Building battery from MAKITA Konion PACK

[marty]

What material is that strip? Copper? What is the thickness? What is the width? Where do you buy it? Do you cut it to size? Do you cut it with snips?

If building a large battery for a electric vehicle, I know that we need to know how many Amps will be used to calculate the size of the metal strip used to connect the individual cells. Lets just figure slow electric bicycles and scooters that are mostly just dreams in my mind.

Think mcmaster.com might be expensive? They got a lot of information on copper and different alloys.

Electrical Conductivity

Copper alloys are known for their excellent electrical conductivity. Ratings for electrical conductivity use Alloy 101 as the standard. Note: SAE 841 is not rated.

For that i use BCAE1.com car audio website wich have many great java applet to calculate your data.

Yes i used copper. I got from surplus material at work. But i know that some house are made with copper top so try contacting some guy working in the construction domain that are specialized in house top cover.

but you can also get some on ebay as well


http://www.bcae1.com/wire.htm

to find the number of square mils you need with copper,

Called a roofing supply place. They got 14 inch wide copper flashing. Cost is $12.91 per foot. They call it 16 once. Thickness is .0216 inch. Also called 22 Mils (a Mil is 1/1000 of an inch)

If I cut battery cell connector strips 3/8 inch wide. 3/8 inch is .375 inch or 375 Mils

22 Mil X 375 Mil Copper strip is = 8250 Mils

I HAVE STOPPED UNDERSTANDING WHAT I AM TYPING!!!!!!

As per calculator at http://www.bcae1.com/wire.htm
8250 square mils is 10504 circular mils.

As per chart at http://www.bcae1.com/wire.htm
10 Gauge wire is 10384 mils which is pretty close to what I think my copper strip might be, 10504 mils.

If I am figuring this correctly a .0216 inch X .375 inch copper strip is about equal to a 10 Gauge wire which I think is more then big enough.

IS MY THINKING CORRECT? I AM NOT SO GOOD WITH MATH AND ELECTRICITY.

Marty goes down to the basement to pound on a 10G solid wire with a hammer and anvil to see what size it is when it is all flattened out.

[Degull]

OK,

What I suggest is to make few different groups of voltage ranges. Let say you make a group for the cell from 2.5 to 2.8V, another for the cell at 2.8 to 3.1V, another group with cell of 3.1 to 3.4V etc.. up to 4.2V ( this step is not to make your pack but just for the equalization step!)

So instead of charging all cell individually, make these groups with all these range of cells voltage and than you can charge these group instead of charging each cells, that will save you a lot of time! so proceding to a charge of 5 or 6 groups is faster than charging 100 or 200 individual cells as well!

After all these groups are charged to 4.1V or 4.2V, the final equalizing step would be to parallel all group cells together.

One of the best way I found to parallel cells fast if to use aluminum foil sheet and some smooth packing material. What you do if to place all cells in a sandwich with one top and one bottom layer of aluminum foil sheet. It work perfectly!




Doc

Doc what do you think about bulk charging these batteries in series before creating parallel strings? I was think about purchasing some cheap 18650 battery holders and stringing them together in 16S (4 x 4 bank 18650 battery holders). They are available on fleebay for a couple bucks each. I have a 48 volt 500 watt Meanwell that is variable up to 60 volts. 16 x 3.7 is 59.2 volts, this would allow 16 batteries to charge simultaneously. Would this work or is there something I'm missing?

[999zip999]

I charge my 15s konion pack to 61.5v or 4.1v per cell

[Doctorbass]

Your calculations look good and 10 gauge equivalent is ok.

[Doctorbass]

Doc what do you think about bulk charging these batteries in series before creating parallel strings? I was think about purchasing some cheap 18650 battery holders and stringing them together in 16S (4 x 4 bank 18650 battery holders). They are available on fleebay for a couple bucks each. I have a 48 volt 500 watt Meanwell that is variable up to 60 volts. 16 x 3.7 is 59.2 volts, this would allow 16 batteries to charge simultaneously. Would this work or is there something I'm missing?

No !!

Absolutly NOT

serie connections DONT balance them.. it's PARALLEL connections that balance them and you need to balance them BEFORE connecting them in parallel groups with a tolerance under 300mV max between the low and the high cell. Once they are paralleld for 12 hours, than you can be sure they are balanced perfectly. THAN you can make your parallel groups and then connect them in serie.


Konion autobalance : YES
Konion autobalance whatever the voltage difference: NO so you can't connect them in serie if they are not equalized before !


bulk charging if your pack have not beed equalized with in a certain level will make the high cell to overcharge.

Please re read what i suggested with the sandwich suggestion

Doc

[Doctorbass]

Here is an exemple of when i had alot of A123 cells to parallel .

It's an easy way to paralell all your cells fast at low cost. ( use this method for all cells grouped with in 300mV difference between the highest and the lowest voltage cell) only.. otherwise too much charge current will flow to the lowest ! and ytou will stress that low cell.

I call this my Doc's perfect cell equalizer !

You can add some weight with a good distribution over the surface to ensure you get a good pressure on all cell tabs. ( not shown in the following pictures)

It also have many advantages like if you reverse one of the cells in the lot to be paralleled, the overcurrent generated thru this cell will just blow the aluminum in this area.. just like a fuse!.. the thickness of this aluminum seem just perfect for that!

Doc

[Degull]

Thanks for the pics and the info Doc!

[marty]

Marty got copper! Beautiful shinny metal!
Bought from a roofing supply place. 14 inch wide copper flashing. Cost is $12.91 per foot. They call it 16 once. Thickness is .0216 inch. Also called 22 Mils (a Mil is 1/1000 of an inch)

How should I clean the copper before soldering? Tried water to clean off fingerprints. Water don't work. I am thinking to clean it with water and dish soap using a green scouring pad.

Picture does not show how shinny this copper is. Told the wife that it was gold

copper600w.jpg (56.99 KiB) Viewed 586 times

[Doctorbass]

Marty got copper! Beautiful shinny metal!
Bought from a roofing supply place. 14 inch wide copper flashing. Cost is $12.91 per foot. They call it 16 once. Thickness is .0216 inch. Also called 22 Mils (a Mil is 1/1000 of an inch)

How should I clean the copper before soldering? Tried water to clean off fingerprints. Water don't work. I am thinking to clean it with water and dish soap using a green scouring pad.

Picture does not show how shinny this copper is. Told the wife that it was gold

copper600w.jpg

The fingerprint on your copper is due to the grease on the finger that trasnform into acid that atack the copper. It's normal !

just using a scotchbright will do the job and clean everything.

Doc

[Ypedal]

after a scotchbright scrub, wipe area with solvent, rubing alc, zippo fluid, varsol, whatever.. but not water. and dont touch that spot with your fingers..

( do this just prior to soldering.. otherwise it will loose it's luster overnight. )

[marty]

Need some insulating plastic to place between 2 groups of cells. Any suggestions on where to get some plastic? Preferably from the garbage can.
Picture stolen from Doctorbass.

04728sm.jpg (110.64 KiB) Viewed 528 times

[Ypedal]

that stuff is G10 or bakeware or fiberglass board .. un-printed circuit board.. pretty tough stuff and almost fire proof.. but you can substitute with all sorts of stuff.. pvc, lexan, acrylic, my personal cheap solution is " Crazy carpet " . . thick plastic kids slide down snow hills on.. 1$ for a big piece of it..

http://www.google.ca/search?hl=en&sugex ... 0gGm8YTLCA

[Doctorbass]

that stuff is G10 or bakeware or fiberglass board .. un-printed circuit board.. pretty tough stuff and almost fire proof.. but you can substitute with all sorts of stuff.. pvc, lexan, acrylic, my personal cheap solution is " Crazy carpet " . . thick plastic kids slide down snow hills on.. 1$ for a big piece of it..

http://www.google.ca/search?hl=en&sugex ... 0gGm8YTLCA

Great idea for teh crazy carpet!

Doc

[swampjeep]

Doc, are you selling these packs? did I miss something about that or is there another thread somewhere about buying /selling them?

[ambroseliao]

viewtopic.php?f=9&t=38961

[mistercrash]

What I used is thin cutting boards bought at the dollar store. The ones I got were something like 3 or 4 mm thick. The crazy carpet is an awesome solution too.

[Teh Stork]

I'm going to assemble around 350 to 400 cells in a pack, but I've come to a problem that proves hard to solve. What glue to use between the cells. I've tested three different substances so far.

Adhesion is between two parallell cells glued to two parallell cells.

1. Normal bathroom silicone. Good adhesion, came loose at ~40N. Good shock properties. Good elastic properties.
2. Wood glue, Brown stuff. Did not state usable for plastics, normally used to glue chipboard/MDF. CRAZY adhesion. Tore the green plastic before giving in. Never expected this. Adhesion? 500N? Not elastic or shock absorbant.
3. Clear acrylic. Adhesion similar to silicone.

I will encapsulate the cells with fibreglass + heathrink after fully assembling them - the glue is mostly for easing the assembly process. Silicone or acrylic will net me the abillity to easily take it apart again, but I'm a bit worried about long time stabillity. Wood glue will make it impossible to exchange cells - but the cells will be firmly attatched to each other..

Any experiences, as of now - I think I'm going with silicone.

[pwbset]

I used to use a generic glue gun with just a small dollop between cells and it worked well enough, but for my next 200 cell project I'm just going to use clear, thin tape for 10p strings. The glue from the glue gun was pretty hot as well, which may not have been good for the cells, and also added more weight that I was interested in. I'm tab welding them all together so that will keep everything together as well. Good luck with your build! Post photos!

[pwbset]

Quick question for the konion lovers out there...

I'm beginning to assemble a 20s10p pack from Doc's V packs I just got. I have a single 4.2v 1.5A charger to work through these 200 cells to get them synced up for assembly. I'm thinking at this point wouldn't it be easier to build my 10p strings with matching resting voltage cells (of which there are great similarities in each pack of course) and then series them all together and blast the whole lot with my 84v charger or would the lower resting voltage parallel strings take too much current or something??

So like it would series like this:

3.12v(x10) -+ 4.06v(x10) -+ 3.75v(x10) -+ etc out to 20S...

I need a quicker solution somehow or I won't be riding for weeks.

EDIT: FYI I'm not worried about internal IR or matching exact capacity with CBA etc. etc. I want to build and ride.

[Teh Stork]

Do you have a old laptop charger? You can probably tie strings of 5s and charge them with that Will bring the cells to ~4V.

Start out with cells in balance. After charging; lower voltage means higher capacity. Rate the cells from A to E based on voltage. Group the cells based on this, and your result will be quite close to what you'd achieve with a better analyzer.

[pwbset]

After charging; lower voltage means higher capacity.

[999zip999]

You can make 10p3s blocks for 12v and make a long string 6 blocks = 74v and have an extra 12v block for replacemant. Yes replacement. Or 21s for 86v. These are used cells.

[pwbset]

You can make 10p3s blocks for 12v and make a long string 6 blocks = 74v and have an extra 12v block for replacemant. Yes replacement. Or 21s for 86v. These are used cells.

That would be too much work. I plan on using the existing 10 cell holders and just snip the negatives within a pack, turn them around parallel with the others and make 20 4.2v ~13.5ah blocks in series. Easy peasy. I may go 18s too as I have a 75.6v charger. We'll see what fits in my triangle.

Can anyone answer my original question?

[pwbset]

This is what I meant... flip every other pair and charge all at once... the pack in the photo happened to have a dead pair so this is a 4 pair experiment. I also found another 4.2v 1.5A single cell charger so paralleled them for 3A. Now we're getting somewhere! .3C charging whoot!!

[999zip999]

That's how mine are use the makita block as 10p. Charge blocks to 4.1v. I used 3 for 12v subpacks. Hook up two togethere with 6s sense wires for checking and balancing 24v. Easy to fit a RC charger for balance at 6s. Yes balancing or to find a low string voltage. I cut the taps over hang on the pos. end with good small sissiors. Carefully. I found the shipping rail for cheap blinds at Lowes and the 10s pack snaps in and can be hang from top rail and one under. This way you could make two 24v for 48v or three for 72v. !80 cells 18s.