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Message |
bob_damm (216.134.163.77)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, April 20, 2004 - 2:31 pm: | |
On the MC-9 what is the factory source of 12v for the headlights, did they use a tap off one of the batteries, or is there some type of voltage converter built into the system somewhere?
On our bus there are two leads coming off the first battery. I know one is running the PA and radio, I haven't checked the other one yet to see if it powers the lights. There is also a 24v to 12v converter in the forward baggage compartment, it is hooked up but is turned off so I have no idea why it is there or what it might run? |
Johnny (4.174.112.51)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, April 20, 2004 - 8:36 pm: | |
Probebly one of 2 setups:
1) Headlights hooked in series. Easy test: disconnect one. If the other still works, this is not the case.
2) Headlights (and other stuff) only hooked to one battery. IIRC, the CUCV's (military GMC pickups & Blazers) were set up this way. |
Jimmci9 (209.240.205.68)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, April 20, 2004 - 9:16 pm: | |
the wiring diagram i have shows a "center tap" on the battery to get 12 volts.... all coaches before s/n 34000 were 24 volt... after s/n 34001, headilghts became 12 volt.... thses were powered by stud #6 in the a/c junction box...a 10 ga white wire to a 4 terminal strip above the driver... |
another opinion (12.73.122.26)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, April 20, 2004 - 10:53 pm: | |
Actually, that's not quite how it works. That 12 volts is only there as a backup to the series bulbs running on 24v. If one bulb in the series burns out, the 12v keeps the remaining bulb lit. Under normal conditions the two bulbs were series paired on 24v... that is unless some mechanic who knows more or has less decided to convert them to 12v direct. |
Stephen Fessenden (Sffess) (65.154.177.32)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, April 20, 2004 - 11:15 pm: | |
An interesting way to describe it, Series with a 12 volt back up. Actually It runs pure 12 volts to each lamp, if it is like Prevost. Even if the lamps are not the same wattage, they still will run at their full brightness. If they were series, this would not be true. One side runs24 volt to 12 volt and the lamp on the other side runs on 12 volts to ground. But to keep the batteries in balance,only use bulbs of identical wattage. |
BrianMCI96A3 (198.81.26.45)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 21, 2004 - 11:52 am: | |
Actually Stephen, although it's been a while since I looked at that circuit, I do believe you are right My MCI at least runs the headlights on 12 volts.
While it is true that two bulbs of different wattage would not be an ideal combination in series, I wonder just how many wattage combinations there are for those types of lamps.
I think as long as you are combining a halogen with a halogen, an incandescent with incandescent, or Xenon with xenon, you should be okay when running two 12V bulbs in series...
Brian |
ChuckMC9 (Chucks) (66.167.95.248)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 21, 2004 - 4:29 pm: | |
The OFFICIAL word from MCI...
"Headlight Wiring - 12-Volt Lights on a 24-Volt System"
http://www.mcicoach.com/serinfo/serinfo1101.html |
bob_damm (216.134.163.77)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 21, 2004 - 8:45 pm: | |
Thanks for the response guys, this gives me an idea of where to start looking to see if everthing is as it should be.
Bob |