Power used by 48 LED cabin light?

[tigermullet]

Just bought a new cabin light which has 48 LED's. I know very little about electrics and the staff at the shop did not know how much the thing will draw. It's not written on the device or package either. Has anyone got an idea what the drain on the battery will be like? I expect it to be low but would like to know how much.

[Simmo2]

I had a quick search and it looks like it will draw about 10mA per led.
So it will draw about half an amp.

[tigermullet]

Thanks very much Simmo - I did a search but could not find any information that I could 'decode'. That will do me and it makes it a little better for power consumption compared with an 8w fluoro and is so much brighter.

[Local_Guy]

LED's last for ever and use next to no power to run them. you won't have to worry on your battery going flat for about 100 hours or so.

[warrior]

i have left my leds on all night and the battery is still good for the weekend you should have no worries

[tigermullet]

Thanks all. That is excellent news. The light came from Whitworths and their price even beat Ebay.

[bungie]

my 48 led runs at 0.34amp

[rumy1]

This a copy and paste straight from the Whitworth site .....

Ideal for many uses this Slim LED board with 48 super-bright LED's and mini rocker switch.

Plastic ABS base.
Plastic clear decorative lens
Length 185mm x Width 110 mm
Designed for either surface or recessed mount
Height after surface mount: 24 mm
Height after recessed mount: 16 mm
12V polarity-free
Current Drawn approx 0.32 Amps

[tigermullet]

Thanks Bungie and Rumy! - sorry for the late response. I have been on the boat for the past few days fitting the light as well as a few other things. It's a great light and fits well into a recessed section of the galley cupboard.

I did not think to search Whitworths site after finding the light in their catalogue and the catalogue does not give the power consumption figure. From your responses I am relieved to know that it will consume less than half of an 8 watt fluoro.

Power consumption is not such an issue after installation of a gas refrigerator and giving away the 12 volt types but is still something that needs to be known for extended stays on the water, especially if the solar panels are limited by cloudy skies.

I know that the purchase and installation of solar panels adds to global warming but they are a great solution for our problems and eliminate the need for a noisy generator.

[Hamish73]

Thanks Bungie and Rumy! - sorry for the late response. I have been on the boat for the past few days fitting the light as well as a few other things. It's a great light and fits well into a recessed section of the galley cupboard.

I did not think to search Whitworths site after finding the light in their catalogue and the catalogue does not give the power consumption figure. From your responses I am relieved to know that it will consume less than half of an 8 watt fluoro.

Power consumption is not such an issue after installation of a gas refrigerator and giving away the 12 volt types but is still something that needs to be known for extended stays on the water, especially if the solar panels are limited by cloudy skies.

I know that the purchase and installation of solar panels adds to global warming but they are a great solution for our problems and eliminate the need for a noisy generator.

How is that???

[tigermullet]

I did not think anyone would spot that.;D

The energy consumed in their manufacture is far greater than the energy produced from them over their life time. Battery banks aren't all that kind to the earth either and I doubt that we will ever exceed the energy return on energy invested that oil gives us.

At least solar panels are fashionable and give the appearance of concern for the environment.

[Simmo2]

C'mon TM, prove it!
Research I have seen is perhaps 4 or so years to recoup the cost of manufacture? Leaving in the case of Siemens panels some 25 yrs of 'free' energy?! (we need a new thread!!)
The latest developments in solar technology could reduce the 'repayable' period substantially so the scientists say!

[tigermullet]

I should have qualified those statements by saying that their use on a boat, especially recreational boats, is not really an energy saving. You are right - the figures given are actually about four years use to return the energy and that figure might reduce if efficiencies are added. However, the return can take up to 20 years depending upon their use and the area in which they are used.

Even using the low figure of four years it would take me about 100 years of boat use to get the return on energy because of the time spent on the water and the fact that only a fraction of the energy produced is actually used.

Our panels give about 60 watts at peak performance for, say, four hours per day which gives roughly 300 to 400 watts per day. That is probably being generous in allowing for cloud, shade, orientation etc. Our use requires something under 120 watts per day and is being further reduced by LED lighting. That adds up to a lot of 'waste' but other boaties might get better use by using inverters to run the TV, Microwave and Jacuzzis on large gin palaces.;D

[Taroona]

A lot of LED lights have the wattage marked on the packing or in the instructions.

Divide the watts by volts and you will have the current drawn in amps.

so if you have a 100 amp/Hr battery and the leds draw .32amps then your battery would last 100/0,32 equals roughly 312 hours

so what you do is add together all the things on your boat in whats called an energy budget to get the max amps that you will use and then you can calculate how long your batteries should last.

your energy budget should diffirentiate between night and day as different items are used at night compared to daytime. also whether you are at anchor or not blah blah

Les

[tigermullet]

Hi Taroona, Yep! That should be so and I did check the packaging. Not one word on power consumption and the staff did not know either. Fortunately this forum has provided the answer.

[Taroona]

You can try this if you have a digital multimeter

Connect the positive of the LED to the pos terminal of a battery the pos of the digital multimeter to the neg of the LED and the neg of the meter to the neg on the battery

make sure you have the meter to current and you will be able to measure the amps drawn by the LED's

Les

[tigermullet]

Thanks very much Taroona. I have copied that and will keep it until it is burned into my memory. That's one of the best pieces of information ever received because I didn't have a clue of how to go about it.

[Hamish73]

just remember to switch the meads and switch back to voltage when you are finished. If you attempt to measure a voltage with the meter in current mode at best it will blow the fuse inside the meter (if it has one), at worst it will destroy the meter.

[Melec]

Les of Taroona , your calculations are close to sound but . When you have a battery rated at say 100AH you only have 40% AVAILABLE . New thinking on deep cycle batteries is only ever discharge them 40% before recharge .

[Taroona]

I wasn't suggesting that the battery would last the 300 odd hrs, merely trying to show how to get the loading and do a rough calculation on battery life.

If an accurate calculation of battery life is needed it would be prudent to get discharge rates from the manufacturers. This is also dependant on temperutre of battery and type of battery i.e. wet cell, gel cell, and many others