constant 12 volt supply to lights ? (flickering)

[sooty]

I have LED lighting throughout my narrowboat. (24 down lighters and strips)

Total current drawn if all on ,a mere 5amp !

Quite often when the charger (sterling) kicks in, or the diesel central heating is being used

(drawing large current), the lighting flickers and is VERY annoying.

 

Is there a device (regulator ?) I could buy that would give me a constant SMOOTH

output and ideally work from an input of say 10.5 volt to 15 volt ?

 

Cheers Steve

[Robbo]

Voltage regulator is what you need

[smileypete]

I have LED lighting throughout my narrowboat. (24 down lighters and strips)

Total current drawn if all on ,a mere 5amp !

Quite often when the charger (sterling) kicks in, or the diesel central heating is being used

(drawing large current), the lighting flickers and is VERY annoying.

 

Is there a device (regulator ?) I could buy that would give me a constant SMOOTH

output and ideally work from an input of say 10.5 volt to 15 volt ?

Something like this'll do it:

 

http://www.ebay.co.uk/itm/280838557271

 

cheers, Pete.

~smpt~

[Bobbybass]

I made these up..simple solder job...but REUK supply them ready made up (sometimes on Ebay)

 

They drop a tiny amount of voltage...if the batteries get low... it doesn't seem to worry my LED's.

 

Using the 100uf output capacitor..it seems to take care of any 'spikes' from things switching on. I bought the 'bits' on Ebay...cost less than £3 each regulator....

 

http://www.reuk.co.uk/LM2940-12V-1A-Low-Dropout-Regulator.htm

Edited February 6, 2013 by Bobbybass

[Chris Pink]

I wonder how difficult it would to design a circuit to only bring it in when the voltage is more than 12.5V

[Bobbybass]

I wonder how difficult it would to design a circuit to only bring it in when the voltage is more than 12.5V

 

Well..this one is a 'little' like that...although it needs some 'excess' voltage in order to regulate. It will drop off the voltage if the batteries drop low..but this has not caused me much problem. On 'the bench'..I fed it with over 17 volts and it kept it nicely at 12 volts and stable.

 

http://www.reuk.co.uk/LM2940-12V-1A-Low-Dropout-Regulator.htm

[nicknorman]

Good quality LED lights have built in switch mode regulators (those that are rated up to 30v). We have mostly those, with still a few halogen. With power supply fluctuations caused by water pump, engine running / stopped etc, its very noticeable that the halogens change brightness, the LEDs never change. Maybe the OP's LEDs don't have regulators built in?

 

The disadvantage of the LM2940 reg is of course that it dissipates excess voltage as heat, whereas the switch mode reg doesn't intrinsically dissipate any heat and is therefore much more efficient and cool-running.

[Ex- Member]

I made these up..simple solder job...but REUK supply them ready made up (sometimes on Ebay)

 

They drop a tiny amount of voltage...if the batteries get low... it doesn't seem to worry my LED's.

 

Using the 100uf output capacitor..it seems to take care of any 'spikes' from things switching on. I bought the 'bits' on Ebay...cost less than £3 each regulator....

 

http://www.reuk.co.u...t-Regulator.htm

 

 

We fitted the reuk ones a couple of years ago. no flickering or bulb failure. We happened to have already purchased LED bulbs that were sensitive to voltage above 12.5 In future though as they need replacing I will probably use the bulbs Nick suggests which aren't so voltage sensitive. I have 25 fitted and 20 spares though, so it will probably be a while.

Edited February 6, 2013 by Julynian

[sooty]

Thankyou for the replies.

 

The DC to DC converter seems the way to go . Can be set to 12 volt output, and Input can vary

from 10v to 30v.

This way the lights should stay constant and shouldn't dim when the battery voltage drops.

I have ordered one of these My link

£14. 150 watt so should be plenty,

I will let you know if its any good.

 

Cheers Steve

[Ex- Member]

Thankyou for the replies.

 

The DC to DC converter seems the way to go . Can be set to 12 volt output, and Input can vary

from 10v to 30v.

This way the lights should stay constant and shouldn't dim when the battery voltage drops.

I have ordered one of these My link

£14. 150 watt so should be plenty,

I will let you know if its any good.

 

Cheers Steve

 

 

 

I think you,ve missed something. Especially if you're fitting this primarily to protect LED's

 

1. DIY an adjustable on-board power supply, you just input DC 12V, then you

can get output DC 12V-35V (adjustable), But the output voltage can not

below the input voltage .

 

 

So if your battery bank is at 14 volts then that's what you'll get via this unit, it doesn't regulate at 12v if the input is 14v

Edited February 7, 2013 by Julynian

[nicknorman]

I think you,ve missed something. Especially if you're fitting this primarily to protect LED's

 

So if your battery bank is at 14 volts then that's what you'll get via this unit, it doesn't regulate at 12v if the input is 14v

 

Yes, if you want to go that route This one might be better as its a boost-buck ie can increase or decrease voltage. However it's only rated at 1A so you may need several.

Edited February 7, 2013 by nicknorman

[Keeping Up]

If you use one 12v-12v converter for all your lights, then it will need to remain on all the time ready for when you switch on a light (or at least remain on for all the time when you might need a light) in which case its standby current will surely negate any benefits that you may have achieved by using LEDs.

 

If you use one converter per lamp, it can be switched off when not in use. However as well as being a very expensive option, again the total power consumed will negate most of the benefits of using LEDs. The ones that are built-in with the LED units that are sold commercially, havegenerally a very high efficiency

[Bobbybass]

If you use one 12v-12v converter for all your lights, then it will need to remain on all the time ready for when you switch on a light (or at least remain on for all the time when you might need a light) in which case its standby current will surely negate any benefits that you may have achieved by using LEDs.

 

If you use one converter per lamp, it can be switched off when not in use. However as well as being a very expensive option, again the total power consumed will negate most of the benefits of using LEDs. The ones that are built-in with the LED units that are sold commercially, havegenerally a very high efficiency

 

Well...although people seem to have dismissed it...we're back to my LM2940 regulator again.

Cost about £3 each if you solder yourself..works great even allowing for a small voltage drop..and at that cost..you have one per light so they are not always on...

 

Not sure about the other ones mentioned here...as they will still need a voltage drop to regulate ?

Not sure you can regulate to 12 volts without a small drop ?.

I did put a heat sink on my LM2940's..but they don't need it. Even with a chunky LED bulb they don't even get luke warm....in fact..not even a hint of warm even if you touch them to your top lip (old computer engineers trick)

 

Running all of my LED bubs at once..I think I lose about 5% in regulator loss...so nothing to worry about.

Edited February 7, 2013 by Bobbybass

[Taslim]

Well...although people seem to have dismissed it...we're back to my LM2940 regulator again.

Cost about £3 each if you solder yourself..works great even allowing for a small voltage drop..and at that cost..you have one per light so they are not always on...

 

Not sure about the other ones mentioned here...as they will still need a voltage drop to regulate ?

Not sure you can regulate to 12 volts without a small drop ?.

I did put a heat sink on my LM2940's..but they don't need it. Even with a chunky LED bulb they don't even get luke warm....in fact..not even a hint of warm even if you touch them to your top lip (old computer engineers trick)

 

Running all of my LED bubs at once..I think I lose about 5% in regulator loss...so nothing to worry about.

 

It's the way to go.

 

The Boost-Buck stabilisers are great for sensitive applications & expensive. The LM2940 is cheap and really works. I've built plenty for chums & everyone has been pleased so far. The light output drops slightly as the batts go down but gradually & no irritating flickers as some other bit of kit kicks in and the bulbs are protected from over voltage.

 

The only thing I would change from the circuit in #4 is to put a small capacitor on the input (a few nf)to keep the switch spike gremlins out. No need for heat sinks. Shop around for parts & the plot can be put together for about £2. Also, think of how much you save by not having to use expensive self regulating bulbs.

 

taslim.

[smileypete]

Yes, if you want to go that route This one might be better as its a boost-buck ie can increase or decrease voltage. However it's only rated at 1A so you may need several.

If the OP's already ordered a boost converter, maybe just use it to make 24V then add a buck converter after it, plenty of 24V to 12V ones on Ebay and I'd expect delivered from the UK too, eg:

 

http://www.ebay.co.uk/itm/271082079128

 

cheers, Pete.

~smpt~

[nicknorman]

 

Not sure about the other ones mentioned here...as they will still need a voltage drop to regulate ?

Not sure you can regulate to 12 volts without a small drop ?.

You can. A boost-buck switch mode regulator has the capability to increase or decrease the incoming voltage - or to put it another way, the incoming voltage can be above or below the desired output voltage, or fluctuating above and below.

 

That may or may not be overkill!

[Bobbybass]

It's the way to go.

 

The Boost-Buck stabilisers are great for sensitive applications & expensive. The LM2940 is cheap and really works. I've built plenty for chums & everyone has been pleased so far. The light output drops slightly as the batts go down but gradually & no irritating flickers as some other bit of kit kicks in and the bulbs are protected from over voltage.

 

The only thing I would change from the circuit in #4 is to put a small capacitor on the input (a few nf)to keep the switch spike gremlins out. No need for heat sinks. Shop around for parts & the plot can be put together for about £2. Also, think of how much you save by not having to use expensive self regulating bulbs.

 

taslim.

 

Hmm..yes you're right...?

 

The circuit originally showed a 0.47uf cap across the input...?

That's what I added...as you say....

 

Not sure why they removed it from the diagram.....but works fine with that..

 

Bob

 

 

 

Also, think of how much you save by not having to use expensive self regulating bulbs.

 

taslim.

I bought mine in Spain...for 1 Euro !!