Dynamo for recharing detector in remote locations

[GoldPandemic]

Hello, I made a pedal dynamo:


The larger cog is 160mm, the smaller cog is 70mm.
Presently I generate about 2 volts (with fast pedalling), my aim is 12 volts.

I was thinking of increasing the larger one's size and decreasing the smaller ones size.
Does anyone have any idea of how I could increase the power I'm generating?

[6666]

What are you useing for a dynamo

[GoldPandemic]

That engine (I believe it is a scooter engine) and the black box contains a 12v regulator.

[junkhunter]

i have seen people on youtube add a transformer to boost the voltage

[darkfibre]

I am unable to see the picture in post 1

[GoldPandemic]

http://www.paydirt.co.nz/forums/yaf_...aspx#post46333
see it here.

[junkhunter]

why don't you put a car alternator or generator on it .that would give out more volts

[junkhunter]

spare batteries would be cheaper , easier and lighter

[eclipse]

I would use a spare external battery pack to charge the batteries if there's enough time to charge them (ie. overnight).

[darkfibre]

Thanks for the link to the pic. Taller gearing will give you more voltage out. Just be aware that when you put a load on it, it will require more effort to pedal.
I once pedaled a generator that had a range of over 400watts and I could only peg it on full for short bursts.
Generating 12 volts should be just gearing - generating many amps at 12 volts will require a lot more effort.

[GoldPandemic]

A car alternator would possibly weigh more?
If I took batteries in addition to this dynamo that would increase my weight. A larger cog it can be hollowed out and because it screws onto the present cog - can be detached for transport.
Yes, I'm prepared for the extra pedalling.

Presently I'm making a test 400mm diametre cog. Will get back to you with the results.