i have a "nub" USB charger that plugs into the wall and i have a "standard" 75W cigarette-lighter-to-wall-socket inverter

i want to use the USB charger on my scooter by tapping into the battery (12V, like this one: http://www.jpcycles.com/product/TV01454)

the USB charger never draws more than (just shy of) 4W (used kill-a-watt to get this), so:

1.) is this feasible to set up
2.) can i use this reliably without killing my battery
3.) will you guys think i'm cool if i do this? just kidding, i don't care...just want to know if it will work

ideally, i'd tap into whatever it is that runs the headlights as those don't come on until the scooter is actually running, but i don't know how i'd do this

12/19/2011 4:25:40 PM

usb and your scooter are both 12v dc, there's no need for an inverter.

buy one of these http://www.amazon.com/Parts-Express-Cigarette-Lighter-Socket/dp/B0006TIRZA
wire it into the harness or directly off the battery, plug your charger into it.

/thread

12/19/2011 5:34:31 PM

he said he has a 120 VAC charger, in which case he will need the inverter

[Edited on December 19, 2011 at 5:39 PM. Reason : or just get a 12v charger]

12/19/2011 5:37:59 PM

yeah, I thought he had both. correction, buy the socket I posted and a usb car charger

12/19/2011 5:52:35 PM

^ but using what i have, i could just get what you posted, and then use the inverter...yes? and if i do that, will the inverter plus the minimal draw of the charger drain my battery if i leave it in? seems like the inverter will draw power when the scooter is off (unless i pull it out, of course)

could i use a "vampire clamp" (or whatever it's called) to tap into the wires that go to the headlights and then buy a 12V charger so as to rig it so that the power is only available when the scooter is on (since the lights only work when it's on)?

12/19/2011 8:12:14 PM

^inverters will always draw power (unless you get a model with an on/off switch.) Most cheap ones are also going to have a cooling fan that will run incessantly - QUICKLY killing that tiny battery.

Due to the multiplying inefficiencies you're stacking up here it sounds like you need to get it over to DC - plus it's going to stand up to the weather for a much longer time.

(for example; say the dc-ac conversion is good and you get 85% efficiency, then ac back to dc is 85% efficient, and through all the extra cabling you lose .1watts. 4W=X(.85*.85)-.1; you're up closer to 6.5watts - burning 50% more power just in conversion loss. And I would guess that you're nowhere close to 85% efficiency on that ac inverter until you get up to about 70-80% of it's rated power.)



[Edited on December 19, 2011 at 9:12 PM. Reason : .]

12/19/2011 9:06:59 PM

Forget the inverter altogether. DC->AC->DC to solve a DC->DC cenversion problem is ridiculous when you can just get $10-15 worth of stuff and do it right.

Buy this:
http://www.amazon.com/RoadPro-RPPS-16ES-12-volt-Auxiliary-Outlet/dp/B001JT7B3A/ref=sr_1_4?ie=UTF8&qid=1324384503&sr=8-4

Posi-tap it into a fused circuit, or add this for protection, and run it straight to the battery with a couple ring terminals:
http://www.amazon.com/Bussmann-BP-HHM-Holder-Protective/dp/B000BXHWD4/ref=pd_cp_e_2


And this:
http://www.meritline.com/usb-car-cigarette-lighter-power-adapter-for-iphone---p-74441.aspx
Or spend a little more on this adapter:
http://www.amazon.com/Griffin-Powerjolt-Dual-Universal-Micro/dp/B0042B9U8Q/ref=pd_sim_auto_51
Dual ports and a flush mount.

Put it under the seat or in the front cowl, wherever. Clean, waterproof installation with no AC inverting to get from 12v to 5v DC. If you need the inverter for something inverter-worthy, like running a laptop, you can still plug that in there.

[Edited on December 20, 2011 at 7:49 AM. Reason : fuse]

12/20/2011 7:44:03 AM

okay, bypassing the inverter and investing a little money to keep it DC-DC makes sense

^ i am a little confused, though...the first thing you posted is (i think) a "wall socket" type thing...the second items are adapters for the car (i actually have the griffin dual port in my car and i really like it)...i'm only trying to make available the wall socket, so all i (should) need are the first two things, yes?

12/20/2011 8:44:40 AM

The socket I posted is a weatherproof cigarette adapter socket. Same idea as the one posted above, just designed to be mounted instead of a loose pigtail

12/20/2011 10:40:19 AM