How to get 8S/33v down to 12v?

[mjp8081]

Just curious, I have my 8S build I'm working on, I have a mini 12v automotive fog light I was thinking would be fun to mount for night riding...

Whats the best way to use 12v accesories with an 8S (32-34v) setup?

 

[Marcin]

The cheapest and easiest way in my opinion would be a DC-DC boost converter

http://www.ebay.co.uk/itm/10A-DC-DC-600W-10-60V-to-12-80V-Boost-Converter-Power-Supply-/171621349446?pt=LH_DefaultDomain_3&hash=item27f56df846

There are smaller, less powerful converters around as well

Regards

EDIT: My apologies, it's 4AM

What you need is a step down converter like this one: http://www.ebay.co.uk/itm/LM2596-DC-DC-Switching-Adjustable-Step-Down-Voltage-Regulator-Buck-Converter-/271632729700?pt=LH_DefaultDomain_3&hash=item3f3e928664
A quick ebay search will bring up various different options depending on the load

Regards

 

[mjp8081]

Thats perfect, its like a little adjustable UBEC. Thanks

What kind of output amperage should suffice? they have little ones that output 2a and up to 9a.

 

[2wayspeaker]

You definitely need a step DOWN. As for amps, check what you appliences use and take something with a higher power output than all of them combined. We can't tell you because we do not know what you want to run, a led strip will consume lots whilst a fan will consume little.

 

[mjp8081]

So this halogen fog light I have will probably want too much current. I could probably re-purpose a CREE headlight/flashlight. Most of the small step down DC-DC converters on eBay are 2amps.

http://www.ebay.com/itm/DC-LM2596-4-0-40-to-1-3-37V-LED-Voltmeter-Buck-Step-down-Power-Converter-Module-/141509440920?pt=LH_DefaultDomain_0&hash=item20f29eb598

 

[2wayspeaker]

You really want to know these numbers: Volts Amps Watts.
For a single halogen fog light I find 12V 55W so rougyly 4A.
For a single Cree u2 headlight I find 12V 30W roughly 2,5A.
Google is your friend.
I get that you want a light, here in Belgium I got pulled over on my regular skateboard because it didnt have lights.
There's a minimun lumen requirement for it to be a proper headlight. I used bike lights that are magnet activated.
No power draw from the battery. (In belgium all streets are lit from 20h to 6h)
What you are looking at are car/motorcycle headlights. If its really dark and you want to see lots, then yes that's what you should use.
200 lumen is already plenty and you can find flashlight leds that work at 5v/3,7v at about 2A. Your BEC integrated into your esc might power these. Mine is 5V 5A so I can run a front and a back light off it.

If you don't know what you are doing you should really study some more about this. A step down doesnt magically provide the voltage you want. You need to calibrate this with the potentiometer on the board. So if you buy one, before you connect anything, finetune the output voltage to 12V.

Also lipo battery falls outside of the "electronics" name and is classified as electricity. These batteries are very dangerous, people use them for portable spot welders. Be carefull and double check what you do with it.