When building a 18650 battery pack...?

Hi, all I’m currently using four 6s 6200mah lipos with 2 series connectors to make two 12s batteries running twin motors.

I recently saw that 18650’s are more efficient and safer to handle than lipos.

So if I set six 18650 6000mah Li-ion batteries in series, that would make them a 6s? With 6000mah?

I will be setting it up with a balance connector instead of a bms.

18650 with 60000 mah? Like two 18650 in parallel? or ONE 18650 with 6000 mah because that’s unheard of.

I’ve seen it on Alibaba, but is the 3000mah easier to get?

If I get the 3000mah batteries, I would need to have 12 of them to make a 6s 6000mah?

6000mah is non existant. Chemistries simply aren’t there yet. Samsung 30Q cells are one of the best on the market right now and are 3000mAh which is a good capacity for a 18650

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So this isn’t real?

https://m.alibaba.com/product/60339405074/18650-li-ion-battery-3-7v.html?s=p&spm=a2706.7843299.1998817009.4.sGffRM

nope. where are you located?

Parallel : add mAh. Series : add voltage so you want 12s, 12 in series, 2p, 2 parallel. Let’s say 18650 is 3000 mah. You want 12 of those in series to make it 12s but it only has 3000 mah. So you need another 12s in PARALLEL to make it 3000 mah + 3000 mah = 6000.

So to your question, yes you would need 12 of them to make it 6s with 6000 mah.

you mean 24 for 12s2p

Thanks boostedbuilder. Km located in Florida (U.S.)

Gee: thanks!

Where is a good source in buying good 18650’s at a good price?

These are US vendors.

https://eu.nkon.nl This one is in the eu but they ship to the US

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The highest mah of any 18650 at the moment is 3500. Those ones you linked to are fake.

You should use either of the following cells in at least 2 parallel; Samsung 30q 3000mah 15A cont. discharge (6000mah 30A) LG HG2 3000mah 20A cont. discharge (6000mah 40A) Sony Konion VT6 3120mah 30A cont. discharge (6240mah 60A)

You should get your cells from a reputable source, I suggest nkon.nl

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So $7 is the average price for one 18650 3000mah battery?

Something around there, unless you buy in very high quantities

Last question for the day, lol. Will 20a do the job, or should I go higher?

It depends on the battery. If you get 30q cells, they’re about $4.00 a piece in quantity. You definitely need more than 2p with them, I wouldn’t go below 3p, and 4p would be even better. If you go with the absolute top of the line vtc6 cells, yes they’re a lot more expensive. You still need at least 2p to get a decent amount of current and range.

Also keep in mind that you’re running 4 6s packs, each 6000mah. To have a similar range with 18650s, you’ll need 12000mah and 12s, which is 12s4p.

That makes sense. It seems like even though 18650’s are safer and more efficient than lipos, I will be sacrificing weight and space management for the same amount of power I’m getting for lipos.

3120mAh with 30A discharge?! Where can I find these things? The only VT6s I’ve seen are 3000mAh and 15A discharge.

Far as I know the chemistry is very similar the package is just different with some safety benefit on the side of 18650s in terms of controlled failure (place on the cell designed to blow out, that said I’ve seen plenty of 18650 boards on fire to let me know it’s not entirely safe). I see this much how I see virus protection on computers, it gives people a false sense of security and safety, these things are dangerous no matter what kind of shell you put the chemicals in.


18650 Volume

(18/2)^2*65 * 3.14 = 16,532 mm^3 = 16.5cm^3

18650 Power Density (power per cm^3)

(3.7V*3Ah) / 16.5 mm^3 = 0.67 Wh/cm^3


Compare with Lipo 5S pack

LiPo Volume

1455041 = 300,000 mm^3 = 300cm^3

Lipo Power

5S3.7V5Ah = 92.5Wh

LiPo Density

92.5Wh/300 = 0.30Wh/cm^3


So in terms of energy density for volume you’re actually better off with 18650s, one thing to keep in mind here though is the packing space lost when stacking cells next to each other, if we assumed the 18650 is a rectangular cube instead it is: 181865 = 21,060 mm^3 or 21 cm^3 which brings the energy density down to .52Wh/cm^3 but still slightly better than a regular 30C LiPo pack.

Personally I use LiPo packs because they are cheaper and I have the equipment (a soldering iron) to remake the connections to wire them together without potentially damaging cells. Also started off with quadcopters before I got into the esk8 hobby so had the charger and knowledge/experience with the batteries.

https://eu.nkon.nl/rechargeable/18650-size/sony-us18650vtc6.html

I’ve been in Drone Racing for 4 years. I’m use to lipos as well and all the tools to build one.

Just thought I’d look into 18650’s as they are another option.