If I install a Apartment size AC Refrigerater that draws 2 amps , with a power inverter to change to DC power. Is the inverter going to use any addional power to run its self? I`m thinking of going this route to save money. and I don`t like the ice box location in my 1981 hunter.
AC Refrigeration/inverters
- Thread starter Chet7135
- Start date
- Status
AC-DC
Yes, inverters draw a small amount of current while "idling" and their efficiency is not 100% at converting DC to AC. Most are around 90%. Be careful as a reefer has an AC motor and those are kinda sensitive to the shape of the voltage-current wave that a "less than true sine wave" inverter puts out. A point though, your 120 volt AC reefer draws 2 amps (240 watts) but the inverter will be drawing 20+ amps at 12 volts (also 240 watts). Even at 50% duty cycle on the reefer that is: 24 hours X 20 amps X 0.5 duty = 240 amp-hours each day!!!!! This WILL kill your electrical system in short order. While on shore power you will be OK however. Better to get a 12 volt RV reefer as they are much more efficient and you bypass the inverter all together.
Yes, inverters draw a small amount of current while "idling" and their efficiency is not 100% at converting DC to AC. Most are around 90%. Be careful as a reefer has an AC motor and those are kinda sensitive to the shape of the voltage-current wave that a "less than true sine wave" inverter puts out. A point though, your 120 volt AC reefer draws 2 amps (240 watts) but the inverter will be drawing 20+ amps at 12 volts (also 240 watts). Even at 50% duty cycle on the reefer that is: 24 hours X 20 amps X 0.5 duty = 240 amp-hours each day!!!!! This WILL kill your electrical system in short order. While on shore power you will be OK however. Better to get a 12 volt RV reefer as they are much more efficient and you bypass the inverter all together.
Right!
Actually it is not that they put 12 systems in but they don't put inefficient AC reefers with 2" of insulation in. I'm looking forward to the day when CNG is available and we can have gas powered reefers. Real ice cream after 2 weeks at sea!!!!
Actually it is not that they put 12 systems in but they don't put inefficient AC reefers with 2" of insulation in. I'm looking forward to the day when CNG is available and we can have gas powered reefers. Real ice cream after 2 weeks at sea!!!!
bill i had no idea ,
there would be that much draw. Thats not going the work then for long term living aboard, my house batteries are three glass mat group 31. still trying to figure out the corect size solar panel to buy.and if wind generter would be better for key west fl. area. thanks for the info. chet
there would be that much draw. Thats not going the work then for long term living aboard, my house batteries are three glass mat group 31. still trying to figure out the corect size solar panel to buy.and if wind generter would be better for key west fl. area. thanks for the info. chet
I have not investigated the details but
a gallon jug of ice will stay cold in my ice box for 4 days. I have considered going the a super market and asking the managor if I purchased 4 gallons of water could he have them placed in his freezer over night for pick up the next day. In that way I would get ice for about the same price as bagged ice but also get clean fresh water. In my ice box 20 ounce bottles thaw in 24 hours, 2 liter bottles last two full days before all of the ice is melted, gallons last 4 days before all the ice melts in hot weather. But 4 gallons of water is about right for four days usage for drinking and cooking. We wash with tank water.
a gallon jug of ice will stay cold in my ice box for 4 days. I have considered going the a super market and asking the managor if I purchased 4 gallons of water could he have them placed in his freezer over night for pick up the next day. In that way I would get ice for about the same price as bagged ice but also get clean fresh water. In my ice box 20 ounce bottles thaw in 24 hours, 2 liter bottles last two full days before all of the ice is melted, gallons last 4 days before all the ice melts in hot weather. But 4 gallons of water is about right for four days usage for drinking and cooking. We wash with tank water.
I`m not sure what your saying there Ross,
I`m planning on traveling the ICW in Oct. And want to get away from buying ice every two days. I won`t have anyway to freeze gallon jugs of water, while living aboard.
I`m planning on traveling the ICW in Oct. And want to get away from buying ice every two days. I won`t have anyway to freeze gallon jugs of water, while living aboard.
I Used This System
I used this same setup the past two falls, doing the ICW, from the NE back to home base in New Orleans. The numbers given by Bill are correct. I had a unit that drew 1.9 amps, on AC, which converts to roughly 20 amps off the batteries. Traveling the ICW, which after Norfolk is mostly motoring, it is not a problem. I have a three hundred amp hour house bank, and I had no problems with overnight at anchor, but could not make 24 hours without recharging. I watched my usage pretty close, and the little fridge ran about 30%. The small office/dorm fridges are not well insulated enough to do a good job on a boat.
I used this same setup the past two falls, doing the ICW, from the NE back to home base in New Orleans. The numbers given by Bill are correct. I had a unit that drew 1.9 amps, on AC, which converts to roughly 20 amps off the batteries. Traveling the ICW, which after Norfolk is mostly motoring, it is not a problem. I have a three hundred amp hour house bank, and I had no problems with overnight at anchor, but could not make 24 hours without recharging. I watched my usage pretty close, and the little fridge ran about 30%. The small office/dorm fridges are not well insulated enough to do a good job on a boat.
Solar/wind systems
I did what i callled alot of research and calls to tech people asking guestions. Thw wind systems really depend on the area you are in. IE: I live along the gulf coast and many times there is little to no wind days on Moble bay. There fore i chose solar. The system i installed is a KC-130 130 watt panel with charge controller. During the early morning hrs when the sun isnt directlt overhead, it puts out abt 2 amps which is the equivilent of a trickle charger or maintainer. however, after 10 am it jumps up to 7.4 amps. I run my ice box conversion unit all night and all day when sailing with only 1 house battery of 85 AHs. THe set-up will produce abt 600 watts a day in my area with only 1 panel. PS ; hey niceneasy, i,ll be leaving Fairhope Saturday morning for big lagoon. Hunter 30 with blue bimin and solar panel mounted above bimin. S/V Jacob's Dream
I did what i callled alot of research and calls to tech people asking guestions. Thw wind systems really depend on the area you are in. IE: I live along the gulf coast and many times there is little to no wind days on Moble bay. There fore i chose solar. The system i installed is a KC-130 130 watt panel with charge controller. During the early morning hrs when the sun isnt directlt overhead, it puts out abt 2 amps which is the equivilent of a trickle charger or maintainer. however, after 10 am it jumps up to 7.4 amps. I run my ice box conversion unit all night and all day when sailing with only 1 house battery of 85 AHs. THe set-up will produce abt 600 watts a day in my area with only 1 panel. PS ; hey niceneasy, i,ll be leaving Fairhope Saturday morning for big lagoon. Hunter 30 with blue bimin and solar panel mounted above bimin. S/V Jacob's Dream
CO2 refrigeration
Tropicool out of Southern Ca. makes a system that uses CO2 for the refrigerent ! It's a 12 Volt system,using a Sterling pump.I am a refrigeration mechanic and have designed and built many system's for pleasure craft in the past,but when i bought my 85 Hunter Cutter i did'nt want to invest the time and money in a complacated unit,so did a lot of research and found the TRopicool the most effecient in amp draw[google Tropicool] The Sterling pump has a Helium head on one end that absorbs the heat from the returning gas and on the other end a muffin fan that draws the hot air away,there is a 3/8 copper tube that goes from the pump to the evaperator in the fridge,and it's easy to install,check it out,Doug.
Tropicool out of Southern Ca. makes a system that uses CO2 for the refrigerent ! It's a 12 Volt system,using a Sterling pump.I am a refrigeration mechanic and have designed and built many system's for pleasure craft in the past,but when i bought my 85 Hunter Cutter i did'nt want to invest the time and money in a complacated unit,so did a lot of research and found the TRopicool the most effecient in amp draw[google Tropicool] The Sterling pump has a Helium head on one end that absorbs the heat from the returning gas and on the other end a muffin fan that draws the hot air away,there is a 3/8 copper tube that goes from the pump to the evaperator in the fridge,and it's easy to install,check it out,Doug.
The ICW
Chet, if your headed south on the ICW and plan on staying mostly inside, you will be motoring enough to keep up with it.
Chet, if your headed south on the ICW and plan on staying mostly inside, you will be motoring enough to keep up with it.
Chuck,
I had planned on being over that way this week. Unfortunately, my brother passed away Friday, and I am now in Dallas. Will be here for an undetermined amount of time, so any sailing plans are now on the back burner.
I had planned on being over that way this week. Unfortunately, my brother passed away Friday, and I am now in Dallas. Will be here for an undetermined amount of time, so any sailing plans are now on the back burner.
Well you guys once again ...
have alot of good information about this post. from what i read here , and because i`m planning on living aboard in fl on mooring, I`m just going to spend the money and buy a icebox conversion unit. sounds like thats the best way to go. thanks everyone.
have alot of good information about this post. from what i read here , and because i`m planning on living aboard in fl on mooring, I`m just going to spend the money and buy a icebox conversion unit. sounds like thats the best way to go. thanks everyone.
H31_83-87 CO2 refrigeration
I installed the Tropicool in my H31 1987. Works GREAT! Max 12V draw 3 Amps, then drops to 1 Amp to maintain (I kept an amp meter on it for the first 30 days after install. Installation help from company-GREAT! Mine has been running 24/7 for the last 18 months, except for turning off to defrost once every several months. See Link below bill
I installed the Tropicool in my H31 1987. Works GREAT! Max 12V draw 3 Amps, then drops to 1 Amp to maintain (I kept an amp meter on it for the first 30 days after install. Installation help from company-GREAT! Mine has been running 24/7 for the last 18 months, except for turning off to defrost once every several months. See Link below bill
Is not as bad as it sounds.
If your apartment size refrigerator is rated at 2 amps per hour at 120V it will be rated at 20 amps per hour at 12V and with the loss of effiency of the inverter I would consider a draw of 22 amps per hour. Now that is when the compressor is running. A well insulated and good working refrigerator should cycle the compressor on for no more than 10-15 minutes for every hour. That reduces the amperage usage to an average of 4 amps per hour or 96 amps for a 24 hour period. With a battery bank of 318 amps and a recommended maximum discharge of 159 amps you could safely utilize the inverter/refrigerator combination but you need to figure out how you will replace those 96 amps plus all your other usage. A charge source of 4-5 amps per hour could keep the batterys charged by replacing what is being spent. The problem arises with the inverter as the electric compressor motor needs about 6-7 times the amount of power to start as it needs to be able to run. 22 amps X 12V= 264 watts. 7 times that would be 1,848 watts so you would need an inverter rated for at least 2,000 watts. A good inverter of that size will run you $300-$400. On our h27 we run a dorm size refrigerator 1.7 cf that draws 1.1 Amps at 120V or 11 amps at 12V and with ineficiecy we round it up at 12 Amps. That is 144 watts or a starting requirement of 1,008 watts. We run it with a 1,200 watt inverter that cost $120 plus installation. we also watch TV out of that inverter so the cost was justified. The beauty of the smaller refrigerator is that the average hourly consumption is around 1.2 amps per hour or 30 amps per 24 hour period. I don't think a cooler 12v conversion will use any less power than this. Consider a smaller dorm cooler.
If your apartment size refrigerator is rated at 2 amps per hour at 120V it will be rated at 20 amps per hour at 12V and with the loss of effiency of the inverter I would consider a draw of 22 amps per hour. Now that is when the compressor is running. A well insulated and good working refrigerator should cycle the compressor on for no more than 10-15 minutes for every hour. That reduces the amperage usage to an average of 4 amps per hour or 96 amps for a 24 hour period. With a battery bank of 318 amps and a recommended maximum discharge of 159 amps you could safely utilize the inverter/refrigerator combination but you need to figure out how you will replace those 96 amps plus all your other usage. A charge source of 4-5 amps per hour could keep the batterys charged by replacing what is being spent. The problem arises with the inverter as the electric compressor motor needs about 6-7 times the amount of power to start as it needs to be able to run. 22 amps X 12V= 264 watts. 7 times that would be 1,848 watts so you would need an inverter rated for at least 2,000 watts. A good inverter of that size will run you $300-$400. On our h27 we run a dorm size refrigerator 1.7 cf that draws 1.1 Amps at 120V or 11 amps at 12V and with ineficiecy we round it up at 12 Amps. That is 144 watts or a starting requirement of 1,008 watts. We run it with a 1,200 watt inverter that cost $120 plus installation. we also watch TV out of that inverter so the cost was justified. The beauty of the smaller refrigerator is that the average hourly consumption is around 1.2 amps per hour or 30 amps per 24 hour period. I don't think a cooler 12v conversion will use any less power than this. Consider a smaller dorm cooler.
- Status