?

This is my first ever pack aside from a 2s2p pack I made for some hand warmers to practice

The sides of the case are lined with closed cell foam as is the bottom, the top is only protected by the hardcases on the individual 2s10p packs.

The Bag I chose is waterproof but I will also be putting a waterproof battery cover on top of it to be safe.

I bought 14 of those same packs, the cases are easy to use and hold the cells very securely. Bolting them together should be fairly simple too.
The problem is, these packs are intended for very low current, and built to suit. They need the series connections beefed up to extract any real power from them.
Also there are 4 plastic dummy cells in each 2s pack. That's a lot of wasted space.
These are a good deal, but I wouldn't,t use them as is.

I tested 28 cells, 3 times each, nd they are very well matched, capacity wise. Cell voltage doesn't stray between cells more than a couple of hundredths, top or bottom of charge. All cells give their rated capacity. Mind you I can only discharge @ 6 amps.
These are low power cells, but still capable of 50amps in 10 p configuration. Those little tabs are good for maybe 10a. Then there is the

I finally got my pack fully built and running using those 10s2P batteryhookup modem batteries! Samsung 18650 26j cells

I used 4 layers of .15ml Nickel Strips for the series connections. The strips were wrapped in this self Adhesive Silicone Electrical Tape prior to spot welding to the packs.

It can handle 400V/mm so I went for a 3 mm wrap all the way along the lengths just to make them extra cut/tear resistant. (I don't want any exposed metal whatsoever on the outside of the hardcases, the goal is to prevent accidental shorts but also to keep the battery bag which is not fireproof from being I'm contact with any electrical contacts.)

For the ends of the nickel strips where they were spot welded to each pack in the series I used this liquid rubber electric tape that is rated for 1400V/mm to cover the actual contact points I went for a 6mm mound here to also add some stability to the welds (unnecessary but why not?)

Here's a picture of the opened pack showing my wonderful series and balancing connections

And one from the side

It's being controlled by a 40A Daly Smart Bluetooth BMS with active balancing, limited to 25 Amps via the BMS.

The pack should ever draw more than 12-15 amps though as it will be run in parallel with another 52v pack at all times using a parallel battery discharger to power my 25A system.

Any glaring problems? Things you liked?

This is my first ever pack aside from a 2s2p pack I made for some hand warmers to practice

The sides of the case are lined with closed cell foam as is the bottom, the top is only protected by the hardcases on the individual 2s10p packs.

The Bag I chose is waterproof but I will also be putting a waterproof battery cover on top of it to be safe.

full rated capacity, and only thtiite
I bought 14 of those packs, tested each cell 3 times, and they are all virtually identical. Full rated capacity, and cell voltages vary by only a couple hundredths of volt, top or bottom of charge.
Good deal, but I wouldn't use them a is.

These packs are intended to be used at very low current, and are built accordingly. They need the series connections beefed up to handle any real power. These are low power cells, but in 10p configuration, thay can still put out 50a. Look at the tiny tabs, good for like 10a. It's no better inside.

Also, there are 4 plastic dummy cells in each pack, so a lot of wasted space.
And ththere is the "please electrocute me wiring". Please rethink your approach.
Man, I'm a downer.

 

[Phasedout]

I finally got my pack fully built and running using those 10s2P batteryhookup modem batteries! Samsung 18650 26j cells

I used 4 layers of .15ml Nickel Strips for the series connections. The strips were wrapped in this self Adhesive Silicone Electrical Tape prior to spot welding to the packs.

It can handle 400V/mm so I went for a 3 mm wrap all the way along the lengths just to make them extra cut/tear resistant. (I don't want any exposed metal whatsoever on the outside of the hardcases, the goal is to prevent accidental shorts but also to keep the battery bag which is not fireproof from being I'm contact with any electrical contacts.)

For the ends of the nickel strips where they were spot welded to each pack in the series I used this liquid rubber electric tape that is rated for 1400V/mm to cover the actual contact points I went for a 6mm mound here to also add some stability to the welds (unnecessary but why not?)

Here's a picture of the opened pack showing my wonderful series and balancing connections

And one from the side

It's being controlled by a 40A Daly Smart Bluetooth BMS with active balancing, limited to 25 Amps via the BMS.

The pack should ever draw more than 12-15 amps though as it will be run in parallel with another 52v pack at all times using a parallel battery discharger to power my 25A system.

Any glaring problems? Things you liked?

This is my first ever pack aside from a 2s2p pack I made for some hand warmers to practice

The sides of the case are lined with closed cell foam as is the bottom, the top is only protected by the hardcases on the individual 2s10p packs.

The Bag I chose is waterproof but I will also be putting a waterproof battery cover on top of it to be safe.

Here's a pic of an opened pack. The series connections are about 5mm of .01 nickel. Should make decent fuses!