Clean 12v ?

[ALANSD]

I recently bought an LCD DVD combo player for my truck , It works great.
I hooked it up in the Airstream, and itplayed with lots of lines running down the screen. It is 12v only, so it was plugged up accordingly in a 12v wall outlet.
Is this due to "impure" inconsistent 12v from the Univolt? And if so , other than buying a new charger/power supply...is there a filter or something that can be done to 'clean' up this power?

[Inland RV Center, In]

Originally Posted by ALANSD

I recently bought an LCD DVD combo player for my truck , It works great.
I hooked it up in the Airstream, and itplayed with lots of lines running down the screen. It is 12v only, so it was plugged up accordingly in a 12v wall outlet.
Is this due to "impure" inconsistent 12v from the Univolt? And if so , other than buying a new charger/power supply...is there a filter or something that can be done to 'clean' up this power?

Filters are available.

Andy

[scottanlily]

Hello AlansD ,I cant' answer your question ,but it seems I recall a similar
thread about this trouble ,i thought it was a DVD system also and it did
the same thing in the trailer .Im sure someone here will come to your aid soon .

Scott

[scottanlily]

See, that was a fast reply from Andy!

Scott

[lewster]

Originally Posted by ALANSD

I recently bought an LCD DVD combo player for my truck , It works great.
I hooked it up in the Airstream, and itplayed with lots of lines running down the screen. It is 12v only, so it was plugged up accordingly in a 12v wall outlet.
Is this due to "impure" inconsistent 12v from the Univolt? And if so , other than buying a new charger/power supply...is there a filter or something that can be done to 'clean' up this power?

IIRC, the Univolt's output does not compare to the current crop of switch-mode electronic converters, making them incompatible with most of the sensitive electronic gozmos that we use now. The output of these are much cleaner than the old style Univolt. Plus, you'll get 3 stage 'smart' battery charging too!

I don't think you'll be happy with the 'filter' results, unless you use a battery in series with the Univolt to act as your 'filter'. These were necessary with all of the ferro-resonant style converters of the past (like the Univolt). You might PM Overlander 68 for his expert opinion on converters.

[ALANSD]

since I am not using a battery right now, think that is causing the problem?

after I posted I found this online quote "
Generally you should not operate the converter without batteries connected because the batteries act as a filter of sorts and provides a more stable voltage to the electronic circuits of modern RV appliances. "

[thecatsandi]

Yes,
The battery will dampen the fluctuations of the Univolt. A Big capacitor from a electronics "junk" place could do the trick as well. However you have to be careful. They can store a large charge and really hurt you.

[dwightdi]

Not having a battery in the system to soak up the spikes and variable voltages output by the old style battery chargers and converters is a definite problem. If you have a Fluke or other digital multimeter, put it in the AC mode and measure variability outputed by the univolt. Then connect in the battery and see how much better it is. You will be amazed. You need a battery anyway so that is cheaper than buying a new converter or a filter. If you want life to be even better go to Radio Shack and buy a filter as well. It will also likely lengthen the life of your set.

[ALANSD]

thanks...I intended to put a battery inline to power the breakaway switch. I will check out the Radio Shack near me also.

[68 Overlander]

Originally Posted by ALANSD

since I am not using a battery right now, think that is causing the problem?

after I posted I found this online quote "
Generally you should not operate the converter without batteries connected because the batteries act as a filter of sorts and provides a more stable voltage to the electronic circuits of modern RV appliances. "

100% yes Alan. Installing a battery will clean that DC power and you should not need a filter. The battery is the filter and does a nice job. There is one catch though because some fuse boards in the past were split where only a few of the circuits are wired to pass through the battery. Usually the lights, radio, antenna are always filtered but some accessories were not.

[Chuck]

fwiw, I have the original looney-volt, AND a battery...my late model stereo and TV (9" ac/dc crt) don't seem to like it. TV randomly shuts off, pesumeably with dips in voltage. I've noticed that it can be triggered by big changes in what is being displayed on the screen...like a scene that is dim, and suddenly changes to a brightly lit one...~poof~.
Radio doesn't completely shut down, but sometimes stops outputting sound to the speakers...but the lights and display remain illuminated, so it isn't quite "off"...but this is triggered by turning on a light or some other device in the trailer.

[SilvrSausage]

A battery and/or capacitor is good for cleaning your 12 volt signal, but beware the harsh modified sine wave produced by most inverters, for your 120 volt gizmos! On a recent camping trip, I let all the smoke out of an electric blanket controller, and almost wrecked a portable DVD player which got so hot it shut down. I was using a Victor inverterer and deep cycle battery, both of adequate capacity.

"True sine" inverters are expensive! One thing I was going to try is a computer UPS (uninterruptible power supply.) The better ones will groom the AC signal as well as protect from dips and sudden outages. I would plug sensitive things into this, and run lights etc right out of the inverter. I'll report how well this works. Clamp lamps with compact fluorescent lamps are great for lighting up the campsite!

One other thought on 12 filtering... car stereos often have an inline filter in the power inputs. You might get one of those for a sensitive low-power device like the DVD player. A junkyard or stereo place where they discard lots of take-out units would be a good source for free or cheap filters like this.

[SilvrSausage]

Chuck, sounds like you have a LOW voltage issue, not dirty. How does that battery test out? Have you measured what the voltage is doing when the devices drop out?

If it turns out to be noise after all, filter capacitors will clean out what the battery cannot. The capacitors should be connected as close to the converter (noisy 12v source) as possible. A 1000 to 4700uf, 18-25 volt unit will do ya, mind the polarity.

[68 Overlander]

Chuck,
You are indeed describing low voltage and if you have a battery connected, it too must be low too for those symptoms to occur. One easy way to tell is to connect a household battery charger to the battery. If it is capable of holding a charge and there are no bad cells, those problems should go away, even during charge.

[Chuck]

Originally Posted by SilvrSausage

Chuck, sounds like you have a LOW voltage issue, not dirty. How does that battery test out? Have you measured what the voltage is doing when the devices drop out?

could be...doesn't seem to last long, thats for sure. first battery I had, I made the mistake of leaving it plugged in too long, and probably cooked it. Brought it back and got a pro-rated replacement (sears...that could be yet another mistake...I don't know ), and this one has never been left to cook...I check the water regularly, etc, etc...
yet, I don't have to turn much on in the trailer to see the voltage at the battery terminals get surprisingly low. Looney-volt seems to be putting out around 13.5v when its plugged in.
from the way it acts, I wouldn't be surprised if a load test showed "junque". but why? even if the UV is putting out the correct voltage, could it still be "mis-treating" the battery in such a way as to cause an untimely demise?

[Chuck]

Originally Posted by 68 Overlander

Chuck,
You are indeed describing low voltage and if you have a battery connected, it too must be low too for those symptoms to occur. One easy way to tell is to connect a household battery charger to the battery. If it is capable of holding a charge and there are no bad cells, those problems should go away, even during charge.

didn't see this before my last post...

TV seems to work fine as long as we're on shore power; but I believe the radio has had the same behavior regardless. main point was that newer "stuff" is more sensitive.

[silver 67]

I am putting a new dsi/gas water heater in and am now worried that I may have problems with the old univolt messing up my circuit board. What do you think?

silver 67

[Jacob D.]

The RV500 heater I put in had very stern instructions not to connect it to an unfiltered 12V source, I think (would have to check the manual) that it was more than 1V AC on the line.

My converter without a battery puts out 5V AC on the 12V terminals...

[Boondocker]

I changed my stereo and it is causing considerable static. I am taking it as a sign to change the 40 year old univolt to a three stage charger....

[lewster]

Originally Posted by Gen Disarray

I changed my stereo and it is causing considerable static. I am taking it as a sign to change the 40 year old univolt to a three stage charger....

I think that is a good move..............................................