Wednesday 11 May 2016

12 volt electrics, continued

Some of our friends wouldn't dream of having a TV on their boat, but there's the most wonderful summer of sport coming up. Erin Mae came with an LG 26" analogue TV, all nicely framed with shelves for, among other things, CDs (remember those?). At the time of the digital switchover, our not-so-youthful eyes were beginning not to see all the detail on our 26" Sony TV at home, so we bought a new one, and installed the Sony in Erin Mae. The two flies in the ointment were (1) the variable signal from the omnidirectional aerial; (2) it's a mains model, and so needed the inverter on – the downside of which I described yesterday.

We decided over the winter that, if we were going to have a TV, it should be a 12 volt version, so the Sony went home and we bought an Avtex. It's a bit smaller than the previous occupiers of this space but, with a suitable bracket behind, is suspended nicely in the air.

A small piece of oak-veneered something-board left over from my wardrobe doors nearly 30 years ago covers lots of holes and wiring. Just behind the set, top left, can be seen the 12 volt socket that we installed for power.

When we came up after the winter the aerial didn't seem to be functioning at all, though we don't yet know whether that's just Great Haywood's reception problems. We adopted a multi-targeted approach. I had a spare wideband aerial, and rigged up a frame with some magnets for it to sit on the roof. That's working well – the best reception we've ever had here. The trailing lead in through the window can be seen in the photo, but we're hoping this will be a temporary / occasional arrangement. Since the TV also has a satellite input, I've acquired a satellite dish for areas (we've encountered a few) where Freeview just doesn't work, usually in those places we've reached just as Wimbledon starts. I suspect it will prove quite a hassle to get it set up – I'll be asking people we meet along the way for advice.

That's just about it for 12 volt devices. The list of what won't work includes the electric toothbrush, my own ancient mobile phone and two nice little reading lights from Ikea – I haven't yet found anything that might replace those. The automatic lighting for oven, grill and hob needs 230 volts but the oven and the hob, though not the grill, will work once lit.

Now we have to get out and about to test it all in the wild. Unfortunately, the weather has been miserable and we have things that require our presence on the south coast at regular intervals. Some day soon…


  1. Re Inverters - all of them draw a certain amount of power even with no load. It's what is needed to run the internal circuitry. This can be anything from about a third of an amp (for small portable units), to one amp or more for large units. This is what kills your batteries, rather than the intermittent current needed to actually run a fridge. Some of the more sophisticated inverters have a "seek" mode where they will monitor the output to see if there are any loads, and if not, they shut down and just check every few seconds. Once a certain minimum load is seen they restart full output. for This would be O.K. for a mains fridge with a simple dial type thermostat, but probably not for newer ones with electronic controls.

    As for running TV's etc. on "12 volts" - do make sure that this means "up to 15 volts" or damage can occur when the engine or battery charger are running. If your TV model is specifically designed for mobile use you should be OK, but just making up a lead to replace a dedicated mains supply is not a good idea (and will almost certainly void your warranty).

    1. Thanks, Dave. The inverter is a Viltron MultiPlus Phoenix 3KW, about as sophisticated as you get for this sort of application, I think, and its manual is quite clear about what sort of efficiency and management power loss to expect . My problem was that the reality did not match the theory, in spite of all my checks and consultations. Nothing from Viltron ever gave a reasonable explanation.