Richard Mackay

In the second graph 'Levelised cost of energy' the progress of battery storage is impressive! It's even more rapid than PV progress was! This is good news because this is the weakest link in RE.

The Economist on energy: Not-so-slow burn The world’s energy system must be transformed completely It has been changed before, but never as fast or fully as must happen now Around the world, governments currently provide more than $400bn a year in direct support for fossil-fuel consumption, more than twice what they spend subsidising renewable production

Then this isn't what you want! The last digits must be: dc12v (This is what is referred to as the 'coil voltage')

You can usually see the internal wiring of these relays. What you a looking for are the terminals that the coil is connected to (very small wires wound on the bobbin) When you find those terminals connect a 12V battery (gate motor or motor car battery) to them.. The relay should pull in when you do this..

Now you're talking!

They are great value but some are difficult to program so check this before buying. Don't switch your geyser element directly with its contacts. I know it's a pain but not doing this will shorten the life of the unit big time!

No sir! A triac is a back to back thyristor (see Plonksters last post) A thyristor either switches or it doesn't. The gate needs a certain voltage to get the thyristor to switch. (once the device switches it conducts until the voltage across the device reduces to 0V) They are good at what they do but still have their limitations. Why Deapsquatter decided to use a SSR I don't know. It's not the ideal solution for this application. But despite all the evidence he continues down this path trying to justify his reasons for using it.. I have listened to claptrap on other forums such as My Broadband. I don't think this site needs to emulate that one!

Another good idea to find relays is to strip them from those silly 600VA UPSs. (If anyone wants one I have a collection) Din rail contactors are quite pricey but are the way to go if you want to do a proper job.

3kW elements are a heavy load in a domestic setup. The 7 day timers that switch electrical loads also take strain when switching this kind of load (despite claims from the manufacturer they can handle it) The only time when one has to use a SSR is when the on/off switching is quick. Contactors aren't a good option in these applications

Is this dump load for an (old school) inverter to manage excess PV power?

Any reason you are using a SSR instead of a regular relay?

Try using the 5V supply from the Venus GX instead of 12V..

The utilities will not only have one billing system. They will bill for total electricity consumed for starters. Then they will penalise you for a reactive load. Then for large users they will hammer you for erratic demand.. Oh yes, they will also charge you a flat fee just to have the service available.. But if you take an interest in how you are billed there are big savings to be had. Most industrial users in my experience don't bother!

The units used for demand charges are kWh (Eskom's Megaflex billing system) Essentially it's the same (average demand over a period) but the units are more universal. And the demand charges change depending on the demand period: There is a High and Low demand period depending on whether it's summer or winter. Also the day of the week matters as well.. So in order to reduce maximum demand charges all these conditions need to be considered. The control system needs to synchronise with the utilities block metering and to extrapolate the projected demand over the period. If this projection indicates that the electricity consumed will exceed the target then a (non essential) load needs to be disconnected to prevent this happening.

You need to take them back to the supplier..(and be prepared to have a barney!)