Hello everyone: I am planning and acquiring all the stuff I need to build the electrical service for my conversion. I am planning for 50 amp service using a inverter and a battery bank with future additions for solar and a generator. Most everything will run off 12 volt, but I will have some 110 also for the fridge, outlets and a TV. Pretty much standard RV stuff.
So far I have the inverter with a built in charger.
On order, I have a 30 foot 50 amp power cord, a 50 to 30 amp adapter and a 12 volt fuse panel. I still have many other things to order, or purchase locally.
I would like to get some opinions on inverter placement. In the living space, or in the basement? I know it must be kept as close as possible to the batteries, but not in the same compartment. Inverter must also have free flowing air to help it stay cool: will placement inside the cabinets of living space be to limiting on air circulation? I have tried to search for RV wiring diagrams to help me with my planning put haven't had much luck, most of what I have been able to find is either stick and staple stuff, or way to simplified to help with the planning and building of a system. Anyone have any good links?
Inverters are kind of loud - fans running and transformers humming. Mine is in the front luggage bay on a wall I built for all my electrical panels, and the batteries are directly forward in the old AC condenser compartment.
Brian
Thanks Brian: Do you a sub panel for 110 and 12 volt some where in the living space? What are you using for batteries and how many in your battery bank? Thanks Mike.
The generally-accepted wisdom is to put breaker panels inside the bus so they are easily accessible without you needing to crawl around outside in the rain in the middle of the night if one trips. The Square D QO panels are good for 12VDC and 120VAC, so one of each is the cheapest and easiest solution for house loads - all the big box stores sell QO breakers (but don't get the Homeline ones which are lower quality and not DC-rated). As Brian says, keep the inverter as close to the house batteries as possible, but in a separate compartment - its main DC feed cables must be short and fat. Its breakers or fuses should be close to the source of the power, i.e at or close to the house batteries.
John
I have an RV panel in the living space that used to be a converter, it has a built in AC breaker space for around 6 breakers, and a separate (as must be separate) DC distribution area with around 12 fuses. I have a second AC pony panel with four breakers beside the inverter - that distributes the inverter-fed loads, so I have a selection of AC circuits that are fed by outside power, generator or inverter, and a second selection that are fed by outside power and generator only. I did this so that there could not be a mistake and my fridge try to run off the inverter and batteries by mistake. Also engine pre-heater, air compressor, those kinds of loads. Everything in the house itself is pretty much run off the inverter, if it is on. There is an ATS to select between outside power and generator, and the inverter only comes on if both of those are not present. Whichever source is in use bonds neutral to ground. I am set up and designed for a normal 30 amp supply.
I have four 6 volt 232 AH wet batteries on the floor in the condenser bay, for 232 AH at 24 volts nominal. Great ventilation and they fit where the fan shroud used to be. Be aware that cutting out the fan shroud is a royal PITA. The red switch you see is a battery selector switch for the inverter. I picked up the main bus 24 volt cable at the AC relay box (roof of the front driver's side luggage bay, and ran it to the selector switch, and the feed from the house bank also comes in to the selector switch. It can be set to off, house bank, or combine house bank and bus start batteries. That lets me run the inverter from the bus alternator and charge the house bank while driving, lets me run the bus (starter, lights, all the regular bus stuff) off just the house bank if there is a problem with the bus start batteries (happened once on a trip, lost a cell in one of the 8D's and I was able to just open their disconnect switch and the bus ran off the house batteries just fine till I replaced the starts with gp 31 truck batteries), and lets me charge and maintain both sets of batteries from the charger in the inverter. I cannot imagine a more versatile way to set up the electrical system to suit my needs. This is Rev. 2.1, btw, it evolved into this over time as I learned what worked and what I needed.
Edit: I agree with John that having the fuse/breaker panels inside is the better way to go. I put my pony panel beside the inverter down in the bay because I didn't have an accessible space inside the bus for another panel. I had already lost half my bar drawer space putting in the first panel, and booze storage was more important to me that the possibility of me having to go outside to reset a breaker (which has never happened, knock on wood).
Brian
I believe in having all electrical service in the living area. I have seen circuit breakers, transfer switches, inverters in the cargo bays. But-I have had too many times the electricity go out during a rain storm. I simply switch to generator, and start from inside. Inverters can make some noise, but just put them up front and can't hear them from the bedroom. Good Luck, TomC
Thanks guys: Very helpful information. Brian, having the battery's in the condenser bay make a lot of sense, but where have you installed your generator?
I have my inverter in my bay, but I really want to free up the bay space. It is also pretty far from the batteries although I have 4/0 cable to avoid voltage drop. I have thought about moving it upstairs, but the only good location is near the bunks where the fans might disturb sleep. My AGM batteries are under one of the bunks.
Same as Brian. Inverter and batteries in front bay driver side. Separated batteries from inverter. 2 breaker Sub panel above driver and front panels 1 being DC with 20 switch breakers and 2nd panel AC with about the same plus a main shut off switch. Remote next to it all. Generator switch above driver also as well as water heater switch.
I used 4 - 6volt Us batteries with 232 Ah at 20% rate. 4024 Hybrid Magnum inverter with Battery monitor and 20-60 Vanner for 24 volt and 12 volt.
Dave5Cs
I have my inverter inside the bus in an electrical closet. The closet is vented and also contains two audio/visual fans thermostatically controlled. These two fans are very quiet but the ones in the inverter are not. This was mostly a necessity as transits aren't exactly overrun with under-the-floor storage space. My AGM batteries are about 4 feet away in a seperate compartment.
I don't really like the inverter inside, as its fans tend to come on during a battery charging event and they sound like a Cessna 150 during take off. Likely each inverter brand would be different in this respect, but mine is too loud for my liking. To minimize this, I installed a Progressive Dynamics 24V charger that has an extremely quiet internal fan. I can't even hear it when it runs. I keep the inverter's charger turned off and just let the PD charger maintain the batteries. It has a 3 step charging program and doesn't boil my batteries.
Mike, my generator also rides in the condenser bay. the front half holds my Yamaha 3000 watt inverter generator, the rear half has the four batteries. It all fits perfectly. If I am going to run the generator for more than a half hour or so I open the door and turn it sideways to point the exhaust outside better, and to let it get more cooling air. Not perfect, but it's what I have.
Brian
I've noticed that my inverter fans will sometimes come on if the bay gets warm inside and power is only passing through the inverter. (It is not charging nor inverting.)
HI Mike, early this summer I finished upgrading my electrical. My system was based on Brian's. (Thanks Brian) It's SOOOOO nice compared what I had before. It wasn't cheap but well worth it. It's amazing how much less I use the generator now. I've got a 10K Onan diesel gen. If that thing takes a dump, I'll replace it with something a lot smaller, which means less expensive. I can only do that because of the nice setup I've got now with the inverter and batteries. 8, 6 volt Golf cart batteries from Sams. 4000 watt, 24 volt Magnum Inverter charger. I run the front air conditioner off the inverter when I go down the road. The bus alternator charges the batteries as we travel. Man I wish this site could handle decent multimedia. I'm not going to piss around with changing the resolution on the photos so that's why I'm posting links.
The Setup: https://docs.google.com/drawings/d/1Us02X_ZduDrJoGBe2yOWzcjrVVp0puUTW0Kp-LTj9J8/edit?usp=sharing
Inverter in the front bay and the battery bank just forward of that in the old condenser bay. I've got a fan that is hooked to a switch right above the driver's seat that I turn on when we are going down the road. The fan is pointed right at the inverter to help it cool. I've touched the outside of inverter after many hours of use and can't feel anything warm. Personally I'm happy that the inverter and sub panel are under the bus. So what if you need to reset a breaker once every 2 years. If it's more than that you really aren't paying attention, right? Of course you can't control what others are doing. https://goo.gl/photos/tgsPyeXYeYfzwHG18
And because I love it when other people post pictures of any sort. https://goo.gl/photos/2bfR42xUNvAYpP6T8
Comments for Brett - I would put a switch in the ground connection to the Vanner, so you can turn it off. I would probably not use fuses in the cable to the start batteries, so that if you need to use the house bank to start the bus the inrush current to the starter motor doesn't risk blowing the fuse. My battery switch is a combiner, so that I can turn power to the inverter completely off if I want to. I have off, house bank, or house plus starter bank. I also love the bus pictures!
Brian
I have an 85 Eagle and want to put my batteries in the area where the bus ac was located and my inverter in the bay in front of the tag axel.
I was wondering if that would be too far apart!
Sorry for highjacking this thread but I felt it was relevant.
Wes
The answer is it depends. What is most important is the current that you will draw from the batteries to the inverter. That depends on the voltage and the wattage of the inverter. Pretty much if you are 12 volts and over 1,000 watts, the distance is too long if it's over three to five feet. You can get around that by up-sizing the cable, but at some point you really need to have the inverter close to the batteries. 24 volts cuts the amperage in half, of course, and really reduces the voltage drop that you get between the batteries and the inverter, and increasing the wattage drawn from the inverter adds to the current and increases the voltage drop. Cable size capacity is measured in amps of current, called "ampacity", so you need to do the math to figure out what your loads are and what your draw will be. Then you can measure your distance, consult a voltage drop table on-line, and have your answer for your situation.
Brian
Quote from: bevans6 on July 19, 2015, 03:36:31 AM
Comments for Brett - I would put a switch in the ground connection to the Vanner, so you can turn it off. I would probably not use fuses in the cable to the start batteries, so that if you need to use the house bank to start the bus the inrush current to the starter motor doesn't risk blowing the fuse. My battery switch is a combiner, so that I can turn power to the inverter completely off if I want to. I have off, house bank, or house plus starter bank. I also love the bus pictures!
Brian
Thanks Brian, my switch is the same. In my setup, will the Vanner back feed and equalize the starter batteries? Is that the influx you are talking about?
Hi Brett. No, as drawn the Vanner will only equalize the house bank - in other words supply +12V current to equalize anything drawn by 12 volt loads - but if the combine switch is thrown it will draw +24V power from both the house bank and the start bank to supply that +12 current to the load. Which is fine, in my opinion. The in-rush current I referred to is the high current spike that any motor has when it first gets switched on and before it starts to spin (and create its CEMF for the electron geeks). This is the reason that there is never a fuse or breaker in the main cable from the batteries to a starter motor on about any vehicle I can think of. If you have the switch set to "combine" and the master battery switch off (it's gonna happen, it happened to me by accident) then if you start the bus it will start from the house bank alone. Depending on things, that stands a good chance of blowing those fuses. You don't need two fuses in series anyway, adds nothing but lack of cash in your wallet to the equation. You show a fuse before the switch and a second fuse after the switch. One would do, and I have none in that location in my setup.
The switch in the Vanner ground is to turn the Vanner off. If it's connected it always draws some power, and if a battery starts to fail it can kill the whole bank trying to keep a dying battery equalized. Again, happened to me.
Brian
Brett: Thanks for the pictures and the diagram, this will really help me alot. I enjoyed the bus picts, I have twin sisters just about the age of the young lady in your pictures and look forward to the day we can take them busing! One of them tried really hard to make an appearance in one of my bus videos! Your system looks like you feed 24 volt to the inverter? My inverter is only rated for 12 volt input. Maybe I'm missing something, but I don't understand how you are isolating the 12 and 24 volt, or is that the Vanners job?
Brian: Appreciate the details and your input on Brett's system, I'm starting to take notes and print off pictures to help me put this all together. Can you guys tell me what a Vanner is? I Googled it and Wikipedia thinks its a guy who builds vans LOL. How is your generator working for you? I Goggled it and I really like the price, if it is working out for you and is as quiet as they say, I would really consider something similar, if not the same thing.
http://www.vannerinverter.com/battery-equalizers/ (http://www.vannerinverter.com/battery-equalizers/)
Something I wrote a few years ago;
http://busnut.com/forum/index.php?topic=1586.0 (http://busnut.com/forum/index.php?topic=1586.0)
Brian
Thanks Brian: It looks like I am going to have to figure out how to rewire Brett's system to work with my 12 volt input inverter.
Mike, you pretty much can't do what Brett and I did with a 12 volt inverter in a 24 volt bus like an MCI. The reason is that our system is built around using the bus to power the inverter and charge the batteries at 24 volts and run the roof top air conditioner on the road. That is the heart of the design. With a 12 volt inverter you need to build your house bank at 12 volts and figure a way to charge it, and you can't reasonably run the inverter at 12 volts from the 24 volt bus alternator. If you can, I would move to a 24 volt inverter as the heart of your system if you plan to run the MCI bus alternator as the charging system and power source for your setup.
Most people who run 12 volt inverters in an MCI (or other 24 volt bus with the big alternator) keep the battery banks separate and run a separate 12 volt alternator, don't bother using the engine to charge the house batteries at all, or you can connect a Vanner in the battery charging mode I outlined in my article. Given that it takes around 165 amps of continuous 12v current to even consider running a roof top AC unit (my killer app, my personal reason for building the system that I built) you can see that you would need a huge 12 volt alternator to do that, and a typical Vanner is around 60 amps max, and not continuous at that level.
Brian
Thanks Brian: Yea, I was starting to get that sinking feeling looking over Brett's diagram. I was looking forward to using a roof mount AC while going down the road, an also running the fridge. I could move up to a 24 volt inverter, but it means this project will have to be put on hold for now while I come up with the funds to due so. I can still go ahead with all the breaker panels and circuit wiring, I have a 30 amp converter I could use to test my circuits, but I guess the system will have to be incomplete until I can upgrade my inverter. I would like to thank you and everyone who had offered their advice, I have decided to install the inverter in the basement and now I have a good plan in place for where I want to put everything and why.
Anybody have any advice on just what inverter would be a good choice, and where is a good place to purchase one?
Magnum or Xantrex.
The solar folk on the Northern Arizona Wind & Sun forum generally prefer Magnum these days over Xantrex, if only because of customer-service issues. Magnum always scores high marks for good helpful customer service, but Xantrex has not done so well since being taken over by Schneider . . .
For a lot less money than new, one can buy factory-refurbished Magnums from Wholesale Solar. I got my MS2000 this way, and it cost less overall than buying a separate Cotek inverter and charger. I would rather have a refurbed US-made repairable unit than a new Taiwan-made unit that may or may not be repairable.
John
You can always put a 12 volt alternator on to charge your house batteries, a lot of Prevosts are this way
QuoteYou can always put a 12 volt alternator on to charge your house batteries, a lot of Prevosts are this way
My son and I were discussing this very possibility. I dont think it would be that difficult, but I was wondering if I would be able to run the air conditioner and the fridge? I could go without the AC if I had to decide between the two, but would like to have the option of running both if I could. What do the Prevosts guys run for an alternator?
Quote from: mike802 on July 21, 2015, 03:46:14 PM
My son and I were discussing this very possibility. I dont think it would be that difficult, but I was wondering if I would be able to run the air conditioner and the fridge? I could go without the AC if I had to decide between the two, but would like to have the option of running both if I could. What do the Prevosts guys run for an alternator?
130 to 170 amp alternator should be able to maintain 2-3 8d batteries under load..
so if that amount of batteries will run your needs for an hour or two static...then my guess, it will run them under way.
if i want AC i just run my generator...uses .75 gallons per hour...about 11-12$ a day while driving.
the numbers don't make sense to me to dedicate batteries inverters and build time to go any other way.
You need to plan on 165 amps of DC power to run an air conditioner at nominal 12 volts. Add 15 to 20 amps when the refrigerator is on. The thing with alternators is they aren't all designed to run at continuously at full rated power. A typical car or truck alternator will start to overheat if you run it continuously at over 50% of rated output, so you need to look for heavy duty continuous power ratings. They do exist, obviously. What you want to do in your design is make sure that the alternator is large enough to run all of you loads with some headroom. If you draw from the batteries at idle, when the alternator output is low, that's fine - but you definitely don't want to be drawing from the batteries with the alternator at full output. Unless the alternator is designed to run at 100% output continuously it will fail, perhaps spectacularly.
Brian
Thanks guys: