mikeymay Posted March 22, 2015 Share Posted March 22, 2015 I have spent about an hour or so looking through threads to try and find out if an inverter is a solution to my problem and I am non the wiser!! I want to use the following in the MH *Standard HD TV (typical usage 38W although some TVs are labelled as 64W maximum) *Standard Blu Ray player (8.8W) *Sky HD box (45W) I have two sets of leisure batteries which I think are 110a and also a solar panel fitted although I don't know what this provides. I generally try to get sites that have a hook up but some foreign sites only have low supplies. If no hook-up then we'd tend not to be away for more than 2-3 days. Could someone give me some succinct and simple advice on the best way to do this if at all possible? Thanks Link to comment Share on other sites More sharing options...
Tracker Posted March 22, 2015 Share Posted March 22, 2015 If you add up all the wattages 64+9+45 = 118 and add on about 20% to cover system inefficiency you will need an inverter of about 150 watts. However 150 watts at 230 volts is less than half an amp at mains voltage but it is getting on for 13 amps per hour at 12 volts which is a big ask for anything other than short duration use. An evening's viewing will knock seven bells out of your leisure batteries to the order of some 52 ah for four hours. If the batteries are sound and fully topped up you might get away with it but all that power consumption added to everything else like lights, heating, water pump will need to be replaced and it will take a big solar input to do that. Say you get 10 hours of strong sunlight and the panel gets as efficient as a flat panel can and is never in shadow you can expect about 50% efficiency so you might well need something like a 100 to 120 watt solar array - or a generator! If you measure your solar panel's dimensions and compare it's size with those on sale you should get an inaccurate but general idea of it's capacity unless it has a label you can spot whilst you are up on the roof! Link to comment Share on other sites More sharing options...
Guest peter Posted March 22, 2015 Share Posted March 22, 2015 All the items listed probably run on 12volts anyway as supplied from a 240 volt block. Just omit the blocks and use 12 volt connection. No inverter necessary. Link to comment Share on other sites More sharing options...
mikeymay Posted March 23, 2015 Author Share Posted March 23, 2015 Thanks tracker If I were to use these via a hook up would the iverter be required and would a supply of 16a be sifdicient? Thanks Link to comment Share on other sites More sharing options...
Tracker Posted March 23, 2015 Share Posted March 23, 2015 As I said earlier, the power used of watts at mains voltage is very small compared to the same wattage at 12 volts. As a general rule of thumb guide, for any item it's power consumption in watts is the same whatever the voltage and as the wattage cannot be changed and neither can the supply voltage all that changes is the current in amps which rises as the voltage supply falls, so in easy figures you can calculate as below. 240 watts at 240 volts = 1 amp. 240 watts at 12 volts = 20 amps Does that help? Link to comment Share on other sites More sharing options...
sshortcircuit Posted March 23, 2015 Share Posted March 23, 2015 Trackers advise is spot on. As far as 16A from an EHU, don't budget on it, 6A or 10A but 16A like hens teeth Link to comment Share on other sites More sharing options...
Keithl Posted March 23, 2015 Share Posted March 23, 2015 mikeymay - 2015-03-23 7:57 AM Thanks tracker If I were to use these via a hook up would the inverter be required and would a supply of 16a be sifdicient? Thanks Simple answer... Don't bother with an inverter. When on a site with hook up the combined current draw of your set up will be around 0.5 Amps, so no problem even on a low Amperage site supply. When on a site with no hook up don't bother even getting the TV out. Simple really :-) Keith. Link to comment Share on other sites More sharing options...
sshortcircuit Posted March 23, 2015 Share Posted March 23, 2015 mikeymay - 2015-03-23 7:57 AM Thanks tracker If I were to use these via a hook up would the iverter be required and would a supply of 16a be sifdicient? Thanks Inverter would not be required when on hook up. 16A more than sufficient. I run my tv on a 150w inverter no problem and it is not pure sine wave as may be recommended Link to comment Share on other sites More sharing options...
mikejkay Posted March 23, 2015 Share Posted March 23, 2015 I have a standard 240v a/c TV which I use via an inverter and have had no problems. However, I must add that I also have a 150w solar panel. I think that if you are going to use 240v a/c equipment then a combination of inverter and a solar panel is essential I did have an allegedly 1000w continuous inverter which blew while charging my laptop. On investigation I found that there was a 4amp fuse hardwired internally..........junk >:-) I currently have a 1500w (3000w surge) Jago inverter SWAND01-1500w which has done all that I have asked of it, including running a 700w (output) microwave and a 600w toaster. It is important to note that both the microwave and the toaster are run for short periods of time. It is also important to note that the inverter must be wired using short runs of heavy cable with properly attached heavy duty i.e. b......y big terminals. I have incorporated a 100amp RCD/trip fuse which I use as an isolating switch. I am sure that you are aware that a short circuit will cause serious damage up to total loss of your m.h. :-( Link to comment Share on other sites More sharing options...
mikejkay Posted March 23, 2015 Share Posted March 23, 2015 I've just noticed that you asked for succinct and simple advice. Get a professional auto-electricioan to do the job! Link to comment Share on other sites More sharing options...
Charles Posted March 23, 2015 Share Posted March 23, 2015 I've had a pure sine wave inverter for years. When the TV was on it took about 3 amps @ 12v we only have the tv on for a couple of hours and the battery has lasted 5 days in the past, the battery didn't go flat. Our new TV is LED backlit and with the energy saving on it takes less than 2 amps out of the battery. If you just put the TV on when there's something on you want to watch the battery will last a good few days even before its at 50%. Link to comment Share on other sites More sharing options...
fesspark Posted March 24, 2015 Share Posted March 24, 2015 I run 2 12v tv,s direct without the use of my inverter they are very low on amps usage, Fesspark, got that right. Link to comment Share on other sites More sharing options...
aandncaravan Posted March 25, 2015 Share Posted March 25, 2015 Tracker is spot on in his reply, even at supplying only 150 watts at 240v an Inverter will hammer the Habitation batteries, shortening their life by quite a margin. . The power that is taken out has to be put back by either the Alternator or mains charger (assuming no Solar Power ) and that is a big workload. This will shorten their life, in some cases cause an outright failure, as we see regularly. We are A and N Caravan who repair Motorhome Charger units and rebuild/replace Alternators Running a 1000w plus Invertor will very heavily burden the mains Charger and Alternator well beyond what they were designed to cope with. We see more issues around the Installation/use of big inverters than any other Motorhome add-on. The load they place on a Motorhomes Infrastructure can be colossal leading to premature Battery, wiring, Charger and Alternator failure. Worse still a big Inverter is often paired with an old style Leisure battery which is designed to deliver a small amount of current over several days, not the big Invertor current draw over minutes. If you do fit a big 1000w + Invertor at least fit batteries that can handle a big current draw. See our advice page on Battery Technology (not sales based as we don't sell batteries) where about 3/4 way down the page you will also find advice on Invertors in Motorhomes : http://www.aandncaravanservices.co.uk/battery-technology.php The page is an Information Page, it does not contain any advertising or Sales, it is all about getting the best from your Motorhome. It goes against the established ideas that have now been superseded by recent big advances in Battery Technology. It also covers the problems that emanate when additional batteries are installed. Link to comment Share on other sites More sharing options...
mikeymay Posted April 2, 2015 Author Share Posted April 2, 2015 Just got back from three nights away on hook up and had a 32" HD TV and a Sky HD box running as well as a few lights, fridge and air blown heater. No problems experienced at all so as long as there us a decent hook up I can't see the point of an Inverter. We are going away for a night with no hook up at the weekend and I am thinking of trying the same with just solar and a bank of 2 leisure batteries. Link to comment Share on other sites More sharing options...
Tracker Posted April 2, 2015 Share Posted April 2, 2015 mikeymay - 2015-04-02 2:29 PM No problems experienced at all so as long as there us a decent hook up I can't see the point of an Inverter. If you only ever camp with hook up you will never need an inverter But if you don't have hook up and you wish to use anything mains powered then you will need an appropriately rated inverter to generate mains voltage from a 12 volt source. Link to comment Share on other sites More sharing options...
sshortcircuit Posted April 2, 2015 Share Posted April 2, 2015 Tracker - 2015-04-02 3:47 PM mikeymay - 2015-04-02 2:29 PM No problems experienced at all so as long as there us a decent hook up I can't see the point of an Inverter. If you only ever camp with hook up you will never need an inverter But if you don't have hook up and you wish to use anything mains powered then you will need an appropriately rated inverter to generate mains voltage from a 12 volt source. Totally agree, or a generator :-D Link to comment Share on other sites More sharing options...
Tracker Posted April 2, 2015 Share Posted April 2, 2015 sshortcircuit - 2015-04-02 5:18 PM Totally agree, or a generator Absolutely! Link to comment Share on other sites More sharing options...
StuartO Posted April 3, 2015 Share Posted April 3, 2015 There are so many boys' toys you can buy for your MH these days and some of them are quite heavy, so if you aren't selective you can soon end up cluttered and maybe even overloaded. I bought a cheap 1500w inverter some years ago, thinking it was a must have but delayed fitting it while I scratched my head about how and where. We had a microwave oven and the option to use that was to be its main job. But we never wanted to use the microwave unless we were on an EHU and rarely used it at all so the microwave came out and the inverter stayed on a shelf in the garage. We had a toaster too, which we do use when on an EHU but we also have a gadget for toasting on the gas hob and that works better for some types of bread, especially foreign stuff. So the 1500w inverter was disposed of recently by donation to a friend who has a caravan, so it can live in his garage for a change. But I do have a portable 150w inverter, which we have kept in the MH and is usueful on a continuing basis - mainly fro charging up electrinic stuff which needs main voltage when necessary. It will charge the laptop when the laptop is powered off, so I suppose I could do with a slightly bigger one, but it's OK, so I stick with it. No installation either, it just lives in a locker and takes up very little space. So inverters, or at least bigger ones, have not been worthwhile for me. Now that we've got solar panels we leave the generator behind too. Tehnology for MHs moves on, some things become obsolete and you certainly need to avoid carrying too much stuff around unnecessarily. I suppose I should count myself lucky that my OH doesn't take a hair dryer; then I might have to fit an inverter. Link to comment Share on other sites More sharing options...
PeteH Posted April 3, 2015 Share Posted April 3, 2015 Hi My experience of using an inverter is based on my last R-V. Having the Spare capacity in both space and payload I upped the "House" capacity to 440ah. Ran a 2KW inverter direct from the bank via short HEAVY (Welding) cable and 40A Isolator, which was then transferred as 230V to the "Shore Power" input and isolated by a 40A Change over switch. Off-line charging was assisted by two 100W Solar panels. This rig gave us the facility not only to watch the Mains T-V and Satellite but also to use the microwave, on occasion, and even make toast! .(not all at once!!!) We still had the on-board Genny, but this rig allowed us to be Relatively Quiet on sites when necessary, and not annoy the neighbours by running the gen set late in the evening or early Mornings, and was a boon when marshalling festivals!!, (Early Mornings and late nights). I did not experience any adverse effect with the Alternator. However it was rated at 180ah!. and sat right in the Air flow over the engine, in front of the pusher radiator. The previous owner had swapped out the Charging unit for an "intelligent" unit of 40amp capacity, which was as sophisticated a unit as was available at the time, being capable of being switched between WET and AGM if required. and had a sophisticated charging program. This system worked well for over 7 years, Using "Cheap" Wet Leisure batteries. only one being replaced under warranty (dead Cell). pete Link to comment Share on other sites More sharing options...
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