my converter hums

[dusty b]

most likely a silly question but i have a 85 a/s 25 and when you plug in for shore power you can hear a audible hum. not bothersome but is there. also if i have the battery turned off my lights aren't as brite as when i have the battery switched on with the shore power. is this as it should be or is my converter getting old? so what's the opinion about this? inquiring minds want to know! thanks all for any help-----------------dusty

[r carl]

Im pretty sure happy wives and transformers hum.

[BIGED52]

It may not know the words!!!....!

Univolt OEM converters are notorious for over charging the batteries. This could be the reason for the lights to be brighter when the battery is still connected on shore power. I think the hum is a good reason to upgrade your converter. Happy Trails, Ed

[Ag&Au]

Originally Posted by dusty b

most likely a silly question but i have a 85 a/s 25 and when you plug in for shore power you can hear a audible hum. not bothersome but is there. also if i have the battery turned off my lights aren't as brite as when i have the battery switched on with the shore power. is this as it should be or is my converter getting old? so what's the opinion about this? inquiring minds want to know! thanks all for any help-----------------dusty

Any device that is powered by AC has the potential to hum and probably does at some noise level. It is because the current and voltage are varying. The hum can be exacerbated by anything that can vibrate. Examples are loose screws, sheet metal objects touching each other but nor secured, bad design in the first place. Generally the more power that is being utilized, the worse (louder) the hum. Some solid state devices whine in addition to or instead of humming.

The hum could indicate a electrical problem or a mechanical mounting problem or nothing at all.

Anytime a charger is charging a battery, the voltage output of the charger must be higher than the voltage of the battery. So any time you turn off the charger, the DC voltage will drop and the lights will dim somewhat. The question is how much, and is it enough to notice.

There is no answer to whether or not anything is wrong with your converter or batteries, without testing the whole system piece by piece. An owner who is familiar with electrical equipment and batteries can most likely figure it out with a multimeter. An owner who is not is best off finding someone local who knows how or taking it to a repair technician.

If I were to make a wild guess based just on what you have said, I would say your battery/batteries need to be replaced. If you have a 2 stage charger, that may be a good time to upgrade to a more modern charger.

Ken

[dusty b]

thanks everybody for your words of wisdom. i have had some other rv's but the transformer was in the basement so it couldn't be heard. we bought the 25 a/s and the transformer is behind the couch which of course we took everything out so now it's right there where you can hear it. it really got me to wondering so thanks again , much appreciated...........dusty

[arcamedies]

My 22 Argosy Univolt hummed loudly, and my 93 Excella hums at about half the level. check your battery fluid level and if they do not seem to be using water let it merrily hum away (in the summer some water use is normal). Every 3 months in my diesel motorhome with 4 deep cycle batteries and a 2000 watt inverter I'd add a quart of water between the battery banks evenly, if one cell uses more water that battery is going south. Now if it sounds like a transformer that's gonna blow and it's boiling the batteries shut the puppy off and get it checked or replaced.

[vswingfield]

All good responses. Happy wives, univolts, anything that handles power. Then there's always:

http://www.youtube.com/watch?v=mRwGqf2glDs

But seriously folks.

The older univolts like the one that came in my Excella are notorious for the humming and overcharging batteries. I replaced mine a couple of years ago for those reasons, it was still functioning well (or as well as they ever did). Also, I had the sofa out, so access was easy.

Yours is about the same age. If you have the sofa out and replacement is easy, that's enough reason to recommend its replacement to me.

[Bettye]

Glad I ran across this thread. We have the same humming in our '84 Excella. Good information.

[perryg114]

It is most likely the iron plates in the core of the transformer vibrating because of the 60Hz AC current. It is normal for a linear power supply like the old Univolts. You can get a modern switching power supply that is smaller and won't make so much noise. If you computer had a linear power supply, the power supply would be the size of the computer case.

Perry