A bicycle dynamo with 6v and 6w?

[TheFrieber]

Hello guys, anyone knows a dynamo with 6v and 6w? I would like to charge with max 2A an li-po battery

 

[Alec_t]

Welcome to maker.pro.
You need at least 4,2V to fully charge a Li-po cell. So at 2A that would be 4.2V x 2A = 8.4W. A 6W dynamo would not be enough.

 

[TheFrieber]

Welcome to maker.pro.
You need at least 4,2V to fully charge a Li-po cell. So at 2A that would be 4.2V x 2A = 8.4W. A 6W dynamo would not be enough.

i would like to use 2x 6v and 6w to generate max 2A
My plan is to convert that to dc and give it to the BQ25798 to let it charge the cell/battery and use another BQ25798 in OTG output mode to charge my phone
The li-po battery has a standardcharge at 1250mA and max/speedcharge 2500mA

 

[Bluejets]

i would like to use 2x 6v and 6w to generate max 2A

Are you pedelling this particular bicycle with 2 dynamos attached (also @ max output for at least 1 hour).......???

 

[kellys_eye]

The faster you charge it the harder it will be to ride the bike! Is there a specific need to charge it as fast as you state?

Either way, any DC source and be boosted/bucked to provide the necessary current/voltage. Such boost/buck devices are readily available modules 'off the shelf'.

 

[Bluejets]

Strap a 600w solar panel to your back............just keep downwind.

 

[TheFrieber]

Are you pedelling this particular bicycle with 2 dynamos attached (also @ max output for at least 1 hour).......???

Yeah, i want 2 dynamos attached and it doesn't need to be always at the max output. It just should generate at fast speeds or while rolling down up to 2A

 

[TheFrieber]

The faster you charge it the harder it will be to ride the bike! Is there a specific need to charge it as fast as you state?

Either way, any DC source and be boosted/bucked to provide the necessary current/voltage. Such boost/buck devices are readily available modules 'off the shelf'.

Now to the harder ride, i got a idea of 3d metal printing and building a centrifugal (mini)clutch together or if the dynamo has a low-resistance/easy-turning feature it would be good to go (the bicycle has gears, hence it is not a big deal to ride it)
And to the why i need 2A, i got a big project with a microcontroller that i want to attach to my bicycle and also charge my phone at the same time

I know the power boost 1000 but it cost around 40 and has a max charge of 1A (Very expensive in comparism to building your own pcb)

 

[TheFrieber]

Strap a 600w solar panel to your back............just keep downwind.

Yeah sure, if you fall of your bike you got a big problem

 

[Bluejets]

Aghhhh...!! Didn't they teach you to just "get back on again"..!!! ???