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steelbreezzz · 10-18-2015, 10:48 AM

Greetings, the TU-740-2 converter charger in my 1986 HR Imperial is humming and giving of a pretty good amount of heat. I have had this RV for a little over a year now.Only been moved to new locations 3 times.I have been in this spot for about 10 months now. When I first got her, it was humming and hot. Over the summer I did not really notice the humming or the heat. Now that it is getting cooler(low 80's here in west TX) the symptoms are back. It does not seem to be any worse than I remember. I read a few post saying these old converters were prone to humming,but nothing was really said about the heat radiating off of it. The converter is located under a set of drawers in a closet and you can feel the heat when you open the closet door. Should I be worried? What would a good upgrade be for it? (sorry about the pic. I don't know how to rotate it.)

ijds · 10-18-2015, 04:40 PM

They should put out some heat but not so much you can't touch it. There should also be some ventilation . One thing that will make them run hotter is if it is under heavy load. Are you running more lights or using other 12 volt devices that draw a lot of current ? Do you have or can you put a amp meter in line and measure the total amp draw and compare that to the size of your converter?

**pasdad1** · 10-18-2015, 05:34 PM

If you decide to replace it, this is a good model. They also make smaller 50 and 60 amp versions.

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wschaub · 10-18-2015, 07:35 PM

I have an old fashioned magnetec that says that this is pretty much normal behavior in the "manual" that came with it (single slip of paper really). I want to eventually move to an intelligent charge controller of some sort but right now with winter coming on and my electrical and holding tanks in the same bay I figure the extra heat may actually be a blessing. (still plan to put a 75 watt bulb in there for extra heat)

Basically the really old converters are Just one giant transformer + heat sink and maybe a thermal cut out and voltage regulator and any decent sized transformer will hum.

CJ7365 · 10-20-2015, 10:49 AM

Normal, mine hummms and gets warm, mine has a built in fan thay kicks in when it get too hot

ahicks · 10-20-2015, 07:43 PM

It might be that it's trying to charge some junk batteries? It's set up to relax when the batteries get up to about 13.5 volts. If they're junk, they may not be capable of charging to that level. For the time and trouble it may cost you, it might be worth the trouble to disconnec your batteries to see if that makes a difference.