AA battery range extender

[Beekeeper]

Wondered how much it would cost to build (using cheap AA rechargeable batteries) an emergency battery pack to carry in rucksack which would give me the equivalent of one bar (20%) on my Cube.
Capacity would be 100 wh.

I’d need 3 battery holders (each holding 10 cells (1.2v each). That’s 30 cells in total to make 36v. Each cell rated at 2800 mah

Cost of battery holders =£10
Cost of 30 AA batteries =£60
Total =£70 for a 20% range extender Equal to 100 Watt Hours.

(This is only theoretical so i’m not suggesting anyone should actually try it ? ?)

 

[paul-g]

hi there
have a look at eequalspower.co.uk
ebay marley4004
both the same person
had conversations with this guy when i
was going to convert a carbon full sus I had
and I maybe needed a backpack battery
seems ok give him a worle
prices are on site

 

[ImSundee]

Youd be better off using 18650s, These have a cell nominal voltage of 3.6v. So youd not need as many. And they can be had for £4 each for high discharge. You'd only need 10 and would have 3600mah too.

AA are extremely low discharge, and probably wouldn't last long

 

[Kingfisher]

>Youd be better off using 18650s
Guess what is inside a battery pack

 

[Beekeeper]

>Youd be better off using 18650s
Guess what is inside a battery pack

Yep that’s true but one advantage of using AA Nickle-metal hydrides for an emergency range extender is the simplicity of charging them with standard AA chargers.
To charge lithium ions you need quite complex circuits / temp sensors / cell balancing / voltage drop protection etc. I like the idea of building something simple without the need for such complex electronics.

 

[ImSundee]

>Youd be better off using 18650s
Guess what is inside a battery pack

Well some of them Alot of newer are running 21750.

 

[ImSundee]

Yep that’s true but one advantage of using AA Nickle-metal hydrides for an emergency range extender is the simplicity of charging them with standard AA chargers.
To charge lithium ions you need quite complex circuits / temp sensors / cell balancing / voltage drop protection etc. I like the idea of building something simple without the need for such complex electronics.

Not at all, you can just install a BMS for it - they can be had for under £10. Then just input 36V from a DC powersupply and the BMS will do all of it for you.