Fridge

[PaulRainbow]

Seriously? You guys can't understand this?
See Post #7 and my reply Post #20

You're only reading part of the question. He want to connect it to shore power, because power cuts are flattening his batteries. How will this device address that ? It won't, it'll side step the issue, because if the power is off the fridge can't run.

There are millions of boats running fridges from 12v, connected to mains via a battery charger, mine is one of them and i have never had the fridge flatten the batteries, or the fridge defrost. If the OP's won't, why won't it ? Address the problem, not work around it, IMO.

 

[Fr J Hackett]

You're only reading part of the question. He want to connect it to shore power, because power cuts are flattening his batteries. How will this device address that ? It won't, it'll side step the issue, because if the power is off the fridge can't run.

There are millions of boats running fridges from 12v, connected to mains via a battery charger, mine is one of them and i have never had the fridge flatten the batteries, or the fridge defrost. If the OP's won't, why won't it ? Address the problem, not work around it, IMO.

Possibly because his fridge has no low voltage sensor and his battery charger trips or boat electric supply trips permanently at the power cut so batteries drain, charger doesn't kick in till breaker reset or something or perhaps even the power cuts are for days! Top and tail is the fridge does not have a low voltage sensor and cut out. Hence my previous question what type of fridge it may be a Peltier type for all we know.

 

[scoty]

Quite right,thanks for the translation,now,where can I buy, "low voltage sensor and cut out"plus where do I fit it,? If that is not a silly question..!

 

[scoty]

Thanks everyone for your comments and those who had a solution, I was short on detail in that the marina trip goes off frequently in summer due to so many using air conditioning and winter due to so many boat heaters, each marina mooring trip needs to be manually switched on after a power cut.quite normal here in spain.....

 

[PaulRainbow]

Quite right,thanks for the translation,now,where can I buy, "low voltage sensor and cut out"plus where do I fit it,? If that is not a silly question..!

It isn't a silly question, but it doesn't seem like a cure. It will stop the battery running flat if the power is off, but then the fridge won't be working.

IMO, you need to make it so the fridge can continue to be used, or you need to empty it and turn it off.

If you post back with :

What boat ?
Fridge type ?
What batteries do you have ?
What charger ?
How long and frequent are these power outages ?
Why don't things return to normal when the power comes back on ?

You will likely get some alternative solutions, some of which will hopefully allow you to use the fridge without any problems, on 12v and shore power.

Edit, makes more sense now, thanks for the update.

 

[PaulRainbow]

What fridge is it ?

 

[vyv_cox]

Thanks everyone for your comments and those who had a solution, I was short on detail in that the marina trip goes off frequently in summer due to so many using air conditioning and winter due to so many boat heaters, each marina mooring trip needs to be manually switched on after a power cut.quite normal here in spain.....

Rather than mess about with unreliable 230 volt supplies, why not spend less money on a decent solar panel and regulator. We are totally self sufficient throughout the summer on 125 watts of solar, fridge runs 24/7 for six months. Now well into September just past the equinox we still have 12.8 volts first thing in the morning. Panel costs are reducing all the time and a decent regulator can be bought for £50, cheaper ones are available if you can trust them.

 

[PaulRainbow]

Rather than mess about with unreliable 230 volt supplies, why not spend less money on a decent solar panel and regulator. We are totally self sufficient throughout the summer on 125 watts of solar, fridge runs 24/7 for six months. Now well into September just past the equinox we still have 12.8 volts first thing in the morning. Panel costs are reducing all the time and a decent regulator can be bought for £50, cheaper ones are available if you can trust them.

I was thinking the same. Just upgraded my controller to Victron with the Bluetooth dongle to monitor it from my tablet/phone.

Wouldn't connecting the fridge to the controller load output act as a failsafe against flattening the batteries ? (not that mine is connected there).

 

[nigelmercier]

Quite right,thanks for the translation,now,where can I buy, "low voltage sensor and cut out" ...

Your fridge probably has one, set to a ridiculously low 10.5V from memory.

However, without setting it at an equally ridiculous high value, your batteries will still get partly discharged. I have already make the correct solution clear.

 

[PaulRainbow]

Your fridge probably has one, set to a ridiculously low 10.5V from memory.

However, without setting it at an equally ridiculous high value, your batteries will still get partly discharged. I have already make the correct solution clear.

No you haven't.

 

[ghostlymoron]

I seem to recall there used to be a device called Fridge mate or similar which turned the fridge off when the battery voltage fell low. The fridge would not work of course so you may return to find a fridge full of rotting food. The Waeco has an auto switchover to use mains when available and 12v until voltage falls to 12.3 or so. Still doesn't keep fridge on when there's no power at all - only Vyv's solar solution will do that. You could move to a marina with a more reliable power supply.

 

[GHA]

Long thread so apologies if it's been suggested. Why not stick a relay on the 12v supply to the fridge?

Assuming the mains also runs a battery charger and there are batteries and that's what the fridge is actually connected to..

Then a 12v wall wart power supply connected to the mains controls the relay to the fridge. Mains on, fridge on, mains off, fridge off.

 

[PaulRainbow]

It's pointless fitting the mains adapter, OP will connect to mains and leave the fridge on. Mains goes off, fridge switches to 12v, mains come back on, fridge is still on 12v as there is no-one there to reset the trip. Fridge flattens battery, then defrosts. OP returns to boat which has flat batteries and a fridge full of rotten food.

Pointless fitting anything that stops the fridge from working below a given voltage. As above, first time the power goes out the fridge will run until the batteries reach the given voltage and switch off. OP returns to a boat with partially flat batteries and the same rotten contents as above.

Given the regular outages and the need to reset the trip there are (IMO) only two sensible plans of attack. Either empty the fridge and turn it off, or configure a system that can run the fridge independent of the mains. That means solar power. Fit a solar panel/s with a decent controller such as a Victron and connect the fridge to the "load" terminals of the controller. That safeguards the battery in the event of something failing on the solar setup.

 

[PaulRainbow]

Long thread so apologies if it's been suggested. Why not stick a relay on the 12v supply to the fridge?

Assuming the mains also runs a battery charger and there are batteries and that's what the fridge is actually connected to..

Then a 12v wall wart power supply connected to the mains controls the relay to the fridge. Mains on, fridge on, mains off, fridge off.

When the mains comes back the OP has to reset a trip, so unfortunately that won't work in this case.

 

[GHA]

When the mains comes back the OP has to reset a trip, so unfortunately that won't work in this case.

so mains off, fridge off.
Mains back on when trip has been reset, fridge back on.
Batteries happy , fridge smelly

 

[PaulRainbow]

so mains off, fridge off.
Mains back on when trip has been reset, fridge back on.
Batteries happy , fridge smelly

lol yes.

 

[nigelmercier]

No you haven't.

I disagree.

He says because of power outages he want to run it off of shore power. If the power has gone off so his battery charger won't charge the batteries how the hell is having it plugged into shore power going to help...

He is concerned that the fridge causes the batteries to discharge when the power is lost, he doesn't care about running the fridge at this time as "food is cheaper to replace".

... I would like the fridge to run directly from the mains, while in harbour.(to save flat batteries) and food is cheaper to replace.

The solution is in Post #7, my reply Post #20, and #23.

 

[PaulRainbow]

I disagree.

He is concerned that the fridge causes the batteries to discharge when the power is lost, he doesn't care about running the fridge at this time as "food is cheaper to replace".

The solution is in Post #7, my reply Post #20, and #23.

Nonsense. Because that will only serve to flatten the batteries AND defrost the fridge.

 

[GHA]

I would like the fridge to run directly from the mains, while in harbour.(to save flat batteries) and food is cheaper to replace.

Why bother running directly from the mains? Why not run off the batteries/charger with a relay turned on/off by a wall wart connected to the mains so the fridge gets disconnected from the batteries when the power trips.

The batteries won't know there is a fridge.

Cost less than a tenner with a car relay.

 

[nigelmercier]

Nonsense. Because that will only serve to flatten the batteries AND defrost the fridge.

How?