Inverter capability

[Craig1]

Hi all

 

I've a victron Phoenix 12/3000VA inverter. I want to power a 700 w oil filled radiator.  Is this feasible if it's on whilst the engine is running?  And what's the highest wattage unit I can run off this inverter?

 

Thanks in advance for imparting your knowledge

 

Craig

[Alan de Enfield]

11 minutes ago, Craig1 said:

Is this feasible if it's on whilst the engine is running? 

 

Yes, but unless you alternator is 70amps plus you will be draining the batteires

 

12 minutes ago, Craig1 said:

And what's the highest wattage unit I can run off this inverter?

 

 

It depends on what you want to run (different appliances have different efficiencies - hence the invertor being rared in VA and not watts.

 

Basically 2500 watts should be OK - but you will be draining the batteries by around 250 amps, so a 100 ah battery will last around 15 minutes.

 

It is not really efficient, or practical to supply heating from the batteries.

[Tracy D'arth]

700W  will be fine.

 

The 3000VA rating of the inverter does not mean it will power a 3kW appliance, it depends on the power factor of the load. However an oil filled heater should not have any inductance or capacitance so in theory you could power a 3kW radiator but I would not advise it as you would be sucking around 280A from your battery.

700W will suck 60A  to 70A from the battery, is your alternator up to it? It will probably get very hot after a while.

[jonathanA]

I'm surprised no one has asked why ?

Yes your inverter will easily power the heater. Whether your 12v system is up to it is another question.... but why would you want to... 

[George and Dragon]

40 minutes ago, jonathanA said:

I'm surprised no one has asked why ?

 

Perhaps because it's none of our business.

The OP may want to ask for advice on different heaters now that they know that the oil filled radiator isn't a great option.

[Paul C]

On a boat, burn something to make heat (unless on shoreline).

[Craig1]

I just knew someone would ask why!  If you're really interested my boat is 70 ft long, Morso squirrel down one end and rads heated by back boiler, rads all down one side.....so, I want a source of heat under my bed (the opposite side to the rads) where it's coldest (and therefore wettest) in the winter, as every time any of us shower in the cold months it gets soaked under the bed.

 

Now you see why I asked the simple question without the lengthy explanation, yes?

 

I cruise throughout the year, the engine on will give hot water for showers and power this additional heat source and save my good lady endlessly getting everything from under the bed and mopping up.

 

So, anyone got a better idea than a little radiator?

[Tony Brooks]

Depending upon how far away from the engine the underbed area is I suspect an extension to the calorifier circuit feeding a small rad or some zigzag copper piping would heat that area when cruising.

 

It sounds as if it could do with more ventilation under there as well.

Edited June 28, 2022 by Tony Brooks

[sunny]

2 hours ago, Tracy D'arth said:

700W  will be fine.

 

The 3000VA rating of the inverter does not mean it will power a 3kW appliance, it depends on the power factor of the load. However an oil filled heater should not have any inductance or capacitance so in theory you could power a 3kW radiator but I would not advise it as you would be sucking around 280A from your battery.

700W will suck 60A  to 70A from the battery, is your alternator up to it? It will probably get very hot after a while.

Have i had a glass of wine or you The guy with the dawn craft you said set it on fire yet this the guy you give good advice who has had a drink before posting youor me

[Craig1]

Sunny, I've no idea what you're on about.  Lay off the methamfetamines.

 

Tony, bloody good idea, sounds easy, I'll have a look into that.  Cheers.

 

Buying a radiator does sound easier though, but your idea is best.

[jonathanA]

29 minutes ago, Craig1 said:

I just knew someone would ask why!  If you're really interested my boat is 70 ft long, Morso squirrel down one end and rads heated by back boiler, rads all down one side.....so, I want a source of heat under my bed (the opposite side to the rads) where it's coldest (and therefore wettest) in the winter, as every time any of us shower in the cold months it gets soaked under the bed.

 

Now you see why I asked the simple question without the lengthy explanation, yes?

 

I cruise throughout the year, the engine on will give hot water for showers and power this additional heat source and save my good lady endlessly getting everything from under the bed and mopping up.

 

So, anyone got a better idea than a little radiator?

It's always worth asking questions to get more info so that's why I asked not being nosey as some one suggested 😀

 

Its also often interesting comparing other people's ideas and thought processes.

 

I have the arrangement the esteemed Mr Brooks suggests with a radiator simply connected across the engine feed to the cauliflower and its does exactly what you want  a tenners worth of 15mm plastic push fit  pipe and fittings and a hour orvtwo of time I would think. Pipe runs under my rear steps to the rad -  happy days. 

I have always said I would install a heat exchanger and pump and have a rad in the bathroom too but have never got around to it....

 

I wonder if you could fit a heat exchanger and plumb that into the existing rads so you can heat them up from the engine too. It would need a pump and I don't see why it would be a problem with the back boiler.  ?  Think there are a few threads covering that somewhere on here. 

[Tony Brooks]

24 minutes ago, jonathanA said:

Mr Brooks suggests with a radiator simply connected across the engine feed to the cauliflower and its does exactly what you want  a tenners worth of 15mm plastic push fit  pipe and fittings and a hour orvtwo of time I would think. Pipe runs under my rear steps to the rad -  happy days. 

 

Not "across" that usually implies a parallel connection. If you do that it or the calorifier may short circuit the other. They need to be in series with the calorifier coil getting the hot water first.

[Tony Brooks]

27 minutes ago, jonathanA said:

I wonder if you could fit a heat exchanger and plumb that into the existing rads so you can heat them up from the engine too. It would need a pump and I don't see why it would be a problem with the back boiler. 

 

That is a possibility and a number have done just that, but it would have some concerns it may allow the engine to over cool because most, but not all, calorifier circuits come from the engine block/head, before the thermostat so there  is no control of flow. I would stick a suitably dimensioned heat exchanger in the hot connection to the skin tank.

[PeterF]

4 minutes ago, Tony Brooks said:

 

Not "across" that usually implies a parallel connection. If you do that it or the calorifier may short circuit the other. They need to be in series with the calorifier coil getting the hot water first.

I put a small radiator after the calorifier in the cupboard behind our shower to act as a drying cupboard, it worked well, it started warming up after the calorifier was getting hot.

[Craig1]

Again, good idea.  For me the main problems are that I've little free time (full time job, 2 home schooled kids and continuously cruising) and a lack of knowledge of just about everything! I've been on the boat 10 years, I've learnt bits and pieces but anything  out of the box is just a mystery to me.

 

I reckon basic understanding of engines, electrics, carpentry and plumbing should be mandatory at school.  It would have my life much easier!  Religious studies has never been useful to me yet, but who knows!

[Alan de Enfield]

3 minutes ago, Craig1 said:

I reckon basic understanding of engines, electrics, carpentry and plumbing should be mandatory at school.

 

 

It always used to be, maybe you were born to late.

 

We even regularly had a blacksmith join us for our metalwork classes and taught us how to forge properly, car mechanics in lunch breaks, woodworking class etc etc.

[Tracy D'arth]

Going back to your 700W radiator, that is a lot of heat in a small closed space. A 100W tubular heater may be all you need?  Even a light bulb may provide enough heat but then there is a fire risk.

I use light bulbs in buildings to stop pipes freezing. Of course they are a endangered specie now and LEDs just are not the same

[BEngo]

How about one of the car dashboard top heater/fan devices?    Example only:

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.machinemart.co.uk/p/12v-portable-vehicle-heater-fan--defroster/&ved=2ahUKEwjwrKW1-tD4AhUThP0HHXvKC5YQFnoECB8QAQ&usg=AOvVaw2izPWNDtVsEZvjoJkcoiRc

 

Draws car -acceptable levels of power, so not likely to upset the alternator, runs off 12 V, so no farting about with mains voltages, moving the air would help with ventilation and could be controlled by either a thermostat or a humidistat.

 

N

[blackrose]

I'm not sure exactly where the cold part of the boat is, but if it's at the other end of the boat to the engine then extending the calorifier circuit might be asking a lot of the engine's water pump and would need a heat exchanger and pump. If it's at the same end as the engine then no problem.

 

I fitted one of these heaters to my Webasto central heating circuit recently and it works well. I don't see why it wouldn't work just as well plumbed into the calorifier circuit. Just needs a 12v supply for the fan.

 

https://www.kuranda.co.uk/product/alize-fai/

 

They've got various models on their website. 

[blackrose]

1 hour ago, BEngo said:

How about one of the car dashboard top heater/fan devices?    Example only:

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.machinemart.co.uk/p/12v-portable-vehicle-heater-fan--defroster/&ved=2ahUKEwjwrKW1-tD4AhUThP0HHXvKC5YQFnoECB8QAQ&usg=AOvVaw2izPWNDtVsEZvjoJkcoiRc

 

Draws car -acceptable levels of power, so not likely to upset the alternator, runs off 12 V, so no farting about with mains voltages, moving the air would help with ventilation and could be controlled by either a thermostat or a humidistat.

 

N

 

That's obviously a lot cheaper but it's still just converting battery power to heat isn't it, albeit without inverting to mains?

 

Since the engine would be running anyway to avoid draining the batteries I'd say it's better to use byproduct engine heat for heating and a very small amount of battery power for the fan. 

[Tracy D'arth]

Can you duct heat from the fridge? A fan cooling the fridge will give you a gain.

[Slim]

4 hours ago, Alan de Enfield said:

 

 

It always used to be, maybe you were born to late.

 

We even regularly had a blacksmith join us for our metalwork classes and taught us how to forge properly, car mechanics in lunch breaks, woodworking class etc etc.

They were the days 😪 

[Higgs]

Have I missed something? Is the shower water not being contained properly?

 

 

[LadyG]

11 hours ago, Craig1 said:

I just knew someone would ask why!  If you're really interested my boat is 70 ft long, Morso squirrel down one end and rads heated by back boiler, rads all down one side.....so, I want a source of heat under my bed (the opposite side to the rads) where it's coldest (and therefore wettest) in the winter, as every time any of us shower in the cold months it gets soaked under the bed.

 

Now you see why I asked the simple question without the lengthy explanation, yes?

 

I cruise throughout the year, the engine on will give hot water for showers and power this additional heat source and save my good lady endlessly getting everything from under the bed and mopping up.

 

So, anyone got a better idea than a little radiator?

I have a back boiler stove (centrally placed), the pipes run through the bathroom, creating an airing cupboard without a door, then a small chrome radiator,  then at they turn ninety degrees along the bed head which allows warm air in to the bed area. It's just enough to keep everything dry. Not an immediate fix, but next time you replace the stove or for anyone fitting  out a boat, this is a clever solution. My boat is only  57 foot. In winter I have heavy curtains (eBay) which isolate draughts from front and back. Of course you must ventilate the boat adequately which is not happening at the moment.

Short term I'd be inclined to go for tubular electric radiator (greenhouse type) under the bed but trying to run heating off the batteries is a recipe for killing batteries. .

If it is dripping wet I'd say this is very unhealthy, so I'd be looking at ventilation as well, a fan to extract shower water from bathroom, maybe an opening window. Keep the moisture inside the bathroom.minimise shower water getting out of bathroom, it just shouldn't. I sometimes just use a big jug of warm water for shampooing my hair and rinse off with the shower, this uses less water, but critically in your case, less water in to the air.

I have my stove working twenty four seven in winter, boat is warm and dry, but you have an extra thirteen feet, and critically the stove is in the wrong place.

I would think  a Webasto, with rads under bed and in bathroom are needed, the only problem is the noise at night, but rather that than this very unhealthy dampness. It's going to be expensive, but your health is going to suffer, not to mention mould. I'm afraid I would also think about selling this boat and getting one which is better suited to liveaboard. Depends on your needs, do you need a narrowboat, do you need seventy feet? Does it have to be long suffering wife who cleans under the bed?

Edited June 29, 2022 by LadyG