Inverters

Hello all

Been thinking of more off grid trips given the recent energy prices, and been looking at lithium battery set ups for use in the summer months with solar but really want better electrical protection as I would like to be able to simply drive the caravan from the inverter to make use of the 240 sockets and hot water boiler set at 1kW, would also disable the 230 volt caravan 12 volt battery charger.

Had a look at https://www.youtube.com/watch?v=mzCGE5wnWos which is a good source and confirms that using Residual Current Device (RCD) with an inverter will not give any protection, hence gone off the idea of using the caravan sockets.

Looking at some other sources it looks like the Australians make use of a Residual Voltage Device (RVD) which allows all of the sockets to be driven from an inverter.

Question:- Has anyone heard of or used a Residual Voltage Device (RVD) ? see https://www.rvdsafe.com.au for example.

You will be hard put to provide 1Kw of power from solar, even through a lithium battery. You'd need a very big caravan with a massive payload to carry the weight of the amount of solar required.

Thanks Cyberyacht, Yep does look a tall order 40 amp hr's for 1/2 an hours use of the boiler set at a kW, will stick with gas for the boiler and fridge. Coffee machine and toaster look more favourable as well as the hair drier.

Have you any comments on the RVD protection ? 

I had my inverter fitted for me. Operates independently of any other van circuits.

This is the theory.....I am NOT an electrician....

You really need your inverter just to run the 230v sockets NOT the fridge or the Truma unit.

the Truma can run off gas (we have refillables) as can the fridge, HOWEVER, with the appropriate regulator (I have a 30amp Epever similar to CY) the fridge can be triggered (by a cable from the regulator) to switch to 12v and run from the batteries provided sufficient solar power is a available and the batteries are full.

in order to run just the sockets, the cable into the sockets trip unit will need to be disconnected and fed into an inverter either via a manual switch (for mains or inverter) or by an inverter that allows pass through of the mains when present but automatically switches to inverter when it isn't.

the output of the inverter is then fed back into the socket trip which powers your van from mains when available, inverter if not.

re the RCD. It is recommended that the output from a large inverter is protected by its own RCD. GOOGLE CLIVEWAY this is Clive Mott's (MMM magazine) all in one switching and RCD unit for inverter that don't have their own pass through.

Like CY, I have 300w of solar which can rapidly replace used battery power...however in winter time, without this luxury, batteries will take a bashing.

remember, with an inverter up scaling 12v to 230v that's a nr 20 times increas when taking amperage from the batteries.

The Cliveway Priority Switch looks interesting, thank you for the info.