Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-22-2003, 08:08 AM   #1
Patriotic
 
Chuck's Avatar

 
1973 23' Safari
North of Boston , Massachusetts
Join Date: May 2002
Posts: 4,547
Images: 260
12v problem

discovered a 12v problem this weekend while dry-camping. Apparently, my battery didn't have much of a charge on it, even though the trailer has been plugged in at my house for the last couple of weeks. I did check the water level before I left, and it was low, so I added water. then I hooked it up to my truck and drove for 4 hours. When we set up camp, I noticed that the interior lights were rather dim. tried to use my tv w/ the 12v plug (first time I've ever tried this) and it wouldn't turn on.

So, I figured that my battery must be toast. I plugged the trailer back into the truck, and the lights brightened up considerably. Still couldn't turn on the tv. (not the end of the world, but made me curious). I tested the 12v receptacle...phone charger lit up, so I know the socket wasn't dead. So I took the tv out to the truck, and plugged it in there. worked fine. I'm figuring that there still isn't quite enough voltage availble to the trailers 12v system, even while plugged into the truck. Why would this be?

the battery is a 1 year old deep-cycle marine battery; trailer still has the original univolt. I haven't had a chance to put a meter on anything yet, but I'm wondering if you electrical gurus might have any insight as to the likely source of the problem.
__________________

Chuck is offline   Reply With Quote
Old 09-22-2003, 08:17 AM   #2
3 Rivet Member
 
Join Date: Aug 2003
Posts: 158
Send a message via Yahoo to Fun-Lovin
I will give you my best guess. I would say your trailer may have developed what can be called a dead cell. This would cause it be be low on power. As for attempting to run the tv from the truck over the distance, once again a low battery will draw from the trucks system and consider the distance the power has to run to get to where you plug in your tv. The power company uses High Voltage lines to transport electricity but when it comes from the generating station (power plant) it is high amp low volt. They convert it to high voltage in order to transmit it. Amperage dont carry well over distance and you may be loosing the amperage needed to run the tv in the trailer from your truck. Im still going to go with the dead cell theory.
__________________

__________________
Greg
1976 Soveriegn 31'
F250 Turbo 7.3L Diesel
WBCCI # 3516
Fun-Lovin is offline   Reply With Quote
Old 09-22-2003, 08:19 AM   #3
Rivet Master
 
Join Date: Mar 2002
Posts: 1,485
Images: 19
You should not discount corrosion on the umbilical plug to the truck. And a weak battery can cause a voltage drop in the circuit. But...

If you are trying to run your coach 12v off the tow vehicle, you have to consider that it is a rather long run from the battery, through the chassis, through the umbilical, and then through the coach. A very heavy current draw (and a tv probably qualifies) could easily drop the voltage down too low.

If the coach battery is weak, replace it and then see where you are.

Mark
j54mark is offline   Reply With Quote
Old 09-22-2003, 08:45 AM   #4
Patriotic
 
Chuck's Avatar

 
1973 23' Safari
North of Boston , Massachusetts
Join Date: May 2002
Posts: 4,547
Images: 260
I re-built the umbilical last year, so it should not have any corosion, fwiw. There could be some elsewhere, though...like back at the univolt. haven't checked it yet, but I will.
I dealt with some corrosion problems in the 110 system earlier this year...had to replace the whole panel. But I didn't look at the univolt at that time, so there could be bad connections there from the same thing that caused the corrosion in the 110 panel. (I suspect just condensation and time; no sign of any bad leaks or anything back there).
Chuck is offline   Reply With Quote
Old 09-22-2003, 08:54 AM   #5
3 Rivet Member
 
71tradewind's Avatar
 
Join Date: Mar 2002
Posts: 172
Images: 4
Chuck I have encountered this EXACT problem on both of my A/S's here is a link to my post on this subject http://www.airforums.com/forum...&threadid=5972 .But to be on the safe side I would still check the output of the Univolt right at the Univolt itself .But keep in mind that it may say 12 volts but when you put it under a load it will drop .Now that mine are both repaired I can turn every light on and still remain at 12 volts .I hope this helps ! Tom
71tradewind is offline   Reply With Quote
Old 09-22-2003, 12:50 PM   #6
Rivet Master
 
wb13798's Avatar
 
2004 28' Classic
Currently Looking...
huntsville , Alabama
Join Date: Jul 2002
Posts: 866
Images: 1
get the battery checked. before you start on the airstream wal mart, auto zone, advance auto parts and zillion orher part places will check it for free. if you put water in the battery plan on charging it for 8 hours before taking a trip. 12.65 volts is what you want to measure with a digital meter for a full charge.lol
al
__________________
AL
2007 chevrolet 2500 duramax 6.6
allison 6 speed
2004 classic 28 WB , Pro Pride P-3 hitch
centramatics wheel ballancers 300-556
wb13798 is offline   Reply With Quote
Old 09-22-2003, 03:47 PM   #7
3 Rivet Member
 
71tradewind's Avatar
 
Join Date: Mar 2002
Posts: 172
Images: 4
I agree with wb13798,whole heartedly and was assuming this was already done !
71tradewind is offline   Reply With Quote
Old 09-23-2003, 06:37 AM   #8
Patriotic
 
Chuck's Avatar

 
1973 23' Safari
North of Boston , Massachusetts
Join Date: May 2002
Posts: 4,547
Images: 260
Do those places do a "load test" on the battery?

I got out my meter thismorning, and did some checking...got some weird readings. (trailer has been un-plugged since driving it home sunday afternoon) At first, the battery read 12.5v, then the meter started climbing. it went slowly up to 14.5, which I thought was very strange. So I plugged in the trailer to see what the univolt would do, and the voltage jumped to 15.2. Ok...it should be higher...but doesn't that seem too high? is my meter f'd up? I unplugged the trailer, and checked the ac voltage on the 75 foot extension cord that goes to my house (12-guage wire in the extension). The voltage read 138, which again, seems high. wondering if I need a new meter. I'll check it with another meter when I get home tonight.....

Or perhaps the battery just needed another 4 hours of charge, which was provided by the return trip home. Before this trip, I probably had it plugged in for too long, too much water boiled off, and that affected the charge.
Chuck is offline   Reply With Quote
Old 09-23-2003, 09:03 AM   #9
3 Rivet Member
 
71tradewind's Avatar
 
Join Date: Mar 2002
Posts: 172
Images: 4
Chuck I would first take the battery out of the trailer and take it to Wally Mart or Peppy Boys and have them do the load test .Then check the battery in your volt meter ,if you replace the battery in the volt meter and you still get weird readings I would try barrowing one from a friend . 15 volts off the Univolt with a load "ie. the battery " sounds a little high mine reads from the mid 12 volts to mid 13 volts.See the problem here can be a combination of bad Univolt and a bad Battery as a result of being hooked to a bad Univolt ,this was the case with mine after 2 batteries I decided to look at the Univolt ,the show stopper in my case was the Univolt appeared to be working .It even worked fine with a few lights on, this decieved me. Anyway one day I decided to take the Univolt out and found one lead goin to the caps was completely blown off......Not a GOOD Sign...too say the least.So the logical thing to do was to solder it back on ....which i did.This work great for .......6 hours....then the it blew the cap completely. So I replaced all 3 caps and have had no further problems.Till I bought my 2nd AirStream which is a 74 tradewind and guess what ........same exact problem. Ok well i just happened to have a spare Univolt in my garage and decided to power it up and You guessed it same thing. So now I have 3 perfectly workin Univolt at a cost of roughly $35 each and about an 1/2 hour work per Univolt.I hope this helps Tom
71tradewind is offline   Reply With Quote
Old 09-23-2003, 09:40 AM   #10
Patriotic
 
Chuck's Avatar

 
1973 23' Safari
North of Boston , Massachusetts
Join Date: May 2002
Posts: 4,547
Images: 260
couple of questions:

what is a good source for these capacitors?

what should the output of the univolt be without the battery connected?
Chuck is offline   Reply With Quote
Old 09-23-2003, 09:40 AM   #11
uwe
418
 
uwe's Avatar
 
2007 25' Safari FB SE
1958 22' Flying Cloud
1974 29' Ambassador
Yucca Valley , California
Join Date: Jun 2002
Location: 1963 26' Overlander
Posts: 4,767
Images: 41
Send a message via Skype™ to uwe
A quick word of caution on digital multi meters!
I own 4 of them. One from Radio Shack, another from Wavetek, a cheap yellow one from Harbor Freight, and an OTC with tach/dwell.
The Wave tek and the OTC seem to agree on the actual voltage, within ~0.1V. The Yellow one and the one from Radio Shack strongly disagree with actual voltages, both A/C and D/C, Meter batteries new.
So please make sure your meter has good batteries and is accurate enough for testing.
__________________
Uwe
www.area63productions.com
uwe is offline   Reply With Quote
Old 09-24-2003, 07:04 AM   #12
Patriotic
 
Chuck's Avatar

 
1973 23' Safari
North of Boston , Massachusetts
Join Date: May 2002
Posts: 4,547
Images: 260
yep, I think my meter was funky. I tried it this morning with another one, and got readings that make more sense:

AC from house: 122v
DC on battery: 12.2v

after plugging in the trailer, the voltage at the battery slowly started to climb up to 13.1 (may have gone higher if I waited long enough, but I had to get to work ). So, I'm leaving it plugged in and will check it when I get home. We'll see what 11 hours on the univolt does......
Chuck is offline   Reply With Quote
Old 09-24-2003, 07:35 AM   #13
Site Team
 
, Minnesota
Join Date: Aug 2003
Posts: 7,473
Images: 59
12V problem

For lot's of information about voltages, charge rates, etc http://www.phrannie.org/battery.html
markdoane is offline   Reply With Quote
Old 09-24-2003, 09:02 AM   #14
Rivet Master
 
garry's Avatar
 
1969 31' Sovereign
Broken Arrow , Oklahoma
Join Date: Jan 2003
Posts: 1,441
Images: 7
You probably already know this but the univolt is a very simple charger and tends to overcharge a battery. Left pluged in to AC with out a batt cut off switch over time will ruin a batt.
If the batt is OK and the TV still dosn't work you will most likely have low voltage at the outlet under load and probably normal voltage at no or small load. This would be caused by a bad or corroaded connection somewhere between the outlet and univolt and it could be the at the fuse.

Garry
garry is offline   Reply With Quote
Old 09-24-2003, 03:53 PM   #15
3 Rivet Member
 
71tradewind's Avatar
 
Join Date: Mar 2002
Posts: 172
Images: 4
It is true there is not a charge circuit that prevents over charging,but this is not just a simple battery charger , It is a split phase power supply that works like a 2 phase ,by using only a single phase power source it has a second primary winding that is coupled with 3 caps,I know everyone thinks those caps are filtering ......but they are not ....rather they are used for phase shifting . These are really cool Clean supplies ,cleaner than switching supplies which is the most common type avil today.Plus it can deliver a true 45 amps at 12.5 to 13.5 volts. All it uses is a huge transformer "ie. lots of cooper" ,3 caps , and 3 diodes, The transformer is the expensive part .Only real down fall of these supplies is that they commonly hum from the windings ,this can range from a very subtle hum to a very annoying keep u up all night hum ,BTW the hum does not affect the perfomance of the the supply. But as Garry stated it will over charge your battery , I am workin on a simple circuit that will eliminate this problem. Chuck if I recall my supply put out about 13.5 volts with no load ,if I get a chance I will go out and check it for you just to make sure .But you still need to take the battery and have it load tested ,it is the only way you can be sure your battery is AOK.
71tradewind is offline   Reply With Quote
Old 09-25-2003, 07:07 AM   #16
Patriotic
 
Chuck's Avatar

 
1973 23' Safari
North of Boston , Massachusetts
Join Date: May 2002
Posts: 4,547
Images: 260
Quote:
But you still need to take the battery and have it load tested ,it is the only way you can be sure your battery is AOK
will do; its on my list. in the mean time, I'm trying to see if I can get a charge on the battery.

So, last night, after leaving it on the univolt for 12 hours, it read 13.2. I unplugged it from the univolt, and it started to settle down to around 12.6...kept moving up to 12.7 and back. I turned on a couple of lights in the trailer, and then the voltage dropped just a little, but below 12.6. after reading phred's poop sheet on the subject, I was aware that the battery would still be "stirred up" from being on the charger, so I let it sit overnight off the charger. This morning, it read 12.45, steady. So I plugged it back in to the univolt for another session. We'll see what it looks like when I get home tonight.

Oh, and 71: can you tell me where I can get these replacement capacitors, should it turn out that I need new ones?
Chuck is offline   Reply With Quote
Old 10-08-2003, 08:34 AM   #17
Patriotic
 
Chuck's Avatar

 
1973 23' Safari
North of Boston , Massachusetts
Join Date: May 2002
Posts: 4,547
Images: 260
Just wanted to report back on the conclusion of this saga....turns out that the battery was indeed "shot". I was able to get it to charge back up to a steady 12.65 volts, but it wouldn't handle any load at all. even a couple of the overhead lights being on would drop the voltage way down.

So I brought it back to Sears...had to deal with some guy with a thick accent that obviously didn't know anything about batteries their rinky-dink simple tester said the battery was "good". (I couldn't tell from looking at this thing whether it was a volt meter, or what. it just had lights on it to tell the monkey operating it "good" or "bad". ). After some prodding, I got the guy to put it on what I "think" was a load tester. whatever it was, it was a serious looking machine that did an exhaustive test, then told us it was going to take a half-hour to charge the battery. So I wandered off into the mall, and when I came back, einstein informed me that the battery failed the test, and needed replacement. They prorated it, so I only had to pay 30 bucks.
so thismorning, I put it in the trailer, and did a quick voltage reading...12.4 . I hope they didn't just give me another lemon. I plugged in the shore power so the univolt could charge it up....we'll see what happens.

Oh, and those funky readings from my voltmeter: turns out that was a bad battery, too. once I replaced it, my "138vac" from the house came down to 118v.
Chuck is offline   Reply With Quote
Old 10-08-2003, 11:12 AM   #18
Rivet Master
 
59toaster's Avatar
 
1959 22' Caravanner
Atlanta , Georgia
Join Date: Feb 2003
Posts: 2,197
Images: 22
I will not buy a Diehard ever again. In my service van I was lucky to get a year out of them.

Running Duralasts from Auto Zone in all my personal vehicles. Never had a problem. We even severly mistreated one by accident. left the lights on a ran it flat dead. Couldn't even get the dome light on. Threw it on the charger for about 5 hours and it made a complete recovery. The battery was already 3 years old and we sold the truck a year after that. The battery had a 3 year replacement warranty and 8 years totale with the last 5 being prorated. Think I paid $70 for it. It was a conventional 1,000 CCA . Biggest that would fit the vehicle (was for a deisel application) I haven't tried their deep cycles but I will once I get this coach back together.
__________________
1959 22' Caravanner
1988 R20 454 Suburban.
Atlanta, GA
59toaster is offline   Reply With Quote
Old 10-08-2003, 11:15 AM   #19
Site Team
 
, Minnesota
Join Date: Aug 2003
Posts: 7,473
Images: 59
12V problem

I guess i would use Interstates for starting and Trojan batteries for deep cycle. Just repeating what a long term gunkholer told me.
__________________

markdoane is offline   Reply With Quote
Reply

Tags
12v


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
electrical problem David Hall Electrical - Systems, Generators, Batteries & Solar 7 12-31-2003 08:46 PM
12V System....Sudden Death! Help, please Alan and Mardel Electrical - Systems, Generators, Batteries & Solar 6 12-13-2003 11:04 AM
No 12v Power wcdelorme Electrical - Systems, Generators, Batteries & Solar 13 05-11-2003 09:53 AM
12V question uwe Electrical - Systems, Generators, Batteries & Solar 16 09-05-2002 01:14 PM
Electrical problem resolved davidz71 Electrical - Systems, Generators, Batteries & Solar 5 08-12-2002 08:21 PM


Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.



All times are GMT -6. The time now is 02:49 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.