| Author | Message | ||
| Bruce Henderson (Oonrahnjay)
Rating: N/A |
__. There's a very useful flat flange on my radiator fan drive -- it will be very easy to add a second alternator. What should it be -- a second 24-volt alternator, or a 12-volt? The idea is that the second alternator will charge the house batteries; I'd prefer to keep the loads as low as possible on the 30-year old bus alternator, although I plan to install an "Ample Power" system that will draw from both alternators to charge house and start batteries. __. I'll need a fair number of 12-volt circuits - does the trick of pulling 12 volts from a single battery in the house bank work or is there a better way? __. I'm at "beginning/basic" planning stage here -- what's the best setup? Bruce Henderson, Wallace NC USA | ||
| FAST FRED Rating: N/A |
If you do not plan on air cond on the road from a large inverter/alt combo, sticking with the coaches 12V should be simplest. 24V is great for huge inverter loads , but not much else in an RV needs thyat much power for that long. If the chasis alt has the usual imbecile regulator it is fine for the start batts. The second alt should get a 3 stage regulator, and your DONE! Monitor for batt SOC for longest house battset life. KISS FAST FRED | ||
| Bruce Henderson (Oonrahnjay)
Rating: N/A |
__. Sorry, I wasn't clear. The existing start battery/bus system is 24 volt. The question is whether the *second* alternator and house charging system should also be 24 volt or 12 volt. Thanks, BH | ||
| Craig (Ceieio)
Rating: N/A |
Bruce - either voltage will work. I like 24 volt because the current for a given wattage is 1/2 of 12 volt and line losses are less. This applies to both charging the batteries and the current necessary to provide your 120v power from the inverter. Lower current is less loss, less heat. 12v Alternators are much cheaper and easier to access, are available everywhere and will get the job done. So the good news is you can't go wrong, so just go with it. As far as picking 12v off of your 24v stack, most would advise against that as it could shorten your battery life. Craig - MC7 | ||
| John that newguy Rating: N/A |
Keeping everything 24v is in -my- drea... err Plans. To me, using a 24 to 12 converter for all the appliances that require a 12v feed, would simplify life. http://www.alfatronix.co.uk/products.php?act=display&productID=P3F02E8E35CEC1 | ||
| FAST FRED Rating: N/A |
"The question is whether the *second* alternator and house charging system should also be 24 volt or 12 volt. Thanks, BH" Its lots cheaper to go with the 12V system as the cost of a high quality unit to pull 12V from 24 {vannier} is very high for not many amps. Most RV and marine stuff IS 12v , so why bother with 24 if no huge inverter loads? FAST FRED | ||
| bowlingshoegiverouter Rating: N/A |
twelve !....I suggest G.M. alt...65 amp=35.00....140 amp=140.00 | ||
| John that newguy Rating: N/A |
Bruce- Couple other things pooped into my head... With the 24v bus alternator that you already have, and a 4024 Trace inverter, you could run both your 110v roof airs, plus a 110vac to 12vdc converter....and/or a 24 to 12v converter. Your 24v battery system will run the Trace to supply the 110v needed to run the 110 to 12v converter without any tremendous draw. There's really no reason you have to have both 24v and 12v battery and charging systems. If I had a 12v bus like FF or TD, I wouldn't bother with 24 at all.. Life would be slightly easier. But like you, my bus is 24v... | ||
| Mike (Busone)
Rating: N/A |
JTNG, Did you really mean to say "Couple other things pooped into my head..." I hate when things poop in my head or on it. | ||
| John that newguy Rating: N/A |
In my head.... yeah... I've been told it's definitely "poop", by several here on the bb.... | ||
| Buswarrior (Buswarrior)
Rating: N/A |
Hello Bruce. You asked "what's the best set-up?" Whatever you decide to do is best for you. Whatever I do is best for me, and probably very different. That said, you have to add up the cost of doing it the different ways, consider the consequences of each component failing, what redundancy or back-up may be built in, or not, and whether that is critical to the way you will be using your coach. Some completely convert their 24 volt coach to 12, some use a combination of 12 and 24, some stay with 24. There are a variety of ways to get 12 volts out of 24. (do not centre tap your batteries without an equalizer, unless you like to buy batteries) Some use the big coach alternator to charge everything, some have two alternators, one for house, one for coach. Some run the genset going down the road for power, some run a big inverter off a big engine driven alternator going down the road. Some are able to jump start using the house batteries, some are able to cross the systems under failure conditions. Some are idiot proof, some are able to run all their batteries flat in under 30 minutes if the wrong switch is left on. Some have a dedicated start battery for the generator, some have dedicated start batteries for the engine, some have dedicated batteries for the house, some use the same two batteries for everything. And we haven't even started wondering about whether you are going to use propane or electricity to power the refrigerator.... Whatever you choose, it will be best for you! happy coaching! buswarrior | ||
| Brian (Bigbusguy)
Rating: N/A |
"I'd prefer to keep the loads as low as possible on the 30-year old bus alternator" If you think that way you should not drive the 30 year old bus also  I would bet 30 years ago it was built as good if not better then one built today . If it was me I would go all 24 volt and use a Vanner equilzer for any 12 volt lights, radio, CB's ,spot lights. And use 110v lighting in the living part of your bus . For now on mine I have a Vanner 100 amp equilzer on the start batts but as soon as I get a house bank I will put it on them so any 12 volt draw with the motor off will not draw down my start batts. For back up I have a 3 stage 24 volt charger wired into the start batts run off the gen set also I have a back up smaller pull start generator and a 12 volt charger if the other one fails . I also have a 110V back up air compressor if the motor driven compressor fails but I doubt that one will ever happen. The only draw back in going 24 volt house batts is the el cheepo inverters are only 12 volt you need to speend a little more $$ on finding a good 24 volt inverter and if you converted all you bus lights to 12 volt like I done the added cost of a larger Vanner equlizer. Brian 4905 Some place on earth | ||
| Stephen Fessenden (Sffess)
Rating: N/A |
I agree with Brian. You just reminded me that I need to remove my house 24 volt alternator for service. It quit in Canada las October and I did not have to fix it on the road becase the bus can operate fine on either alternator. Reduncancy. |