how to figure max current available

two12
Copper - Posts: 84
Joined: November 24, 2009
Posted: November 14, 2010 at 9:07 PM / IP Logged
hello,
Im trying to figure out if my bikes stator is upto the task of running a heated jacket. its an old Honda, the manual says the output is 0.2kw@5,000rpm
how many amps is this? (@12vdc)
thanks
oldspark
Gold - Posts: 4,913
Joined: November 03, 2008
Location: Australia
Posted: November 14, 2010 at 9:32 PM / IP Logged
P=VI
Hence I = P/V
So I = .2kW/13.8V = 200/13.8 = 14.5A
(since normal 12V "ratings" are at 13.8V)
(else 13.8A@14.4V or 16.6A@12V).
i am an idiot
Platinum - Posts: 13,623
Joined: September 21, 2006
Location: Louisiana, United States
Posted: November 14, 2010 at 9:44 PM / IP Logged

How much current does the vest draw?   You need to realize that the bike needs to run off of the available 14 amps.  Headlight, taillight ignition etc.  what kind of bike is it?  The stator on my Silver Wing failed at around 70K miles.  I installed an Alpine head unit which I figure draws between 3 and 5 amps of current.  I ride with my High beams on during daylight hours.  The bike has 2 separate lamps and they both burn when on High beam.  Since the failure I only flash the High beams when needed.  I would never attempt any kind of heating device on it.  A Gold Wing with an actual alternator, no problem, but I would not do it on any other Honda.

Unless of course the vest draws only a couple amps.  Does it have a wattage spec on the vest?

two12
Copper - Posts: 84
Joined: November 24, 2009
Posted: November 14, 2010 at 10:19 PM / IP Logged
hi Oldspark & IAAI
then it looks like I have ~210w total. the jackets that Im looking at draw 65w and upto 90w.
now I need to find out what the C.D.I (ignition) draws.
if I convert the lights (including headlight) to LEDs it might work.
I could learn to rewire the stator if I have to but Im trying to avoid doing that. I wouldnt hesitate if I had an identical back-up bike to play with though.
thanks
oldspark
Gold - Posts: 4,913
Joined: November 03, 2008
Location: Australia
Posted: November 15, 2010 at 2:28 AM / IP Logged
The CDI is probably only 10W-20W.
If it is a stator type alternator, I wouldn't bother - probably not much to gain.
A rotor controlled alternator has possibilities. (Unlike stator type, it uses brushes for the rotor - it is not a spinning permanent magnet.)

Sorry, you can NOT post a reply.This topic is closed.

 You cannot post new topics in this forumYou cannot reply to topics in this forumYou cannot delete your posts in this forumYou cannot edit your posts in this forumYou cannot create polls in this forumYou cannot vote in polls in this forum

•
 Search the12volt.com