12 VOLTS v/s 24 VOLTS

[sivrtnge2]

Just wandering, which is better 12 or 24 volt system. My coach is set up on the 12 volt system however, I see a lot of talk about the 24 volt system. Since im looking for a new inverter charger, I'm looking to do a major upgrade. I would like to be able to run anything that i want off the house batteries when driving. At the present time, I have to run my genset while driving to operate lights, heat, etc. I know this will cost a few grand or so but it will pay for itself over time by the savings in fuel. I think I read somewhere that the 24 volt inverter/chargers produce more continuous watts. Please advise me on what my options are and if i go the 24 volt route, what all have to be changed over???
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BILL

[Beatenbo]

I would take 12 over 24 any day because of availability on 12V stuff. bulbs TVs water pumps just to mention a few. I have a 24V inverter and battery bank because my bus is 24v and can keep batteries charged while driving. I still use a 120 AC to 12 DC for my house stuff. If my coach was a GM pre 68 or so 12v or Eagle 12V I wouldn't even consider a high priced 24v bulb. Thats just my take. Good Day

[Ross]

My next bus will be 24V with a 12 converter or equalizer for the house loads.  The 24V inverter is more capable of handling large AC loads like AC's and the 24V bus alternotor is more than capable of keeping up.  However, there is nothing wrong with 12V either.  My house system is 12V with a 12V alternator on the engine and it works fine.  If your bus is already set up for 12V, a nice 12V inverter, like the Xantrex RS3000 would be easier than converting to 24V.  To go to 24V, you'll probably need more batteries, charge solenoid, more battery cable....all that costs money.

Ross 

[sivrtnge2]

My coach is a re-titled 94 eagle 10. It has a 12 volt system. how would i run my basement a/c unit or units if needed while driving down the road without running my genset??? is this possible??? 

[Ross]

If your bus electrical system is 12V then changing to 24V doesn't make sense.  You could do it, but it would be very expensive.  Most buses are 24V, so using a 24V inverter is a good way to go.  I have an RS3000 12V inverter and it will run 2 roof AC's.  My 12V alternator is only 140A so it will only keep up with one AC.  The usual debate is whether you are better off using engine horsepower to recharge the battery bank while the AC's are running, or just run the genset.  I can run one AC no problem, but I still run the genset when I need AC.  I need all the HP going to the rear wheels and in the grans scheme of things, the genset doesn't burn much diesel.

Ross

[Nick Badame Refrig/ACC]

Hi Guy's,

Whichever systems you choose, try and have the foresight of being on the road having a problem. Which systems

will you be able to aquire parts or repairs for the easiest?  Having Redundency in invaluable....

I try to keep spare parts to as many things that I canot easily find on the road. Like, 12v waterpump, 400amp fuses,

freon,[thats just me lol] lots of 24v bulbs, 8 ft. of oooo wire, [in case i have to divert batt power] pex fittings and pipe,

fuel filters, hose clamps, portable air compressor, automotive battery charger, lots of tools, and on and on and on.....

We drive a vehicle that is Not a common RV or truck, so we should think differently and compensate accordingly!!!!

Nick-

[sivrtnge2]

I appreciate the quick responses today. MERRY CHRISTMAS to all !!! ...so as far as the system, I see that Ineed to stay with the 12 volt system however, do I need to go to a larger battery bank??? maybe stacked inverters??? I'm new to this and would like to solve this one of many problems. i took a 250 mile round trip and burned almost 80 gallons of fuel with the genset running. I realize that I won't get 21 mpg however i thought i should get at least 6.
FYI, the genset ran the entire trip with the exception of shutting everything down when we got to our destination!!! I have a mechanical 6v92ta and was in south GA and FL area.

[Ross]

One AC running will need about 140A of DC to keep the battery bank from draining.  What kind of alternator output do you have?  If you're alternator is not putting out close to 300A, running 2 AC's down the road is probably not practical.  You can stack inverters to get the AC output, but if you don't have the alternator to keep up, it will only run until your batterys drain, which won't be long with two AC's running.  You're best bet is probably to install a good quality 3000 watt sine wave inverter which will get one AC running down the road.

What do you have for a genset?  My 8KW burns less than a gallon an hour loaded.  That's 6 or 8 gallons for a days worth of driving.  I think I'm money ahead by running the genset rather than running the AC on the inverter.

Ross

[sivrtnge2]

The genset is a 20kw powertech

[TomC]

Whether you have a 300 amp alternator with a larger inverter to run the A/C down the road, or run the generator to run the A/C, the power for the A/C has to come from somewhere-whether it be an extra drag on the engine alternator or running the extra engine for the generator.  Personally, the most efficient is running the Diesel generator.  Why?  Because running through the inverter-first you loose power just because of using DC power with the alternator.  Then your inverter will be maybe as much as 90% efficient (which causes extra heat you have to get rid of).  So going through the engine alternator, then through the inverter, you'll be lucky to be 80% efficient, and that's with a true sine wave inverter.  As compared to just running the generator that makes a perfect sine wave, and you're getting the electricity directly.  If you want to run an A/C from the big engine, use an automotive type of A/C with an evaporator unit in front. Then the compressor is running directly off the engine.  I choose to use three roof tops off the generator since I didn't want to run any of the A/C's off the inverter or did I want to run nearly 40ft of freon lines from the back.  Just my choice.  Good Luck, TomC

[rayshound]

I had removed everything including wiring that was 24v. Rewired and went all 12v with one exception. A second alt. that is the 50dn 24v (original alt) It powers the 3600w inverter and battery bank. Just my way but I love it.  Ray