Immersion heater replacement

[grockell]

Hi all,

 

I have a faulty 3kw immersion heater in my calorifer. I intend on replacing it with a 1kw heater to power off the mains when on shore and potentially an inverter when out cruising in the summer months.

 

I just wanted to ask about getting an inverter seeing as getting one to withstand 1kw will cost a fair chunk.

 

I have 660watts of solar on my roof, so was thinking in the summer I’d generate enough power during sunny days to whack on the inverter and power the 1kw immersion heater. Has anyone have experience with this type of setup? If yes, which inverter do you run the heater off? Does an inverter rated at 1kw advisable or should I aim a little higher?

 

Just as a side, I have looked into diverting surplus power from the solar into a 12volt immersion heater, but, in my opinion, don’t think it’s worth the hassle.

 

Cheers

 

George

[DaveR]

I have a 1600 watt inverter and have, this summer for the first time since fitting the panels, run the immersion from the solar panels (same output as you have).

On a good day the panels gave me 40 amps and the inverter was taking 110 amps to run the boat and immersion. 

I  have 6 x 110Ah batteries on the domestic set up and so I  believe that the required 70 amps from 6 batteries acceptable in the short term.

I ran the immersion for 30 minutes at a time with at least 1 hour recharge time after that. If all was well I would repeat. For a 50 ltr calorifier I found that 90 minutes of immersion time gave a tank full at 60 degrees C from a start of ambient about 16 deg C

[grockell]

2 minutes ago, DaveR said:

I have a 1600 watt inverter and have, this summer for the first time since fitting the panels, run the immersion from the solar panels (same output as you have).

On a good day the panels gave me 40 amps and the inverter was taking 110 amps to run the boat and immersion. 

I  have 6 x 110Ah batteries on the domestic set up and so I  believe that the required 70 amps from 6 batteries acceptable in the short term.

I ran the immersion for 30 minutes at a time with at least 1 hour recharge time after that. If all was well I would repeat. For a 50 ltr calorifier I found that 90 minutes of immersion time gave a tank full at 60 degrees C from a start of ambient about 16 deg C

This is really promising, thanks. I have just 4x 110ah lead acid batteries, but do have another 4 going spare so may increase the bank to 6, as you have. Can I ask which inverter you use? 

[Jen-in-Wellies]

A time lag switch to automatically turn the immersion off after a set time would be a good idea. Save trashing your batteries if/when you forget. Set to whatever time you think appropriate.

Jen

[Tracy D'arth]

Do you not heat water with your engine?

 

Heating water with electricity from other than a shore line is very heavy on the batteries and solar will only assist in the few summer months unless you are in the tropics.

[DaveR]

22 hours ago, grockell said:

Can I ask which inverter you use? 

Victron 1600/40 inverter charger.

 

7 hours ago, Jen-in-Wellies said:

A time lag switch to automatically turn the immersion off after a set time would be a good idea.

I use the countdown timer in the galley

7 hours ago, Tracy D'arth said:

Heating water with electricity from other than a shore line is very heavy on the batteries and solar will only assist in the few summer months unless you are in the tropics.

We are summer only sailors and so only use the solar set up in good sunny days otherwise it is the engine to supply heat. During this last summer we were away for 6 weeks only after the main lockdown ended. In that time I saved 17 hours of engine charging/heating and so did not burn 20 ltrs of diesel. Save money and the environment - can't be bad.

[grockell]

8 hours ago, Jen-in-Wellies said:

A time lag switch to automatically turn the immersion off after a set time would be a good idea. Save trashing your batteries if/when you forget. Set to whatever time you think appropriate.

Jen

Good idea!

8 hours ago, Tracy D'arth said:

Do you not heat water with your engine?

 

Heating water with electricity from other than a shore line is very heavy on the batteries and solar will only assist in the few summer months unless you are in the tropics.

I’d like to have multiple options and harness the suns energy whenever I can. I use shoreline in the winter then hope to gain hot water through a combination of eberspacher, engine and solar in the summer