Somewhat puzzled by converter?

[Anniedog]

Tore couch out. Now can stare right at the battery boxes in 1988 Excella 29'. Also see the Magnetek sitting there. It is Mod 7455, series 7400, 5.5amp with output of 55 amps. It was put in in 2002. To be best of my knowledge it works as it should. However, if the trailer sits for a couple of weeks the batteries will die. They come right back when I plug in normal AC. But I had to disconnect it to remove some of couch stuff and found this: two normal brass terminals on the battery ON/OFF switch and there were THREE red cables connected to one of them and only ONE red cable to the other. And of course a power cord that plugged into a wall outlet.
And, one last thing: is it true Airstream's are something OTHER than negative ground? I saw something that confused me.
Don't want to get too deeply into this electrical stuff because it has been my experience that there are as many theories about some of this stuff as there are stars in the sky.
All works well now, but should I upgrade to a more modern unit while I'm down there??

[HowieE]

First if your batteries are going dead in several days they are most likely bad. Batteries that discharge below 8 volts and are recharged tend to "Sulfide" and are bad. If you want to check the batteries remove them from the trailer charge them for at least 24 hours and take them in for a discharge test.

As for the 3 wires on on of the battery switch. If you have 2 batteries one wire goes to each battery and one to the 12 panel. This is normal.

As for numbers of theories on electrical systems that is not the case. Electric is a mathematical science and there is only ONE way. Its is as exact a science as making change for a dollar. Then not everyone can do that either.

[garry]

If you have a cut off switch and leave it in the on position when unplugged from shore power the batteries will run down from parasitic loads such as CO detector, control board in refrigerator, etc.

If you have the cut off switch in off and they run down you have bad batteries.

What is the battery voltage when you say run down or are they completely dead?

Sounds as if the converter is doing what it is designed to do provide the 12V and charge the batteries.

Garry

[Anniedog]

I also forgot to ask: do you folks see any reason for me to upgrade my converter from the Magnetek in there now? It was put in in 2002 and I know there are fancier units available now. It appears to work just fine and I only consider it because I am re-doing the area etc.
Thanks.
Oh....and I KNOW electrical and electricity are hard science....its all the THEORIES that sometimes develop around the subject that are distracting! Ha!!

[DEITZ645]

Anniedog,
I will echo HowieE's and Gary's statements. I am not familiary with your converter, but in looking them up on the Internet it looks like the Magnatek that was in our '06 which boiled two relatively new batteries so I replaced it with a new 60 amp Intelli-Power 9260 and have had no problems (I also put the sme thing in our '87 and that was about three years ago). Your converter is probably a single stage charger that has a constant output which is sometimes tough on batteries when plugged into shore power for extended periods of time. The newer converters are three stage converters that lets the output of the charger "float" to meet the demands on the electrical system and the batteries charging needs.

You may want to look at this thread as it sounds like it is the same model converter and problem you are experinecing...

http://www.airforums.com/forums/f449...ery-46735.html

[HowieE]

If you replace the converter make sure you get one with a monitoring system. This will give you a visual check on just what the converter is doing, heavy charge, low charge, or storage charge.

Converters have a history of going out of regulation and Over Chargeing and thus boiling the batteries.

[Aage]

In this thread, the poster had a similar problem, and appears to have found that a fuse was dead in the negative side of the 50 amp line.

http://www.airforums.com/forums/f449...ery-46735.html

[garry]

To upgrade or not?

IMO.

1st you need to know what's going on with the batteries so have them tested.

The Magnetek my be OK however if it is a single stage charger then now would be a good time to replace it.

I replaced mine last year with the Intelli-Power 9260 and found it on line (e-bay) at a very good price.
There are several very good converters on the market today if you upgrade just make sure you buy one with a 3 stage charger.

Garry