Generator for Heating system

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malteselady

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Joined
Jan 27, 2007
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Alabama
Since you guys did so good with my other question here is one that I should know but don't and can't simply try out as my propane tank is completely empty - will be filling it up before heading to a dog show next weekend.

I know the generator is required for the AC to run but next weekend I'll be without dock power and it will probably be cold enough to need the heat.  Will the heat (well really I guess the fan and the thermostat)  work without running the generator?

Since I'm asking generator questions - can you guess I haven't used the generator very much.  In grooming the dogs I use a high powered blow dryer and also hair straighteners.  Will these run on the battery power or will I need to use the generator when using them?
 

John From Detroit

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Apr 12, 2005
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Davison Michigan
Short answer: RV furnace runs off batteries, not generator

RV's contain 2 or 3 kinds of heat.  One (electric heat strips in the AC) need shore power or generator power, This is also the worst choice of ways to heat if your concern includes the option of freezing pipes.

The furnace is 12vdc, you will need to run the generator from time to time to keep the batteries up (perhaps morning and evening) but not all day.

The other choice is a radiant heater, only useful in small rigs, no forced air fan, unless it has an electronic control system (rare) it needs on power of any kind

Oh yes, I forgot space heaters, they are not standard though.
 

Karl

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Mar 3, 2005
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Elkhart Lake, WI for the summer. Work at Road Amer
Debbie,
Those ceramic or 'cube' space heaters require 120VAC. This would mean you need to run your generator most of the time while using them; using the inverter to run them will drain your batteries in short order. I have a catalytic heater, 8,000 btu's, that will keep my 39' rig nice and warm in pretty cold weather. Being as it is a radiant heater, you would also want to install a small 12V fan to circulate the warm air throughout the coach. There are other radiant heaters that will run on propane too, but some of them use an open flame to generate the heat, whereas the catalytic heaters do not. No flame - minimal carbon monoxide.

Regarding the hair dryers and such: Unless specifically designed to run on 12VDC, they too will require 120VAC, either through the inverter or the generator. Like the space heaters, don't expect to use them for long on battery/inverter power - they are power hogs too.
 

John From Detroit

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Davison Michigan
Karl is correct, Most of those devices which Karl mentioned (Cube or other electric space heaters, Hair dryers and such) are 1,000 to 1,500 watts,  My Group 31 AGM's provide a bit over 100 Amp Hour at 12 volt (That is at the 20 hour rate) which rounds off to between 1,000 and 1,500 watts.  So you need one group 31 AGM Deep cycle per hour of operation or more.  "Quite hours" here are 8 hours long, 2 space heaters, times 8 hours is close to 20 batteries, I've only got a thousand pounds of cargo carrying capacity, that would exceed it.

Of course the RV furnace runs on a lot less power (just the 12vdc fan and the control/ignition electronics) since it heats with propane.  I am a fan of gas-heat by the way.. here is why

To make gas heat you burn fuel  (NOTE: Gas, in this context includes diesel fuel, Gasoline, and Propane/Butane/___ane)

To make electric heat you start by burning fuel (May be one of the above, may be coal or other) either to run an internal combustion engine or to boil water,  The steam from the water is then used to turn a turbine and the turbine (or internal combustion engine) turns the shaft of a generator which creates electricity.

The most efficient part of this procedure is the generator, it can hit over seventy percent efficiency converting mechanical energy to electricity.

Now we are going to send this power down lines and through transformers (Each of these introduces more loss) and finally into a resistor to make heat.. This, and only this is 100% efficient.  All resistive heaters are 100% efficient as all losses are expressed as heat.

However... That is a lot of loss between "Burning fuel" and "Heating house"  Loss that does not exist if you heat with gas, oil, or other fuel direct  (As for the chimmney loss.. You get that at the power plant too)
 

Marsha/CA

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Mar 9, 2005
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Hi Debbie,

Let's start over.  Some of these guys get way too technical and detailed.  Here's a woman's answer....no offense to the guys.

Your furnace will keep you warm and you don't need shore power to do it, just make sure you have full propane tanks.

If you have a couple of batteries in your coach they will need to be charged every once in a while to keep them going.  If you run your furnace through the night, your batteries will run down, so you will need to recharge them.  If you have a meter reader in the coach you can look to see how the batteries are doing.  If not ,the standard answer is to run the generator a couple of hours in the morning and couple of hours at night.  That will keep the batteries charged.  Be sure and check to see if the water level in the batteries is over the cells. 

Most of the time, if you run the furnace through the night, you will have to run the generator for a couple of hours in the morning to recharge the batteries.  Most quiet hours at campgrounds, and most likely at your dog show, will be from 10 pm until 6 or 7 am.  As soon as you get up in the morning, and it's not during quiet time, run your generator to recharge the batteries.  A couple of hours will most likely recharge them.  Then when you get back to the coach at night and you use your lights, TV, radio, etc turn your generator back on to keep your batteries charged.  When you go to bed, turn everything off except the furnace and you'll do fine.

If you need to run the hair dryers for the dogs, turn on the generator.

We are camping out in Quartzsite, AZ at the moment and there is NO shorepower, we are running off of the generator.  Oh, I just thought of something, make sure your generator starts up before you head to the show.

BTW, I'm gathering from your name that you show Maltese, right.  If so, my neighbor has a couple and they are cute as can be.

Also, John, there are other forms of heating besides the ones you mentioned.  There are also heat pumps besides electric strips.  I'm not sure electric strips are used much any more in the newer coaches.

Marsha~
 

Karl

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Mar 3, 2005
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Elkhart Lake, WI for the summer. Work at Road Amer
Marsha,
Sorry, but we sometimes have to get a little technical. Depending on how discharged the batteries are and the charging rate of the generator, a couple hours in the morning and at night might not be enough. Example: The Honda EU1000i and EU2000i generators only put out 8 amps to charge batteries; not nearly enough. It would then be wise to install a converter/charger to boost the charging level to something reasonable. If, however, she has something like an Onan 4 or 7kW genset and a decent size inverter with charging capability, there shouldn't be a problem because the inverter will probably charge at 65 amps or more, then taper off as the batteries come up.

Debbie, what exectly do you have installed as far as generator, converter, inverter, etc.? Please provide make/model. How many batteries and what type/size?
 

malteselady

Member
Joined
Jan 27, 2007
Posts
7
Location
Alabama
Thanks Marsha for the woman's interpretation!  I did crank up the generator today and it cranked right up  - heavy sigh!!  I'm not sure what size generator it is - will do some research on that and I do have a test panel so I'll keep an eye on it an run the generator enough to make sure the batteries stay charged up.  Thanks for all the great input.  I am sure I will be back to this site often as it seems I have a new question each time I take out the MH.

Yes, I do raise and show Maltese and really got my RV to facilitate taking puppies with me.  I love being able to be right at the show site.  Many sites have hookups but sometimes they are limited (this weekend is the Atlanta show and it is at an Expo Center with only a few hookup sites - always taken by the time I can get there.
 

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