Backyard Aquaponics
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Hi All

I made an automatic switchover that swaps between the output of my solar inverter and mains power depending on the ability of the solar panels and batteries to provide power. This was basically a DPDT switch from Jaycar - it lasted about 12 months before it conked in.

i am looking for something a bit more reliable.

I noted the attached on fleabay. Does anyone have experience with this type of changeover switch - - or can recommend a reliable alternative?


http://www.ebay.com.au/itm/371069949442?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Any input is much appreciated



Gabe

What happened to the DPDT relay, did it just burn out? Im guessing it would be flicking over to mains a couple of times per day, more in cloudy weather?

could you consider heatsinking the relay somehow to run it cooler. I am quite fond of relays and have found if I choose the correct relay for the job and don't overheat them they are quite reliable

If one pulled the cover off the transfer switch in your ebay link, would not one find some kind of relay in use perhaps with a heatsink and some electronics? Or are they doing it another method eg monitoring the solar voltage electronically and switching over to mains when it gets too low

Hi Jono

The contacts overheated and fused together.

After some consideration i probably will give a relay another go. At around ~$10 each and replacing once a year i will only break even if the commercial switchover last 20 years!


Do you have any recommendations for switches?

PS - I like the idea of a heat sink and will make this modification.

Gabe

Hey Gabe

Firstly what's your input voltage - are you wiring in the relay before the inverter (low voltage) or after (high voltage)?

Also what sort of current are you putting through it?

It may be worth looking at a heat sinked solid state relay which are more reliable than mechanical relays (eg DPDT relays)

There are no mechanical contacts opening/closing with solid state relays, so there is no arcing or pitting of contact surfaces. There is less to wear out. As a result solid state relays can operate for many millions of cycles with no deterioration of performance

Hi Jono

Coil voltage is 240V (from an inverter)

Current is ~ 2 amp (max).

I had a look at solid state relays today at Jaycar - the salesman recommended against them. I bought a normal 240V, 5A relay. It wasn't very expensive so if it fails i'll try the solid state relay.