How to hook up 12v accessory on a 36v system?

[kmxtornado]

I know one of you experts out there think the answer to this question is simple, so hopefully you can help me out. Thanks in advance for anything you can do to help. I'd like to hardwire some 12v accessories to my 36v scooter. I'm using 3 12v SLA batteries hooked up in series. Is there anyway I can power my 12v lighting accessories by tapping into one of the batteries somehow? My concern is that if I did that, it would discharge that battery first compared to the other two. Perhaps there's another way to go about this? Or do I really need a separate designated 12v battery? Tap into the throttle wire?

A wiring diagram would be awesome. I should be able to figure out out from there.

 

[wesnewell]

Take your pick.
http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=48v%20buck%20converter&rt=nc&LH_FS=1&_trksid=p2045573.m1684

 

[kmxtornado]

Thanks. Can you clue me in on this step down gadget? I can hook this up to a 12v accessory but still continue to use the 36v battery to power the scooter at the same time, right? How does this get installed?

 

[Tamaz]

You just connect it to the battery, in parallell with the bike. Ad a separate Fuse as close to your connection to the battery as possible, and you might also want an on/off switch to hinder it from draining your battery when not in use.

 

[amberwolf]

Dunno about the linked one; cant' open that link (thanks, centurylink ).

What you're looking for is a DC-DC converter.

You can use dedicated ones, or you can use wallwart / AC Adapter / Laptop PSU types, like I and some others do.

I'm using a 15V wallwart on CrazyBike2 to power all the 12V accessories (becuase 12V on a car is not 12V, it's more like 13-15V depending on the alternator and load). My traction pack ("48V", ~58V fully charged) is wired via switch to the point the AC connection to the wall would have been, and the output is wired to all my lights and turn signals. Only thing not on it is the car headlight and horn, and my portable air compressor, because those use so much current at startup that they cause any DC-DC I've tried to shutdown. So I still have a separate 4s (16v full) battery for those.


I've also used an actual DC-DC converter block on DayGlo Avenger, which used the scooter headlight and incandescent turn signals presently on the SB Cruiser (which uses the same separate battery CrazyBike2 does, until I find a wallwart or other PSU to use on the trike), but every bilink of turn signal would cause headlight to dim. It didn't shutdown, though, as long as I never used "bright" highbeam headlight filament.




There are dozens of threads about this type of thing, if you want to poke around and see what others have used.

 

[kmxtornado]

Thanks. I just wasn't clear on what search terms to use. I'll start with your project threads detailing the setup you've discussed. I understand it somewhat in principle but will need to see your photos. Looks like I have some homework to do tonight.

 

[amberwolf]

I wish I could point you to a specific part of one of the threads, but I don't have an index to the threads (keep wanting to make one...never got around to it).

DGA's DC-DC was from Icecube57, so a search on that found this:
http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=15443&p=451353&hilit=icecube*+dayglo#p451353

with some pics.

Hard to see here
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=15570&p=297697&hilit=icecube%2A+dayglo#p297697
but that's when I first installed it I think.
but the next post has links to specs and stuff.

No pics in the post itself, but here's where I added the 15v wallwart on CB2 for it's lighting
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=920487&hilit=15v+charger+light%2A+crazybike2#p926060

 

[kmxtornado]

Thank you so much for taking the time to do this. I'll have more homework tonight.