gherriott Posted January 24, 2009 Share Posted January 24, 2009 Hi, I am writing this post on behalf of a colleague who needs to run 15 or so 230V tungesten golf balls bubbles off a 12V battery for a scene. They only nned to be about 15W each, but even so they are still pulling about 20A which requires a very expensive battery to get at least 20Ah out of it! Do you know of any alternatives? The bubbles have to look like a tungesten source in a golf ball shape. There is a limited budget of about £80 for this effect. Is it possible to do without an expensive battery and inverter? Quick responces would be much appreciated! Thank you for help. Greg Link to comment Share on other sites More sharing options...
boswell Posted January 24, 2009 Share Posted January 24, 2009 In a word No!cheapest way is to swap the 230v bubbles for 12V ones then wire in parallel across a 12V battery, size of the battery depends on how long you want the light on for. Look at 10 or 20w 12V G4 bubbles, they are cheap Link to comment Share on other sites More sharing options...
KevinE Posted January 24, 2009 Share Posted January 24, 2009 You can now get LED golfball lamps if that's any use cpc led golfballs Link to comment Share on other sites More sharing options...
dbuckley Posted January 24, 2009 Share Posted January 24, 2009 GridGirl is doing this for her current show - a coffee bar on wheels, lots of 12V golfballs, and a deep cycle battery in the back stopping the bar from floating away. A lovely bit of staging. Perhaps she might post a pic...? Problem is, budget wise, you do need either deep cycle batteries, or vastly overrated car batteries. Modern car batteries are designed to do just one job, which is to crank an engine, but they are really poor as as power source where you want to get a significant fraction of the rated amp/hours out of the thing. Deep cycles you can discharge down much further, just how far depending on how fast you discharge it. Of course, deep cycle batteries cost far more than car batteries. Ask the boaties where they buy theirs from! Link to comment Share on other sites More sharing options...
gherriott Posted January 24, 2009 Author Share Posted January 24, 2009 Thanks for your suggesttions. Unfortunately LED gives the wrong colour temperature for a tungsten look which is what has been specifically asked for. I have come across a unit that has a normal golfball bubble in a holder witha built in battery, giving off a tungsten light. Not quite sure hwat type of bubble it must have maybe something similar to that of a torch, but I am hoping that will do the trick. It's about £6.00 which works out much cheaper than inverters and batteries which are in excess of 20Ah. Still, any other suggestions would be greatly appreciated. Link to comment Share on other sites More sharing options...
Tom Baldwin Posted January 24, 2009 Share Posted January 24, 2009 12V lamps, 12W (amongst other flavours) here. It seems the magic search term is "bus bulb" 12V or "bus lamp" 12V ... Link to comment Share on other sites More sharing options...
gherriott Posted January 24, 2009 Author Share Posted January 24, 2009 12V lamps, 12W (amongst other flavours) here. It seems the magic search term is "bus bulb" 12V or "bus lamp" 12V ... That's perfect! Thank you so much. Greg Link to comment Share on other sites More sharing options...
GridGirl Posted January 25, 2009 Share Posted January 25, 2009 GridGirl is doing this for her current show - a coffee bar on wheels, lots of 12V golfballs, and a deep cycle battery in the back stopping the bar from floating away. A lovely bit of staging. Perhaps she might post a pic...? I would if I had one! Deep cycle battery is working well for us, the only issue we've had was that the (slightly underrated) switch imploded the other night...now have two switches in parallel to stop further meltage.... Link to comment Share on other sites More sharing options...
gyro_gearloose Posted January 25, 2009 Share Posted January 25, 2009 If you can't afford one big battery, just use two or more cheaper batteries and connect them in parallel. This will give you more Amp/hours to play with, but you must use diodes or bridge rectifiers to connect your batteries together. These will prevent one battery from reverse-charging the other if one one battery runs out before the other. The easiest way of doing this would be to get yourself a bridge rectifier. It will have four terminals marked '+', '-', and two with '~'. Connect the '+' from one battery to one '~', and the other batteries '+' to the other '~'. Join both '-' terminals on the batteries together. This will be your ground, and the '+' terminal on the rectifier will be your positive supply. Connecting batteries in this manner is common on caravans and boats. If you want to charge both batteries just connect the positive lead from the charger to the '-' terminal on the rectifier and the negative lead to the batteries negative terminals, leaving the rectifier in place. This will charge both batteries from one charger. Link to comment Share on other sites More sharing options...
dmxtothemax Posted January 26, 2009 Share Posted January 26, 2009 Thanks for your suggesttions. Unfortunately LED gives the wrong colour temperature for a tungsten look which is what has been specifically asked for. I have come across a unit that has a normal golfball bubble in a holder witha built in battery, giving off a tungsten light. Not quite sure hwat type of bubble it must have maybe something similar to that of a torch, but I am hoping that will do the trick. It's about £6.00 which works out much cheaper than inverters and batteries which are in excess of 20Ah. Still, any other suggestions would be greatly appreciated. A standard car battery of medium size is good for about 60 amp hours, So depending on the time required, yes it will work! easily one hour, posssibly two. or just get more or bigger batteries.Let us know how it goes. A concurrent post has been automatically merged from this point on. If you can't afford one big battery, just use two or more cheaper batteries and connect them in parallel. This will give you more Amp/hours to play with, but you must use diodes or bridge rectifiers to connect your batteries together. These will prevent one battery from reverse-charging the other if one one battery runs out before the other. The easiest way of doing this would be to get yourself a bridge rectifier. It will have four terminals marked '+', '-', and two with '~'. Connect the '+' from one battery to one '~', and the other batteries '+' to the other '~'. Join both '-' terminals on the batteries together. This will be your ground, and the '+' terminal on the rectifier will be your positive supply. Connecting batteries in this manner is common on caravans and boats. If you want to charge both batteries just connect the positive lead from the charger to the '-' terminal on the rectifier and the negative lead to the batteries negative terminals, leaving the rectifier in place. This will charge both batteries from one charger. Adding a bridge rectifier to the circuit during discharge, will add at least 2 diodes to the circuit, and that means a loss of 2 times .6vthats 1.2v! leaving 10.8v, this will trip the low voltage cut out on the inverter.Put two batteries in parrallel, and so long as there voltages are close, they will soon stabilise.any discharge is likely to be small enough to ignore! Link to comment Share on other sites More sharing options...
boswell Posted January 26, 2009 Share Posted January 26, 2009 OP says he does not wanto to use inverterand the diodes will only give a 0.6v drop, not 1.2V, think about it !! Link to comment Share on other sites More sharing options...
adam2 Posted January 26, 2009 Share Posted January 26, 2009 I would use 12 volt bulbs of a large 12 volt battery. 10 watt bulbs should be suitable, 15 of these would draw about 12 amps at 12 volts.To supply this for an hour you will need a battery of at least 30 amp hours since the battery wont give its rated capacity if discharged over only an hour. Remember that batteries can deliver vast currents if shorted, a fuse in one of the battery leads is essiential, a heavy duty vehicle type fuse holder with a 15 amp fuse would be fine. Link to comment Share on other sites More sharing options...
musht Posted January 26, 2009 Share Posted January 26, 2009 I would if I had one! Deep cycle battery is working well for us, the only issue we've had was that the (slightly underrated) switch imploded the other night...now have two switches in parallel to stop further meltage.... Really want a battery isolator switch like: http://www.vehicle-wiring-products.eu/VWP-...ns/battisol.php Just to add to what Adam2 said, put a fuse in the + line as close to terminal as possible, in car audio competition more than 2" from terminal was a disqualification. Its only 12V but available current across a shorted lead acid battery is MANY THOUSANDS OF AMPS, it will vaporise copper and weld steel. Outside chance of a shorted battery exploding. A fuse straight off the terrminal before the switch eliminates these possibilities Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.