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tn2 · 10-22-2007, 08:19 AM

Can someone help me with a light problem? I have a 1978 Argosy Motorhome. When I'm connected up to external power....such as at a camp ground.... it seems like my overhead ceiling lights start getting dim after just about 5 minutes of use. Also...the lights dim when any other electrical unit is turned on. I don't have a wiring diagram....and to be trueful...I'm not even sure if these lights are coming off the battery or house voltage (120). Think it must be battery.....in that case...shouldn't my internal battery charger....which by the way is the old original thing under the passenger seat....shouldn't it keep the battery charged? Should I convert over to a new inverter? The battery is a new, deep cycle type...but I only have one house battery....do I need two?

Thanks for your help
Charles

tphan · 10-22-2007, 08:56 AM

yup- sounds like a converter problem. An inverter, by the way, goes from 12vDC to 120AC, if I'm not mistaken. You want it the other way around. I'd suggest getting a new 'Intellipower" converter/charger- many members here have switched over to them and are pleased with the results. Good luck!

bkahler · 10-22-2007, 11:40 AM

Charles,

I agree with tphan, most likely your converter is bad. However check out all of your grounds on the dc system just to be sure. Bad connections can also give similar results.

Keep us posted as to what you find.

Brad

Inland RV Center, In · 10-22-2007, 02:31 PM

Quote:

Originally Posted by tn2

Can someone help me with a light problem? I have a 1978 Argosy Motorhome. When I'm connected up to external power....such as at a camp ground.... it seems like my overhead ceiling lights start getting dim after just about 5 minutes of use. Also...the lights dim when any other electrical unit is turned on. I don't have a wiring diagram....and to be trueful...I'm not even sure if these lights are coming off the battery or house voltage (120). Think it must be battery.....in that case...shouldn't my internal battery charger....which by the way is the old original thing under the passenger seat....shouldn't it keep the battery charged? Should I convert over to a new inverter? The battery is a new, deep cycle type...but I only have one house battery....do I need two?

Thanks for your help
Charles

There are two main 12 volt fuses in your univolt.

One, is in the charge line.

The second is between the univolt and battery.

From what you describe, it sounds like the fuse from the univolt to the battery is open.

I would suggest you check it before you buy another univolt.

By the way, the new style univolt that Airstream has used for years, is solid state, therefore is quiet, at least until the cooling fan engages.

Andy

rickandsandi · 10-22-2007, 03:03 PM

Charles- from your brief description it does sound as if when you plug into your shoreline the power is not connecting to your system. Best wat to test is to plug into the shoreline power and then plug a light into your 120V outlet and see if it goes on. If it does not go on you have confirmation that the 120V is not getting past your univolt.

HowieE · 10-22-2007, 03:21 PM

You did not mention how long the lights work when you are just on the batteries. Sounds like you are just running on the batteries but the following will test things out.

Get a voltmeter and before plugging into the shore check the voltage on the output side of the convertor. This should be your battery voltage about 12.7. If not check the voltage at the battery again about 12.7. If you see voltage at the battery and not at the convertor you have an open wire or fuse between them

If that test is OK, battery voltage at both places, plug in the MH and again check the voltage at the output of the convertor. It should be at least 1 volt higher than when you check at that point while not plugged in. If you do not see a higher voltage the convertor may be Toast.

If you have a higher voltage at the convertor check to see if that same voltage is getting to the batteries. If not clean and tighten all connections from the convertor to the batteries and check again.

Poor connections can cause a voltage drop and offer a high resistance to the system.

tn2 · 10-22-2007, 05:07 PM

Thanks to all for your help....it's raining cats and dogs here in Tennessee...and we really need the rain...but I don't want to do any troubleshooting until it stops. One other bit of info I should add....

After seeing the lights go dim....my LED test panal will show the battery only 3/4 charged. I turn the lights off and in a matter of minutes the battery will recharge to full charge.....I would take that to mean at least the univolt is charging okay. It seems the lights are using more than what the univolt can put out. I would think that the univolt should be able to supply power for many items to be used at the same time. Like I have said....while the lights are on...even turning on the smallest of light bulbs in another area of the RV causes the overhead lights to dim even more. It does sound like the univolt is not putting out enough....but I wonder how it is able to recharge the battery so quick if it gone bad. Thanks again for your thoughts....I will check those fuses and the grounds soon as it quits raining.

Charles

HowieE · 10-22-2007, 06:12 PM

The voltage dropping to 3/4 while the lights are on and back up when off is normal.

Check the voltages as I mentioned above then let us know what you find.

rickandsandi · 10-23-2007, 11:03 AM

Gentlemen- do not be mislead by volts. You need to measure amps!

HowieE · 10-23-2007, 11:31 AM

Quote:

Originally Posted by rickandsandi

Gentlemen- do not be mislead by volts. You need to measure amps!

His question refered to the Display showing a drop in Voltage while the interior lights are on and then returning to display a full charge once they are off. The sensitivity of the panel is such that the first light lite will cause the panel to display a reduction in the battery voltage.

As long as he is not seeing this drop in the display when he is plugged into shore power this is a normal situation. If that occured while plugged in I would assume the convertor was not working at all and he was just running on the battery.

Yes over time current flow is what will cause a battery to reduce it's charge and thus have a reduced voltage.

tn2 · 10-23-2007, 02:29 PM

Well the rain has finally let up.....
I checked voltages at the distribution panel and found that all fuses are good. With nothing turned on I get 13 volts at the input to the aux battery. When I turn on the furance it goes down to 10 volts. Turn the furance off and the over head lights on the voltage goes down to 10 volts. I figure this must be saying that the univolt is not keeping up with the demand. The univolt is rated at 50 amps....but I'm pretty sure the lights do not require 50 amps....so I'm guessing the univolt isn't putting out it's rated capacity....time for a new converter.
Has anyone swapped out their univolt for a different unit? Is it an involved job to make the switch. I can get a new 80 amp converter for about $250.

Your help is appreciated
Charles

HowieE · 10-23-2007, 04:30 PM

You may be right but before you spend $200.00 go back to my post above and complete the troubleshooting. Lets prove the point before spending the money.

Was the MH plugged in during yor test? If so did you measure the output of the connvertor?

10 volts with interior lights on is a bit much. Where did you take that measurement, at the battery or at the fixture? If at the fixture you may be looking at some poor connectiions in the circuit. If at the battery it may be a bad battery. How old is the battery? Is there any indication the battery side have swelled out, an indication of ovre heating ofter from an unregulated convertor.

tn2 · 10-23-2007, 05:48 PM

On my univolt unit there is no conveient place to check output voltage. Keep in mind this is probably the original (1978) converter...it's old. I took the readings in the DC power distribution panel under the passenger seat. I took reading on the red wire coming from the converter. The Aux battery is about a year old but I bet there's not more than 40 hours of use on it....it is of the deep cycle type. This RV was manufactured with only one Aux battery....I know many RVers have install a second aux battery. (maybe that is what I need to do????). Another possible clue.... when I operate the lights with engine running....the lights are nice and brite.

richinny · 10-23-2007, 05:50 PM

i'll echo the battery test including the cleaning of the battery terminals.

tn2 · 10-23-2007, 05:59 PM

Howie....Because there is no point on the converter to check output voltage...I did what I thought was next best thing....followed the output wire to the DC power distribution panel and checked voltage there. Like I said....with nothing turned on I get 13 volts...granted...that's not amps...but I assume that's pretty normal reading. Now....when you turn on the lights that reading drops to 10 volts. I would think...in order to operate the lights plus keep the battery charged....it should continue to put out somewhere around 13 volts. I will run the test you gave but I ran out of time today....thanks much for your help

Charles

tn2 · 10-23-2007, 06:02 PM

Thanks Ricky.... I will check voltage at the battery tomorrow

tn2 · 10-24-2007, 05:19 PM

Okay....here's what I get when I check voltage at the aux battery post.

To start with....the ground power (120) has been connected for 24 hours.

I started with unplugging the ground power and took a reading...I got 9 volts. Then I plugged in ground power and I got 13 volts. Then I turned on the lights and the voltage dropped back down to 9 volts.
The troubleshooting continues
Charles

richinny · 10-24-2007, 05:32 PM

pull that battery and have it tested, it seems to be bad.

HowieE · 10-24-2007, 08:05 PM

Sounds like that battery has at least one shorted cell.

Since a battery has to be charged to realy test it I would just try another battery overnight and test in the am.

tn2 · 10-26-2007, 02:16 PM

I really hate to admit this......

My light problem was just a aux battery very low on water.

What I am wondering about....since that battery is almost new....is it a problem to leave my external power plugged in all the time. I thought the univolt system would just drop off to nothing when the battery was fully charged. It appears to me this isn't the case and it is overcharging the battery...with the results it boils the water out.

Thanks for all your help...you actually did lead me to the problem

Charles