24-volt 50 amp alternator..

[robertglines1]

If The only need for 24 volts in my coach are running lights and defroster fans and misc relays and solenoids..will a 50 amp alternator be sufficient for these circuits...no bus air or heat blowers. I have a 12 volt alternator on engine now(freightlinner) transplant into my 98 prevost..will have separate 12 and 24 volt systems...starter is 12 volt...observations please...I do not use inverters.(my life style choice)I run gen set or am plugged in..might experiment with inverters later (I have several)but would adjust then..would use 2 group 31 batteries for 24-volt system.....Bob     not trying to reinvent wheel..just make a salvage shell functionable with the least amount of complex systems.

[Busted Knuckle]

Bob,
I don't see why a 50 Amp would not be plenty for what your doing with it. (you are using led lights aren't you?)
  BK 

[robertglines1]

yes on led...wipers and defroster along with anti lock brakes and some selonoids are the only loads..less than 50$for a new 50 amp 24 volt alternator..thanks BK for helping me reason thru...Bob

[Lin]

hey, I just paid $95. for a rebuild of my 45 amp, 24 volt alternator!

[buswarrior]

Do you have a 24 volt battery set? You'll need a small one to get this to work, alternators can't behave without a battery.

happy coaching!
buswarrior

[Busted Knuckle]

Do you have a 24 volt battery set? You'll need a small one to get this to work, alternators can't behave without a battery.

happy coaching!
buswarrior

Yeah BW he said he'd use a pair of 31's to make a 24 V bank.

If The only need for 24 volts in my coach are running lights and defroster fans and misc relays and solenoids..will a 50 amp alternator be sufficient for these circuits...no bus air or heat blowers. I have a 12 volt alternator on engine now(freightlinner) transplant into my 98 prevost..will have separate 12 and 24 volt systems...starter is 12 volt...observations please...I do not use inverters.(my life style choice)I run gen set or am plugged in..might experiment with inverters later (I have several)but would adjust then..would use 2 group 31 batteries for 24-volt system.....Bob     not trying to reinvent wheel..just make a salvage shell functionable with the least amount of complex systems.

[fortyniner]

Thats roughly equivalent to a 100 amp 12v alternator which would be sufficient for a car without AC or power accessories. I figure 60% of rated capacity on a hot day which is about 720 watts. Subtract 400watts for headlights and you have 300 left for everything else. If your wipers are still air powered I think you could get by ok.

-Tom P.

[buswarrior]

yup, I'm losing it.... 

happy coaching!
buswarrior

[BG6]

I wouldn't use a 50-amp alternator on my SUBURBAN, much less my coach.

It looks like you have put a 12-volt engine into a 24-volt conversion.  I think it would be worth your time and money just to make the jump all the way to 12 volts.  You can simplify the wiring at the same time (do you really need all of the solenoids?).

The one thing you need to make sure of is that your wires are big enough.  Your main power cable from batteries to the starter is probably 4/0 gauge -- more than enough, and you can tap off that if you need to.  If your battery bay is up toward the front, you can run whatever wiring you need to power anything.

Spend a couple of hours with your electrical schematics.  A lot of those solenoids are probably for factory environmental controls, and if you took that system out, you can dump the solenoids, too.

In the long run, you will be far happier with a coach running one voltage.

[James77MCI8]

I think he is keeping the 24 volt system just downsizing the alternator

[robertglines1]

the vanner was taken out of bus..so just trying to simplefly cost of rebuild...I need minim 24 volt supply..It would be quite expensive to change all 24 volt wiper motors and defroster blowers to 12 volt.I have both 24 &12 volt starters available..engine was a 12 volt set up..Drivers ac compressor has a 12 volt clutch but needs 24 volt for defroster/drivers air blower..cost Of 24v volt alternator on EBay as low as 50$new..so if you have to split 24 volt system at vanner to 12 why not just have 2 separate systems..wiring in back of rear axle is toast.so will have to be rewired anyway....will supply both 12 and 24 to front junction box so lights blowers and any other 24 volt needs will be attend to..ddec system is 12 volt---anti lock brakes control is 24 volt but requires intermittent low amperage 24 volt..so it is a cost thing and is simpler

[Chopper Scott]

I have both 12 volt and 24 volt systems and they work well. In fact I even changed the headlights to 12 volt, a huge improvement. If you go with a 24 volt alternator make sure it is internally regulated which I'm sure it is. If it is a one wire system it takes care of itself but won't excite itself to make a charge until the rpms get up there. If it isn't a one wire set up you will have to wire in a Hobbs switch that activates with oil pressure or an on/off switch so that the alternator doesn't backfeed and run your batteries down when shut off.