I recently took delivery of a new passage 450 and was surprised to see it installed with an AC powered refridgeration system by Grunert. The box would not hold it's temp. between genset running cycles (morning and night) and when I ran it through the inverter it would draw 150 amps out of the batteries, albeit a short amount of time. It would cycle about once an hour for 1 - 2 minutes. Hunter said they have been putting them on big boats and have had no complaints. I am worried about my battery bank and am expecting a call from thr grunert rep. Does anyone have the AC compressor on their fridge and how do you like it? How often does it cycle? How are your batteries? The boat came with a 470 amp hour battery bank. Any info would be a big help. Thanks in advance. Kevin
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Richard Owen
Grunert System
Kevin: You should get good advice on this here - it has been a hot topic previously. As far as Hunter saying they have had no complaints - I don't think so!!! We have a 460 with the same system. First, I have never seen a draw of 150A when the fridge is running. For our system, max is about 105 when starting, and usually settles down to about 75, 85 if both sides are on. Second, the system should not short cycle like that. When we got our boat, it had many control problems. It works well now - both controls have been changed. In my experience, the system will run for about 10-20 minutes at a time. It even does this at first use, cycling on and off until the set temperature is met. Once the set point is reached, it will run about 15-20 minutes every 4 or 5 hours. (assuming wise use of the doors). Total draw should be in the range of 100-150 A/Hrs. per day. If you live in a very warm environment, you will have higher use. As far as the system in general, now that ours is working correctly, I like it. We actually shut it off at night - it holds temp very well, and run it in the morning which is often when we will be motoring, thus saving on the batteries. If we aren't moving, we run the genset for an hour or so each day. Our batteries have been boosted to about 700 A/H. Our total usage daily varies between 200 and 300 A/H depending on how hard we try. We wanted to be able to go two days without necessarily re-charging, but that doesn't really work because it will take too long to re-charge if we draw to the full 350 A/H available. The answer for us is to run the batteries between 50 and 250. Hope this helps some.
Kevin: You should get good advice on this here - it has been a hot topic previously. As far as Hunter saying they have had no complaints - I don't think so!!! We have a 460 with the same system. First, I have never seen a draw of 150A when the fridge is running. For our system, max is about 105 when starting, and usually settles down to about 75, 85 if both sides are on. Second, the system should not short cycle like that. When we got our boat, it had many control problems. It works well now - both controls have been changed. In my experience, the system will run for about 10-20 minutes at a time. It even does this at first use, cycling on and off until the set temperature is met. Once the set point is reached, it will run about 15-20 minutes every 4 or 5 hours. (assuming wise use of the doors). Total draw should be in the range of 100-150 A/Hrs. per day. If you live in a very warm environment, you will have higher use. As far as the system in general, now that ours is working correctly, I like it. We actually shut it off at night - it holds temp very well, and run it in the morning which is often when we will be motoring, thus saving on the batteries. If we aren't moving, we run the genset for an hour or so each day. Our batteries have been boosted to about 700 A/H. Our total usage daily varies between 200 and 300 A/H depending on how hard we try. We wanted to be able to go two days without necessarily re-charging, but that doesn't really work because it will take too long to re-charge if we draw to the full 350 A/H available. The answer for us is to run the batteries between 50 and 250. Hope this helps some.
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Bryan C.
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Gordon Myers
Ref. / Freezer
Kevin, I am a little confused. We also have a 450 with Ref./Freezer on 110 volt AC power system. This was the 1st year we have had the boat and are not currently living on it. Just using the boat for weekends. The Ref. works so well that with the exception to test the freezer, we have not used it. When we start the Ref. up for the weekend, it runs for about 1 hr to 1.5 hours before it cycles off. It will recycle back on in about 2 hours for 20 +/- mins. After that (if we leave in overnight) it will recycle about every 3 hrs. for about 20 +/- mins. We, other than to test the inverter system with the Ref., do not run the Ref. off of the batteries. The batteries with the engine running will run the Ref. (through the inverter), but you are eating up battery cycle life. When the Ref. starts up, the AC amps are high for just a moment (start up amperage). Once running the Ref, only draws 10 amps (AC). We have the Ref. temperature set below 1/2 (on the higher box temperature side). The items we place on the plastic tray, under the cooling plate, will freeze and stay frozen with 1hour of Ref. use (turned on) in the morning and evening. So the total power, on hours is less than 3 hours, usually around 2 hours per day. We only run the Ref. with shore power or the generator. I must admit that if we were on a motoring trip of 24 plus hours, we would run the Ref. off of the batteries (inverter). If you are not getting this type of results, check the gasketing material. The box MUST close tightly. If you are getting condensation, then your box is leaking air. You should also be using the stoppers to plug the drain holes in the bottom of the Ref. and between the Ref./Freezer (we use 2, one each side of the Ref./Freezer). Good Luck.
Kevin, I am a little confused. We also have a 450 with Ref./Freezer on 110 volt AC power system. This was the 1st year we have had the boat and are not currently living on it. Just using the boat for weekends. The Ref. works so well that with the exception to test the freezer, we have not used it. When we start the Ref. up for the weekend, it runs for about 1 hr to 1.5 hours before it cycles off. It will recycle back on in about 2 hours for 20 +/- mins. After that (if we leave in overnight) it will recycle about every 3 hrs. for about 20 +/- mins. We, other than to test the inverter system with the Ref., do not run the Ref. off of the batteries. The batteries with the engine running will run the Ref. (through the inverter), but you are eating up battery cycle life. When the Ref. starts up, the AC amps are high for just a moment (start up amperage). Once running the Ref, only draws 10 amps (AC). We have the Ref. temperature set below 1/2 (on the higher box temperature side). The items we place on the plastic tray, under the cooling plate, will freeze and stay frozen with 1hour of Ref. use (turned on) in the morning and evening. So the total power, on hours is less than 3 hours, usually around 2 hours per day. We only run the Ref. with shore power or the generator. I must admit that if we were on a motoring trip of 24 plus hours, we would run the Ref. off of the batteries (inverter). If you are not getting this type of results, check the gasketing material. The box MUST close tightly. If you are getting condensation, then your box is leaking air. You should also be using the stoppers to plug the drain holes in the bottom of the Ref. and between the Ref./Freezer (we use 2, one each side of the Ref./Freezer). Good Luck.
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Dick McKee
We have the same system on our 430
and gave up trying to get it to stop cycling. At the start of the weekend it will run till everything is cold in the upper compartment and almost frozen in the lower compartment. It will then cycle off and on about every10 to 15 min. It was enough to make us nuts. What we did discover though is that it is insulated so well we just trun it on for about 30 min in the morning and about 30 min before we hit the sack and everything stays cold and we have very little battery draw... Dick McKee S/V Constellation
and gave up trying to get it to stop cycling. At the start of the weekend it will run till everything is cold in the upper compartment and almost frozen in the lower compartment. It will then cycle off and on about every10 to 15 min. It was enough to make us nuts. What we did discover though is that it is insulated so well we just trun it on for about 30 min in the morning and about 30 min before we hit the sack and everything stays cold and we have very little battery draw... Dick McKee S/V Constellation
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John Van Stone
refrig on a 450
I was having similar problems on my 450 when I got it. I had it looked at by a refrig guy and he found it was low on freon and there were several leaky joints. When those were fixed and it was recharged the system has been great for the last 6 months. The service call was arranged and paid for by my dealer "Whitney's" and Hunter without any problems. I very seldom run it from the inverter unless my batteries are full and I am motoring. If you are docked with shore power then the refrig stays cold and the freezer frozen all day. When at anchor I run it with the genset(unless I am going to be motoring)in the morning and evening until it cycles off. It ussual takes 30 to 60 minutes depending on how often we opened it.
I was having similar problems on my 450 when I got it. I had it looked at by a refrig guy and he found it was low on freon and there were several leaky joints. When those were fixed and it was recharged the system has been great for the last 6 months. The service call was arranged and paid for by my dealer "Whitney's" and Hunter without any problems. I very seldom run it from the inverter unless my batteries are full and I am motoring. If you are docked with shore power then the refrig stays cold and the freezer frozen all day. When at anchor I run it with the genset(unless I am going to be motoring)in the morning and evening until it cycles off. It ussual takes 30 to 60 minutes depending on how often we opened it.
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Don Guggenheim
Excellent system used correctly
Be sure the thermostat is not set higher,lower temperature, than it's ability to cool. I have found the point where my refrigerator is at 38 to 40 degrees and the freezer is at 20 degres. At these temps the compressor is able to cycle and not stay on either freezing the frig, or trying to reach a freezer temp too cold to be efficient causing the compressor to run too long. It takes far more energy to maintain zero degrees than 20 degrees and 20 is quite adaquate over time to freeze. For cruising or even weekend overnights, I find turning the system off at the breaker except for 45 minutes morning and evening when charging the batteries keeps both the freezer and frig at within five degrees of the 38 and 20 degree temps. Using the inverter will work but is not necessary and places large point demands on the battery bank. Cycle time is everything. The system uses between 9 and 10 amp hours, including the water pump, at 120 volts. At 12 volts that's 100 amp hours, and with inverter loss of say 7% then the amp hour demand on the battery bank is 107.5. Using this system you will should not put too much demand on your batteries.
Be sure the thermostat is not set higher,lower temperature, than it's ability to cool. I have found the point where my refrigerator is at 38 to 40 degrees and the freezer is at 20 degres. At these temps the compressor is able to cycle and not stay on either freezing the frig, or trying to reach a freezer temp too cold to be efficient causing the compressor to run too long. It takes far more energy to maintain zero degrees than 20 degrees and 20 is quite adaquate over time to freeze. For cruising or even weekend overnights, I find turning the system off at the breaker except for 45 minutes morning and evening when charging the batteries keeps both the freezer and frig at within five degrees of the 38 and 20 degree temps. Using the inverter will work but is not necessary and places large point demands on the battery bank. Cycle time is everything. The system uses between 9 and 10 amp hours, including the water pump, at 120 volts. At 12 volts that's 100 amp hours, and with inverter loss of say 7% then the amp hour demand on the battery bank is 107.5. Using this system you will should not put too much demand on your batteries.
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Ken Roker
AC Refrigeration Problems
Previous article by Richard Owen has given you some good advice. I have the same system on my 460 and I find it to be a very poor system indeed. I'm surprised that Hunter says they haven't had any complaints because this particular problem will not go away and my dealer has had to talk to them on a number of occassions. If you use your boat for short trips like on weekends then the problem can be reasonably managed by turning the compressor off at night like many have suggested. However if you go on serious extended cruises this system is less than adequate. I've just finished a 1,700-mile cruise. The freezer was full of previously flash frozen food and the fridge was not over loaded. I have over 800 amp hours available in my main battery bank. The refrigeration compressor + cooling pump consumes between 100-120 amps per day which is not good. Having to use your engine to charge up takes about 1.5-2 hours with a high output alternator and if you are a long range cruiser like me even 100 gals of fuel is a precious commodity. I've had all the insulation and Freon charge checked. I work for a controls company and had the controls checked. There is no condensation anywhere in the box so there are no obvious leaks. I belong to the Bluewater Cruising Association and a normal consumption for similar capacity systems is approximately 85 amps per day maximum. On my last cruise I discovered another disturbing problem with this system that you should be aware of. Whenever the compressor cycles on the amperage will surge momentarily to 150 amps. That kind of surge will take your house battery amperage down below 11 volts for a fraction of time on day one of a cruise and even for longer periods of time on subsequent days if you don't recharge. The inverter requires DC power from your battery bank to operate. Your electronic controls are also fed by that same DC source. So if you need the inverter on for periods of refrigeration, and the autopilot is also engaged and, or, radar on, what happens is that the autopilot requiring more than 11 volts to stay engaged will drop out. Believe me having your boat suddenly take off in a direction you don't want it to go is not a fun experience. Also when voltage drops, amperage increases and in this case enough to blow the radar in fuse thus disabling it. The only way around this problem is to install 2 extra batteries and have them completely isolated from the main battery bank. Reconnect all your primary DC systems to that new bank and that will solve any further problems. As far as I'm concerned Hunter's 110-volt ac refrigeration system is an extremely poor design and it is very unfortunate that they see fit to suggest that they haven't had any complaints. Regards Ken
Previous article by Richard Owen has given you some good advice. I have the same system on my 460 and I find it to be a very poor system indeed. I'm surprised that Hunter says they haven't had any complaints because this particular problem will not go away and my dealer has had to talk to them on a number of occassions. If you use your boat for short trips like on weekends then the problem can be reasonably managed by turning the compressor off at night like many have suggested. However if you go on serious extended cruises this system is less than adequate. I've just finished a 1,700-mile cruise. The freezer was full of previously flash frozen food and the fridge was not over loaded. I have over 800 amp hours available in my main battery bank. The refrigeration compressor + cooling pump consumes between 100-120 amps per day which is not good. Having to use your engine to charge up takes about 1.5-2 hours with a high output alternator and if you are a long range cruiser like me even 100 gals of fuel is a precious commodity. I've had all the insulation and Freon charge checked. I work for a controls company and had the controls checked. There is no condensation anywhere in the box so there are no obvious leaks. I belong to the Bluewater Cruising Association and a normal consumption for similar capacity systems is approximately 85 amps per day maximum. On my last cruise I discovered another disturbing problem with this system that you should be aware of. Whenever the compressor cycles on the amperage will surge momentarily to 150 amps. That kind of surge will take your house battery amperage down below 11 volts for a fraction of time on day one of a cruise and even for longer periods of time on subsequent days if you don't recharge. The inverter requires DC power from your battery bank to operate. Your electronic controls are also fed by that same DC source. So if you need the inverter on for periods of refrigeration, and the autopilot is also engaged and, or, radar on, what happens is that the autopilot requiring more than 11 volts to stay engaged will drop out. Believe me having your boat suddenly take off in a direction you don't want it to go is not a fun experience. Also when voltage drops, amperage increases and in this case enough to blow the radar in fuse thus disabling it. The only way around this problem is to install 2 extra batteries and have them completely isolated from the main battery bank. Reconnect all your primary DC systems to that new bank and that will solve any further problems. As far as I'm concerned Hunter's 110-volt ac refrigeration system is an extremely poor design and it is very unfortunate that they see fit to suggest that they haven't had any complaints. Regards Ken
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