Konion Makita LiMn battery care and feeding by Doctorbass

[marty]

x
After I get them charged up ill just be waiting for my spot welder to arrive.
x

Spot welder details please.

 

[jitup]

Hello,
I bought 100 of these a couple months ago, and after months of testing, I am ready to assemble my 7s10p pack. I only have a one main point of confusion. Where do I attach the balance wires? What connector do you guys use for the balance wires at the end?
Thanks

 

[arkmundi]

Hello,
I bought 100 of these a couple months ago, and after months of testing, I am ready to assemble my 7s10p pack. I only have a one main point of confusion. Where do I attach the balance wires? What connector do you guys use for the balance wires at the end?
Thanks

Its completely up to you how to do that. A set of balance wires are at +cathode and -anode poles, creating a voltage potential between those poles. Logical placements are on either each individual cell or on each series string (10 sets) or parallel string (7 sets). If your pack design is to string cells in parallel and then string those in series, then the latter would work fine. Your balance charger, if that is what you're using, needs to match the voltage and amperage characteristics of its target, different in each case. Programmable balance chargers can enable that.

In my packs, I have balance wires on each cell, but I don't do balance charging. The 16S1P pack set of wires is there to simply monitor the health of each individual cell, with celllogs. 16 sets to two celllogs. Using JST connectors.

 

[amberwolf]

+cathode and -anode

 

[arkmundi]

In a device which consumes power, the cathode is negative, and in a device which provides power, the cathode is positive: http://en.wikipedia.org/wiki/Cathode

In batteries, the cathode refers to the entire positive plate, the terminals to which are exposed, the ends on cylindrical cells, but which internally is rolled and comprises a significant part of the battery by weight.

 

[mistercrash]

Hello,
I bought 100 of these a couple months ago, and after months of testing, I am ready to assemble my 7s10p pack. I only have a one main point of confusion. Where do I attach the balance wires? What connector do you guys use for the balance wires at the end?
Thanks

I hope this makes sense. Like it was said, use any kind of connector you want as long as you install the matching connector on the balance charger. Pictured is a crummy drawing of a JST connector.

 

[Doctorbass]

Hello,
I bought 100 of these a couple months ago, and after months of testing, I am ready to assemble my 7s10p pack. I only have a one main point of confusion. Where do I attach the balance wires? What connector do you guys use for the balance wires at the end?
Thanks

I hope this makes sense. Like it was said, use any kind of connector you want as long as you install the matching connector on the balance charger. Pictured is a crummy drawing of a JST connector.

Just to avoid confusion, Mistercrash i think your schematic require somem corrections . I can not see any connections going to the buttom of the cells, i can see only the black negative... ?

Also did you forgot to add the serie link between the cells parallel group?

Doc

 

[mistercrash]

Wow! Now that is embarrassing. There would've been some KFF on the drawing I made before. I made the corrections. I hope I got it right this time. You'd think I never did batteries out of Konions before. :lol:

 

[jitup]

Fantastic! Thanks for all the help guys.
@mistercrash - pictures are worth 1000 words! That resolved any confusion I had. Also what program did you draw that in? How quick is the work flow?

 

[Doctorbass]

Wow! Now that is embarrassing. There would've been some KFF on the drawing I made before. I made the corrections. I hope I got it right this time. You'd think I never did batteries out of Konions before. :lol:

My pleasure :wink:

Doc

 

[anttipaa]

Anyone build pack from samsung sdi inr18650-15U or us18650vt3 cells that are found from makita packs also? Wondering are there real difference compared to us18650V cells.

 

[team_EMUS]

We were just given a large amount (2000) of used US18650V cells for our electric motorcycle. 8) (Project EMUS)

We compared a few other cells and our optimum design would use LG ICR18650HE2 cells, but since those were given to us, we might aswell use them!

Looking at the discharge curves given by Doctorbass, I calculated an internal resistance of 38.5mOhm.

Our requierements are:
Maximum Open-Circuit Voltage 700V
More than 10kWh of energy
We want to break our batterypack appart into 9 sub-modules
Joules losses must be reduced to a minimum
Battery must be able to push 240A peak

After calculation and analysis,using the Sony SE US18650V cells, we get:
162S14P
Voc=672,3V
13,5kWh
100W losses
Imax=16A (at the cell)

2430 cells are required for this battery pack.

Let's assume that the unit price of these cells is 5$, it would cost us 12150$.
Luckily for us, we won't have to pay for them!

On the other hand, we need to dissasemble packs and sort them... (But I sure Doctorbass would love to give us a hand ! )

We might start a new thread to show how our design is going...

 

[riba2233]

Dont waste your time, you will end up disappointed. Samsung 25R cells are pretty cheap these days, and you would need much less in parallel because they are 2.5Ah.

 

[team_EMUS]

Dont waste your time, you will end up disappointed. Samsung 25R cells are pretty cheap these days, and you would need much less in parallel because they are 2.5Ah.

Even when these cells are given fo free?

We could at least verify our design and have a decent battery pack to ride with this year... Perhaps not the best, but functionnal.

 

[litespeed]

You will be just fine with the FREE cells that were given to you. I can't wait to see this pack.

Tom

 

[anttipaa]

http://www.stensat.org/docs/battery_test_results.pdf

Is it true that if you overcharge it pops seal and there is no fire? And after that cell has no short circuit? Is there even possibility to get short circuit inside these cells? Im asking because Im planning to build a pack for electric car and Im thinking cell level fusing. Is there really need for it?

 

[riba2233]

I would say no. There is almost zero chance that new 18650 cells will develop internal short.

Dont waste your time, you will end up disappointed. Samsung 25R cells are pretty cheap these days, and you would need much less in parallel because they are 2.5Ah.

Even when these cells are given fo free?

We could at least verify our design and have a decent battery pack to ride with this year... Perhaps not the best, but functionnal.

Yes, you will have pack that is too heavy. But if you have resources and time, you can build it, and use better cells next year, when 3.0 Ah cells will be common and cheaper. But they are already available.

 

[team_EMUS]

The time we spend designing for the US18650V is not going to be wasted, as we are going to keep in mind that the cells could be swapped for LG or Samsung cells in the future. Modularity and standardization are key!

 

[Doctorbass]

removed

 

[team_EMUS]

Ah haa. I know you dont bother with using over 2000 of these used 18650V cells because you now have the magic tool to match them :wink: ...

Doc

Indeed! Thanks Doc!

 

[anttipaa]

Ah haa. I know you dont bother with using over 2000 of these used 18650V cells because you now have the magic tool to match them :wink: ...

Doc

Indeed! Thanks Doc!

Please let me know what magic tool? I have allready ~2000 cells to sort out and more is coming..

 

[Doctorbass]

UPDATE 2017

How to disassemble MORE RECENT makita:


[youtube]Oz6Uis05ewA[/youtube]

Enjoy !

Doc

 

[litespeed]

Doc, are you getting many of the VTC5's yet? I'd be interested in 25 or 30 of those.

Tom

 

[Matador]

UPDATE 2017

How to disassemble MORE RECENT makita:
[see video in post above]

Enjoy !

Doc

Thanks Doc for this exellent video.

I'm still very interested to buy some of your stock (20 BL1840) as we discussed by PM in late december.
My money is already saved the counter, and I'm waiting for your "feu vert" to come pick them up as soon as you have them in stock!

Matador