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JackW
Rating: N/A Votes: 0 (Vote!) | Posted on Thursday, March 10, 2005 - 12:17 pm: | |
To anyone with a bus that has been converted to 12V, or ones that were OEM 12V, what do you use for an inverter/ battery bank. 12V? What are the pro's/ con's using 12V, as opposed to 24V? TIA, Jack |
gillig-dan
Rating: N/A Votes: 0 (Vote!) | Posted on Thursday, March 10, 2005 - 12:22 pm: | |
The biggest advantage to 24 volt is that the battery cables only carry half the current to produce the same power (watts). I would say that 12v accessories are more common. If were me, I'd go with whatever voltage the rest of the bus used. Gillig-Dan |
TWODOGS (Twodogs)
Rating: N/A Votes: 0 (Vote!) | Posted on Thursday, March 10, 2005 - 12:34 pm: | |
I would use 12v for inverters UNLESS you are planing to run A/C off the inverter |
Sean Welsh (Sean)
Rating: N/A Votes: 0 (Vote!) | Posted on Thursday, March 10, 2005 - 12:47 pm: | |
Jack, We were able to do almost everything in 24 volt. The only exceptions were FanTastic fans, our satellite positioner, our tank level monitor, and the dash stereo. We use a battery equalizer for these few items. Going with a 24-volt house bank means we can use our massive 270-amp, 24-volt main alternator to good advantage, charging both the chassis and house banks as we drive, with power to spare for running our all-electric dash air and even a roof air as well. On top of that, we have a 4kw continuous/8kw surge inverter. AFAIK, there are no inverters that large available in 12 volt (understandably -- the DC input cables would be nearly unmanageable). And, as Dan points out, we use much smaller cables on our DC side all around than if we had a 12 volt system. We studied this issue long and hard before we made our decision. Sticking with a 24 volt house system made the most economic sense. Sure, I pay about double for all my light bulbs -- 24v models have a premium over 12v in the same wattage. But I'll have to replace hundreds and hundreds of light bulbs before I'm up to what it would have cost me to implement a 12 volt house battery system. Just my $0.02. -Sean |
JackW
Rating: N/A Votes: 0 (Vote!) | Posted on Thursday, March 10, 2005 - 2:00 pm: | |
OK,here's the deal: I have a MC8 that the previous owner converted to 12V. Alot, or I should say all the wiring is suspect, so at this point I'm going to rewire the entire coach eventually. The 12V alternator that came with the bus doesn't work, and the only other major 12V item is the starter. Am I missing anything? The control switching, gauges, marker lights and turn signals on a standard 24V coach, are these 24V? The other thing is I'm installing a large 12V car audio system. How about battery capacity? Are 24V systems about twice as efficient as 12V as well? |
Ron Walker (Prevost82)
Rating: N/A Votes: 0 (Vote!) | Posted on Thursday, March 10, 2005 - 2:02 pm: | |
Hi Jack...I use 12v for the house batteries (6-2volt AGM cells @ 1000 AH each / 6000 AH total) and I converted the coach as well to 12v. Yes, you have to run a larger cable to the inverter but that's a small price to pay campared to the price of 24v stuff. This is one of the reasons why I converted the coach as well, I can buy a package of 8 12v bulbs for the price of 1 24v bulb, same as relays ...if you can find them. I converted to Bosch cube relays and ripped out all that 1940's circuitry. This also allowed my to put in 12v elec wipers, 12v 3 speed defrost fan and a electronic dash out of a NavStar Hwy truck, @ a 1/4 of the price that you can buy in 24v....again if you can find them without going back to the bus manuf. and paying there premium price. I have got rid of as much "Bus Parts" as I could and replaced with truck parts, so I can pull into any truck shop or auto store or junk yard and buy any thing I require, without paying for the "Bus Price". I also don't have to worry about wiring the toad. It's just made things way easier and cheaper in the long run. Ron |
JackW
Rating: N/A Votes: 0 (Vote!) | Posted on Thursday, March 10, 2005 - 2:38 pm: | |
Thanks for your input Ron, I was hoping you would reply, as your reply on an earlier thread was what prompted me to post this. What inverter are you running? Jack |
Brian Brown (Fishbowlbrian)
Rating: N/A Votes: 0 (Vote!) | Posted on Thursday, March 10, 2005 - 2:39 pm: | |
I would worry about any coach wiring converted from 24v to 12v, since all wires would now carry twice the current than original rating. This is a fire hazard, plain and simple. I think it's good advice to use whatever voltage the coach wiring is for the house side. That said, if one had a 24v coach, they could run a completely separate 12v house system for accessories. A 12v alt. could charge that side of the system. Even once the charging was worked out, there would be tradeoffs with such a system, though. Big #0000 cables vs. #00 for the high amp draw stuff like inverter(s). DO the research, make a list of pros and cons and decide accordingly. I have a 12v neg. grnd. coach side and will use 12v. neg. grnd. for the house side as well. It just makes sense for my coach and my lifestyle. YMMV... HTH, Brian Brown PD4106-1175 |
JackW
Rating: N/A Votes: 0 (Vote!) | Posted on Thursday, March 10, 2005 - 2:50 pm: | |
Hi Brian, All the wiring was removed and replaced. Thanks for your concern though. In a conversion, there is alot of unused "commercial coach" wiring. There really isn't alot of coach wiring in a diesel bus conversion. The bus was already converted to 12V when I bought it. If it hadn't been, I would definately be sticking with factory voltage, however, due to the way it sits right now, I am doing research (here, and myriad other locals) to find what will work best for me. Thanks for your reply, Jack |
Brian Brown (Fishbowlbrian)
Rating: N/A Votes: 0 (Vote!) | Posted on Thursday, March 10, 2005 - 5:10 pm: | |
Jack: Glad to hear all of the wires were replaced. It's just that you mentioned "all the wiring is suspect", so I'd go over every circuit with a voltage drop chart or actual measurements and be sure. There's quite a few long runs of coach wiring that will still remain, even in a converted coach... signals, brake and tail, markers, gauges, etc. Also, the engine harness stuff. If all these were replaced, fine, but make sure it was replaced with appropriate spec. and gauge wire (for its run) and appropriately terminated. But high-draw, starter and alternator wires are the biggest concern for "crispy coach" syndrome. Also, I'd look into a "disaster fuse" to cover the whole rig in case something really, really bad happens, electrically-speaking. HTH, BB |
Sean Welsh (Sean)
Rating: N/A Votes: 0 (Vote!) | Posted on Thursday, March 10, 2005 - 8:02 pm: | |
Jack, You're in a tight spot. I did not realize your MCI had been "converted" to be all 12-volt. Given that situation, I suspect your most economical alternative is going to be to stick with 12 volts. I think you'll find that 3KW is about the largest inverter available in 12 volts. The other problem you will run into, and this is the reason that these coaches are made 24 volt to begin with, is that 12 volt alternators simply can not put out the sheer amount of power that 24 volt units can. So you need to look closely at your charge output. Good luck! -Sean |
CoryDaneRTS
Rating: N/A Votes: 0 (Vote!) | Posted on Thursday, March 10, 2005 - 8:28 pm: | |
(" What are the pro's/ con's using 12V, as opposed to 24V? ") You have gotton some good answers but you need to understand the numbers. If you have 4- 12volt batteries good for 200 amp hours each: At 24v, that is 2 sets of 2 12v batteries in series = 24v @ 200 per series or 400 amps. At 12v, that is 4 12v batt in parallel, or 800 amps Now this is starting to show the need for the Larger cables from the battery to the inverter. Because you are feeding 12vdc to the inverter, whatever it would take to feed 24v current to the inverter to make 120v, for 12v DOUBLE THAT! 20 amps at 120vac = roughly 4 x 20 or 80 amps at 24v 20 amps at 120vac = roughly 10 x 20 or 200 amps at 12v You see the picture? 2 aircons = roughly 30 amps 30A at 120vac = 4 x 30 or 120amps at 24vdc 30A at 120vac = 10 x 30 or 300 amps at 12vdc. NOW ALSO NOTE that you have to wire for the extra start up surge for ONE air con. Most inverters wont handle both AC start-up at one time. The Cable carrying 12volt to the inverter will be taxed much more at a double rate compared to a cable carrying 24v to the inverter. Don't forget fuses. cd |
Gary Carter
Rating: N/A Votes: 0 (Vote!) | Posted on Thursday, March 10, 2005 - 9:24 pm: | |
About the only reason to have a whopping big inverter is if you are going to run the A/C going down the road. Personal opinion, you are better off spending the money on your genset. Running the A/C off the engine is not free power. Not only that but you can run two or three a/c off you generator. Seems when you need one going down the road you need two. |
JackW
Rating: N/A Votes: 0 (Vote!) | Posted on Friday, March 11, 2005 - 10:28 am: | |
Cory, thanks for the explaination. Makes more sense now. Gary, thank you for your input. |
Ron Walker (Prevost82)
Rating: N/A Votes: 0 (Vote!) | Posted on Friday, March 11, 2005 - 10:53 am: | |
I agree Gary...run the genset for A/C. Jack I have 2- Trace DR 2512 Inverters (one for each leg) and a 8 KW Kabota diesel genset. One of the reasons I went with 2 inverters was to increase my charge rate on the house batteries, they will take 50 to 60 amp charge( they're flipping huge). You could use just one inverter. Brian..I ran some new larger wires 10ga. I don't have very many high load circuits running to the back of the bus (running lights and start, is about it and they run solenoids at the back) the rest are signal wires for the gauges (low load). I move my coach batteries (2 8D's) to where the old A/C compressor was, right beside the starter, So I did have to up size any of the large cabling running to the front of the bus. (starter is 12V) Ron |
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