smart converters

[tut60]

hi. I am new to this.I have problems with my 55 amp converter. my motorhome is a 1992 friendship, witha 250 hp cummins.It has 92000 miles on it.25000 are mine.Bought it in 1999. i have replaced the house batteries 3 times.Burned up the converter once,replaced it 2 years ago. It worked for about a month then it fried it's self. Now i just put a charger on the house batts. when we are parked. any Ideas? When i tried to put a new conv. on and hook up it sparks like it is reverse polarity.

[tut60]

hi. I am new to this.I have problems with my 55 amp converter. my motorhome is a 1992 friendship, witha 250 hp cummins.It has 92000 miles on it.25000 are mine.Bought it in 1999. i have replaced the house batteries 3 times.Burned up the converter once,replaced it 2 years ago. It worked for about a month then it fried it's self. Now i just put a charger on the house batts. when we are parked. any Ideas? When i tried to put a new conv. on and hook up it sparks like it is reverse polarity.

[Bob (WA0MQE)]

Make sure your house batteries aren't hooked up backwards. Some of the stuff in your coach doesn't care if the positive is grounded instead of the negative because of the isolation. Obviously some sensitive electronics do and you might fry them if things are hookep up backwards. I hooked mine up accidently one time and all it did was blow the main converter fuse. The lights still worked although they came ON when the switch was off and were OFF when the switch was on. Luckily it blew the main converter fuse before it had a chance to fry any of the sensitive electronic parts.

[Gary RVRoamer]

Something is seriously wrong in your 12V system if it is burning up batteries and converter/chargers. Since it seems to be OK if you just charge while parked, I wonder if the engine alternator could be pumping high voltage DC back into the house system? It may be putting out 15VDC or more and that might be overwhelming the converter, since it is connected to the batteries too. In systems that allow the engine alternator to charge house batteries, there is normally a relay that prevents both converter and alternator from being connected at the same time. Maybe yours has failed? Or you could try adding a diode to the converter output line, preventing any backflow into the converter.

About the only other possibility I can think of is bad AC input to the converter. Or perhaps power from a modified sine inverter, if you have one?

You shouldn't see sparks when hooking up to batteries that are already charged, but may see them if the battery is low.