| Author | Message | ||
| David Lower (Dave_l)
Registered Member Username: Dave_l Post Number: 48 Registered: 11-2007 Posted From: 204.110.227.11  Rating: N/A |
Hello all. Has any of you changed a bus from 24 to 12v? Why I was thinking of doing this is the only 24v parts still on mine are starter, alternater and V regulator. I have yet to check the bulbs but I see a resistor on the power feed to the light switch, I figure it would be easier to get 12V bulbs on the road at smallville garage. I have already found a source here in London that has 12V starter and alternater for my 8V71. Thanks in advance for any input! Dave L | ||
| Ben B. Wolff (Ben_mc7)
Registered Member Username: Ben_mc7 Post Number: 24 Registered: 4-2007 Posted From: 24.73.7.114 Rating: N/A |
I changed mine from 24v to 12v not long after I got mine 10 years ago. Of course it helped that the bus electrics were in a mess to begin with. I totally converted my bus electrics (fuse panels, switch/relays) to 12V with the alt/starter. I have not had any problems with what was completed and I removed all the old wire that seemed to go nowhere. | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 622 Registered: 7-2006 Posted From: 68.18.41.11  Rating: |
David - Take note of what Ben said about it: "I totally converted my bus electrics (fuse panels, switch/relays)" The gauges, sending units, dash panel lights, alarms, etc., may all need to be changed as well. 24vdc bulb sockets are configured differently than 12vdc bulb sockets, so swapping bulbs isn't an easy task; the socket has to be changed to match the bulb type. Also, the wire gauge for 24vdc may not be suitable for the higher amperage needed for 12vdc components. I gave the idea of conversion to 12vdc when I first bought my bus, but after posting the question here, the job seemed almost overwhelming after reading the answers. Nothing's impossible, but many things are (or can be) impractical. | ||
| John Lacey (Junkman42)
Registered Member Username: Junkman42 Post Number: 53 Registered: 3-2007 Posted From: 69.19.14.30  Rating: |
David, I gave changing to 12volt a passing thought and could not justify the added work to gain nothing. When winter rolls around You will be glad that You have a 24volt starter! 24volts is just more efficent. I would predict that cars will shortly be 24 volt or higher. My two cents which will not get a cup of coffie! John | ||
| James Robinson (Jjrbus)
Registered Member Username: Jjrbus Post Number: 152 Registered: 12-2000 Posted From: 70.10.141.102 Rating: N/A |
I like the way John thinks on this. The only advantage I could see is 12V bulbs are cheaper and more available. Comparing this to 100's of dollars and many days to do the conversion. There are enough things to do on a conversion. The 24V bulbs are available at NAPA, which can be pricy or online. I order bulbs online at about $1 each. I make up a list from my service manual and order a few of each. I always have spares on hand and I only pay one shipping fee. There are many places on the web to order bulbs from, they will sell brand name bulbs and generic. The generic are the same as the brand name with out the name and big price. Here is the outfit I use http://www.lamptech.com/ | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 527 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
Dave, John got my vote above, because he's right. You also left out the start relay, and the start solenoid, which are both 24V. Your driver's heater/defroster fan was also 24V... Do you still have the stock 24V MCI speedometer? How about the low air and low oil and hot eng buzzers? I'll stop asking questions now. BTTDB, George | ||
| FloridaCliff (Floridacracker)
Registered Member Username: Floridacracker Post Number: 386 Registered: 7-2004 Posted From: 24.27.228.155 Rating: N/A |
Dave, I did what I feel is the best of both worlds. Since I was replacing the outside lights anyway, I ran a 12vdc main distribuition up to the front panel. I was switching to LED lights so power consumption wasn't an issue using any of the old wiring to the lights I am either using the original switch with 24vdc as a control voltage to a relay or wiring 12vdc through the switch, whichever is easier. I also ran a 12vdc distribution to the rear. If in the future I want to switch an individual itemto 12vdc it is fairly simple. The only 24vdc exterior lighting I have is on the engine cover and this will be changed when I finish making a new hatch frame. I just like having options. Cliff | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 279 Registered: 3-2007 Posted From: 71.55.199.152 Rating: N/A |
hey here is my 2 cents worth while I am drinking a cup of coffee. I thought about,like so many, of changing over,however a brain storm hit me and I used the Vanner eq for suppling my 12 volts and then rewired the lights for 12 volts. Most coaches use 12 volt headlight bulbs but all the rest were 24. So I hook-ed up the lights all on the eq unit and down the road I went just a coaching.LOL Gomer | ||
| David Lower (Dave_l)
Registered Member Username: Dave_l Post Number: 49 Registered: 11-2007 Posted From: 99.249.16.254 Rating: N/A |
Thanks guys I guess it is a lot more than I thought,The PO took out all the blower motors the factory AC and it is a birds nest of wires in the front and rear panels, but the lights, buzzers and speedo work the lights work but now I am puzzel'd as to what the resistor is doing on the main feed to the headlight dimmer switch.I was thinking that as far fuse panel breakers or fuses would it mater if it was 12 or 24v I thought fuses and breakers triped on amperage not voltage. At least I have lots to think about this winter.Dave L | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 534 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
Dave, Fuses/breakers do indeed trip on amperage, but it takes twice as much amperage to do the same work on 12V as it does on 24V. So, the wire size has to double, as does the fuse rating, when you convert from 24 to 12. I don't know what the resistor is in your headlight circuit, but if it is someones' idea of a 12V conversion, there should be two, one for high, and one for low beam. There is a problem with either running two 12V bulbs in series, or running the same two 12s in parallel with a resistor in a 24V bus. Said problem is instant darkness with the series arrangement when one bulb fails, and 2 or 3 seconds of brightness on one side, followed by a flash and darkness when the second bulb fails from over-voltage in the parallel/resistor configuration, after one bulb fails. IMNSHO, the solution is to leave one bulb, high and low, wired from the dimmer switch, then move the ground wires from them to the connection between the batteries. Then you need two continuous duty relays with 24V coils, wire the coils to the dimmer switch terminals, high and low, the other sides of the coils to ground, the hot sides of the relays to the same mid-point battery connection, and the hot wires from the other two bulbs to the switched side of the relays, leave the grounds on them as they were. This gives you 12V headlights, one doesn't affect the other if it burns out, AND you don't boil the battery that isn't used when you 'mickey mouse' it by just moving the grounds to the battery mid-point! Comprende? HTH, George | ||
| David Lower (Dave_l)
Registered Member Username: Dave_l Post Number: 55 Registered: 11-2007 Posted From: 99.249.16.254 Rating: N/A |
George, Being an electrician do you think I am barking up the wrong tree with converting it over or should I pullout the wireing diagrams and go over what is there and repair/replace as needed Thanks for your advice. Dave L | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 286 Registered: 3-2007 Posted From: 71.55.199.152 Rating: N/A |
George; On my coaches the head lights are 12 volts and they are wired series/parallel and they have no resistor in the circuit. On low beam the are series and on high the relay is energized and takes over the parallel on the quads. The only problem I ever had was when a rock hit my low beam light and knocked it out and then left with only high beams till I got to an auto store. gomer | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 815 Registered: 12-2000 Posted From: 76.3.173.51  Rating: N/A |
David, When changed over our headlights from 24 volt to 12 volt, we did ours a little differently. First we ran all new wiring. We picked up 12 volt from our house batteries using 10 gauge wire and a 30 amp auto reset breaker. This wire feed 2 40 amp relays. The output from the relays goes to the low and high beam circuits. The relays are controlled by the dimmer switch, which in turn gets its power from the headlight switch. If you keep the 24 volt for the switches, simply but 40 amp relays that have 24 volt coils. At the same time we re-wired, we modified the inside headlight can to allow us to run 4 Hi-Low bulbs. We now have 4 bulbs on low beam as well as the 4 bulbs on high beam. Because low beams aim the light lower to the ground, we have never had anyone flash their lights at us and we now have redundancy, should we loose a low beam, we still have at least one light on each side. Jack | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 536 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
Gomer, This is exactly what I said above, if they are wired in series, when one fails, they both go out. I think if you look closely at your circuits, you will find that the high beams are in series also... Jack, That will work well, if you have an equalizer. If you are running your headlights off of the grounded 12V batt, all of the current drawn by the headlights has to go thru the other battery first. This IS hard on it. I know this is done a lot of the time, and probably most people don't notice that it is always the battery connected to the positive cable that fails first, and that they were always adding more water to it also. My suggestion isn't nirvana, but it does avoid the total failure scenario of the series connection method, leaves the headlights on the chassis batts, and isn't hard on any of the batteries! FWIW, there was a study done many years ago when quad headlights came out, and people asked why? The answer was focusing, two filaments can't be in the exact center of the reflector. So, they put the low beam filament in the center of the 'outside/low' bulb, and the single filament in the center of the 'inside/high' bulb. Regards, George | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 538 Registered: 8-2006 Posted From: 207.231.75.253 Rating: N/A |
Dave, In answer to your question, I would not change voltage for the following bunch of reasons: 1. It would take at least the same amount of rewiring as cleaning up the present mess. 2. Some wires/cables would have to be enlarged. 3. Some automatic resetting circuit breakers would have to be changed to higher amperage. 4. As previously mentioned, the speedometer, and the low air and low oil/hot engine buzzers would have to be changed. All of the dash lights would have to change. 5. You will have to buy an alternator, regulator, and starter, plus the other stuff mentioned above. 6. If you are into boondocking with an inverter and lots of batteries, a 12V bus pretty much rules out an SW4024, or any other 4KW inverter. I practice what I preach, mine is 24V, and will stay that way. From the excellent links posted here by others, you can order a stock of 24V bulbs cheap, and have them on hand for burnouts and rocks. 12V headlights, done properly, are worthwhile in my opinion, because of the better bulbs available. 24V starting is MUCH better under adverse conditions. Now, add up about how much it will cost to change everything, the cost of all new bulbs, if they fit the sockets, relays, skinner valve, {fast idle solenoid valve, jake brake solenoids, house/chassis charging solenoid} alt, reg, starter, speedo, buzzers, larger cables with new lugs, new circuit breakers, etc. Then, subtract the cost of an order of bulbs, including 3 or 4 headlights, from one of the aforementioned suppliers, and YOU decide whether or not you want to do it! Did I mention time? { } Indicate optional equipment that may not be there. This looks like a one-sided way to present it, but it is how it is... Regards, George | ||
| David Lower (Dave_l)
Registered Member Username: Dave_l Post Number: 57 Registered: 11-2007 Posted From: 99.249.16.254 Rating: N/A |
Thanks every one, and George thanks I appreciate your advise. I will leave it 24v and repair the mess. Dave L | ||
| Stephen Fessenden (Sffess)
Registered Member Username: Sffess Post Number: 741 Registered: 1-2002 Posted From: 66.38.120.219 Rating: N/A |
12 volt bulbs aren't even cheaper. You can store all the bulbs you need in a very small space. Then you won't have to worry about buying them on the road. I bought a lot on Ebay and bought out the stock at a parts store that was doing away with 24 volt bulbs. |
