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Old 01-12-2008, 01:59 PM   #5
N7OQ
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Join Date: Nov 2007
Location: Yuba City, Ca
Posts: 304
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These converters are made as cheap as they can make them and sense they are switching power supplies they create a lot of RF noise. The reason they make so much noise is that to keep them small and light weight they take the AC in and convert it to DC than chop it with a Oscillator at around 20 to 100 KHZ now this much higher freq (compared to 60hz) can be stepped down to 13.5 volts with a very small transformer because you have a much shorter duty cycle. Now with a old fashion linear power supply you would use a huge step down transformer (60 cycles has a much longer duty cycle) step it down to maybe 18 volts run it through a regulator and filter it. Much cleaner, no RF noise but much heaver and larger. With a switching power supply you really need a lot of filtering to get a half way clean output. It needs filters on the AC input each stage and the output something that cost more to make and the manufactures just don't care about our hobby.

My now work around will be to turn off my converter with the circuit breaker and then use a old linear converter I have in the garage to charge the batteries and run everything. This converter is rated at 40 amps is rather large but all I need to do is connect it to the batteries like a charger and plug it in. A person could do the same thing with a lest say a 20 amp battery charger as long as it is linear type (Heavy) I would imagine a 10 amp would also do the trick. I used this setup when I had a tent trailer and it worked like a champ then all I will need to do it install caps on all my fans like in the heater and exhaust fans.
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RV: 2006 Outback 23RS
USAF Retired, God Bless our Troops
Licensed in 1978 ex N7AFX, DA1VW, KK6GR
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