12v Booster Pack

[don27dog]

Anyone have any idea what kind of cells they put into these? http://www.ebay.com/itm/12V-20000mA...:g:QsEAAOSwKtlWngVt&item=172046636925&vxp=mtr

Why couldn't / or shouldn't I buy four of these to make a cheap 48v 20AH battery with a 200A discharge rate? I have never made a battery so I am open to ideas/suggestions.

 

[Syonyk]

Something that can source a lot of current.

The 20000mAh rating is almost certainly at 3.7v - that's how external battery packs are almost always rated. So, less capacity than you might think. I'd expect it's about a 6Ah pack at 12v, and if you can get more than about 5Ah out of it, I'd be surprised.

Someone recently was doing some testing on a bike powered by 4 Walmart jumper packs, and apparently it worked decently enough.

I expect you'll run into longevity issues. It'll work for a while, but they're not designed for daily full cycling, so they cells won't last very long, and the power conversion circuitry may or may not last that long either.

 

[Hillhater]

For it to be truely 12 v , 20Ahr,.. It would have to contain at least 18 (3s, 6p) of the VERY BEST 18650's....
...the type that sell for $8- $10 each minimum !
So, NO ...they are lieing !

 

[dogman dan]

More likely you'd get a 6 ah 48v pack, and maybe 15 amps capability.

There is about three other threads, all from the same guy, who did buy 4 and is running his bike. It's not taking him that far, not 20 ah worth at all.

 

[Syonyk]

The thing is, it's not going to be 20Ah at 12v. It's almost certainly 20Ah at 3.7v. :/

 

[dogman dan]

Right, that's how the capacity lie works. Look at the size. If it's not big enough for more than 2 or 3p, then figure the capacity is 5 or 7 ah.

Or is there a 10ah 18650 cell? :lol:

 

[Syonyk]

Or is there a 10ah 18650 cell? :lol:

Oh, they're using the new XTREEMFIRE XZ 18650s! Man, I've heard about those! 100A or 200A depending on which label version you find, 10000MAH!!! per cell, unlimited cycle life, and like $0.99/cell with free shipping on eBay!

**sigh**

At least it makes it easy to find the fake and impossible ones...

 

[whatever]

here is a link to a 50800mah (supposedly) car starter pack, that has been torn down.
http://honda-civic-hatchback-mk9.blogspot.com.au/2015/06/multi-function-50800mah-car-jump.html
The cells are only 5,600mah ( written on the cells) and 3.7v.
No wonder there are recalls of these products, an extreme fire hazard I would think.

 

[Hillhater]

here is a link to a 50800mah (supposedly) car starter pack, that has been torn down.
http://honda-civic-hatchback-mk9.blogspot.com.au/2015/06/multi-function-50800mah-car-jump.html
The cells are only 5,600mah ( written on the cells) and 3.7v.
No wonder there are recalls of these products, an extreme fire hazard I would think.

But at least they are 40C lipo ( claimed)....and they do start engines as claimed !
It wouldnt surprise me to heare that some fools try to use them as full time replacement batteries in their cars !
No more a fire hazard than a spare can of gas stored in the garage !