Newsletter Archive

240V Fridges

Over the past several months we have published a number of ‘reservations’ about running conventional AC fridges on solar systems.
One or two people reported some success at reducing their power consumption by disabling the ‘auto defrost’! A number of people reported that this caused other problems. We certainly do not recommend that you attempt any modifications unless you have suitable qualifications. Modifications could also void your warranty!

Jeff has offered the following further technical comments about this issue.

I surfed across your newsletter number 42 recently and noticed an article about cyclic defrost fridges, specifically the Kelvinator models. In the article, mention is made of the nip and tuck on the ‘defrost element’. As far as I know, this model fridge (as are most nowadays) use the cyclic defrost technique wherein the refrigerant is reverse cycled to defrost the freezer. The element referred to is most likely a small single wire element of around 1800 ohms (130mA or about 30 Watts) used to keep the back wall of the freezer frost free.
Disconnecting it wouldn’t save very much in the way of electricity, 30 watts cycling on for 10 minutes every eight hours is not a lot.

If you search the web trying to find out how these things work, all you will find is references to US web sites describing using a big heater of about 250 Watts + to defrost the fridge. In this case you will definitely save heaps by disconnecting the heater. Most fridges I have come across are reverse cycle defrost. Now you CAN disable the reverse relay in these types but then they ice up in about three days and their cooling capacity goes way down because the temperature sensor is now buried in ice. (Then it wont need to cool as much, so it WILL cost less to run, but not for the right reasons).”

P/R Motion Detector

We have now sourced a 12V one with similar specifications to our previous model. We hope to also convert this to make it suitable for 240 Volts. More details will be available in the next newsletter but if you are keen for the details or to buy one, drop me an e-mail and I will let you know as soon as they are in stock.