Retrofit solar I Boost quote

QrizB

geronimo101 said:

does anyone know exactly how they work iboost for example.

An immersion heater has an electrical resistance that's more-or-less constant. The power (in watts) dissipated by the heater equals the square of the applied voltage (volts) divided by the resistance (ohms).

For a 3kW heater designed to operate at 240V, that resistance is 19.2 ohms. 240 * 240 / 19.2 = 3000.

If you reduce the voltage you apply to the heater, you'll reduce the power. At 120 volts, the power from the heater is only 120 * 120 / 19.2 = 750 watts. At 60 volts, 60 * 60 /19.2 = 188 watts.

The iBoost or whatever will do something clever to adjust the voltage the immersion heater sees and make sure it only feeds it  enough power to balance out the surplus of your solar generation.

70sbudgie

Magnitio said:

70sbudgie 

Can I ask what tarrif you are on for exporting electricity and how you would normally heat your hot water? It could be that you are better off exporting the surplus electricity rather than using it for the immersion.

I have just completed my first month on Octopus Agile Outgoing and earned about 38p/kWhr. This is higher than my day import rate, let alone my gas rate (current method for heating water). Which is why I haven't yet installed my Solic 200 (which is what I bought instead of the iBoost, in the end).

I am in the process of analysing my data to see whether it would be worth changing to an EV tariff and the 4.1p export over winter. In which case, it might be worth using what solar generation I do get to heat the hot water.