confusion with my electrical system

[funkill]

I did a few google searches to try to find some clarification, but the posts I read that came up are confusing me even further. I hope you can bear with me - this is my first trailer and I am not particularly electrically-inclined.

I read some articles on “RV electrical systems” and thought I understood what happened with the converter, inverter, battery and shore power. But I’m definitely missing something. I believed that my 73 Overlander came equipped with a Univolt system that would convert shore 120v to 12v (DC current, right?), except on the A/C & like. And, I thought the Univolt also had a charger to maintain the battery charge. I basically thought the univolt was a converter/charger. Then, an inverter could be used in the 12v plugs to power 120v items (when boondocking and/or on shore power). My thought is that a converter *converts* 120v to 12v and inverter *inverts* 12v to 120v. ….I’m guessing the charger needs 120v to charge the 12v battery.

My Overlander has a deep cycle battery (not sealed) and in the adjacent compartment, an independent converter (purchased by PO) and a fuse panel with about 5 or 6 fuses. I found what I believe is the 120V panel in the bathroom, with two circuit breakers.

After towing her home I secured shore power. Everything seemed to work well – A/C included! Though it cycled in a peculiar way (question for later). I unplugged her for about 2 days, then plugged it back in. Inside the A/S, the 120v house fan, light and radio were working fine. But, when I turned on the three original overhead lights (at the vents) dimmed substantially!!!! There was no change in the 120v items. I noticed the battery showed low on the interior control panel. I figured that, even with a low battery, the 12v overhead vent lights would be unaffected. And I can’t figure out why the battery would have discharged so quickly. I did leave the house table fan, light and radio plugged in while the A/S was disconnected from 120V. Could residual draw from those three items affect the battery so much? Oh, I did notice the A/C buzzing while in the OFF position after I reconnected to shore power. Any idea what is going on?

I asked the PO about steps for recharging the battery using the charger. And I sort of described the problem. His response was that when the A/S was new “she had a charging system like you describe. Somewhere along the line it was removed. I don't recall the 12 volt lights going dimmer when the battery was charging.” Communication error in that I was not charging the battery when the lights dimmed. Sorry this got so long …. sigh.

[purman]

So did the PO say the system was changed?
How new is the battery?

Most don't have inverters in them I could be wrong on this though.. Mine doesn't and neither does my friends 2004 Safari.... Plus you would zap your battery pretty fast going to 120v and plugging something into it.... like a toaster or hair dryer...
And yes you do need shore power to charge your battery, It should also charge while you drive but not very fast...

[azflycaster]

The first thing I would do is check the condition of the battery. Most likely the output of the converter is tied to the battery and the 12 volt systems at the fuse panel. If the battery has an internal short (bad cell) it could pull the output of the converter down to the point where the lights might dim. You could also disconnect the battery and see if the lights work, that would tell you if the converter is working at all.

[garry]

You have it figured out;
Converter= 120VAC to 12VDC

Inverter= 12VDC to 120VAC

When on shore power the converter provides 45/60/80 DC amps depending on the converter. It also charges the battery.

It sounds to me like you may have a battery charger and not a RV converter. Most chargers won't supply the amps a converter provides.

I agree with azflycaster you most likely have a bad battery.

Garry

[Ramp]

The Univolt dose a piss-poor job of charging the battery. Most of the time it melts the battery down (mine killed a brand new Optima gel battery). Best fix is to dump the univolt and buy a new converter that will not kill batteries.

[funkill]

The battery is less than 6 months old... but too dark now to check the condition of the cells and see if any are dry. I don't have a way to check the battery myself, but I can get someone to help me with that.

There is definately an individual charger laying in the compartment adjacent to the battery. This same adjacent compartment has a glass fuse panel. The charger is not permanently connected to the battery, but requires me to hook up the clamps for charging.

Would it be reasonable to believe that, since there is no OEM charger, there is no coverter either? I was thinking that all the regular home-style receptacles inside were actually only providing 12v because it was going through a converter --- heck, maybe I'm really getting 120v at those receptacles! I guess it will take a meter to figure this out! Thanks for the help thus far, I will report back with findings soon!

[azflycaster]

The home style outlets will be 120 volts ac. A 12 volt DC outlet is round like a auto cigarette lighter. You should have about 3 of these in your trailer. I have 4, but I added one.

Sounds like the PO might have tossed the converter and charged the battery as needed. Not the best solution. Your battery at this point might just need a charge.

Once you determine what you have it will be easy to figure out what you need. Don't worry too much about the original converter being gone, they were not that good to begin with.

[funkill]

Till I can really look at the parts tomorrow... here's some pics of what I'm working with... I don't know what the univolt system is suppost to look like... but I don't see anything other than the battery, independent charger, and fuse panel. I can't really see what's behind the fuse panel - but that's where I assumed the univolt system was located.

[Jim & Susan]

Looks like a battery charger, not a Univolt. Give me a minute and I'll get a picture of the Univolt and it's proper location. That charger may be frying the battery by constantly charging the battery without ever shutting off.

Jim

[Jim & Susan]

Try this again. Messed it up the first time.

The Univolt mounts over the battery box and under the bathtub.

Jim

[azflycaster]

The 12 volt distribution panel (fuse block) looks like the original. There should be 2 terminals on the back side that would connect to the converter.

[Lumatic]

Originally Posted by funkill

After towing her home I secured shore power. Everything seemed to work well ? A/C included! Though it cycled in a peculiar way (question for later). I unplugged her for about 2 days, then plugged it back in. Inside the A/S, the 120v house fan, light and radio were working fine. But, when I turned on the three original overhead lights (at the vents) dimmed substantially!!!! There was no change in the 120v items. I noticed the battery showed low on the interior control panel. I figured that, even with a low battery, the 12v overhead vent lights would be unaffected. And I can?t figure out why the battery would have discharged so quickly. I did leave the house table fan, light and radio plugged in while the A/S was disconnected from 120V. Could residual draw from those three items affect the battery so much? Oh, I did notice the A/C buzzing while in the OFF position after I reconnected to shore power. Any idea what is going on?

I asked the PO about steps for recharging the battery using the charger. And I sort of described the problem. His response was that when the A/S was new ?she had a charging system like you describe. Somewhere along the line it was removed. I don't recall the 12 volt lights going dimmer when the battery was charging.? Communication error in that I was not charging the battery when the lights dimmed. Sorry this got so long ?. sigh.

How old is the battery?
Check the electrolyte level in the battery and have the battery load tested.
Yes those things you describe can drain the battery in a few hours

You've got the general principle down of how the system works.

From what I can see in your photo the original charging sytstem is there, not removed.

[funkill]

Well, I got into the respective compartments this afternoon and confirmed that there is no univolt system in place. The fuse panel is intact, and the battery is hooked through there... I was able to charge the battery using the independent charger.

Question: should I have any concerns about the current setup? And is there anything else that I need to check? Thanks for your help - this is really making me crazy.

[azflycaster]

The setup you have now works, but it is not the best solution. A 3 stage converter will make thing much easier to deal with and your battery will like it too.

[ronstory]

... and Randy at www.bestconverter.com can set you up wit Xantrex converter with the 3 stage charger. Randy's helped me out after my adventures with the "univolt" I found in my 75 Safari.

http://www.airforums.com/forums/f449...ari-43821.html

[Smokin Camel]

Nothing to the electrical system in an Airstream . Most of it is just remembering basics.

Just pay attention and keep to the schematics in the manual. Oh and don't do what I did back when I was just called the camel!

Got the green wire and the black wire confused, then there was something about the 4-3 generator plug and something about 3 phase. not a good day The AC ran so hard I got ice crystals dangling from the cabinets Everyone started calling me Smokin Camel that afternoon. In fact it was right after the green wire-black wire thing

Do try a 3 phase battery charger, I got one from Randy and it was one of the best investments I made. Not to mention taking 30 Lbs. off of the rear area.