I was at the newport boat show and saw a new hunter 36 with microwave and inverter,how much can you use the microwave when away from shore power.
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Hi Nick, that depends on the amp rating of...
the microwave and the amp hours available in the house bank. If you know those two numbers you can do the math to come up with an estimate. Keep in mind that if the house bank is rated at 300 amp hours, one half of that becomes useable for appliance consumption. The other factor is the loss of available battery amps to the conversion to AC process; about 30%. We run ours to warm meals and heat liquids, usually in two to five minute intervals. No big deal unless you also watch movies, play music, run the furnace, etc., etc., etc. If your bank has 150 useable amps, they will be flat (12 volts) in no time if you have that kind of demand. Like others we have a Genset on board which makes extended life on the hook much more pleasant. Terry
the microwave and the amp hours available in the house bank. If you know those two numbers you can do the math to come up with an estimate. Keep in mind that if the house bank is rated at 300 amp hours, one half of that becomes useable for appliance consumption. The other factor is the loss of available battery amps to the conversion to AC process; about 30%. We run ours to warm meals and heat liquids, usually in two to five minute intervals. No big deal unless you also watch movies, play music, run the furnace, etc., etc., etc. If your bank has 150 useable amps, they will be flat (12 volts) in no time if you have that kind of demand. Like others we have a Genset on board which makes extended life on the hook much more pleasant. Terry
Very little.
A microwave oven rated at 700 watts would seem to draw 5.8 amps at 120V. But the Power Factor of a microwave oven is around .6 so the actual draw would be closer to 9.6 amps. At 12v the draw would be approximately 96 amps but with the inverters loss of efficiency you would probably be looking at 113 amp/hours. I would say if ran from a 200 Amp hour battery bank in 15-20 minutes the low voltage shut down switch on the inverter would be tripped. Batteries do not take kindly to such a high rate of discharge. The inverter on those boats is not meant to run the microwave oven; they can run a refrigerator and other small appliances. Of course the usage is subject to the recharging capabilities.
A microwave oven rated at 700 watts would seem to draw 5.8 amps at 120V. But the Power Factor of a microwave oven is around .6 so the actual draw would be closer to 9.6 amps. At 12v the draw would be approximately 96 amps but with the inverters loss of efficiency you would probably be looking at 113 amp/hours. I would say if ran from a 200 Amp hour battery bank in 15-20 minutes the low voltage shut down switch on the inverter would be tripped. Batteries do not take kindly to such a high rate of discharge. The inverter on those boats is not meant to run the microwave oven; they can run a refrigerator and other small appliances. Of course the usage is subject to the recharging capabilities.
No problem running micro
I run a microwave on my boat quite a bit. If I feel I'm using it too long (which never seems to be an issue) I'll fire up the motor and help keep the batterys up while running the microwave. I have 470 amp hours on my banks also though. I don't think I could do without the microwave now that I have it and use it. It's a 2000 watt continuous with a 4000 watt surge invertor. Tim Welsh Hunter 34 S/V Cabo Wabo
I run a microwave on my boat quite a bit. If I feel I'm using it too long (which never seems to be an issue) I'll fire up the motor and help keep the batterys up while running the microwave. I have 470 amp hours on my banks also though. I don't think I could do without the microwave now that I have it and use it. It's a 2000 watt continuous with a 4000 watt surge invertor. Tim Welsh Hunter 34 S/V Cabo Wabo
Hunter 356-36
Ok I guess I new that I would need to know the amp hours of the bank and draw of the mic,I guess my next question would be has any hunter 356-36 have the factory mic and inverter and what amp hours do they have and how much can they use it. And all that have answered thanks we are looking to move up to the hunter 36 and the wife is asking all these questions and what to add to the boat when we make the move.
Ok I guess I new that I would need to know the amp hours of the bank and draw of the mic,I guess my next question would be has any hunter 356-36 have the factory mic and inverter and what amp hours do they have and how much can they use it. And all that have answered thanks we are looking to move up to the hunter 36 and the wife is asking all these questions and what to add to the boat when we make the move.
No problem with microwave
Nick: I would suggest you specify two lifeline 4d batteries for your new H36. They will deliver 420 amp hours and they are closed cell units that need no maintanance and will last up to 600 cycles. I changed out my lead acid to these after the second season, so the life cycle cost of the lifelines is much better than the lead acid. Had I changed them to lifeline at commissioning, I probably would have spent an additional $150 to $200. My new batteries, a G24 and 2 4d's cost about $900. I think they will last me a long time! I also installed a link 20 which allows me to monitor the discharge levels and I never discharge past 50%. I have the factory installed Xantrex Freedom 2000 inverter. As to your microwave, it is 800 watts and takes a while to heat up something as opposed to one at home. It will run fine off the inverter, but you will need a good sized house bank similar to mine if you plan on running off batteries for long. I have a generator that we run for cooling and heating almost all the time, so I don't worry over battery capacity. I have checked my loads on the link 20 and they are as follows: Ref/Sonar/Radar/GPS/VHF/Wind/Speed/Autopilot = 7.9 amps - my minimum Add int lights/TV/KVH tracking antenna/laptop/cell phone chargers/ I get up to 30 amps - without microwave. Microwave should be around 9 amps, including the inefficiency of the inverter. You don't use it more than a few minutes and if you want to cook a large meal on it, just turn on the engine and that will replace your amp hours at about 65 amps/hour. It takes about 2-1/2 minutes in this microwave to warm a cup of cold water for coffee or tea. That is only 1/3 amp hour per cup. I'll be at the boat this weekend and will actually run the microwave on inverter and see what the actual load is and post it here for you. I think you have indicated you are moving to Punta Gorda - if so, I would certainly consider a Northern Lights 5.5 kw generator. It is HOT and HUMID in Punta Gorda much of the year like it is here in Tennessee and Kentucky. It can also get cold there. Being able to go down below and cool off or warm up is a tremendous benefit and makes sailing much more pleasant. I have sailed out of Punta Gorda several times and have friends that live there. My generator uses about 6 gallons in 24 hours of use and we turn it on at the dock and run pretty much continuously 80% of our sailing season. It has a custom sound shield and is very quiet. Without it, my wife wouldn't spend much time on our boat. As it is, we spend about 80 days a year on-board. I still only use about 100 gallons of fuel per year from March through November. With the lifelines and the generator, you won't ever worry about electrical consumption. I think the generator has been one of the best items we put on the boat. You will really enjoy the 36, it is a great boat!
Nick: I would suggest you specify two lifeline 4d batteries for your new H36. They will deliver 420 amp hours and they are closed cell units that need no maintanance and will last up to 600 cycles. I changed out my lead acid to these after the second season, so the life cycle cost of the lifelines is much better than the lead acid. Had I changed them to lifeline at commissioning, I probably would have spent an additional $150 to $200. My new batteries, a G24 and 2 4d's cost about $900. I think they will last me a long time! I also installed a link 20 which allows me to monitor the discharge levels and I never discharge past 50%. I have the factory installed Xantrex Freedom 2000 inverter. As to your microwave, it is 800 watts and takes a while to heat up something as opposed to one at home. It will run fine off the inverter, but you will need a good sized house bank similar to mine if you plan on running off batteries for long. I have a generator that we run for cooling and heating almost all the time, so I don't worry over battery capacity. I have checked my loads on the link 20 and they are as follows: Ref/Sonar/Radar/GPS/VHF/Wind/Speed/Autopilot = 7.9 amps - my minimum Add int lights/TV/KVH tracking antenna/laptop/cell phone chargers/ I get up to 30 amps - without microwave. Microwave should be around 9 amps, including the inefficiency of the inverter. You don't use it more than a few minutes and if you want to cook a large meal on it, just turn on the engine and that will replace your amp hours at about 65 amps/hour. It takes about 2-1/2 minutes in this microwave to warm a cup of cold water for coffee or tea. That is only 1/3 amp hour per cup. I'll be at the boat this weekend and will actually run the microwave on inverter and see what the actual load is and post it here for you. I think you have indicated you are moving to Punta Gorda - if so, I would certainly consider a Northern Lights 5.5 kw generator. It is HOT and HUMID in Punta Gorda much of the year like it is here in Tennessee and Kentucky. It can also get cold there. Being able to go down below and cool off or warm up is a tremendous benefit and makes sailing much more pleasant. I have sailed out of Punta Gorda several times and have friends that live there. My generator uses about 6 gallons in 24 hours of use and we turn it on at the dock and run pretty much continuously 80% of our sailing season. It has a custom sound shield and is very quiet. Without it, my wife wouldn't spend much time on our boat. As it is, we spend about 80 days a year on-board. I still only use about 100 gallons of fuel per year from March through November. With the lifelines and the generator, you won't ever worry about electrical consumption. I think the generator has been one of the best items we put on the boat. You will really enjoy the 36, it is a great boat!
My Microwave
Mine draws 75 amps and it is a 700 watt unit which came with the boat. We often run the engine at low revs when using the microwave. The alternator provides 45 amps so there is a net drain of 30 amps. For the relatively short times we run the microwave the impact on battery state is not significant. DON'T forget to turn the immersion heater in the calorifier off though as it draws 147 amps.
Mine draws 75 amps and it is a 700 watt unit which came with the boat. We often run the engine at low revs when using the microwave. The alternator provides 45 amps so there is a net drain of 30 amps. For the relatively short times we run the microwave the impact on battery state is not significant. DON'T forget to turn the immersion heater in the calorifier off though as it draws 147 amps.
Donalex, Don't forget to turn off WHAT???
Must be one of those European things huh? As I recall, my Microwave is rated at 900 watts. The Prosine 2.0 inverter gives it 9 amps A/C. My new Xantrex battery monitor says that equals 100 amps DC. OH! Another revelation with the new monitor; My inverter, on standby, wired into the electrical system but with NOTHING turned on, draws 3 amps DC. That's equal to the flat screen TV. And the TV is wired directly to 12 volts as is the nav station laptop.
Must be one of those European things huh? As I recall, my Microwave is rated at 900 watts. The Prosine 2.0 inverter gives it 9 amps A/C. My new Xantrex battery monitor says that equals 100 amps DC. OH! Another revelation with the new monitor; My inverter, on standby, wired into the electrical system but with NOTHING turned on, draws 3 amps DC. That's equal to the flat screen TV. And the TV is wired directly to 12 volts as is the nav station laptop.
Hey Fred...
that must be the Brit name for a water heater! LOL!!! Gotta go buy an English/American translation dictionary!
that must be the Brit name for a water heater! LOL!!! Gotta go buy an English/American translation dictionary!
Donalex, I suspect the net Amp drain
may be higher than assesed. I don't dispute your methodoligy which indicates that in theory as well as in practice you can run your MW for a short period of time. But if you wanted to asses the limits please look deeper. You have to take into consideration not only the microwave oven draw but the additional draw due to inverter inneficiency which may average 10 to 15%. Also by idling the engine it is very unlikely you are getting the full output of your alternator; with heat losses and other you may be getting from 25 to 30 amps tops. Under best conditions your net defficiency would be around 50-55 amps. I agree it is ok to use it to defrost food or heat up for a couple of minutes but stay away from baked potatoes. What really is of concern is the rapid rate of discharge as it pertains to battery capacity. The faster you take energy out of a battery the less of it will be available. At a rate of discharge of 50+ amps you would be diminishing your battery's capacity by about 1/2. All of a sudden that 200 amp bank behaves more like a 100 amp bank. The best practice would be to use a generator to run the appliance.
may be higher than assesed. I don't dispute your methodoligy which indicates that in theory as well as in practice you can run your MW for a short period of time. But if you wanted to asses the limits please look deeper. You have to take into consideration not only the microwave oven draw but the additional draw due to inverter inneficiency which may average 10 to 15%. Also by idling the engine it is very unlikely you are getting the full output of your alternator; with heat losses and other you may be getting from 25 to 30 amps tops. Under best conditions your net defficiency would be around 50-55 amps. I agree it is ok to use it to defrost food or heat up for a couple of minutes but stay away from baked potatoes. What really is of concern is the rapid rate of discharge as it pertains to battery capacity. The faster you take energy out of a battery the less of it will be available. At a rate of discharge of 50+ amps you would be diminishing your battery's capacity by about 1/2. All of a sudden that 200 amp bank behaves more like a 100 amp bank. The best practice would be to use a generator to run the appliance.
You guys not familiar with a "calorifier"
it is usually hooked up to a rainmaker in the water closet.
it is usually hooked up to a rainmaker in the water closet.
Donalex,
Out of curiosity, do you run 110 or 220 in the boat? 220 = smaller wires and less current.
Out of curiosity, do you run 110 or 220 in the boat? 220 = smaller wires and less current.
Hey, Benny...
if you watch enough of the BBC channel you'll eventually see one of those things on the wall above the tub in the loo. Dontcha just love their names for things?
if you watch enough of the BBC channel you'll eventually see one of those things on the wall above the tub in the loo. Dontcha just love their names for things?
Calorifier!!
Hey guys I used the Calorifier word in anticipation of getting someone to respond. Yes it is a very old term for the hot water tank. Only used nowadays by oldies and pedants - and others who like to have a bit of fun. Maybe, one day, I will write an English to "English?" dictionary. Ref my microwave (Fred, Benny & Dan) I have a Link 2000 controlling my Freedom 1000 - now sold by Xantrex. The amps drawn are read from the Link which is pretty accurate. The alternator is only a 55 amp unit but has an external high rate controller. Its output is also read on the Link. In my book 75 amps at 12 volts equals 900 watts. The microwave draws 3 amps at 240 v 50Hz. This leaves the losses in the cabling, internal resistance of the 360 Ah battery bank and the inverter as 200 watts which means a 22% power loss. So the inverter etc. efficiency is only 80% but this is quite normal for this class of equipment. I am a, now retired, electronics & mechanical engineer with power experience, so I have heard of and set the Link up to cope with Peukerts Exponent.
Hey guys I used the Calorifier word in anticipation of getting someone to respond. Yes it is a very old term for the hot water tank. Only used nowadays by oldies and pedants - and others who like to have a bit of fun. Maybe, one day, I will write an English to "English?" dictionary. Ref my microwave (Fred, Benny & Dan) I have a Link 2000 controlling my Freedom 1000 - now sold by Xantrex. The amps drawn are read from the Link which is pretty accurate. The alternator is only a 55 amp unit but has an external high rate controller. Its output is also read on the Link. In my book 75 amps at 12 volts equals 900 watts. The microwave draws 3 amps at 240 v 50Hz. This leaves the losses in the cabling, internal resistance of the 360 Ah battery bank and the inverter as 200 watts which means a 22% power loss. So the inverter etc. efficiency is only 80% but this is quite normal for this class of equipment. I am a, now retired, electronics & mechanical engineer with power experience, so I have heard of and set the Link up to cope with Peukerts Exponent.
Jerry
Jerry thanks for the help I am looking in to adding the generator,any other help and advice will be appreciated. nick
Jerry thanks for the help I am looking in to adding the generator,any other help and advice will be appreciated. nick
Actual Measured Microwave Draw
Nick: Got to boat last night and wanted to actually compare my actual readings with theoretical draw for the microwave to give you real numbers to think about before your purchase of the H36. Shut off shore power this morning and went to inverter. Loads without microwave were TV, KVH Antenna/Dish box, and other 110 outlet draws. The base load over a couple of minutes read from the Link 20 was about 24 amps using the inverter Heated a cup of hot water for 2-1/2 minutes. Draw on batteries before was reading 24.7 Amps/Hr draw. About midpoint of the 2.5 minutes, the draw was 109 Amps/Hr. The difference is 84.3 with the microwave running. That is about 1.4 amps per minute, so a cup of coffee is about 3-1/2 Amps from your battery bank. Total use getting things set up and then going back to shore power after this experiment used about 25 amps from the battery. I have really heavy loads compared to most people. The load to make the coffee was a little less than 1% of my bank and about 1.6% of what I use before recharging (50% draw). If you want to do much microwave cooking without the engine running, I would definitely recommend you get a generator. If you decide to do so, there are several considerations I want to share with you before you decide which one and how you install it. The speed of the generator, number of cylinders, location of thru-hull and sound control are all important factors. The above readings are pretty consistent with the rule of thumb that the 12 volt amps drawn are about 10 times the 120 volt draw. From my previous post, we estimated that the 120 amps were about 1/3 amp per cup or .33 - multiply times 10 and thats about 3.3 amps - very close to the 3.5 that we got using the Link 20. If you want to do much microwave cooking without the engine running, I would definitely recommend you get a generator. If you decide to do so, there are several considerations I want to share with you before you decide which one and how you install it. Also Fred, Phukert is alive and well this morning! Those amps were flying out of the battery!
Nick: Got to boat last night and wanted to actually compare my actual readings with theoretical draw for the microwave to give you real numbers to think about before your purchase of the H36. Shut off shore power this morning and went to inverter. Loads without microwave were TV, KVH Antenna/Dish box, and other 110 outlet draws. The base load over a couple of minutes read from the Link 20 was about 24 amps using the inverter Heated a cup of hot water for 2-1/2 minutes. Draw on batteries before was reading 24.7 Amps/Hr draw. About midpoint of the 2.5 minutes, the draw was 109 Amps/Hr. The difference is 84.3 with the microwave running. That is about 1.4 amps per minute, so a cup of coffee is about 3-1/2 Amps from your battery bank. Total use getting things set up and then going back to shore power after this experiment used about 25 amps from the battery. I have really heavy loads compared to most people. The load to make the coffee was a little less than 1% of my bank and about 1.6% of what I use before recharging (50% draw). If you want to do much microwave cooking without the engine running, I would definitely recommend you get a generator. If you decide to do so, there are several considerations I want to share with you before you decide which one and how you install it. The speed of the generator, number of cylinders, location of thru-hull and sound control are all important factors. The above readings are pretty consistent with the rule of thumb that the 12 volt amps drawn are about 10 times the 120 volt draw. From my previous post, we estimated that the 120 amps were about 1/3 amp per cup or .33 - multiply times 10 and thats about 3.3 amps - very close to the 3.5 that we got using the Link 20. If you want to do much microwave cooking without the engine running, I would definitely recommend you get a generator. If you decide to do so, there are several considerations I want to share with you before you decide which one and how you install it. Also Fred, Phukert is alive and well this morning! Those amps were flying out of the battery!
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