12s A123 ANR26650 Battery Pack

It would seem that this is the setup that Boosted Boards have according to their blogs. I wasn't sure which battery technology to use and I wanted something safe for my electric longboard. The BB apparently has a battery with 38.4v and 12 a123 cells in series.

I was thinking about creating a similar pack since the battery technology seems to be decently "safer" compared to Lipo etc. Any suggestions on other options for a battery pack for my skateboard or how to create a a123 battery pack?

Thanks

Why not use 18650?

rmrf said:

Why not use 18650?

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Are there any benefits? I would have to put two packs in parallel to get about the same mAh.

Actually depends on your power goals.

For example, 26650 a123 provide 2.5Ah per cell and 70A continuous discharge, 120A burst. Combined with LiFepo4 stable chemistry, that's HUGE power source but small capacity, for a bit heavy cells and big format.

12S1P made of these cells give you 108Wh fully charged at 43V.

Now say that you will never need these 70A continuous and can live with 40A continuous (like many skateboarders around ES) and 60A burst, well you can do a 10S2P setup made of LG HG2 for example (I love LG cells) and this brings you to 252Wh. That's more than double the cap. But you need to check your space, the maximum weight you want and your budget too, of course.

Keep in mind that quality Li-Ion cells are already safer than Lipos. LiFepo4 are even more safe. If you want a dragster, go for a123. If you don't need a dragster, you can consider Li-Ion options (which are mostly in 18650 format).

I'm myself always thinking abotu different batteries layouts including yours, so I had to let you know

Vanarian said:

Actually depends on your power goals.

For example, 26650 a123 provide 2.5Ah per cell and 70A continuous discharge, 120A burst. Combined with LiFepo4 stable chemistry, that's HUGE power source but small capacity, for a bit heavy cells and big format.

12S1P made of these cells give you 108Wh fully charged at 43V.

Now say that you will never need these 70A continuous and can live with 40A continuous (like many skateboarders around ES) and 60A burst, well you can do a 10S2P setup made of LG HG2 for example (I love LG cells) and this brings you to 252Wh. That's more than double the cap. But you need to check your space, the maximum weight you want and your budget too, of course.

Keep in mind that quality Li-Ion cells are already safer than Lipos. LiFepo4 are even more safe. If you want a dragster, go for a123. If you don't need a dragster, you can consider Li-Ion options (which are mostly in 18650 format).

I'm myself always thinking about different batteries layouts including yours, so I had to let you know

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Thanks for commenting.

That's a good point for using LG HG2 cells. Do you recommend a good, genuine supplier for them?

Also could you talk about how LG's cells react if over discharged/charged? I totally loved the "safe" factor of the A123 cells in case the cells were not treated well.

Vanarian hit it spot on.. A123 cells is what boosted uses and 12 of them at that.

Get about 5-7 miles at most with this 12S1P pack. It can push out enough power to power you up hills. LifePo4 so it's safer. The cells are about $9.50/each or so.

We use 18650 because we want the pack shorter/smaller. 18mm diameter versus 26650 A123 is 26mm in diameter.

Both are great options. We should experiment more with A123.

I'm going to be using 36 a123 26650's in the monster board I'm building. It's designed to have maximum acceleration and it will have a top speed of 45mph, although I'll probably never go that fast. Those cells are unmatched imo. Btw, a123 also produces 18650 cells that do 30A continuously. However, they are only 1.1Ah capacity so there's that. See more info here: http://www.a123batteries.com/v/vspfiles/images/pdf/APR18650M1A.pdf

I'm about to release a 12s1p and a 12s2p A123 26650 with 60A BMS. This will mainly power my Single Hub. The thing with the 18650 is, even though the LG and Samsung cell has 20A max discharge, you would not want to constantly pull that much amps out of it. It will substantially decrease its life cycle of 300-500, which is already lower than the 1000+ life-cycle of A123 26650.

To realistically use a powerful and long-life 18650 pack, you would have to build 4p or bigger. That's a lot cells to put together.

torqueboards said:

Vanarian hit it spot on.. A123 cells is what boosted uses and 12 of them at that.

Get about 5-7 miles at most with this 12S1P pack. It can push out enough power to power you up hills. LifePo4 so it's safer. The cells are about $9.50/each or so.

We use 18650 because we want the pack shorter/smaller. 18mm diameter versus 26650 A123 is 26mm in diameter.

Both are great options. We should experiment more with A123.

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Well I am planning on using one motor so 12s1p is overkill V for a motor that takes max 37v. If I make a pack 6s2p, 19v wouldn't be enough for a decent ride right?

s28400 said:

I'm going to be using 36 a123 26650's in the monster board I'm building. It's designed to have maximum acceleration and it will have a top speed of 45mph, although I'll probably never go that fast. Those cells are unmatched imo. Btw, a123 also produces 18650 cells that do 30A continuously. However, they are only 1.1Ah capacity so there's that. See more info here: http://www.a123batteries.com/v/vspfiles/images/pdf/APR18650M1A.pdf

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Could you link your project link if you have one yet for when you build it? Thanks!

To be precise, a123 cells are 3.2/3.3V nominal - 3.6V max and rest of Li-ion cells like LG are 3.7V nominal - 4.2V max.

So you need 12S a123 cells to equal 10S LG cells as far as voltage goes. It's also true that a123 cells have WAY more cycles under the belt than other cells. Bad quality Li-ion can vent + catch fire, but known brands like LG, Sony, Panasonic, Samsung, Sanyo know their homework so it takes really lot of abuse to get the cells to catch fire (like actually throw them in fire or short them or heat them like in a oven). At worst cells will generally vent and die if mistreated.

For reliable sellers, I don't know where you're located but in Europe you can get from Nkon and Akkuteile (most known sellers), you can get from Fasttech too but takes more time for delivery. There are of course many other trustworthy sellers, including members of ES :wink:

About your motor's ratings, motors work with phase-amps. Generally a well built motor does have enough iron and copper, so you can alter the relation VxA = W inside it. You can disregard max Voltage rating as long as you respect maximum power rating. Hysteresis is not the main threat for a quality motor (ex : Tacon bigfoot). You could run a 37V rated motor at 48V as long as you lower amps to stay under its total power ratings.

But in the end, it is useless to do this by itself, you need to match your whole setup (motor power/ motor Kv / battery power / ESC). But we're straying a bit from your batteries there!

If you build packs of matching voltages and capacity from the two mentioned cell chemistrys and both packs are fully charged so at rest voltage they have a comparable voltage value as they become discharged with use the lifepo4 pack will hold its voltage higher less sag under high loads and drop off quicker at the end making its power more usable and stable u can look at the widely available discharge curves of each cell and then add in cycle life and we have a clear winner.
I'm in the dark ages still using lipo for now 12s2p I have experience with a 10s9p 18650 pack and though they work well enough and beat lead acid into the ground all them cells are just like links in a chain bigger the pack greater the odds of a cell dropping out of the pack with age, if a cell does fail in a pack it becomes a dead short and if not caught in time will pull all the other cells down that its parallel with to 0v unless there's indivudual fuses on each cell even then the packs capacity will be left uneven amongst the groups so there's potentional for over discharge problems and trying to keep all the grouped cells equal under charge etc.
My ideal pack would have no parallels only series cells if one cell fails only that cell drops out, less cells means a closser resistance in between the grouped cells giving a more even dischage and making it easier to balance and control the current flow through the pack.
As battery's age the resistance changes across the pack so a large amount of parallel cells will carry the current very differently giving hot spots then this is series'd up so the problem gets larger.
If 1 18650 cell has a life span of 600cycles then as part of a large parallel and series pack I would say you will be lucky to get 400 cycles meaning they are marginally better than lipo when combined in large numbers but are alot safer, the resistance of each cell is key to how it will act in a pack its all math.
Maybe graphinne enhanced batterys will change all this and give a cell that can discharge hard, stay cool and have such a low resistance that paralleling them will have virtually no effect they will spilt the load nearly perfectly even among themselfs throughout their lifespan giving the perfect battery for all pack configuratuons only the future knows peace out.

Pantologist said:

s28400 said:

I'm going to be using 36 a123 26650's in the monster board I'm building. It's designed to have maximum acceleration and it will have a top speed of 45mph, although I'll probably never go that fast. Those cells are unmatched imo. Btw, a123 also produces 18650 cells that do 30A continuously. However, they are only 1.1Ah capacity so there's that. See more info here: http://www.a123batteries.com/v/vspfiles/images/pdf/APR18650M1A.pdf

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Could you link your project link if you have one yet for when you build it? Thanks!

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Will do! I have a lot of work to do before I start posting though.