LED lamp bodge

[red1]

Electrical knowledge a little above zero so bear with me.

I have an LED lamp that's powered by 2 AA batteries. It's a nice small size and I'd like to keep it on the bike for emergencies.

What I would like to do is simply get a piece of wire, connect it to a aux plug and solder other ends to + and - inside lamp, therefore not have to worry about dead batteries etc.

As bike is 12v and batteries are 1.5v is it possible or will it involve all sorts of resistors, voltage dropper type things or what?

 

[NeilDD]

Simply put Yes

The torch needs 3V from your 2 AA's

Easiest option is to get a 12V LED sidelight bulb (get one with pins BA9S) same as your bike sidelight.
Goto any motorfactors/accessory shop and get a bulb holder to match, make some long leads and put the Hella plug on the end.

Hope this makes sense?

Neil

I'll take a pick of what I made up in the morning

 

[B4ndit]

What if the bike battery dies?

Consider this

http://www.google.co.uk/products/ca...a=X&ei=tYvXUKK4JK_Z0QWHuoDYBQ&ved=0CF8Q8wIwAw

 

[red1]

What if the bike battery dies?

Consider this

http://www.google.co.uk/products/ca...a=X&ei=tYvXUKK4JK_Z0QWHuoDYBQ&ved=0CF8Q8wIwAw

Won't need a light to fix it then will I

 

[Black Rooster]

get a wind up led torch

 

[MattW]

Not worth the faff IMHO. Get a Petzl head torch.
Shines where you're looking and no third hand needed.

 

[red1]

get a wind up led torch

Not energy efficient

 

[red1]

Not worth the faff IMHO. Get a Petzl head torch.
Shines where you're looking and no third hand needed.

Needs batteries so not fit 'n forget

 

[MattW]

Needs batteries so not fit 'n forget

The batteries last forever and you can always fine the space to stash a spare set of three AAA's somewhere on your bike

And you can always use it away from the bike ...

 

[warmshed]

You will need to solder a resistor in series with the LED you could then use it as you want, Someone on here is bound to give you the value of the resistor needed, but from my failing memory it will need to be about 470-500 ohms (1/4 watt or greater) as your leds are 3 volt. only about 10p each from maplins ot RS so cheap enough.

 

[Bendy toy]

This is regulated so gives correct output voltages. To save space put the guts into a smaller case. I did this with a pair of 4.5V LED torches on my other bike. They made great marker lights, lasted 2 years and only packed up because I used an unregulated supply.
http://www.ebay.co.uk/itm/12V-DC-DC...ervan_Caravan_Accessories&hash=item3357962c7a

But as others have said - decent batteries in the torch will last a very long time and you can walk away from the bike.

These are good & what I used as daytime marker lights
http://www.ebay.co.uk/itm/ROLSON-3x...ing_LightsLanternsTorches&hash=item5ae52cd19f