How to build a individual 18650 battery pack, Example 12S8P
- Thread starter ecross
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quick couple questions.
1. Does it matter in which cell you place the balance and discharge wires? I see you put them on a few cells down in each parallel section. Could it be put on the first cell?
2. When you install the balance wires, lets just say you did a 6s pack, where do you know where to put the + and - on the balance tab, same with discharge wires?
3.Can many noobs do this pretty easy as long as they learn to solder? ETA on developing a pack like this?
1. Does it matter in which cell you place the balance and discharge wires? I see you put them on a few cells down in each parallel section. Could it be put on the first cell?
2. When you install the balance wires, lets just say you did a 6s pack, where do you know where to put the + and - on the balance tab, same with discharge wires?
3.Can many noobs do this pretty easy as long as they learn to solder? ETA on developing a pack like this?
dnmun
1 PW
1KW said:
you should avoid soldering to these lipo cells in cylinders. especially if you are just learning to solder and have no heat control or low melting point solder. you should use a spot welder for the connections. when you solder to the case it is in direct contact with the ends of the electrode/separator sandwich inside.
on the anode end it is separated from them by the pop top disc inside.
kfong
100 kW
ecross said:
Nice work, I would of went with copper braided wire. Less solder and heat time needed.
kfong said:
-thanks for your thinking, please explain your thinking and send some pics from your pro solder points with "copper baided wire" and some measurements from less heat time and how many less solder do you need, sorry some joke :lol:
tomtom123
100 W
whats the nominal discharge current on these cells?
tomtom123
100 W
are these ok? i doubt they're real ultra fire cells. but anyone used these before and know their discharge rate?
http://www.ebay.com/itm/8pcs-Ultra-Fire-Efficient-18650-3-7V-5000mAH-Lithium-Rechargeable-Battery-Yellow-/360712561632?pt=US_Rechargeable_Batteries&hash=item53fc24e3e0
http://www.ebay.com/itm/8pcs-Ultra-Fire-Efficient-18650-3-7V-5000mAH-Lithium-Rechargeable-Battery-Yellow-/360712561632?pt=US_Rechargeable_Batteries&hash=item53fc24e3e0
tomtom123 said:
-thanks for your good question
-my buddies and I are always looking for the Holy Grail
-please save your money and buy only high quality cells from Sony, Sanyo, Panasonic, Samsung and LG
-I think the cells from DrBass are fine because these Sonys are real, and very good for DIY and more, these cells are 1100mAh, 1300mAh and 1600mAh
-Good new cells are more expensive like about from 4USD to 7USD
-How much discharge current do you need?
Thx for your building thread. Its very nice and i think even skilled users can learn something new 
what i do not really understand is why you only connect the 8p packs together with 2 bricks of cable. Thats definitely to weak for 140A and will cause more heat in the battery and more voltage drop - even if it is silver coated wire..
For instance i connected my 22s9p pack with 9x 2,5mm² in series and 1mm² parallel with sticks from single copper wire.
The solder points do not look very well flown but maybe that happened due to the removed welding tabs. You should try "Fluitin L-Sn60Pb38Cu2 " from Conrad Electronis. This special soldering tin does flow much faster with less heat :wink:
If you want longer lifespan you can charge to only 4,1V / cell. This will cause in about 10% less usable capacity but will more than double the usable watt hours over the whole lifespan of the battery (2-3 times more cycles).
my battery build:
Im very interested in Sony Konion US18650VTC4. These Cells have >2000mAh, 15C continuos and do not need balancing.
what i do not really understand is why you only connect the 8p packs together with 2 bricks of cable. Thats definitely to weak for 140A and will cause more heat in the battery and more voltage drop - even if it is silver coated wire..
For instance i connected my 22s9p pack with 9x 2,5mm² in series and 1mm² parallel with sticks from single copper wire.
The solder points do not look very well flown but maybe that happened due to the removed welding tabs. You should try "Fluitin L-Sn60Pb38Cu2 " from Conrad Electronis. This special soldering tin does flow much faster with less heat :wink:
If you want longer lifespan you can charge to only 4,1V / cell. This will cause in about 10% less usable capacity but will more than double the usable watt hours over the whole lifespan of the battery (2-3 times more cycles).
my battery build:
ecross said:
Im very interested in Sony Konion US18650VTC4. These Cells have >2000mAh, 15C continuos and do not need balancing.
arkmundi
10 MW
That would be most audacious and I'd definitely be interested. The following is a repost of some ideas of how to make that happen in a manner that is fair and doesn't leave anyone burned (which has happened).ecross said:
new guy looking for a great battery manufacturer to buy bulk
To that, I'd add the possibility of more than one agent and drop point. There could be one purchase contract so as to garner the best price, and then an agent/drop point in the USA, Europe and Australia, for instance.myself said:
Man_dizel
1 mW
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- May 27, 2013
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What charger are you going to use when you are finished? I'm also planning a battery pack 48v15a and figuring out what battery I'll use and charger for it. Still at planning stage so any help is welcome. I live in Sweden by the way, so batteries from Germany is manageable with post to Sweden. [SMILING FACE WITH SMILING EYES]
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