dc power

[pelon]

I have a new mark dc50f power converter.
Is it suppose to deliver pure 12volts dc? I seem to read ac voltage at the output, as well as dc.
I also get a reading of twenty two volts under no load. Is that normal?
Do I need to add a rectification bridge to the output?
I am trying to use this in conjunction with a deep cycle marine battery to power an ac inverter that powers my laptop when I am on the farm.
Pelon.

 

[cdstahl]

how much AC, how much DC?

 

[Hero999]

That sounds pretty typical for a cheap and unregulated wall wart power supply.

How much did it cost?

If you've payed good money for it then you're been ripped off.

 

[pelon]

power supply newmark dcv50f

how much AC, how much DC?

22 volts ac and dc. this is a fifty amp power supply used in motor homes.

 

[kchriste]

There is typically no filter capacitor on those. It just outputs raw rectified DC, so it would be normal to see both AC and DC on a meter. I am surprised that the output voltage reads that high. There are typically two types of outputs on RV power converters. One is for charging the battery and one for directly running the accessories in the motorhome. The accessories output should read around 14-16V with a small load on it like a typical 12watt RV light. The charger output could be acting strange because it isn't connected to a battery yet. What type of meter are you using to measure it?

 

[Roff]

Are you sure you posted the correct part number? Google doesn't come up with anything.

 

[pelon]

dc supply reply

There is typically no filter capacitor on those. It just outputs raw rectified DC, so it would be normal to see both AC and DC on a meter. I am surprised that the output voltage reads that high. There are typically two types of outputs on RV power converters. One is for charging the battery and one for directly running the accessories in the motorhome. The accessories output should read around 14-16V with a small load on it like a typical 12watt RV light. The charger output could be acting strange because it isn't connected to a battery yet. What type of meter are you using to measure it?

The supply has a 12 mf capacitor in it, two taps come from the transformer to two dc rectifers mounted in an aluminum plate. I am running the thing on a generator so some my voltage readings may be off slightly. I have both analog a digital meters to check with. I am using a generator to power the supply so my readings may be of slightly. the supply does come down to 12volts when under load. the problem is that when connected to a battery it wants to climb towards the 22volts make.

 

[pelon]

The supply has a 12 mf capacitor in it, two taps come from the transformer to two dc rectifers mounted in an aluminum plate. I am running the thing on a generator so some my voltage readings may be off slightly. I have both analog a digital meters to check with. I am using a generator to power the supply so my readings may be of slightly. the supply does come down to 12volts when under load. the problem is that when connected to a battery it wants to climb towards the 22volts make.

 

[kchriste]

The supply has a 12 mf capacitor in it,

Do you mean 12 milli farad, as in 12000uF? Where is this capacitor connected? Maybe post a picture of the innards.

 

[stevez]

I have some experience with RV power convertors. One type is a big transformer with rectifier providing rough DC for heavy loads - as already mentioned. A small amount is sent to the battery for charging - via a relatively simple control board w/relay. I recently replaced it with what amounts to a switched mode convertor. I've never checked the output with a meter or scope. If you have the transformer type supply I'd say you need to test it under load - measure the DC and AC - likely lots of ripple. If it's a switched mode supply and you are getting 22 volts -something is very wrong. The switched mode supply delivers a rock solid 13.8 vdc with input voltage from below 90 to over 130 - the variations I see where I have the RV parked.

 

[carmusic]

what is the rated voltage of your laptop? some model can run directly on 12 volt and even if it runs at 18volt for example there is dc/dc converter that would be a lot morer effecient than having 12 volt batteyr through a inverter to 120v then back to 18volt