Mumblix_Grumph Posted May 22, 2012 Share Posted May 22, 2012 Hi all. I just bought an old 1979 Dolphin and was wondering if a standard alternator on a 20R engine is enough to power an inverter powerful enough to run a microwave oven. I'm thinking maybe 1000 watts. Can you swap out the alternator for a more powerful one? Should that even be considered? Any advice would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
stamar Posted May 22, 2012 Share Posted May 22, 2012 hey bud i just bought a 79 dolphin too, and have had some similar research. Real rvers learn to use the propane stove for everything. The cost of running a gas engine, using 2 deep cycles and a 1500 watt inverter to make a cup of soup costs about 50 c just in gas compared to 3 cents in propane. the rvers who have the set up you want, would never regularly run a microwave off a gas engine. 'never mind the investment of whatever you are missing from it a generator gets better but is still terrible. however my friend who literally has a propane generator meaning the fuel comes from the same tank, says that coffee costs at least 30 times as much from an electric coffee maker as from heating up water. And in a race it took 45 seconds longer. A bigger alternator would make it more effecient to microwave popcorn, but permanently reduce the gas mileage. Meaning you pay a lot for the concept of running electrical kitchen equipment off of an automobile engine. It is a terrible idea!!!!!!! the microwave in an rv is primarily for a permanent landline plug in, or a very occasional back up, or literally during a road trip use while on the road. Quote Link to comment Share on other sites More sharing options...
Mumblix_Grumph Posted May 22, 2012 Author Share Posted May 22, 2012 hey bud i just bought a 79 dolphin too, and have had some similar research. Real rvers learn to use the propane stove for everything. The cost of running a gas engine, using 2 deep cycles and a 1500 watt inverter to make a cup of soup costs about 50 c just in gas compared to 3 cents in propane. the rvers who have the set up you want, would never regularly run a microwave off a gas engine. 'never mind the investment of whatever you are missing from it a generator gets better but is still terrible. however my friend who literally has a propane generator meaning the fuel comes from the same tank, says that coffee costs at least 30 times as much from an electric coffee maker as from heating up water. And in a race it took 45 seconds longer. A bigger alternator would make it more effecient to microwave popcorn, but permanently reduce the gas mileage. Meaning you pay a lot for the concept of running electrical kitchen equipment off of an automobile engine. It is a terrible idea!!!!!!! the microwave in an rv is primarily for a permanent landline plug in, or a very occasional back up, or literally during a road trip use while on the road. Ok...fair enough. I guess I'm going to stick with the propane stove and oven for cooking. All other electrics will run on 12V: laptop, lights, fan etc. Haven't had a chance to test the fridge on propane. The DC and shore power AC work on it. Thanks for responding. Quote Link to comment Share on other sites More sharing options...
stamar Posted May 22, 2012 Share Posted May 22, 2012 the power needed to run a 600 watt microwave for 1 minute actually exceeds the storage of two large deep cycle batteries. So the actual cost of running the engine to finish the 1 minute, plus literally running the engine for a half hour to recharge the batteries is so much with the cost of gas these days. When you look at it its off the hook. Quote Link to comment Share on other sites More sharing options...
stamar Posted May 22, 2012 Share Posted May 22, 2012 the 3 way fridge will also be much colder on propane.\\ but best on land ac. Quote Link to comment Share on other sites More sharing options...
stamar Posted May 22, 2012 Share Posted May 22, 2012 nice mine all works too. I havent tested a few things yet. great condition too and I got it for 300 dollars. Quote Link to comment Share on other sites More sharing options...
waiter Posted May 22, 2012 Share Posted May 22, 2012 I installed a 1500 watt inverter, mainly to run the microwave to heat up dinner, and make a pot of coffee in the morning. Not a problem. My alternator re-charges the coach battery when I start the truck. Our microwave is a small 600 watt unit (draws about 1000 watts), This unit draws about 60 - 70 amps at 12 volts through the inverter. I have standard alternator and battery systems as they came from Toyota and National RV (Nothing special). We did install LED lighting everywhere to reduce battery and alternator loads. When we're on the road, we use the microwave maybe 5 to 10 minutes a night and make two pots of coffee in the morning. For a typical one night stop, the standard coach battery does OK, without a recharge. A typical one night stop would be: Warm up soup or leftovers in the microwave, TV runs for a couple hours. Several LED lights on for several hours, In the morning, make a couple pots of coffee (small pot). If I get a low voltage alarm on the inverter, I press the "Start" button on my remote car starter and let the truck run for about 15 minutes to charge the coach battery. Our longest boondock was in a Sams Club parking lot in the middle of a severe snow storm. A day and a half, running TV, furnace, microwave, lights, I started the truck once just to top off the coach battery. If we used our toyhouse to boondock for long periods, I would probably get a small portable generator to re-charge the coach battery once a day rather than run the truck. Solar or a small wind turbine would also be an option. Adding higher capacity batteries might also be an option, but look at usage before adding battery capacity (i.e. LED lights and Catalyst heat instead of running furnace) Inverter Install Boiling Water Interior LED conversion Running light LED conversion Taillight LED conversion Ventless heaters John Mc 88 Dolphin 4 Auto Quote Link to comment Share on other sites More sharing options...
Maineah Posted May 22, 2012 Share Posted May 22, 2012 hey bud i just bought a 79 dolphin too, and have had some similar research. Real rvers learn to use the propane stove for everything. The cost of running a gas engine, using 2 deep cycles and a 1500 watt inverter to make a cup of soup costs about 50 c just in gas compared to 3 cents in propane. the rvers who have the set up you want, would never regularly run a microwave off a gas engine. 'never mind the investment of whatever you are missing from it a generator gets better but is still terrible. however my friend who literally has a propane generator meaning the fuel comes from the same tank, says that coffee costs at least 30 times as much from an electric coffee maker as from heating up water. And in a race it took 45 seconds longer. A bigger alternator would make it more effecient to microwave popcorn, but permanently reduce the gas mileage. Meaning you pay a lot for the concept of running electrical kitchen equipment off of an automobile engine. It is a terrible idea!!!!!!! the microwave in an rv is primarily for a permanent landline plug in, or a very occasional back up, or literally during a road trip use while on the road. I agree also the cost of the equipment to run the micro wave inverter, bigger battery (or batteries that won't last forever), generator to recharge or replacement alternator, wiring, labor and a place to put it. I guess it's all in what you feel you need I have one at home but don't think I need to lug one around to each their own. Quote Link to comment Share on other sites More sharing options...
Mumblix_Grumph Posted May 22, 2012 Author Share Posted May 22, 2012 I installed a 1500 watt inverter, mainly to run the microwave to heat up dinner, and make a pot of coffee in the morning. Not a problem. My alternator re-charges the coach battery when I start the truck. Our microwave is a small 600 watt unit (draws about 1000 watts), This unit draws about 60 - 70 amps at 12 volts through the inverter. I have standard alternator and battery systems as they came from Toyota and National RV (Nothing special). We did install LED lighting everywhere to reduce battery and alternator loads. When we're on the road, we use the microwave maybe 5 to 10 minutes a night and make two pots of coffee in the morning. For a typical one night stop, the standard coach battery does OK, without a recharge. A typical one night stop would be: Warm up soup or leftovers in the microwave, TV runs for a couple hours. Several LED lights on for several hours, In the morning, make a couple pots of coffee (small pot). If I get a low voltage alarm on the inverter, I press the "Start" button on my remote car starter and let the truck run for about 15 minutes to charge the coach battery. Our longest boondock was in a Sams Club parking lot in the middle of a severe snow storm. A day and a half, running TV, furnace, microwave, lights, I started the truck once just to top off the coach battery. If we used our toyhouse to boondock for long periods, I would probably get a small portable generator to re-charge the coach battery once a day rather than run the truck. Solar or a small wind turbine would also be an option. Adding higher capacity batteries might also be an option, but look at usage before adding battery capacity (i.e. LED lights and Catalyst heat instead of running furnace) Inverter Install Boiling Water Interior LED conversion Running light LED conversion Taillight LED conversion Ventless heaters John Mc 88 Dolphin 4 Auto Great links...thanks! Quote Link to comment Share on other sites More sharing options...
stamar Posted May 22, 2012 Share Posted May 22, 2012 no debate necessary.... but the cost of starting a car, and running it for 15 seconds is much much more than turning on propane and boiling water. The cost of sitting there and recharging the batteries ( if youre not going anywhere) is um.... I cant say i estimate 2$ for your hot water versus less than 5c...... But if thats how you roll thats how you roll. I wont say rvers dont do that becuase they do it all day long, what I mean is fulltime rvers dont do that. They dont use the microwave at all until they are plugged in, even if they have an onan generator and it costs them like 50c. I cant really give advice to a newbie to invest in a set up that they should never use.... Quote Link to comment Share on other sites More sharing options...
wistoy Posted May 25, 2012 Share Posted May 25, 2012 Advice on a 1500 watt inv. I installed a second coach battery (vented and sealed box), bought a 1500 pure sine wave inverter, to install, but when I read the cautions I am not sure if I should install -- heat warnings, and warnings not to set on near anything flamable (dry rv framing, and or carpet?) How do you deal with the heat from the inverter? I do use a roof top mounted 80 watt solar tops up my batterys for night time use, not sure about the auto pilot furnace demand on the batterys ( using a buddy heater instead- but would like to leave one more piece of equipment home) The inverter's need is mainly for 2 CPAP machines, and 1500 is overkill, but I like the option for other use. Dale Quote Link to comment Share on other sites More sharing options...
waiter Posted May 25, 2012 Share Posted May 25, 2012 My inverter is a modified sine wave type (less expensive) which is different than the one your proposing. I've had no problem with heat produced by the unit, as I don't think I run it long enough to build up heat.. Mine is installed in a closed space (under the table bench seat)) I had planned to install a small 110 Vac box fan to blow air into the compartment if I found heat was an issue. The inverter needs to be mounted as close to the battery as possible to keep the wire length as short as possible. Also , I would use at least a #4 wire, #2 or even #0 would be better, especially if your going to be using the inverter near it capacity. There are two issues with the furnace: 1) Very inefficient as far as converting LP to heat , about 1/2 of the heat produced is dumped overboard in the form of burner exhaust. I like the Wave 3 heater, its a catalyst type but only puts out 3000 btu. The Mr Buddy I have will put out 9000 btu, but its a ceramic. The catalytic puts out significantly less emissions than the Ceramic. you can read about these in the other post. Follow the directions for keeping a vent open. We crack one of the roof vents up about 1/2 inch, and open the drivers window about 1/4 inch. You should also get a CO2 alarm, these are about $20 at the big box store, get the kind that has a readout. The danger from the Catalysis type is oxygen deprivation, the danger from the ceramic type is CO2. 2) Battery consumption - the blower is what sucks up the battery. ALSO - The original control board makes one attempt to light, if it fails to light, the blower keeps running as long as there is a call for heat. On out trip last winter, we ran the Wave 3 all night and set the furnace at 55. It kicked on a couple times. We spent one night in Iowa with Outside Air Temp of -10 Deg and winds, We ran the Mr Buddy that night at to 9000 setting. John Mc 88 Dolphin 4 Auto Quote Link to comment Share on other sites More sharing options...
wistoy Posted May 25, 2012 Share Posted May 25, 2012 Thanks for the info. always easyer and less costly to learn from the who already figured it out.[ Dale Quote Link to comment Share on other sites More sharing options...
WME Posted May 26, 2012 Share Posted May 26, 2012 Here is an alternative to leaving the window open in real cold, and still having a very low draw heater. http://ventedcatheater.com Quote Link to comment Share on other sites More sharing options...
waiter Posted May 26, 2012 Share Posted May 26, 2012 WME - Yes, these are a Catalytic heater, similar to the Wave 3. like this one because it has a thermostat and electric ignition. The wave 3 does not, its ON or OFF and you need to light it manually. The problem is, this unit needs to be mounted permanently, the Wave 3 can be moved around. Catalytic heaters (NOT to be confused with Ceramic heaters) produce heat through a chemical reaction with a special chemical embedded in the heating pad. There is no flame However, this unit is NOT a ventless heater, You must install the power vent with this system. John Mc 88 Dolphin 4 Auto Quote Link to comment Share on other sites More sharing options...
WME Posted May 26, 2012 Share Posted May 26, 2012 Yes its vented, that why I said you did not need to open a window in cold weather. Helps keep things warmer. There a bunch of different type of RV heaters, each one fills a need. Me, I just went solar, big batteries and just use the propane furnace Quote Link to comment Share on other sites More sharing options...
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