LED Stop & Tail light bulb

Just fitted one of these to my Bandit to replace the normal bulb thinking it might be brighter and more visible? (during the daylight at least, it's ok at night) Anyway, it's no brighter whatsoever! it should last longer though? so not really a tenner wasted.

http://www.ebay.co.uk/itm/131329281653?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Here's the Bonus/Downfall? When I fitted the Givi Top Box with built in LED Brake Light every thing worked fine & dandy (amazing with my electrical skills) press the brake, the top box LED's light up! release and the lights go out (bike light stays on) all present and correct and gave myself a pat on the back   anyway, since fitting the LED stop & tail light to the bike the LED's on the top box are working like a stop & tail light? they work fine and don't seem to take any brightness out of the bikes rear light when I lift the top box lid to break the circuit. How are they working though? I only wired them to the Brake light wire, not the back light wire, surely they should go off when the brakes not pressed. 

Mr Intruder (Dave) would be the guy for that info but he don't bother answering many questions anymore. 

They're just a row of 5 LED's, they just light up like a usual back light then go brighter when the brake is pressed, just like the back light of the bike, they didn't light up like the back light before I changed the bikes stop and tail light to LED though? they only came on (bright) when the brake was pressed, then went off when released, plus they're only wired to the positive for the brake light so should only get power when the brake is pressed?

When this sort of things happens I always suspect a back feed from the earth side....how its happening i don't know.
Could you make sure the two circuits have different earths ?

Different Earths Al, I earthed the top box to the frame because the earth from the back light was flimsy at best.

I think it may simply be that because you have put a lower pull bulb into the system, your LED, then it will activate the top box circuits making them work as an additional stop light as well as the pilot light. I could be wrong but I have a feeling I'm right, ask Doc, he'll know I'm sure.

Hi Sim. have you tried putting the old bulb in to see what happens, also check the new  bulb with a battery to see if it is wired correctly, as Peter said it sounds like an earthing fault, if you have no luck let me know as I have one of these bulbs in the garage and I could put it in Daves bike to see what happens, will keep my ears peeled to see how it goes, regards Doc Cox.

Sometimes advice is hard to give, other than to make friends with your Voltage multi - meter. Sorry couldn't of been more use, but this is a hands on issue. Sounds to me like you have inadvertently uncovered an existing hidden issue.
I can't say much more than I already have, other than...... check all wires and connectors with the multi-meter. Clean wiring connections and slap a thin layer of Vasoline on each of tem when done to stop further corrosion.

I'm wondering? if with the old incandescent bulb having two Lives (one for each filament), and one earth wire and the new LED still with 2 connectors but the bulb being variable brightness (not more LED's  lighting), it's creating some sort of loop and making the LED's in the top box light up normally and brighter when the brake is pressed, if so? could this cause any damage? I'm quite liking the idea of two stop & tail lights on the back, just don't want to cause any damage 

That,s an interesting one Sim, as Dave said a check round of all connections and all earths, sorry I misread the bit about Bandit.

As you say Sim for the combined LED light to use the same bulbs to get brighter when the brake is pressed then the two circuits must be interconnected in the LED unit.
Seems like its feeding back into the top box LED's

Just accept it Sim as it gives them something to zero in on other than looking through you!!!

If you want to stop it you will need to put a diode in circuit, something like this:

v-twin wrote:

If you want to stop it you will need to put a diode in circuit, something like this:

I'm not really bothered about stopping it, it won't do any damage to anything working like that will it?

It looks like the lamp on the Topbox is LED, if so it should be ok, if not the 21watt load of a normal lamp going through the new LED lamps circuit board could cook it.

If you do not have the lights on and you put the breaks on does it bring on the side lights??

Lights are on all the time, there's no switch to turn them off, both stop & tail and top box lights are LED's now so shouldn't be drawing much power.

Sim, the LEDs will run at a much lower current than your 5 / 21w stop / tail lamp. Doubling up should not cause any problems on electrical load if thats what you're thinking ?

Is there a rating ( wattage ) on the retrofit stop / tail LED board ?

I know the Philips retrofit stop / tail is rated at only 2 watts

Tried a different type of LED stop & tail light in the bike tonight thinking it might be brighter due to having LED's on the side as well?, it's not as bright!, and the top box LED's are even brighter with that one fitted?    I'll just stick with the original LED bulb on the right I got.   

More does not always mean more Sim I'm afraid & you've found that one out. Those left side LED's don't work well as there are too many small ones that equal probably less than the right bigger ones.

I was hoping that with the left one having LED's on the side they might give more light from the silver reflector overall? instead of just a central bulb area brightness, they didn't though 

You'll find the centralization of the first bulb with the glass around the LED will be reason for the dilation of the light spread whereas the multi LED just gives a central light which just does not spread as you have found out as I said more does not always mean more I'm afraid.

Peters right Sim ..... The one on the left has what are called SMD chips but they are left bare so the light emits in one direction only.
By comparison, the one on the right has what are called "optics" covering them ( the clear plastic bubbles ). These distribute the light in all directions and will give a more uniform coverage.
There are huge disparities in light output between LED chips even of the same wattage due to differing tolerances in the manufacturing processes. Obviously the more you pay, the better quality the chips, the more light output you will get.

Fore sale: 2 SMD chip stop & tail light bulbs 

IF you stick them where the sun don't shine!