Solar PV Power Immersion Heater - Have I Lost The Plot?

[dtmpower]

fredfred2 said:

How can you run a 3kW heater with a 2kW solar panel, and still not draw grid power? Beats me.

Turn down the input voltage - for example, put it through a 'building site' 110v ac transformer.

[fredfred2]

dtmpower said:

Turn down the input voltage - for example, put it through a 'building site' 110v ac transformer.

Yeah, but this box I saw had a straight connection with the 3kW immersion heater and nothing in between. Also, is it legal to use 110V in a UK house? That's against the regs isn't it? (I'm an electrician)

I once came across a house where they had a 110 transformer in place to run American equipment. Then a few months later I heard that they'd had a fire or something and the insurance company refused to pay up...

As this is for my own place I don't want to take that risk. 3kW is a lot of power to put through a transformer, even though it'll be reduced by the voltage change.

I can see how that works though. Good idea.

[dtmpower]

fredfred2 said:

Yeah, but this box I saw had a straight connection with the 3kW immersion heater and nothing in between. Also, is it legal to use 110V in a UK house? That's against the regs isn't it? (I'm an electrician)

I once came across a house where they had a 110 transformer in place to run American equipment. Then a few months later I heard that they'd had a fire or something and the insurance company refused to pay up...

As this is for my own place I don't want to take that risk. 3kW is a lot of power to put through a transformer, even though it'll be reduced by the voltage change.

I can see how that works though. Good idea.

Some of the solar immersion controller seem to have both direct and stepped down input - which ode is used depends on the power generated at the PV. Maybe your client just has it on 'half power' at all times as they never produce over 3kW.

[Chris Type R]

I

fredfred2 said:

I'm new to this forum, but have been looking to find out who makes this box. The owners of the house weren't in when we were doing some wiring, but this thing controls a standard 3kW immersion heater directly. The panels are only 2kW capacity, so my guess is that some electronics must turn down the mains to the heater element. There is nothing between the box and the immersion heater, which is rated at 3kW.

How can you run a 3kW heater with a 2kW solar panel, and still not draw grid power? Beats me.

But does anyone know who makes this little solar immersion heater controller?

cheers,

fred


Sorry about the image quality- from my phone...

Spotted on eBay as a "Solic 200".

http://www.earthwiseproducts.co.uk/info/solic-200+...

Edited by Chris Type R on Sunday 1st March 18:48

[anonymous-user]

Not sure if it has been said but make sure the installation has Code of Mortgage Lenders approval as not having this causes problems if you need to sell the property. Personally I wouldn't consider buying a house with a rent-a-roof installation on it unless the seller could buy out the agreement which is typically 25 years and no doubt quite expensive to do.

[hairyben]

fredfred2 said:

Yeah, but this box I saw had a straight connection with the 3kW immersion heater and nothing in between. Also, is it legal to use 110V in a UK house? That's against the regs isn't it? (I'm an electrician)

I once came across a house where they had a 110 transformer in place to run American equipment. Then a few months later I heard that they'd had a fire or something and the insurance company refused to pay up...

As this is for my own place I don't want to take that risk. 3kW is a lot of power to put through a transformer, even though it'll be reduced by the voltage change.

I can see how that works though. Good idea.

Why are you asking us what the regs are if you're an electrician? Why would it be illegal to run things off transformers? Are you saying everything from low voltage lighting to cellphone chargers are all illegal? problems with american equipment will more likely arise from the frequency difference with motorised stuff.

Besides, a 3kW 230v heater won't be a 3kW heater on 110v, it'll be just under 750w. In fact your magic solar controller is probably a multi tapped transformer with a smart controller- this is first year stuff...

Edited by hairyben on Sunday 1st March 19:52