Cheap Battery

[micamb]

I could not find the above in "search" but I'm new. I saw a faq about watt hr per £. I tried to
work it out for aa batteries and got 1/5 the cost and only about 80 needed. Would anyone like to straighten my thinking on this issue.
Thanks, Mike.

 

[flecc]

We need a start point to know what you are trying to find out really Mike.

Can you say what voltage of battery you are trying to make up and the bike it's needed for. Also let us know if you intend using NiMh rechargeable batteries or disposable ones, since they are different voltages.

In general AA batteries don't have enough current delivery capacity for use on our e-bikes, though they can work as supplementary batteries in parallel with the existing one.
.

 

[micamb]

Thanks for replying. The plan is to get a big Chinese motor, power my streamlined recumbent and go fast. I suppose 40 nimh D cells in series would also not work. perhaps
I'll get the motor and try it out with lead acid and see if that's what I really want.

 

[Footie]

Just a thought, but have you taken a look at the Endless-sphere site?
There’s information on powered recumbents from those who have converted.
May give you an idea of what you want

Endless-sphere.com • recumbent
.

 

[Andy_82]

Thanks for replying. The plan is to get a big Chinese motor, power my streamlined recumbent and go fast. I suppose 40 nimh D cells in series would also not work. perhaps
I'll get the motor and try it out with lead acid and see if that's what I really want.

so is it 48V that you are trying to get?

 

[micamb]

Nothing is definite. I fancy 48v 1000watt. I haven't found any info on the result of soldering together nimh torch batteries (or lithium?)
Mike.

 

[flecc]

Nothing is definite. I fancy 48v 1000watt. I haven't found any info on the result of soldering together nimh torch batteries (or lithium?)
Mike.

Lithium cells aren't so readily available, a BMS is needed and the cells are not quite as good as NiMh in handling the high discharges needed to power such a powerful motor. NiMh is the best bet, but any old torch batteries will not be good enough, you need high discharge rated cells, either D or F cells in series or C cells in a parallel as well as series array in order to get a high enough discharge potential.

Here's a number of postings in this thread from Fecn who built such a pack:

Fecn's home built pack

I've built an experimental AA batery pack and tested it on a motor of about half that power and you can read the results in this article on my webpages where you'll see that generally available AA cells just are not up to what you want.

Flecc's experimental AA battery
.

 

[micamb]

Thanks very much, You have given me much to consider.
Mike.