Need help understanding the power systems in the trailer please

[rbryan4]

Originally Posted by TAfraser

I believe the term Compressor-Locked Rotor Amps is a confusing way of stating the amount of current that’s required to start the compressor. The fan on an air-conditioner starts only once when first turned on, then runs all the time, but the compressor starts and stops as needed to keep things cool. You can hear when the compressor starts, both from the air-conditioner and from the generator if you’re using one.

When we purchased our Casita in 07 I read all kinds of posts where people were having issues powering their air-conditioners with the Honda 2000. They would go through specific light-off procedures (sometimes successfully) in order to start and run their A/C units, they would link two Honda 2000s together, purchase the Honda 3000, or they would install “Soft Start” circuits in their air-conditioners.

Soft Start circuits consist of capacitors that are charged during operation and used for power assist during compressor start-up. Adding the Soft Start circuits would allow the use of a smaller generator. I've been told, I don’t know where, that the newer A/C units all have the soft start circuits installed. I can’t verify that because we own the Yamaha 2400 and have never had a problem.

Makes sense to me TA. I don't know why they publish it as a means of expressing the surge at startup, but they do. If the soft start circuit is there it makes even less sense because the surge is handled by the capacitor - similar to the run capacitor on a home AC unit. Oh well, it IS Dometic.

[kvermeulen]

Originally Posted by rbryan4

Just looked it up Ken. You're right. It will run on 115v ac input.

-->Compressor Loaded Amps: 9.5
-->Fan Motor Loaded Amps: 3.1
-->Compressor-locked rotor amps: 53.0
-->Fan motor-locked rotor amps: 8.8

So, with a Honda Gen you could run just the AC, but nothing else.

thanks for looking that up. Its nice to know we wont have to do anything special for the very occasional times when we really need to run the ac... Like we had to in Ottawa in a mosquito infested prov park when is was around 90 above.

Ken

[Brian B-P]

Originally Posted by Jill

Laptops run on 12V for recharging right?

The input to the laptop - to run or to charge the battery - is DC (which means "direct current"), but it is rarely if ever as low as 12 volts. That's why running or charging a laptop from 12V DC power still requires an adapter to convert the 12V power to a higher voltage (e.g. 19 volts for most the HP laptops I've had) as Jim mentioned.

[Jill]

So much great input in this thread. Many thanks to all who contributed. I don't think we want to go down the generator route, So when dry camping we'll try to adapt what we can to 12v (laptops, TV/DVD if we decide we want one) to make life simpler, we'll get the inverter too, and we'll do without AC. It'll be nostalgic to sleep under the stars if the trailer gets too hot right?

[Mary F]

For what it's worth, I don't think we're going to get an inverter. (Our 21' build date is Sept 14, 2015.) We have a small inverter (Kensington) for charging my laptop; 12V adaptors will take care of our smaller electronics. Watching t.v. isn't a priority, and neither is using a microwave. (We sometimes use both when we're camped with hookups, but not even very much then.) We ARE going to spring for a couple of extra 12v outlets. (We already have a 12v Endless Breeze fan, which I want to be able to plug in outside, under the awning.) It'd be different if we needed a CPAP machine - I mean, I get that. But we boil water on the stove and make coffee with a Melitta, don't use a hair dryer at home, so don't need one at a campground, etc. And it uses power to invert 12v to 110, ya know?

At least, this is my thinking on this so far - for our camping style/needs. YMMV.

[gbaglo]

Mary F, reads like perfection to me.

[Jim Bennett]

my thinking regarding an inverter is the same as Marys. We have nothing that we would want to run off of one anyway. At least at this point of time anyway. We actually set our self up purposely to not have to use 120 volts for anything.

[gbaglo]

I have a couple cheap inverters from Canadian Tire that are sufficient to charge my MacBook or charge my camera batteries. I think they are rated 50 and 100 watts. Cheapest was $12.99 on sale.

[alanmalk]

Originally Posted by gbaglo

Mary F, reads like perfection to me.

I'm with Mary - 12 volts all the way. But I do have one weakness - an electric blanket is so nice on those cold nights. No noise and the electrical drain is manageable, especially if the blanket is on the smaller size.

--
Alan

[cpaharley2008]

Alan, they have 12v electric blankets
http://www.amazon.com/Trillium-World...s=12v+blankets

[skiman]

Originally Posted by Mary F

For what it's worth, I don't think we're going to get an inverter. (Our 21' build date is Sept 14, 2015.) We have a small inverter (Kensington) for charging my laptop; 12V adaptors will take care of our smaller electronics. Watching t.v. isn't a priority, and neither is using a microwave. (We sometimes use both when we're camped with hookups, but not even very much then.) We ARE going to spring for a couple of extra 12v outlets. (We already have a 12v Endless Breeze fan, which I want to be able to plug in outside, under the awning.) It'd be different if we needed a CPAP machine - I mean, I get that. But we boil water on the stove and make coffee with a Melitta, don't use a hair dryer at home, so don't need one at a campground, etc. And it uses power to invert 12v to 110, ya know?

At least, this is my thinking on this so far - for our camping style/needs. YMMV.

Your thinking is right on the money!

We got extra 12 volt outlets based on Cpaharley's recommendation. Even doubled at the nightstand for the TV. Really glad we did.

How does your Endless Breeze work out?

[Vermilye]

Originally Posted by alanmalk

I'm with Mary - 12 volts all the way. But I do have one weakness - an electric blanket is so nice on those cold nights. No noise and the electrical drain is manageable, especially if the blanket is on the smaller size.

--
Alan

Be careful running a 120V electric blanket on an inverter. Most electric blankets do not mix well with modified sine wave inverters (the type usually installed in trailers & motorhomes), and will be damaged if run on one. Pure sine wave inverters are OK, but more expensive and less common. The Perfect Fit low voltage blanket is one of the few 120V blankets that will survive on a MSW inverter.

One other consideration - even though they draw fairly low amounts of power, it does add up. Since the inverter inputs draws 10X the amps of the output, even small current draws over long periods can pull down your battery. Some users have used the electric blanket to pre warm the bed, then shutting it off for the night...

[LeonW]

When I was considering options for the Skylark, I puzzled over the inverter question. Someone on the board suggested that if I wanted the inverter, I should "go all the way" or not at all. As I thought about it, the only things we run that need AC are the Air conditioner and the microwave, neither of which are essential (well the Air conditioner is essential some days, but when it is really hot we are probably in a camp ground). We have 12 volt sources for everything else, including charging the laptop. I found a 12 volt charger for my macbook pro on Amazon for less than $30.00 -- much better than an inverter since there isn't any overhead. So far really pleased and pretty sure we could be boon docking for as long as the tanks will hold out.

[Dave Whiting]

Originally Posted by Mary F

For what it's worth, I don't think we're going to get an inverter. (Our 21' build date is Sept 14, 2015.) We have a small inverter (Kensington) for charging my laptop; 12V adaptors will take care of our smaller electronics. Watching t.v. isn't a priority, and neither is using a microwave. (We sometimes use both when we're camped with hookups, but not even very much then.) We ARE going to spring for a couple of extra 12v outlets. (We already have a 12v Endless Breeze fan, which I want to be able to plug in outside, under the awning.) It'd be different if we needed a CPAP machine - I mean, I get that. But we boil water on the stove and make coffee with a Melitta, don't use a hair dryer at home, so don't need one at a campground, etc. And it uses power to invert 12v to 110, ya know?

At least, this is my thinking on this so far - for our camping style/needs. YMMV.

My thinking exactly. And I have a CPAP machine that I was able to get a 12 volt power cord from the same manufacturer (ResMed) for so I do not need an inverter.

Dave W

[alanmalk]

Originally Posted by Vermilye

Be careful running a 120V electric blanket on an inverter. Most electric blankets do not mix well with modified sine wave inverters (the type usually installed in trailers & motorhomes), and will be damaged if run on one. Pure sine wave inverters are OK, but more expensive and less common. The Perfect Fit low voltage blanket is one of the few 120V blankets that will survive on a MSW inverter.

One other consideration - even though they draw fairly low amounts of power, it does add up. Since the inverter inputs draws 10X the amps of the output, even small current draws over long periods can pull down your battery. Some users have used the electric blanket to pre warm the bed, then shutting it off for the night...

Sigh...
A good example of how "new and improved" has made things more difficult.

Back in the old days - my inverter was a simple modified square wave with a horrible waveform when viewed on an oscilloscope. But it worked fine with my ancient electric - non-smart - blanket. Which was basically a bunch of resistance wires and a thermal on-off switch.

Now - my electric blanket has its own power supply and smart cold-sensing zones. And my inverter is an expensive pure sine wave design. But I've gotten older and colder.

Maybe it's time for a 12v blanket to simplify my life?



And yes, its a good idea to pay attention to the wattage of your chosen blanket and add about 10 - 15% for efficiency losses to the total.

--
Alan

[Red Dog]

Great reading resource... Thanks!

Fred M.

[FMLNM]

Originally Posted by alanmalk

I'm with Mary - 12 volts all the way. But I do have one weakness - an electric blanket is so nice on those cold nights. No noise and the electrical drain is manageable, especially if the blanket is on the smaller size.

--
Alan

A hot water bottle in a fleece envelope placed under the covers at the foot of the bed - or elsewhere - will do as well as an electric blanket....

[Jim Bennett]

Originally Posted by FMLNM

A hot water bottle in a fleece envelope placed under the covers at the foot of the bed - or elsewhere - will do as well as an electric blanket....

Or snuggling. Nothing beats some good cuddling to warm up a bed.

[FMLNM]

Originally Posted by Jim Bennett

Or snuggling. Nothing beats some good cuddling to warm up a bed.

Employs a different kind of electricity and battery....

[Jim Bennett]

Originally Posted by FMLNM

Employs a different kind of electricity and battery....

Yes, but a renewable resource, it is.