Rechargable battery question

[davidP]

I'm looking to put together a NiMH rechargable battery pack of either 13.2 or 14.4 volts to power some home-made lights for my bike. This means 11 or 12 1.2v batteries in sequence, but the bit I'm not sure about is the life/capacity of them. I'm told I need somewhere in the region of 4Ah (amp hours). If I buy batteries individually rated at 1600mAh does this mean that my completed pack will also have a rating of 1600mAh, or is there a calculation involved. Also if anybody knows of a good site that explains this kind of area I would be gratefull.

[chris parker]

Don't know much about batteries but can't you use one of the sealed lead acid type that are in angler's headlamps?

[Guest Ferret1959]

Just buy a 12v sealed lead acid battery.

Maplins sell them.

A 7.2 amp battery will only be about 6x4x3 in size and a lot easier to store on your bike.

 

you are right in the figure of 1600mAh so would only be 1.6Ah.

Wouldn't last very long.

 

I use a sealled lead acid 7.2 for a night light when out shooting and last for ages even with on/off loading.

 

Oh my battery was just under 20 quid a month ago.

[Newt]

davidP - I also don't know spit about the electrical part but do have a thought to pass on.

 

NiCad and similar batteries are nice because they give full power until they are near drained.

 

But for a bike light, the fact that they go from full power to no power in a VERY short period of time would make be avoid them.

 

At least with the older style lead-acid ones, you noticed the fading and still would have time to get somewhere albeit with a weaker light.

 

Unless you have a good way to carry a fully charged spare with you, this might not be the way to go for an essential safety feature on the bike.

[rich]

just buy these

[Leon Roskilly]

I've found the ideal combination for my bike, is to have a dynamo driving a halogen light at the front, and a bright red LED light at the back (fed by the dynamo but through a capacitator, so that it doesn't go out when I stop).

 

These are backed up by LED battery lights, front and rear. I change the batteries for these just once a year.

 

No more worrying about batteries going flat, or bulbs blowing, leaving me unlit, and the whole lot weighs very little.

 

I also use reflective tape, white on forward facing objects, such as the the front forks and handlebars, red on rear facing surfaces such as the back of the saddle and rear mudguard.

 

A fluorescent tabbard with white reflective strips helps too.

 

Tight Lines - leon

[poledark]

They should call you "Flash Harry" Leon

 

 

Den

 

[ 05. December 2003, 09:06 AM: Message edited by: poledark ]