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Immersion heater less than 3kW?

Radian

By Radian
in Boilers & Hot Water Tanks

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Radian Advanced Member

Radian

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I'm looking for an immersion that's less than 3kW. According to this Tesla data sheet TIH642 is 1kW and marked "Recommended for solar". Perfect.

But nowhere seems to stock it and it doesn't even come up in a search on the Tesla webshite.

Anyone managed to find such a beast anywhere?

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Carrerahill Advanced Member

Carrerahill

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2 hours ago, Radian said:

I'm looking for an immersion that's less than 3kW. According to this Tesla data sheet TIH642 is 1kW and marked "Recommended for solar". Perfect.

But nowhere seems to stock it and it doesn't even come up in a search on the Tesla webshite.

Anyone managed to find such a beast anywhere?

If you are trying to do what I think you are trying to do, then what about this?

 

Solar iBoost?

 

https://www.heatershop.co.uk/solar-iboost-solar-immersion-controller

 

 

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Radian Advanced Member

Radian

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2 hours ago, dpmiller said:

Pricey, but just what you're looking for:

 

Ouch! But thanks anyway.

 

16 minutes ago, joth said:

If you have a spare 110V site transformer, hook up a 3kW element on the secondary side of that and it'll draw about 1.5kW :)

 

True, but a bit bulky for the airing cupboard.

 

4 minutes ago, Carrerahill said:

Solar iBoost?

Ha yes! But I've already built my own. The problem with driving a 3kW element is that power control is either burst mode (effectively PWM using whole cycles) which can mean on/off cycling over sub-second intervals - which can produce flicker in lights. Other modes have their own issues - phase angle control is just nasty at these power levels and true AC PWM is nightmare expensive compared to Triac switching. Which is why most DIY solutions use burst. Just thought a smaller immersion might be better for this but it turns out they're super uncommon. Oh well.

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ProDave Advanced Member

ProDave

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49 minutes ago, joth said:

If you have a spare 110V site transformer, hook up a 3kW element on the secondary side of that and it'll draw about 1.5kW :)

 

 

 

No it will be more like 700W

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ProDave Advanced Member

ProDave

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14 minutes ago, Radian said:

The problem with driving a 3kW element is that power control is either burst mode (effectively PWM using whole cycles) which can mean on/off cycling over sub-second intervals - which can produce flicker in lights.

But at the times when the sun is shining and you are using surplus PV, there won't normally be any lights on (except in a basement perhaps?)

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Radian Advanced Member

Radian

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1 hour ago, JohnMo said:

https://www.backerelectric.com/shop/domestic-immersion-heater/?index=24

 

 

That's more like it. Not heard of that company before. Great selection!

 

1 hour ago, ProDave said:

But at the times when the sun is shining and you are using surplus PV, there won't normally be any lights on (except in a basement perhaps?)

Basement no, kitchen yes. The under-cupboard LED strips are pretty much always on despite having windows facing NW, NE and a small but stylish SE facing vertical slot window. I've yet to verify that a 3kW element would cause flicker but I just wanted to see what my options were if it did.

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Radian Advanced Member

Radian

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20 minutes ago, SteamyTea said:

Wasn't it our @Ed Davies that played about with a modified 3 phase element to get a range of different powers. Not sure if it was an academic exercise or he did it for real. 

Give him a shout.

https://edavies.me.uk/

Aw, nice old blog there. More bedtime reading.

 

Yep, Ideally I'd have had two immersion ports on my shiny new cylinder but alas not. A series/parallel switching system using two bog standard heaters would have covered all bases nicely and cheaply. At the moment I've only got a spare half kW doing nothing but making an occasionally slightly embarrassing increment in my export register (just a little over 2kWh so far, but difficult to explain away), so a small immersion would be the best fit. My homebrew diverter is just starting to take care of the embarrassment but it's currently dumping unwanted heat via a 750W convector heater in my already scorching workshop 🙄

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SteamyTea Advanced Member

SteamyTea

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2 minutes ago, Radian said:

My homebrew diverter is just starting to take care of the embarrassment but it's currently dumping unwanted heat via a 750W convector heater in my already scorching workshop

I have always fancied an outdoor fish pond, with colourful tropical fish in it. Goes back to my time as a kid living in West Indian islands where we used to get guppies out of ditches and cross bread them to make them colourful.

So why not dump the power into a small pond. Kind of thing @ProDave would do just to stop the DNO having any. He you use it to rear trout in the winter, then boil them up for supper in the summer.

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ProDave Advanced Member

ProDave

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8 minutes ago, Radian said:

At the moment I've only got a spare half kW doing nothing but making an occasionally slightly embarrassing increment in my export register (just a little over 2kWh so far, but difficult to explain away), so a small immersion would be the best fit. My homebrew diverter is just starting to take care of the embarrassment but it's currently dumping unwanted heat via a 750W convector heater in my already scorching workshop 🙄

I am now exporting about 2kWh per week.  That is mostly mid day when if nothing else is running in the house, the PV generates more than my immersion can absorb (it's actual power appears to be 2.8kW) and it's too hot in the house to dump any to the 700W convection heater.

 

I do say out of spite I will just move that dump heater out to the garage.

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Radian Advanced Member

Radian

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2 hours ago, ProDave said:

I do say out of spite I will just move that dump heater out to the garage.

I've been thinking about all the little things that might benefit from surplus power. My distributed mains signaling system easily enables me to switch a wide variety of different loads anywhere the mains is available:  Electric Towel rails wouldn't add too much unwanted heat in the house if there was a moisture sensor gating their operation. PIV is another candidate. And what's that hot water circulation thing called? Y'know, where you have a loop circulating HW to taps driven by a pump to ensure instant HW? I tend to think they're a bit of a lossy luxury but if the cylinder is already max'd out and there's still power to spare, why not pump it around some? I've already got my double Makita battery charger set up to come on automatically. Sounds silly but it actually draws around 400W for half an hour if there's a couple of empty 5Ah batteries sat waiting on it. Every little helps 😇

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SteamyTea Advanced Member

SteamyTea

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7 minutes ago, joe90 said:

We’re not the YMCA

The worse job I every had to do was cleaning out the DE filter at the Sheffield YMCA.  I have no idea what those young men got up to in it.

It was worse than removing the Queen's Club, in Bayswater, steamroom in the early 90's

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