Do 12 volt appliances count against "amp" count?

[DXSMac]

In previous RV's, I've had electric televisions (that came with built in DVD players). In those RV's, I couldn't run electric water heater, space heater, and a TV, I always tripped a breaker. So, if I watched TV, either my space heater was turned off or I switched water heater to propane.

Ok, now all three of my TV's are 12 volt (Jensen, been pleased with them so far.... cross fingers). I've had all three TV's on at once along with other appliances and haven't tripped breakers.

Just wondering if 12 volt appliances count against amps. Also, these TV's don't have the built in DVD player and I'm glad as when I have had those, each time the DVD player went POOF and had to buy an external one anyway. (I currently have the MagnaDyne system, see my rants in other threads on this....)

[BarryD0706]

Divide the 12-volt amps by 10. That's the number (approximately) that counts toward your 30-amp limit. (120 = 10 * 12)

[Batts-toy]

If I understand your situation in the previous units those items were on a 110 volt circuit which were fed from a single breaker which would trip (a space heater pulls a lot of current). Now you have 12 volt Televisions and no problem, to explain this you need to understand the circuits you are dealing with (everything pulls amps) what is different in your scenario is previously you were overloading an AC circuit probably a 15 amp AC breaker. The 12 volt televisions are powered though different circuitry as DC voltage from the battery or batteries as the case may be, if you were to overload the circuit the televisions are on now you will find it would blow a fuse in the DC power part of the power panel. If you are referring to the main 30 amp breaker supplying the MH check Barry's comment above. Like I said everything pulls amps but then your in a different loading situation tha before.

[DXSMac]

Thanks. I already knew about watts divided by volts. I just wanted to know if 12 volt appliances counted toward the "amp count." Batts-toy kind of explained it, albeit he explained it more like an engineer would. Batts, are you an engineer by any chance? All I know is I am able to run 3 TV's that are all 12 volt when I am running other appliances and I haven't tripped breakers; whereas, I tripped breakers when I ran an electric TV and other appliances.

[wmtire]

Howdy DSXMac. When you are plugged into a form of 120 volt AC power, your converter is what powers the 12 volt DC things in your RV.

The converter takes 120 volt AC power and converts it to 12 volt DC power. You converter uses different amounts of AC amps according to how many DC things it needs to power. The converter does have a maximum amount of DC power it can provide, which is when it draws the most AC amps (probably around 8 amps AC is common).

This great article by Mark Polk may help you understand it all better, which also has a chart of common electrical draws in both AC and DC.

RV Converters and Amp Draw - RV Information (RV Maintenance)

[BarryD0706]

Originally Posted by DXSMac

...
All I know is I am able to run 3 TV's that are all 12 volt when I am running other appliances and I haven't tripped breakers; whereas, I tripped breakers when I ran an electric TV and other appliances.

There was some loss of efficiency inside the TVs because they had to convert that 120v down to lower voltages. I doubt that was significant however. It's most likely just that newer TVs have lower power draw than old ones did.

[Batts-toy]

Originally Posted by DXSMac

Thanks. I already knew about watts divided by volts. I just wanted to know if 12 volt appliances counted toward the "amp count." Batts-toy kind of explained it, albeit he explained it more like an engineer would. Batts, are you an engineer by any chance? All I know is I am able to run 3 TV's that are all 12 volt when I am running other appliances and I haven't tripped breakers; whereas, I tripped breakers when I ran an electric TV and other appliances.

My appologies for sounding so 'engineerish' I am not a degree'd engineer though others have made similar comments. I have been doing a job for many years that the company would normally hire an Chemical Engineer to fill additionally I spent 7 years as the Safety and Health department manager where I dealt with many things including electrical, perhaps that is where it comes from. Between myself, Barry and wmtire's feedback how are you now with all this, can we clarify any of our comments? I will not try to add more at this time since you haven't had a chance to read the latest comments. Just so I am clear what breaker was tripping a small breaker in the power center or the main 30 amp breaker?

[DXSMac]

Oh Batts.... no need to apologize it was just an observation, not meant as criticism. Putting everyone's comments together, I think it's sort of yes and sort of "kind of." I would trip one of the breakers in the power box, just flip the switch and back on. And I think it's sort of what Barry said, the 12 volt TV's that are just TV's and don't have DVD players draw less power.

If my understanding is wrong, please clarify some more, I appreciate it.

[Batts-toy]

No harm done, don't worry I didn't take it that way. You have been on top of what was happening all along just overloading the 15 or 20 amp AC breaker. As wmtire said the 12 volt tv's are being supplied by the converter when you are connected to shore power and since they are not AC this takes some load off the small breaker and brings it through the converter instead (if you use more amps than the 8 or so the converter supplies or if you are not on shore power the battery(ies) will pick up the slack I believe).

My explanations do get long winded at times, I'll tell a little story if you don't mind,
Long, Long ago when I was 32 years old (now 66) I was attending junior college (with a bunch of 18 year olds) to pick up some advanced classes needed for the job (engineer position) the professor had several of us write our advanced algebra problem on the board, the youngsters wrote theirs up skipping steps as they went, I took longer and was the last to finnish and as I sat down the teacher asked me if I supervised other people at work and I responded yes I do, and she say's then thats why you feel you needed to write all the steps and details on the board.

[Batts-toy]

Just thought of something if you are using a 12 volt adapter for the tv's that plug into the 120 volt outlet you are still pulling through the same breaker as the old tv but the 12 volt units are probably using less AC amps.

[DXSMac]

Yes, the 12 volts are all plugged into 12 volt plug ins. I'm just amazed I can run all three TV's along with appliances and no breakers tripped.

[bgilly]

Originally Posted by DXSMac

Just wondering if 12 volt appliances count against amps. Also, these TV's don't have the built in DVD player and I'm glad as when I have had those, each time the DVD player went POOF and had to buy an external one anyway. (I currently have the MagnaDyne system, see my rants in other threads on this....)

In a short answer - yes and no.
As others have stated the 12 volt system does get the power from the 120 volt power (when plugged into shore power) through the converter.


So, now to:

Originally Posted by DXSMac

Just wondering if 12 volt appliances count against amps.

Indirectly - yes they count against your total amp. But only up to the maximum amp draw of your converter (8 amps? depending on the converter size).
The more you draw on 12 volt power, the more the converter has to draw to maintain. The good side about the 12 volt power is your coach batteries will take on some of that power demand so 30 amps 12 volt doesn't mean it will result in 30 amp draw at the converter or 120 volt power side.

Also, as others have stated, the 12 volt appliances already use DC so there is no power loss of the power brick (taking 120 volt and converting to 12 volt). The old television would use around 5 amps 120 volt AC - the new television uses around 3 amps 12 volt DC.
The old 5 amp television counted against your total load. The new 3 amp television can draw a little from your total amp draw but it won't likely be the total of the 3 amps.

Drats, I tried making this read in laymen but I don't think I succeeded.

Bobby

[DXSMac]

Thanks, this explanation made more sense to me. I can figure this out out. It kind of confirms my thought of "yes and no."