So, I've been posting about my plan to add 12V refrigeration kit to my H-34. I plan to leave it on all the time for the most part. It occurs to me that even though I will be plugged into shore power this is still being run through the batteries. Will this be hard on the batteries? I've thought about installing a 110AC/12V converter with an A/B switch so that I can run directly off the AC if battery strain is an issue. I would like to hear from folks who have dealt with this.
Refrigeration and battery life while on shore power
- Thread starter markwbird
- Start date
My 12VDC refrigeration is supplied by my 600Ah house batteries and my Freedom Inverter uses 120VAC shore/genset to charge the batteries.
I had a lightening storm trip the harbor breakers during the night and when I came on boat to check for storm damage, the batteries and inverter appeared DEAD.
The refrigerator was ON, before loss of shore power.
After restoring shore power, the Inverter had "no heartbeat". Then after about 15 minutes of screaming panic, I read the manual for the Inverter. There is a low battery (10.8VDC) Inverter (battery saving) shutoff. I isolated one house batt, put on a jump charger to bleed charge it and magically the Inverter revived and began to recharge. I did the same for battery 2 and have tested the batteries with no significant detectable damage.
Lessions...
1) Your refrigerator will suck down your battery rapidly and without mercy.
2) The smart Inverter/charger saved the batteries.
3) My jump start portable battery is always a handy on board tool.
I have the 40A version of this link and you might read the West Marine Advisor at bottom of the web page.
http://www.westmarine.com/buy/west-marine--1000-amp-jumpstarter--15808512
PS: When in berth, cold beer for guests is always nice.
I had a lightening storm trip the harbor breakers during the night and when I came on boat to check for storm damage, the batteries and inverter appeared DEAD.
The refrigerator was ON, before loss of shore power.After restoring shore power, the Inverter had "no heartbeat". Then after about 15 minutes of screaming panic, I read the manual for the Inverter
. There is a low battery (10.8VDC) Inverter (battery saving) shutoff. I isolated one house batt, put on a jump charger to bleed charge it and magically the Inverter revived and began to recharge. I did the same for battery 2 and have tested the batteries with no significant detectable damage.Lessions...
1) Your refrigerator will suck down your battery rapidly and without mercy.
2) The smart Inverter/charger saved the batteries.
3) My jump start portable battery is always a handy on board tool.
I have the 40A version of this link and you might read the West Marine Advisor at bottom of the web page.
http://www.westmarine.com/buy/west-marine--1000-amp-jumpstarter--15808512
PS: When in berth, cold beer for guests is always nice.
My frig & freezer have been on continuously for 21 years and the refrig on my prior boat for 9 years. Both of my refrigeration techs and the manufacturer tech said to leave them on full time, and even when off shore power, just turn them down to minimal acceptable temperature maintenance for power draw minimization. I thought about doing the same as you suggest, feeling the parasitic draw must have some effect on battery life. However, I did not install the 12 volt inverter after getting uncomfortable with having that item full time on the boat. I felt it was a danger. To do something similar, I put my two battery banks into one and added a simple group 24 deep cycle as the second bank, figuring all the loads would go through it. After two years doing it that way, I detected no gain from that arrangement. So, my answer to you would be simply: don't worry about it.
I think if you have a smart battery charger it will maintain the correct float voltage on your batteries as the refrigerator, stereo, fans etc. are turned on and off. We have a digital voltmeter at the nav station and I've observed the battery voltage stays right at 13.2 V as things get turned off and on. We have a Sterling 50 A charger.
Bob
Bob
If you are on shore power and your battery charger is on, it should be smart enough to keep you batteries on float and provide the DC power your refrigerator (house load) requires. If not, you may need an improved battery charger as part of your install. I would also include a battery monitor so that you can keep on your battery and house systems.
Couple of thoughts.
While convenient to have the fridge always on there is always risk too.
Risks:
* Marina power is anything but reliable. Muffy & Skippy unplug your cord when heading out on the Sea Ray and forget to plug it back in. A breaker trips because the pedestal was over loaded etc.. Darrell & Darrell are working on the dock system and forget to re-power your finger pier..Your own boat develops a fault and AC is interrupted etc.. These are not at all rare incidents when you are a marine electrician and are actually quite common. While folks can get lucky, sometimes for many years, this still represents and n=1 data set.
* Not all chargers are actually smart. A fridge load can kick many chargers back into absorption mode and wind up over charging the batteries. One would think that boats plugged into shore power would see longer battery life but due to loads rebooting absorption I frequently see batteries that get abused even when tied to shore power. In a perfect world the charger would stay in float but they don't all do this.
* When plugged in, and the batteries are full, the charger is supplying 100% of the fridge load, but during start up the battery usually kicks in some because the power supply in the battery charger is a bit slow to keep up. In theory the batteries should just sit there and float but the reality is far too many chargers are not smart enough to know the batteries are full and they can get triggered back into a higher absorption voltage when the fridge compressor kicks on. Some will drop back to float quickly others may start a two plus hour timer once absorption has been re-triggered.
* If you do lose power your batteries can be sucked below the chargers safe "turn on" voltage and even though power was restored the charger may not resume charging the batteries. This is a built in safety feature to prevent chargers from charging into a shorted battery.
Options:
* Add a low voltage cut off to the fridge circuit. Set it at 12.1V and this will prevent your batteries ever being sucked below about 50% SOC regardless of whether or not you lose shore power. It will also ensure your batteries will have enough voltage to allow the battery charger to re-boot when the fault or power has been restored. The Blue Sea m-LVD is a good choice in a low voltage cut off.
* Use a good charger that has a power supply setting or force to float feature or custom programming ability where you can manually set it at your float voltage when you leave the vessel. Often times a custom setting can be configured so the bank won't go above 13.XX volts no matter what.
* Most AC to DC power supplies need a battery in the circuit as a buffer for start up loads. Ones that can handle motor in-rush, without a battery can get a bit expensive.
While convenient to have the fridge always on there is always risk too.
Risks:
* Marina power is anything but reliable. Muffy & Skippy unplug your cord when heading out on the Sea Ray and forget to plug it back in. A breaker trips because the pedestal was over loaded etc.. Darrell & Darrell are working on the dock system and forget to re-power your finger pier..Your own boat develops a fault and AC is interrupted etc.. These are not at all rare incidents when you are a marine electrician and are actually quite common. While folks can get lucky, sometimes for many years, this still represents and n=1 data set.
* Not all chargers are actually smart. A fridge load can kick many chargers back into absorption mode and wind up over charging the batteries. One would think that boats plugged into shore power would see longer battery life but due to loads rebooting absorption I frequently see batteries that get abused even when tied to shore power. In a perfect world the charger would stay in float but they don't all do this.
* When plugged in, and the batteries are full, the charger is supplying 100% of the fridge load, but during start up the battery usually kicks in some because the power supply in the battery charger is a bit slow to keep up. In theory the batteries should just sit there and float but the reality is far too many chargers are not smart enough to know the batteries are full and they can get triggered back into a higher absorption voltage when the fridge compressor kicks on. Some will drop back to float quickly others may start a two plus hour timer once absorption has been re-triggered.
* If you do lose power your batteries can be sucked below the chargers safe "turn on" voltage and even though power was restored the charger may not resume charging the batteries. This is a built in safety feature to prevent chargers from charging into a shorted battery.
Options:
* Add a low voltage cut off to the fridge circuit. Set it at 12.1V and this will prevent your batteries ever being sucked below about 50% SOC regardless of whether or not you lose shore power. It will also ensure your batteries will have enough voltage to allow the battery charger to re-boot when the fault or power has been restored. The Blue Sea m-LVD is a good choice in a low voltage cut off.
* Use a good charger that has a power supply setting or force to float feature or custom programming ability where you can manually set it at your float voltage when you leave the vessel. Often times a custom setting can be configured so the bank won't go above 13.XX volts no matter what.
* Most AC to DC power supplies need a battery in the circuit as a buffer for start up loads. Ones that can handle motor in-rush, without a battery can get a bit expensive.
You might want to listen to the doom-and-gloom guys, in lieu of the it's-always-worked-for-me-keeping-it running crowd.
I'm not sure if folks supporting the latter theory are full time liveaboards or not. If they are, then there's a good reason to keep it on 24/7. They LIVE there!
If you're just a weekend warrior, listen to Maine Sail and James.
I've been having this discussion for the past 17 years, it never ceases to amaze me why anyone would choose to leave a piece of machinery ON when they are not there. Would you do so for a summer cabin you only visited on weekends? Sure, I've heard the horror stories about seals going bad. Only time I ever KNEW of that happening was a tightwad friend of mine who never ran his air conditioning on his ancient Volvo station wagon for ten years, and then wondered why it wouldn't work when it got hot here.
If you use it periodically, it will NOT die a premature death. I've been doing it this way for the 17 years I've had our boat. It's still working just fine. And the fridge is now almost 30 years old.
Sure, cold beer is nice. So, stop at a 7-11 on the way to the boat. My fridge will cool down in less than half an hour, and start cooling anything in it soon after. I put a few in the evaporator right away.
What's NOT nice? Decaying mayonnaise in a closed-up fridge a week after the power has gone out and your charger didn't kick back in.
Yeah-- even w/o the always fine analysis from Main Sail, to me it's strange behavior to leave the fridge or anything else "running" on the boat when gone home (i.e., not as a live-a-board). The only thing "hot" on the Bavaria when I'm gone home is the bilge pump and alarm. The boat is usually not even plugged into shore power. If you're in a hurry for a cold one, grab a bag of ice on the way down and shove a couple of brewskies in the bag. A few minutes and you're on your way. Or, switch to IPAs which you can happily drink barely cooled.You might want to listen to the doom-and-gloom guys, in lieu of the it's-always-worked-for-me-keeping-it running crowd.
I'm not sure if folks supporting the latter theory are full time liveaboards or not. If they are, then there's a good reason to keep it on 24/7. They LIVE there!
If you're just a weekend warrior, listen to Maine Sail and James.
I've been having this discussion for the past 17 years, it never ceases to amaze me why anyone would choose to leave a piece of machinery ON when they are not there. Would you do so for a summer cabin you only visited on weekends? Sure, I've heard the horror stories about seals going bad. Only time I ever KNEW of that happening was a tightwad friend of mine who never ran his air conditioning on his ancient Volvo station wagon for ten years, and then wondered why it wouldn't work when it got hot here.
If you use it periodically, it will NOT die a premature death. I've been doing it this way for the 17 years I've had our boat. It's still working just fine. And the fridge is now almost 30 years old.
Sure, cold beer is nice. So, stop at a 7-11 on the way to the boat. My fridge will cool down in less than half an hour, and start cooling anything in it soon after. I put a few in the evaporator right away.
What's NOT nice? Decaying mayonnaise in a closed-up fridge a week after the power has gone out and your charger didn't kick back in.
I think the original question was, will it hurt my batteries to leave the fridge on ?
As far as the rest of the advice is concerned some may or may not apply. We can't assume how others use their boat. There are some sailors that are not liveaboards or weekend warriors. They may be by the boat every few days or even daily and so want to keep the fridge stocked. When we kept a boat near by in our sailing club we were by almost daily, had lunch or dinner in the cockpit in the slip a couple of times a week. Just something to consider.
Bob
As far as the rest of the advice is concerned some may or may not apply. We can't assume how others use their boat. There are some sailors that are not liveaboards or weekend warriors. They may be by the boat every few days or even daily and so want to keep the fridge stocked. When we kept a boat near by in our sailing club we were by almost daily, had lunch or dinner in the cockpit in the slip a couple of times a week. Just something to consider.
Bob
Yeah, "gone home" to me means away from the boat; i.e., not using it daily, or even every few days. Right now, home is 90 mi. from the slip, etc. I imagine that's likely not the case for many who choose to leave stuff "on." However, even at 12 mi. I would rarely leave the fridge running on indefinitely. Of course, I'm the guy who unplugs the power cord too.
But, then, I have an aluminum saildrive leg that I would not wish to see dissolve away. So, there's method in madness. Perhaps the question should be, will it hurt/deteriorate the metals of my boat to stay plugged in to shore power and run the fridge continuously?
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If you have a capable charger it will keep the batteries charged and provide the pass through power to run the fridge. The batteries will just serve to stabilize the voltage as the compressor cycles. A little exercise will not hurt them. A quality converter will do the job but if the power goes off your beer will start getting warm right away.
Off-topic: my brother had this happen with a small freezer-full of chopped up bait squid, when someone he had hired to clean the boat neglected to plug the shore power back in after he unplugged it for some reason. My brother said the smell was unreal ... he said that he nearly passed out several times cleaning it up. Lesson learned I'm sure.What's NOT nice? Decaying mayonnaise in a closed-up fridge a week after the power has gone out and your charger didn't kick back in.
Lots of interesting stuff. Thanks all for the well thought out input. I am glad to know about all of the side effects associated with leaving my fridge on. I live nearby so I use the boat frequently. That is why I want to keep cold drinks aboard. No mayonnaise, though. Actually, the main reason for the fridge is to be able to take overnight trips and bring food and not have to dig through a bunch of wet groceries stored in ice every time I want a beer. I hate that.
My Pearson 30 had an icebox with a drain and a Whale foot-pump that could pump the ice melt out one of the sink-drain thru-hulls. So we did not have to dig through "wet groceries." That could work as well; avoid some of these other "issues."
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The contingencies MS has mentioned are "unlikely" on any given day, but given that you plan to own your boat for several thousand days have a way of eventually happening.
And with an low voltage disconnect and good charger all you will be replacing is some spoiled mayonnaise instead of $1500.00 worth of batteries and the mayonnaise. Don't get me wrong I don't mind boat owners who rely on shore charging, then leave loads on without an LVD... It helps feed my family...
I love interesting POV (point of view) threads. This shows the variety of boats and experiences. I take the extra mayo "in a pack" at the sandwich shop, that requires no refrigeration. On a long cruise, we take the refrig kind. One thing that "splits the blank" is a very well insulated unit. I can put 2-10 lb bags of ice in mine and it lasts for 3 days.
https://www.bluesea.com/products/7635/m-LVD_Low_Voltage_Disconnect
This one says 13VDC cutoff/restart which is pretty sensitive, but it will certainly stop the refrig from draining a battery. I forgot to turn refrig off and found it draining the batteries after the shore power disconnect. Not fun thing to have your radar go down, in a fog, because your beer is cold.
BTW during the summer, part of boating to me is sharing a beer with others in the marina, so I am on the boat a lot.
Jim...
PS: Main Sail you are full of it! Good tips I mean.
I am getting one of those too. Other than the high drain from the 12VDC refrigerator, I won't worry about the Inv/Charger being the last/first line of battery defense. Little need for long recharge with the LVD installed.
https://www.bluesea.com/products/7635/m-LVD_Low_Voltage_Disconnect
This one says 13VDC cutoff/restart which is pretty sensitive, but it will certainly stop the refrig from draining a battery. I forgot to turn refrig off and found it draining the batteries after the shore power disconnect. Not fun thing to have your radar go down, in a fog, because your beer is cold.
BTW during the summer, part of boating to me is sharing a beer with others in the marina, so I am on the boat a lot.
Jim...
PS: Main Sail you are full of it! Good tips I mean.