9°C
Porth, Newquay, Cornwall. UK
Updated06/02/2026 19:00 
 




Solar PV - Immersion Heater





29/6/2013 System live at 13:00

Project:- Use excess electric generated to heat the hot water

I heat the hot water by gas, which on average costs 37p per day, based on a sample of 7 days (10th to 17th June 2013), can this be reduced ?

Yes hopefully especially in summer, I wrote an extra script to deal with this, it checks the current output agaist a threshold figure, if its below this nothing happens if above, it switches an ip power switch on which in turn operates a relay putting the immersion heater on, should the output fall below the threshold it switches off the ip relay and contactor and immersion heater, the script checks every 2 minutes output against threshhold setting.

The immersion heater is 3 kw, appears to take less than an hour to heat water,so unless brillant sunshine there will be usage from the grid, say max 1kw that equates to 12.6p, still a possible saving of 25p. Ideal solution would be a 1kw element thereby increasing the time over threshold.

12-10-2023 Takes about 50p to heat water now using gas.

Script and ip power relay installed and electrical work completed. Scripting work not finished, when complete this page will show status of immersion heater/solar pv heating.

immersion

immersion control ip switch

 Immersion Mod Cost

 including p&p
 Meter, switch and cable I already had

IP Power Switch Ebay £112-98
Din Rail Relay Ebay £14-95
Din Rail Enclosure Ebay £4-95
2m Female kettle extn lead Ebay £2-39
  Total £135-27

Solar PV - Immersion Data
Date / Time 06-02-2026 17:20
Threshold - Autumn 2700 W
Current Output 0 W
Peak Output 3279 W
Last Update 06-02-2026
Meter # 5238.73
Days solar 2817
Days Gas 1707
Aprrox Savings Gas ## 2817 days @37p = £1,042.29
# Meter since 29th June 2013, updated most days
## Approx saving on gas,averaged 37p per day


Immersion Data
Date/TimeThresholdOutputAction
06-02-2026 11:02 26002775ON
06-02-2026 11:06 26002521OFF
06-02-2026 11:10 26002710ON
06-02-2026 11:12 26001742OFF
06-02-2026 11:14 26002677ON
06-02-2026 11:16 26002585OFF
06-02-2026 11:18 26002798ON
06-02-2026 11:22 2600546OFF
06-02-2026 11:30 26003013ON
06-02-2026 11:42 26001119OFF
06-02-2026 11:54 26002985ON
06-02-2026 12:00 2600728OFF
06-02-2026 12:12 26002926ON
06-02-2026 12:14 26002370OFF
06-02-2026 12:16 26003059ON
06-02-2026 12:32 26002588OFF
06-02-2026 12:48 26002867ON
06-02-2026 12:50 26002502OFF
06-02-2026 12:56 26003025ON
06-02-2026 12:58 26001274OFF
06-02-2026 13:08 23003109ON
06-02-2026 13:12 23002212OFF
06-02-2026 13:38 23002676ON
06-02-2026 13:46 23002292OFF
06-02-2026 13:52 23002324ON
06-02-2026 13:54 23002226OFF


Immersion Time
Date / Time ONDate / Time OFFTime ONTotal Time On
06-02-2026 11:0206-02-2026 11:0644 mins
06-02-2026 11:1006-02-2026 11:1226 mins
06-02-2026 11:1406-02-2026 11:1628 mins
06-02-2026 11:1806-02-2026 11:22412 mins
06-02-2026 11:3006-02-2026 11:421224 mins
06-02-2026 11:5406-02-2026 12:00630 mins
06-02-2026 12:1206-02-2026 12:14232 mins
06-02-2026 12:1606-02-2026 12:321648 mins
06-02-2026 12:4806-02-2026 12:50250 mins
06-02-2026 12:5606-02-2026 12:58252 mins
06-02-2026 13:0806-02-2026 13:12456 mins
06-02-2026 13:3806-02-2026 13:46864 mins
06-02-2026 13:5206-02-2026 13:54266 mins

Log

17/4/2019 Immersion Heater Replaced
12/4/2019 - Immersion Heater faulty, awaiting plumber
5/4/2017 - 8 SunTech panels replaced with 7 LG panels
2/2/2014 - Added Status of the ip power switch ports
29/6/2013 - Electrical work completed, live at 13:00, then the fog rolled in off the sea.
23/6/2013 Started on addition to script to show minutes on and total time over threshold.

Page under construction - updated 2nd February 2014
Update to display ip switch port status