12 vs 24 volt starter?

[robertglines1]

I have 2000 model 60 series out of a freightlinner.  I have a 12volt starter that came on engine. Also Dick gave me a 24 volt starter with the deal.  The batteries will be located less than 18 inches from the starter. Very very  Rare would I start this engine below 32F. Would be easier to just do 12 volt system.  Very little other 24volt in coach as bus air has been taken out.   opinions???       I can go either way and use other as spare.  Bob

[luvrbus]

Go with the 12V Bob with the new reduction starters and without the fan draw on buses with factory air no need to worry about 24v

good luck

[bevans6]

The big load on alternators, after the rest of the stuff is gone, is recharging after the start.  What voltage is your main charging system, since you say there is still a little 24 volt left?  Anyway, just mentioning that you have to consider the charging of the main start batteries, whether they be 12v or 24v.  I agree that it doesn't matter much which voltage you choose, about the same power required.  Bigger cables needed with 12v maybe, two batteries in parallel for the current rather than two batteries in series.

Brian

[TomC]

All trucks made, except for military and foreign, are 12v.  My bus is 12v and I love it. Keep the 12v starter. On the big Series 60 highly recommend you use 4-size 31 batteries, or whatever combo will give you around 3,000cca.  I realize you don't need that much, but it sure makes the starter last longer and if you do get into cold weather, will also be able to roll over that big engine.
I would suggest you install a solenoid between the starting batteries and the deep cycle batteries.  You can use this for starting the bus on dead starting batteries, charge the batteries going down the road.
If your bus was wired for 24v starter, you should add another set of starting cables since the 12v starter will draw twice the amperage.  My bus has two sets of 0000 cable going to the starter-on both the positive and negative side.  Good luck, TomC

[Sean]

Unless you are completely rewiring the coach from scratch, to include all new lights, gauges, relays, and solenoids, my recommendation would be to stick with the factory voltage for the bus.

This goes way beyond the starter.  Presumably to have a 12v starter you'd change to a 12v alternator and 12v chassis batteries.  This would mean most of your existing 24v gauges will not work correctly, all your relays and solenoids would need to be replaced, and all your lights will need to be either rewired or changed over to LED (wire gauge for 12v is larger than for 24v).

If you keep "a little" 24v stuff, now you have to deal with two different battery voltages on the chassis.  Do you use a 24v alternator or a 12v alternator, or maybe have to have one of each?  If you go with a 12v alternator and batteries, how will you derive 24v for the items that need it?  If you go with a 24v alternator, you'd need a 24v battery system, and how would you turn your 12v starter with that?  Yes, all of these problems can be solved, but that's a lot of work for little or no benefit.

All of that aside, IMO, 24v is a far superior system to 12v in every way.  The only downside to it (in the US -- the rest of the world is ahead of us in this regard) is that 24v parts are harder to find and slightly more expensive.  12v is easily derived from a 24v system for a few items that may need it, whereas the other way around is much more difficult.

HTH,

-Sean
http://OurOdyssey.BlogSpot.com

[robertglines1]

The engine came with all accessories 12 volt alternator   12 volt ac compressor for drivers ac.  So will do 12 volt. What little 24 volt I need I will either convert from 12 volt or have small separate 24v volt system for  wiper motor- defroster motors.. The leveling solenoids are 12 volt already  all running lights are 12 volt.  Will keep 24 volt starter AS back up/ in emergency a little engineering could get 24 volt to it. DDec is 12 volt. All bay lighting etc is 12 volt. If I had more accessories that were 24 volt I would be  more concerned. I have a small 24 volt alternator that I could power a separate small 24volt system with. Probably easier to just change the remaining 24 volt stuff out and keep one voltage thought out.   Bob        Nice to be getting final little details in line... starting to get fire up fever.

[TomC]

My Kenworth truck has a 12v system with a 24v starter.  They used what is called a series/parallel solenoid to jump the batteries to 24v only for the starter.  With the advent of higher powered 12v starters, the series/parallel solenoid was eliminated.  Good Luck, TomC