Inverter / Charger Newbie

[nbk3ad2]

Hey Guys!

I FINALLY bought my first Airstream! I always thought they were so cool when I was a kid and now I have my own to restore. I'm new to this forum site, so please go easy on me - I have a million questions and you all seem to be extremely educated (my hereoes). I definately need some help on some things.

My trailer is a '64 Tradewind and I've just completed teardown and am strategizing what systems I want to put in. My goal is to make it as modern and convenient as I can within my budget - And when it is finished will look and function like a brand new trailer. It will have tankless hot water, black and grey tanks, electronic dump valves and possibly a vaccum generation toilet system. I'm pretty confident with all the plumbing and waste systems but electrical is not my strongest point. All the amps this, watts that and volt whatsoevers is all a learning curve for me.

I've worked in construction and fabrication for as long as I can remember, but I have to admit not being an expert on electrical - especailly low voltage systems. Anyway, I've been reading all your posts and looking over the original diagrams of how these trailers were put together (yes I actually have the original manual for mine) and here's what I understand so far about the original setup...

2 sources of potential power - Battery or Shore
goes to> Swich in back of trailer

(First question - do the AC loads for the 120vac systems connect to their breakers before or after the Shore/Battery switch?)

if on Battery>
12vac systems work (lights, 12v appliances) AND
12vdc outlets work

if on Shore>
runs 120vac systems AND
goes through converter and runs 12vac systems or 19vac switched pumps/fans AND
runs 12vdc systems AND
charges the battery


What I want to do is setup the trailer primary to be running at a full hookup sites as we don't do alot of dry camping. However I may take some trips that will be "dry" and will want the trailer to function that way as well. I've seen lots of people using the ProSine Inverter Chargers, but from what I understand the are designed to run off of the DC Battery and INVERT the power to 120vac. Is this correct? There are so many inverters, converters, chargers and stuff out there that my head is spinning. I just want to understand from scratch how the whole thing is supposed to work. Any help or even a diagram of a modern setup would be great!

Sorry for the long post - thanks in advance for the help.

[silverback]

nbk3ad2,
You have the basic concept. An inverter will produce an AC sine wave from your battery 12 VDC source. I think the main thing you will want to do is calculate how many watts you will need and then find the inverter that will provide that. If you only have one battery I would upgrade to two deep cycle AGM types. I would also suggest a couple of Kyocera solar panels (if you're going to be boon-docking a lot).
-Ken

[Safari Tim]

First off I'd suggest Trailer 101

If you are going to be camping with power most of the time you don't need an inverter. As you know thats for getting 110vac from your batteries when your dry camping.

I'm not sure how deep into the restoration you are going. But modern pumps and fans do not use 19vac. Everything is pretty much 12vdc now days. When you are plugged in the converter chargers the battery while powering all your 12vdc stuff like lights, water pump, fans, etc.

I would suggest a new converter for part of your restoration. You can get a 45 amp - 50 amp model and easily retorfit it. This might be a helpfuld diagram.

Here is a great site that talks about RV power systems.

Good luck with your project!

[47WeeWind]

If you are like me, you have to read something more than once for it to sink in. Here's a great book to teach you about 12 volt electrical systems for RVs:

Managing 12 Volts: How to Upgrade, Operate, and Troubleshoot 12 Volt Electrical Systems, by Harold Barre.



You will refer to it often, so get it now before you wire your trailer. It is available for purchase from many places online, just do a Google search. Or check your local RV orientated bookstore.

[nbk3ad2]

Okay guys, here's what i've got so far - Inverter is for DC to AC usage, Converter is for AC to DC usage, right?

And just to add to things, I'm planning on a COMPLETE restoration teardown so I can wire it from scratch how I want.

Also, how do I calculate the Watts I will need and should I consider putting in and inverter AND a converter or is that counterproductive?

thanks

[Phil Gobie]

In am also relatively new but what I have found so far is for most systems you don't want to reinvent the wheel. Most of the basic systems (even from 1964) that are found on the AS are well thought out and work well. That said allot of the systems like the converter chargers have been improved and the chargers are three stage etc. As for the Inverters I thought initially I would use a inverter charger but after research I stuck with a converter. The converters are more efficient and most of the items I thought I wanted a inverter for the are available in 12 volt. I found a 19" LCD TV w/a DVD player built in. I am using an auto stereo connected to the TV for simulated surround sound. I also added a Intili meter so that I can monitor the 12 volt load, battery charge and have a better feel for what is happening with the 12 volt system.
As for your water heater I think you will find that a camper style water heater (gas) will serve you best. Tank less heaters need very large energy source so they can heat as they are used. Storing water in the tank with a smaller heat source is easier to live with. A 110 volt in-line heater will give a very low flow and minimal heat gain. It will also max out your panel.
Enjoy your exploration and I am sure you will find what will suit you best Phil

[nbk3ad2]

Thanks Phil,

does that apply also to the RV500 tankless water heater? Everything I've read on them seems fantastic and they are designed to run on propane...

[silverback]

Phil is right you only need an inverter if something you must have is not 12 VDC (like a coffee maker?). Also to truly measure your current draw you want a meter that will give you amp hours. Then you can subtract (turn off) appliances/devices to determine their draw. Do a forum search on amp hour meter. You can always get a small quiet Honda or Yamaha generator for AC.
-KL

[nbk3ad2]

okay, now i'm getting it - thanks for the tips

I think I've got what I'm looking for now - I intend to run a regular tv and one desktop imac (and probably my powerbook at night to charge). Those will both need 120vac and so will the microwave. Should I install both an inverter AND converter with switches so that all my bases are covered regardless of where I'm camping?

[prairieschooner]

Volts X Amps = Watts
12 volts DC X 5 Amps + 60 Watts
100 Watts (Light Bulb) / 120 Volts AC = .83 Amps
100 Watts / 12 Volts DC = 8.3 Aps

[prairieschooner]

The Microwave is a large Power Draw, look for a smaller unit with less Wattage so you can use a smaller Inverter, but you will need to size the Inverter for your Expected Wattage = a little.
The Cool part is if you get a good Inverter you will be able to buy one with the Charging Function. The Charging Function on these Inverters is capable of Charging the Different Type of Batteries (Yes Another Decision!). I have chosen AGMs (Absorbed Glass Mat and you could simply Google this for more information).
All of this having been said, I have also chosen a Generator rather than an Inverter.
Steve

[Phil Gobie]

Your Imac will have a 12 volt charger available I use one with my laptop in my truck every day. I had an inverter before I got the 12 volt converter for my laptop and it was noisy and the batteries would run down much faster.
Look for a TV that has a converter on the cord. Lots of (reg. TVs) come with a converter on the 110 cord set. Look at the rating plate and you will see the actual voltage and watts.
As for the tank-less heater I am not familiar with that brand and model. But what may stop you is the peek BTU rating and the venting it may require. Check it out very carefully. If you have a spec sheet or broacher post it or send it to me and I would be happy to take a look. I am a plumber by trade.
Phil

[nbk3ad2]

Originally Posted by Phil Gobie

Your Imac will have a 12 volt charger available I use one with my laptop in my truck every day. I had an inverter before I got the 12 volt converter for my laptop and it was noisy and the batteries would run down much faster.
Look for a TV that has a converter on the cord. Lots of (reg. TVs) come with a converter on the 110 cord set. Look at the rating plate and you will see the actual voltage and watts.
As for the tank-less heater I am not familiar with that brand and model. But what may stop you is the peek BTU rating and the venting it may require. Check it out very carefully. If you have a spec sheet or broacher post it or send it to me and I would be happy to take a look. I am a plumber by trade.
Phil

To clarify, the IMAC is a desktop computer - 110vac as far as I know but I haven't researched a 12vdc option for it. I do know that the laptop (powerbook) DOES have a 12vdc charger and that is what I will plan to use for it. The TV I'm using is a samsung 19" lcd tft and I don't know about the 12vdc option for it, but I'll check.

As for the RV500 tankless water heater, here's the best link I found for it.

http://www.gaswaterheaters.com/boats...V500/index.htm

Thanks again for the advice.

[Phil Gobie]

Looks great! The only down side might be the price. It looks like it is more than dble the price of a tank type. For me it would be a tough choice if I had to by one any way. The tank type are less $ but it would seem this one may have some advantages. Guess you have to weigh that out. The only thing I can tell you is we have not had any issues with the tank type. Remember that unless you are connected to sewer hookup you want to limit your water volume any way!

[nbk3ad2]

Thanks Phil,

I do plan on being hooked up to full service rv campgrounds MOST of the time so water volume isn't a problem. thanks for checking the heater out for me - I think I can fit it into my budget so it's likely I'll go the tankless route - it will also make winterizing easier.

Also, since you are a plumber, how about this setup: I'm putting in a grey tank and a black tank which will both have electronic dump valves that will tee into a main outlet on the side of the trailer which I can manually hook up at full hookup sites and then just push a button when I want to dump each tank from inside the trailer - no mess! Do you see any issues with that setup?

[lewster]

Originally Posted by nbk3ad2

Thanks Phil,

does that apply also to the RV500 tankless water heater? Everything I've read on them seems fantastic and they are designed to run on propane...

Rather than beating around the bush, why not ask one who uses it.....ME!

I've been using them since 2000, first in my 40'Monaco Dynasty and now in my 19CCD. Installation was no problem and it works flawlessly. The main power source is propane , not electric so it is great for boondocking, plus it draws nothing until there is a demand for hot water.

I highly recommend it!

On the electric side, I would stay away from an inverter unless you plan to carry a very large battery bank. And speaking of batteries, I would use a pair of Lifeline GPL-4C 6 volt golf cart batteries in series as your power bank. They have the longest run time of almost anything out there, no outgassing and they will sustain many more charge/discharge cycles than just about any other battery.Lifeline Marine Batteries - AGM Marine Battery

[Phil Gobie]

Sounds like it would be a slick set up. The challenge will be setting up reliable check valves so that one side does not wash back up into the other. Swing checks are what you would need to use unless the pumps have something integral that prevents back-flow. As usual the easier it is from the control panel the more complicated on the back side. I am using the Sewer Solution and we leave the Grey water tank open and the black closed till the tank is 50% or more. It is pretty simple and clean. I am happy for now. The main advantage to the electric pumps is there ability to pump up hill. The Sewer solution will pump up a couple feet but it is limited there. It does not require any electrical power though and still macerates using water pressure. They are about 100.00 you may want to check it out.

[nbk3ad2]

WOW - i got my first RIVET! I have no idea what it means, but I'm excited! And i didn't even have to shave it!

Anyway Phil, i know this is quickly turning into a discussion about plumbing, and I might have to start a new post somewhere else on the forum, but for now, i'm just wondering - i wasn't aware that a pump was needed on the black/grey tanks and i was just planning on gravity to do the job and use remote sprayers installed in the sides of the tanks to clean them out - am i mistaken here? the only thing mechanical on the setup was to be the electronic dump VALVES - all they do is slide open much like a pocket door allowing the waste or water to exit the normal path which would be into a Y style fitting and straight out the hose (already in place) that way I could leave the gray valve open and only open the black one when it's 50% full.

[Phil Gobie]

I just re-read your previous post. I thought i read something about a electric pump but I see you just said valve. That should work fine you just want to open one at a time. I would like to see the valves you are referring to they sound interesting. I think in the end the manual ones are fine by me because I will still want to be out there watching what is happening. The idea of macerating has the advantage of using a small smooth hose and getting away from the stinky slinky 3" hose. So you could still use the sewer solution or one like it you will just want to run water through the venturi while you dump the black tank to break up the solids. PM me if you like and I will be happy to talk on the phone. It may be easier. Phil 305-992-5974

[nbk3ad2]

Phil, here's the best link I could find on the electronic dump valves:

Tote-Alongs

I'll hopefully call you later today - thanks for all the help!