Converter - exactly what does it do?

[ruthandken CDN]

Ok I do know that it converts power to 12 volt so that you can use some lights etc.  in the MH when you are not connected to any power.  But what I am wondering is when you are connected to shore power, why do I still hear it cycling on and off periodically?  Why does it need to do this when you are connected to electricity and there is no need to convert any power for my 12 volt lights?

 

[Ned]

You have it backwards.  It's when you're connected to shore or generator power that the converter is used.  The cycling you hear is the fan turning on as the converter heats up.  When you're not on shore or generator power, the converter is off.  It not only powers all the 12VDC lights and control boards, but also charges the batteries.

 

[Woody]

A converter/charger such as contained in many older motorhomes converts AC to DC to power your DC lights when hooked up to shorepower and also charges to DC batteries.
An Inverter which is installed in many newer motorhomes converts DC power to AC.

Woody

 

[John From Detroit]

I thought I posted an answer to this, perhaps you asked it elsewhere.

Yes the converter lets you use your 12 volt lights and such on 120 volt shore power (or generator power)

But a good converter is silent, (at least it should be, More later) you won't hear it cycle.. What you do hear is the converter FAN cycling on and off,  This is a cooling fan and it's on a thermostat. When it gets hot it turns on, when it cools it turns off.

Heat can come from two sources (Which answers the question "I hear the converter runnand and I'm not plugged in)

One is heat generated by the operation of the converter.. Only one electrical/electronic device I've ever seen is 100% efficient (An electric heater) all the others have losses, and that loss is always heat, sooner or later (Which is why a heater is 100% efficient by the way, all losses become heat)

So as it works it warms up, and then the fan comes on and cools it off

Heat can also come from OUTSIDE (Sun shining on the compartment for example) which is why the fan may run even if you are not plugged in.


I promised more on the silent comment... Some,epically older transformer types, may have loose laminations on a transformer and these can HUMM fairly loud.

Alas, the only cure for that is .. Replacement.. Modern switching units you should not hear any sound save the fan.  But again, sometimes it hapens

 

[Dar]

Hi Ruth,
I just had to go through an education on the RV electrical system and batteries. I found this link helpful, maybe you will to?
http://www.ccis.com/home/mnemeth/12volt/12volt.htm

 

[JerArdra]

Ruth,

We had converters in our first 3 Class C MHs.  The primary thing we did not like is that the converter did a very poor job of charging the 12 volt house batteries and it takes a very long time to do it.  Sometimes our converter did not fully charge the batteries overnight.

We like inverters because they charge the 12 volt house batteries quickly and they are 3 stage chargers.  The first stage is bulk charging sometimes as high as 100 amps DC,  the second stage charges at a lower amperage and voltage level, and the final stage "float charging" keeps the batteries topped off and the inverter will keep your batteries "just right" when you store your MH.

OTOH, todays newer converters MAY now have 3 stage chargers built into them.

JerryF 

 

[maddog348]

How do you get an INVERTER to charge a battery????????????????

 

[Ned]

The typical inverter installed in today's RVs is an inverter/charger.  Check out the Xantrex product line for the more commonly used ones.

 

[John From Detroit]

To Ruth and Jerry... Well, from time to time I refere to a specific converter by punning it's name to ###ajunk.  Key word, Junk) and you did a very fine job of describing half the reason why.. The other half is given time it will boil your battery dry.

On the other hand I often name two brand/lines

Progressive Dynamics 9200  and Xantrex Truecharge XADC.

And both of those are 1st rate chargers.. For different reasons I give 'em both top of the field ratings. 

Your inverter, by the way, is an "inverter/charger" if it's charging, LIke the Prosine 2.0 (Also a Xantrex product) it has some fancy switching and control logic in it's brain.

The Prosine (Specific) also gets top ranking as a converter/charger..

(There are a lot of 'em that get top billing) 

But just so you know there's piece-o-junk converters, and there are really good ones out there.. damon blessed me with a PDI 9100 plus charge wizard (Equal in fact identical to the 9200 line I praised above,, once you plug in the charge wizard, which they did for me)