27W LED on the front

[Scimitar]

Today, my 27W LED lights arrived. By'eck they're bright, totally outshining the motorcycles own headlight. It was my original intention to have one main, one dip, as supplementaries for the existing headlight, but after I jury-rigged a portable unit to a 12V battery and carried them out into country lane I live on, I let them rip. First one - impressive enough, then the other - very much more useful with two on.
I'll be putting these ones on the motorcycle, but it occurred to me that the cheap DC/DC converters will easily run one of these from the bike battery and 27W from 36V isn't going to be much of a hindrance to the main battery pack.

The light output is just; oh wow...
It's the square ones down the page...
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[103Alex1]

Today, my 27W LED lights arrived. By'eck they're bright, totally outshining the motorcycles own headlight. It was my original intention to have one main, one dip, as supplementaries for the existing headlight, but after I jury-rigged a portable unit to a 12V battery and carried them out into country lane I live on, I let them rip. First one - impressive enough, then the other - very much more useful with two on.
I'll be putting these ones on the motorcycle, but it occurred to me that the cheap DC/DC converters will easily run one of these from the bike battery and 27W from 36V isn't going to be much of a hindrance to the main battery pack.

The light output is just; oh wow...
It's the square ones down the page...
Aliexpress.com : Buy 20% Off 2pcs 4" inch 27W 9 LED Working Light Spot Flood Lamp Motorcycle Tractor Truck Trailer SUV JEEP Offroads Boat 12V 24V 4WD from Reliable Work Light suppliers on LarcoLais

Less than 2 single CREE T6 packs and 20-27W per light rather than a likely 5-10W max... That's pretty good going - tried and tested too now. . Am pretty much persuaded to put 2 of these in as an off-road lighting circuit mounted on a bracket off the fork stem. Town road lights / backups can go on the handlebars.

Just over an amp per light @ 24V for 27W - that's more like it. They'll actually run at up to 30V according to that tech spec description so can get current down to under an amp per light. Perfect.

Did you specify flood / spot or a combination of the two for the ones you've received & tested ?

 

[Scimitar]

I ordered square spots (you have to, else they'll send round floods).
In pleasant contrast to other sellers of these things, their lumens claim is a modest 70lm/W which is more believable and certainly borne out by observation. I always take the lumens claim with a large pinch of salt anyway and generally only believe what I see with such items. As a bicycle headlamp this would be utterly fantastic, but dipping it is problematical and I wonder if the dimmer mentioned before would work on this.
Also - I notice its working voltage is 12~30V, so I wonder what effect a 30V input might have on the buck driver within - better or worse light output?

 

[103Alex1]

I ordered square spots (you have to, else they'll send round floods).
In pleasant contrast to other sellers of these things, their lumens claim is a modest 70lm/W which is more believable and certainly borne out by observation. I always take the lumens claim with a large pinch of salt anyway and generally only believe what I see with such items. As a bicycle headlamp this would be utterly fantastic, but dipping it is problematical and I wonder if the dimmer mentioned before would work on this.
Also - I notice its working voltage is 12~30V, so I wonder what effect a 30V input might have on the buck driver within - better or worse light output?

If there's a buck converter inside the lights (I suspect there is if they take variable input voltage but have a 12V operating voltage) then my guess is that there would be no effect on the brightness. The amps drawn by the lamps would be set by the buck output rather than the input voltage but it would be suitably rated to cope with the current load. That's my guess anyhow. Presumably there's a capacitor in the lights somewhere if they're LEDs too. You could check the effect of input voltage by rigging one up to a higher voltage battery alongside the one rigged up to a 12V .

Will look again at the dimmer - if there's a buck converter in the lights themselves it might not work, if variable current is what regulates brightness and that current draw is effectively regulated within the lights by way of a constant voltage output device.

I mainly had in mind using these off-road at night so dipping not such an issue. But since they presumably require remote switching anyway you could just rig them up to a Hi-LO switch which gives you either one or two on if you really wanted as a crude dip-function.

Having your town cycling lights on their own circuit makes total sense to me - they draw neglibible power, can be left on if you also use these beasts on dark empty lanes - and then if you have to dip for an oncoming vehicle round the bend you just flick them off. Your "town cycling" lights will be enough till you pass each other at the hedgerow pull-in.

Tractors go up and down our lanes all the time with arrays of lights more like these (which are never dipped)

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... so frankly, I don't see what all the fuss is about cyclists on rural lanes at night being expected to be forced into the nearest bramble bank by a speeding car who didn't see them till the last minute. What's good for the farmer is good for the butcher .

In case anyone is worried (and I don't expect they are) I'm not suggesting for one minute that you go riding around street-lit roads in London or Plymouth with a pair of these turned on. They're rural lane / off-road spotlights for dark quiet roads or country tracks imho - and sound pretty great for using in that way.

 

[Scimitar]

In case anyone is worried (and I don't expect they are) I'm not suggesting for one minute that you go riding around street-lit roads in London or Plymouth with a pair of these turned on. They're rural lane / off-road spotlights for dark quiet roads or country tracks imho - and sound pretty great for using in that way.

That's exactly my application anyway - especially for the bicycle and even the motorcycle isn't on the main roads much. Traffic density around here is fairly minimal, especially at night, compared to the S. of England. A decent set of lights is an absolute essential, to avoid potholes, ditches, and being punted off the road too.
However, I don't feel comfortable not having a proper dip/dim setup, especially on the motorcycle, so I'll be looking at this in more detail. I hate being dazzled by others and have no wish to inflict it.

 

[103Alex1]

Finally rigged this up across one of those LM2956HV DC-DC converters. Have set it to 12V for testing and yes, it's very very good. All you need for dark lane riding - the whole road ahead is lit with very good near and long distance illumination.

I'd have to desolder it off the DC-DC converter to adjust the converter using multimeter in order to test it off a higher input voltage - and see if that affects the light output (not sure whether that's more economical in terms of power consumed ) - it'll take input up to 30V but I'd probably not risk it above 24V. The amps drawn will decrease if I up the input voltage but it seems OK at 12V anyway.

It's going on the 'high' setting of my handlebar dip switch.

As this won't be plugged in on the bike all the time I'm tempted to splice the 'off on low' / 'on on high' switch output to supply both this and the 36V aluminium 3-LED light. That means if this big one is plugged in it'll one will come on in addition to the smaller one but if it isn't I'll still have the smaller 3-LED light available. The switch output wires can handle up to 10A so should be fine.

Looks like I'm finally getting there - so thanks for the recommendation .

 

[Deleted member 4366]

If you push the voltage higher, the current will most likely go up too in proportion, so much higher than the 3 amp rating of the converter.

 

[Scimitar]

Finally rigged this up across one of those LM2956HV DC-DC converters. Have set it to 12V for testing and yes, it's very very good.

Pics, pics, pics.

The amps drawn will decrease if I up the input voltage but it seems OK at 12V anyway.

With an electronic regulator of unknown design in the circuit, you can't know what it's going to do in that respect until you connect it and measure things.
I idly wonder if it might be more efficient at higher voltage, but it might make no difference whatsoever, depending on the regulator. The losses might be fixed, irrespective; although, as you would expect, some regulator circuits become more efficient the closer to the needed voltage the input voltage is; but in this case 36>12>5 for the LEDs is going to be lossy (but not disastrously so).

 

[103Alex1]

If you push the voltage higher, the current will most likely go up too in proportion, so much higher than the 3 amp rating of the converter.

... it's a variable input light so if output is fixed then I was guessing that if output is fixed regardless of input voltage then for example :

27W / 12V = 2.25A current

but

27W / 24V = 1.125A current (lower)

Is that wrong ?

Pics, pics, pics.


With an electronic regulator of unknown design in the circuit, you can't know what it's going to do in that respect until you connect it and measure things.
I idly wonder if it might be more efficient at higher voltage, but it might make no difference whatsoever, depending on the regulator. The losses might be fixed, irrespective; although, as you would expect, some regulator circuits become more efficient the closer to the needed voltage the input voltage is; but in this case 36>12>5 for the LEDs is going to be lossy (but not disastrously so).

Can't be sure of the 27W (probably more like 20W @ 12V) and main thing is I don't know if output is fixed regardless of input voltage (in other words whether there is a buck converter in the light itself in which case total losses will probably be neutral - I may get more efficiency in the DC-DC by only dropping voltage to 24V rather than 12V but then lose more in the light instead).

It's not great round here for taking pics as I'm in a streetlit area and can only get pics in a dark forecourt. When I turned it on I got a massive tree 20m away clearly lit up from root to top of the tree. A triple CREE T6 on full blast will only light about 1/4 of that depending on the angle it's shone at.

The light is amazingly 'non-dazzling' for its power and has a wide enough throw for riding in any conditions.. but I'd still dip it for oncoming vehicles at close range. It's not the lightest solution but it's one heck of a bike light and I reckon possibly as useful as some of those £450-£500 Lupine ones.

 

[Alan Quay]

... it's a variable input light so if output is fixed then I was guessing that if output is fixed regardless of input voltage then for example :

27W / 12V = 2.25A current

but

27W / 24V = 1.125A current (lower)

Inside the lamp units I expect it has a buck converter. It could also be a linear regulator though. The way to tell the difference (and confirm the wattage) would be to test the current at different voltages. If the current drops (about half) when you double the voltage, then its a buck converter. if it remains the same, then its got a linear regulator.

If it has a buck converter then its real power (consumed by the LED's) is aprox V x A x 0.8.

If it has a Linear regulator, then turn voltage down until it stops working. This figure will be about 2 volts higher than the regulator output voltage. You can then calculate LED power from this. The current will be the same on the input side as the output side.

 

[103Alex1]

Inside the lamp units I expect it has a buck converter. It could also be a linear regulator though. The way to tell the difference (and confirm the wattage) would be to test the current at different voltages. If the current drops (about half) when you double the voltage, then its a buck converter. if it remains the same, then its got a linear regulator.

If it has a buck converter then its real power (consumed by the LED's) is aprox V x A x 0.8.

If it has a Linear regulator, then turn voltage down until it stops working. This figure will be about 2 volts higher than the regulator output voltage. You can then calculate LED power from this. The current will be the same on the input side as the output side.

How does one test current ? I have a multimeter if that helps.

Wd also welcome a quick eye over this schematic of what I'm planning to do for rigging this light up together with the one in "New light runs direct from battery" thread from the same switch output wire (Off on LOW / On on HIGH).

The 2 things which make me pause are ...

1) Where to put the inline fuses after the switch on the +ve feed (see diagram);

2) Whether OK to splice the 0V wires to cut down on the number of BUSBAR terminals used up (I may have to get a 12-way otherwise or else solder-bridge the 2 4-way blocks on the BUSBAR to free up an extra terminal)

Any other things to watch out for wd be appreciated. Sorry it's gone 'portrait' ... I saved it as landscape in Photobucket but Pedelecs wants it flipped 90 degrees !

Thanks.

 

[Scimitar]

They're down to $50 a pair, now.
20% Off 2pcs 4" inch 27W 9 LED Working Light Spot Flood Lamp Motorcycle Tractor Truck Trailer SUV JEEP Offroads Boat 12V 24V 4WD-in Lights & Indicators from Automobiles & Motorcycles on Aliexpress.com

 

[Alan Quay]

Measuring current with a multimeter:

1. Important to note that the positive lead may need to moved to a different socket on the meter. Check manual, and be very sure to put it back in the voltage sockets at the end. If you measure 220 ac with meter configured for current you can destroy it. Trust me, I've done it. Several times. On expensive Flukes.
2. Stick it on to Amps, DC range.
3. It needs to be connected IN SERIES with the load.
4. Did I mention putting the leads back to voltage position?

Will look at drawing in a mo....

 

[Alan Quay]

1) Where to put the inline fuses after the switch on the +ve feed (see diagram);

2) Whether OK to splice the 0V wires to cut down on the number of BUSBAR terminals used up (I may have to get a 12-way otherwise or else solder-bridge the 2 4-way blocks on the BUSBAR to free up an extra terminal)

1) Depending on current, you will probably get away without any additional fuses. It might be wise to have one on the output side of the DC-DC converter to protect it, however not necessary from a safety point of view, and might cost more than the converter.

2) Either is good. I would bridge the terminals.

i am confused by the drawing, and assuming it represents 1 x 27w lamp and 1 x 36v lamp. I don't understand what the pair of scissors represents (poss switch?), but this wont get you any high/low - just on/off

 

[103Alex1]

Measuring current with a multimeter:

1. Important to note that the positive lead may need to moved to a different socket on the meter. Check manual, and be very sure to put it back in the voltage sockets at the end. If you measure 220 ac with meter configured for current you can destroy it. Trust me, I've done it. Several times. On expensive Flukes.
2. Stick it on to Amps, DC range.
3. It needs to be connected IN SERIES with the load.
4. Did I mention putting the leads back to voltage position?

Will look at drawing in a mo....

Here's the multimeter I have - with pins plugged into 10ADC and COM :

Gone to look for the instruction leaflet !

 

[Alan Quay]

Here's the multimeter I have

Unfortunately, the black lead is covering up the important information, which is the current range on the un-connected socket!

 

[Alan Quay]

I'll assume its 200mA on right hand socket. So you have the leads in the right place. Turn the dial to about 5 O-clock, where it says 10A, break circuit somewhere, connect red lead to broken circuit closet to battery +ve, and black lead closest to battery -ve.

 

[103Alex1]

OK found the instructions. They say put black in COM and red in V.ohm.mA unless measurement is for current between 200mA and 10A in which case put red in 10ADC slot (which is is now).

Then says set rotary switch at desired DCA position - which I assume is 10A about 100 degrees clockwise from noon).
(green section - just before hFE)

Then says open circuit in which current to be measured and connect test leads in series with the circuit. I have no idea what they mean by that

 

[Alan Quay]

See above....

 

[Alan Quay]

You measure voltage in paralell, current in series:


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