PINNED - Lithium battery conversion/info

[Burgerman]

https://f47fb5b4-a-62cb3a1a-s-sites.goo ... edirects=0

this is a 6 cell charger. So 7 pins. 2nd one down...

Or... plug seen from top...

http://www.wheelchairdriver.com/convert ... ithium.htm

[cdb0ewm]

Sorry for being so thick headed. I've reviewed your several postings on this and here's what I've got.

[Burgerman]

No.

One of your problems is that you have the connectors numbered BACKWARDS. Which makes any simple explanation really involved.

Connector A goes (as I said above, twice) starts at 1 ONE on the right, Same on connector B.

Other than this, connector A is wired correctly,
But B is wrong. And the last pin, is for cell 14 and we only have 13.

These are the connectors pins... AS YOU LOOK AT THE CHARGER.

unused pin then 14 13 12 11 10 9 8N ---- 8 7 6 5 4 3 2 1N

1N = NEG
8N = CELL 8 NEG
NUMBERS = CELL POSITIVE ENDS STARTING FROM THE NEG END.
PIN 7 AND 8N GO TO BTHE SAME POINT ON THE PACK.
PIN/CELL 14 IS UNUSED.

If you were charging 2 cells you would use:
1N for the neg
2 for the first cells pos
3 for the second cells pos
Etc...

Do the same for B

[woodygb]

Your pic also seems to show numerous short circuit connections .

I think that this is correct ..BUT I could be wrong.

PACK MOD.png (129.44 KiB) Viewed 13823 times

[Burgerman]

Connector B should be:

14 13 12 11 10 9 8 8N cells
8 7 6 5 4 3 2 1 pins

Where 14 in not connected. And 8N goes to the same place as pin 8 on connector A...

[Irving]

Your pic also seems to show numerous short circuit connections .

I think that this is correct ..BUT I could be wrong.

The attachment PACK MOD.png is no longer available

You're right, it does.. & I think yours is right...

Here's my drawings of a 4p3s pack. I've doubled-up the 'inter-S' connection but its not strictly necessary on a small pack. I'd probably do 3 on an 8p pack

pack_front.png (113.89 KiB) Viewed 13821 times

pack_rear.png (130.72 KiB) Viewed 13821 times

[woodygb]

Your right that a few more bars would ideally be wanted ...but I thought that me drawing them in might cause extra confusion.
Here's a revision for B.M. to comment on the plug numbering.

PACK MODb.png (132.52 KiB) Viewed 13819 times

[Burgerman]

Correct!

[cdb0ewm]

OK...one more try. Part of my confusion was I though only 14 of the connections on the charger was used when it looks like 15 connections are used.
If I understand correctly the only connector pin not used is Connector B, pin 8 which is a red wire.
I also moved/added to the serial busbars.

[Burgerman]

Yes I think. I have never seen such a confusing drawing for something so simple. And your battery cell joining bus bars are all wrong. That will short it all out.

[woodygb]

Here's a pic using your notations.

I've shown just ONE horizontal bus bar joining each 6 cell battery ..... you could add more ... as many as an additional 5 .... shown as purple bus bars @ the far right of the pic.

BUT only add them .... in a ladder .... to the ones I have drawn in the left of the pic.

PACK8.png (149.94 KiB) Viewed 14256 times

[cdb0ewm]

Thank you for the feedback. Is there a clearer picture available that is less confusing

[woodygb]

Does this single row make sense?

single row.png (39.85 KiB) Viewed 14254 times

[cdb0ewm]

Absolutely...thank you for sharing

[woodygb]

Then you need to think of each vertical stack of 6 cells as ONE SINGLE CELL.

single row column.png (73.04 KiB) Viewed 14253 times

[cdb0ewm]

One last question
What is the purpose of the additional purple busbars and why only on the 'B' side

[woodygb]

One last question
What is the purpose of the additional purple busbars and why only on the 'B' side

The additional bus bars are optional ... depending on current draw from your pack ... I'd probably add at least one more.

I could only bothered to draw one set of bus bars....I've added them in this pic of " 3" super cells ... remember ... ONE column of six cells = A Super cell .

busbars.png (26.69 KiB) Viewed 14248 times

[Burgerman]

http://scriptasylum.com/rc_speed/lipo.html

Theres a site here that tries to prevent blown chargers and burned down houses!

[woodygb]

Whoops! ... missed drawing in one of the optional bus bar ...but you should get the idea.

I'd probably go for two connecting bus bars per paired column.

[Burgerman]

http://www.wheelchairdriver.com/BM-MK3- ... rchair.htm

Scroll...

[BounderGimp]

I find the wiring diagrams for the battery pack confusing. Would it be possible instead to just draw a circuit digram for the pack using the schematic symbol for a battery cell, showing all individual cells wired correctly for parrell/series connections? It would be a very basic two dimensional schematic which would eliminate all questions as just what is connected to what.

[woodygb]

Is this drawing of a 7 cell pack ... 6 cells per column = ONE CELL .... less confusing ?

SYMBOL.png (52.74 KiB) Viewed 14634 times

[Burgerman]

http://scriptasylum.com/rc_speed/lipo.html

On here you can choose cell count, and parallel count, show balance wires or not etc in super simple graphics.

[Burgerman]

It just occurred that because of the exchange rate at 1.70 dollars to the pound, approx. that it will be costing those in the US about 70 percent more to buy lithium cells. Since they all originate in china.

[cdb0ewm]

Ok ... thanks to input from you and Woody, along with his review, here's my battery pack wiring with the balancing connectors.

[Burgerman]

Yes.



Its easier to do it than draw it because you can physically see what is connected to what.

[shirley_hkg]

Found 2 cells and they are really a bargain.

42110 --- 11Ah --- IR 4-6 mohm --- @ $4.5 US
38106 --- -8Ah --- IR 9-11 mohm -- @ $3.2 US

[Burgerman]

That would be true, if they are what they claim. Cheap cells from china tend to be anything but!

[ex-Gooserider]

The other problem with those cells (possibly solvable, but not easily) is that they have plain terminals - not the threaded ends like the Headways. This will make getting a secure and reliable connection to them much more of a challenge. The two approaches that seem most likely would both be difficult - either some sort of mechanical clamping, which is going to need hardware on the ends and be a challenge to keep tight under bouncy conditions, or to tack weld connecting strips between the cells - this is what the commercial pack makers usually do, but requires some fancy and expensive gear to do....

ex-Gooserider

[Burgerman]

http://www.ebay.co.uk/itm/110V-Hobby-Mi ... 233b2875e5

I used to make hobby batt packs without one of these, with an old 2v battery cell although you are supposed to use AC. Some use a rewound microwave oven transformer. Google. Easy project. But they are a bit big. An old instant 100 watt soldering iron, with the "loop" replaced with two electrode points works as well. You need some thin stainless steel sheet for connecting straps. I also used to build pulse jet engines with spot welds the same way.