12v verses 24v

littlehouse · June 02, 2006, 02:44:03 PM

i have two buses, one an old '72 Flix 35' Portlad Or. city tran. with 8V71 auto. trans. it's all 12v starter & alt. everything.
i just got my MCI 8 about two mouths ago, it's 24v start & alt. [ alt was add to right rear with belt drive, they said old
eng. drive alt & bearing plate was bad? ] so why not take starter & alt. & reg. out of old bus and make MCI 8 all 12v, i've
stripped almost everything already, i know i'll need a 12v speedo. i'd run bus battery's in parallel instead of series
any ideas welcome
ray with little house on wheels

Rick Brown · June 02, 2006, 06:45:12 PM

Generally a 24V system is prefered because only half of the current of a 12V system is required for the same amount of power. That means you can use smaller or longer wires or get more power to the load using the existing wires.
-Rick Brown in Reno, NV

phil4501 · June 02, 2006, 07:08:45 PM

Maybe the grass is always greener on the other side. If I had 24 volt stuff I would continue with it. I am trying to justify switchiing my already all 12v coach to 24v. I have never had 24v anything before, and I know it can be a hassle. It just seems that the higher voltage is superior in every way except that it isn't as common. I have never heard of anyone switching to 6 volt from 12 in the old days.
I just saw a show that showed new high performance cars will be 24 volt soon. If you want some more info on this superior system, I would be happy to send you the video on Sony betamax cassette.

TomC · June 02, 2006, 08:02:50 PM

If you rewire your coach with the proper wire gauge for 12v, since 24v uses smaller gauge, then go for it. Big rig trucks are all straight 12v, and that's powering sometimes three trailers behind. Trucks also are going to higher voltage. Probably 56 volts (14v x 4 batteries) for higher computer power. I know Caterpillar runs their computers on the engines at an internal 120v. Good Luck, TomC

littlehouse · June 02, 2006, 08:36:25 PM

i think maybe i'm looking at this wrong, but it seems everyone is talking about how to hook up 12v led lights & 12v inverters an
how to savely take 12v off your 24v system. now my rig is older; no comp. to run anything; so all my lights, fans, pumps, so on
will be 12v i'm not sure why i need 24v system, what am i missing. any help would be appreciated thanks
ray with littlehouse on wheels

phil4501 · June 02, 2006, 09:15:38 PM

I asked for it but this thread is what really got me going on 24v

http://www.busconversions.com/bbs/index.php?topic=570.0

niles500 · June 03, 2006, 01:13:52 AM

The current trend is for a future of 42 volt standard for cars and light trucks - FWIW

prevost82 · June 03, 2006, 09:26:54 AM

The current trend or not...I rewired my prevost to 12 volt and I don't regret it one bit. I brought 2 trace inverters for the price of 1-24 v. Lights, relays, gauges are cheaper ...you can go to any auto parts store and get what you need (in stock) is stead of running around town looking for the same part in 24 v that probably has to be order.

Bottom line....everything is easier to find and cheaper in 12 Volt.

DrivingMissLazy · June 03, 2006, 10:03:09 AM

Quote from: prevost82 on June 03, 2006, 09:26:54 AM
The current trend or not...I rewired my prevost to 12 volt and I don't regret it one bit. I brought 2 trace inverters for the price of 1-24 v. Lights, relays, gauges are cheaper ...you can go to any auto parts store and get what you need (in stock) is stead of running around town looking for the same part in 24 v that probably has to be order.

Bottom line....everything is easier to find and cheaper in 12 Volt.

Did you find it necessary to completely re-wire the coach, including all lights? I assume you replaced the alternator and starter and any other 24 volt components that were required for the operation. Did you replace starter and battery cables?
Richard

prevost82 · June 03, 2006, 12:34:24 PM

Richard...I replaced the dash and all the old relays in the front connection box (under drivers side window) I took the electronic dash out of a 96 Navistar hiway truck with all the relays and fuse box ( as a side note I also took the electric wiper motor, dash defrost fan motor and tilt telescope steering /w integrel steering box). The front connection box is just that, a clean connection box with no 1940 relay and diode set up for the alarm system.

I had to run about 6 new 10ga wires from the front connection box to the back connection box and that was it. I simpliflied all the wiring on the bus by rewiring the bus as per the Navistar electical schematics and removed all other circuits that were requ'd the the bus was a bus.

I replace the motor out of another wreaked truck I bought...got rid of the 8v71 and put in a 8v92ta 475hp (I live in the mountian in BC. ...there's not a flat road out of this town). I had remove the OTR bus air so I didn't requ'd the big 24v alternator (and that to me looked like another big expence if it broke) The 8v92ta had 5000 miles on it when it crashed (DD relibuilt) and had all 105 amp 12v alt and starter on it. I added another 150 amp alt 12v for the house batteries.

I wouldn't recommend this for everyone ...you have to be able to read and understand schematic and have a good understanding on DC circuits and power loss / lenght of run / loads, etc.

DrivingMissLazy · June 03, 2006, 12:47:55 PM

Quote from: prevost82 on June 03, 2006, 12:34:24 PM
Richard...I replaced the dash and all the old relays in the front connection box (under drivers side window) I took the electronic dash out of a 96 Navistar hiway truck with all the relays and fuse box ( as a side note I also took the electric wiper motor, dash defrost fan motor and tilt telescope steering /w integrel steering box). The front connection box is just that, a clean connection box with no 1940 relay and diode set up for the alarm system.

I had to run about 6 new 10ga wires from the front connection box to the back connection box and that was it. I simpliflied all the wiring on the bus by rewiring the bus as per the Navistar electical schematics and removed all other circuits that were requ'd the the bus was a bus.

I replace the motor out of another wreaked truck I bought...got rid of the 8v71 and put in a 8v92ta 475hp (I live in the mountian in BC. ...there's not a flat road out of this town). I had remove the OTR bus air so I didn't requ'd the big 24v alternator (and that to me looked like another big expence if it broke) The 8v92ta had 5000 miles on it when it crashed (DD relibuilt) and had all 105 amp 12v alt and starter on it. I added another 150 amp alt 12v for the house batteries.

I wouldn't recommend this for everyone ...you have to be able to read and understand schematic and have a good understanding on DC circuits and power loss / lenght of run / loads, etc.

WOW. Looks like a labor of love. I am impressed.
Richard

littlehouse · June 03, 2006, 02:41:41 PM

well this sure gives a nut alot to think about but when i do it hurts. so i'll have to sit on this for awhile i really thank all of
you for all the great insight pro & con.
thanks again
ray with littlehouse on wheels