richie1575 Posted September 1, 2009 Share Posted September 1, 2009 Hi All! My Father in law has run a Christmas Sleigh feature outside the local shops for many years. (charity boxes shaking, Santa waving etc.) Historically they have used a cheap gennie to power a few carniaval bulbs and the music system. 'Elf an Safety will no longer allow him to use the gennie due to the fire risk (plus it's knackered!!) Since they recently replaced the carnival lights with a set of LED fairy lights and the Realistic PA horns with a cheap CD ghetto-blaster (not much better I know!), I was wondering if they could run off a 100VA leisure battery via an inverter. I was looking at the Eagle Inverter/Charger as this will be easy for them to recharge (eg just plug it in!) This will be used by some very non-techincal people (beleive me!!) My Question is how long will it last... I'm guessing mains loading will be no more than 50watts and does anyone see any other pitfalls? Thanks! Richie Link to comment Share on other sites More sharing options...
timtheenchanteruk Posted September 1, 2009 Share Posted September 1, 2009 leisure batts are usually measured in Ahrs, most common being 85 and 110. a 150W inverter should do fine, a 50W load at 12V is just over 4A, so assuming about 6A to allow for losses, a 110Ahr will last you about 12Hrs ( theory 18, but never flatten the battery)if you get a Ctek charger or similar to keep it conditined, it should last you 4 years or so. a more efficiant way would be find some 12V fairy lights, and use a 12V amp. that way power is not wasted in the inverter. Link to comment Share on other sites More sharing options...
benash Posted September 2, 2009 Share Posted September 2, 2009 and use a 12V amp. that way power is not wasted in the inverter.Easiest way is to grab an old car stereo system and hook that up. Link to comment Share on other sites More sharing options...
Jivemaster Posted September 2, 2009 Share Posted September 2, 2009 The inverter seems a perfect solution to the problem. I'm sure there are alternatives though. Link to comment Share on other sites More sharing options...
Robin D Posted September 2, 2009 Share Posted September 2, 2009 You may find if you look hard that the LED fairy lights are running from a 12v transformer - many do so just run them straight from the battery. I concur with teh 12v amp as well. We have a motorhome and were away last Christmas complete with small tree and 12v fairy lights. A big leisure battery will run many hours unless you really crank up the sound system. Link to comment Share on other sites More sharing options...
adam2 Posted September 2, 2009 Share Posted September 2, 2009 As others suggest, an inverter certainly could be used, but 12 volt direct from the battery is probably more efficient, and is certainly simpler and safer.Cheap inverters are far from reliable and failure would be embarassing unless a spare was to hand.Most cheap inverters have a sqaure wave output which may reduce performance of loads that use a transformer. A cheap car stereo would work fine, as would a basic 12 volt input amplifier. Most "mains" LED Christmas lights use 24 volts AC from a small transformer and without labour intensive modification cant be used on 12 volts DC.Many suppliers sell battery operated LED Christmas lights that are intended to work from 3 AA cells in a holder.Obtain 3 similar such sets, remove the battery holders, wire the 3 sets in series and connect to your 12 volt battery via a 1 amp fuse.(take care not to remove or bypass the current limiting resistors when removing the battery holders) Link to comment Share on other sites More sharing options...
richie1575 Posted September 2, 2009 Author Share Posted September 2, 2009 That's a very good call! Why waste money on an inverter only to step it down again! It had breifly crossed my mind, but seeing it written here... it really makes sense! I guess that using 13a plugs is idiot-proof... this needs to be idiot proof, so has anyone any suggestions of a nice way to fuse and distribute this 12v supply. The connectors would need to be robust... and the battery would need to go for a charge every so often! Some advice on chargers would be really helpful too! I've checked the fairly lights and thay are indeed 12volt!! Thanks again! Richie Link to comment Share on other sites More sharing options...
Roderick Posted September 2, 2009 Share Posted September 2, 2009 How about car cigarette lighter plugs rather than 13A plugs?You can get the plugs, with a build-in fuse and outlets at all car accessory shops. Link to comment Share on other sites More sharing options...
daifuse Posted September 3, 2009 Share Posted September 3, 2009 To get really high brightness fairy lights in fairly bright ambient conditions on stage last year I resorted to using 240v fairy lights (and it takes a fair number to decorate Cinderella's coach!) running off an inverter and a 12 leisure battery which will take a heavy discharge beyond 50%. But, I must agree, stepping up the 12v and back again does seem like a waste of time - and innefficient to boot! Link to comment Share on other sites More sharing options...
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