mj818 - changing modes?

mudcow007

right i got a MagicShine MJ818 on the arse end of my bike

for the past week it has been changing flashing modes randomly

the only time the mode doesn't change is when the light is on "eye burning" steady fixed light - but i dunno how long my battery pack will last on this mode

any ideas

the bezel doesn't seem to be moving as i'm riding along or anything?

fossyant

You haven't got a broken wire ?

Mine sometimes does it, and it can be that you haven't turned the bezel far enough past the magnetic sensor - i.e. if it's close it could cause a mode change with vibration.

I use mine on steady most, and are powered by 6x AA packs I home brewed so only have 2500mah. Work for a good 6 plus hours on steady.

mudcow007

dont think i broke any wires....(hopefully)

i wil try an figure out where it changes the sequences an adjust.

it keeps defaulting back to the flash that has a massive pause between flashes grr

daxplusplus

Did you get to the bottom of this? I have two of these on the back of my bike and neither of them will stay constantly on - they randomly switch modes.

The fact that both of them have started doing it points to something common to both of them .. and that's the batteries (they share via a y splitter cable .. long story). I just don't understand how it could be the batteries .. they seem to be holding their charge fine.

Thanks.

slowbike

I believe it's to do with short interruption to power - I had similar issue with my UltraFire torch - mine was fixed by shimming the battery with some paper to stop it breaking contact inside the housing.

So for an external battery pack you need to check that any and all connections are secure and sound.

tgotb

Possibly a connector issue, momentarily breaking contact when you go over a bump? Check the connectors themselves, and also the cable where it goes into the back of the connector.

I had connector issues with my MagicShines and ended up removing the connectors completely and soldering everything together; the only connector remaining in the system was one to plug the charger into...

Sharkyssurfers

when i had two they lasted a month each before i got a refund, the problem with mine was the twisting action actually cut through the wires. I have one of them big water bottle batteries that i now use with my big 2000 lumens jobby, when i spoke to magicshine a few weeks back they did say they have improved the rear light, so might invest in one.

daxplusplus

Thanks for the quick feedback :-)

I'll look at the connectors.

Checking the batteries may be an issue as I think they may be sealed up but I'll have a go.

And yep I know about the eating the wires design flaw. One of mine self destructed a year or two ago - i soldered it back together. This design flaw is "fixed" by _always_ turning the bevel one way. Has worked for me ever since (and I run them during the day too so they get a lot of use) but I'll have a look at the state of the connectors over the weekend just in case.

Apart from this I love them .. last ages and very bright.

fossyant

I've switched to the c&b seen rear lights now. Still got the magicshines, but the mode changing was a pain.

The c&b seen lights are seriously bright. I run 2 from a home made 18650 pack, but they still eat charge at a fast rate.

tgotb

DaxPlusPlus wrote:

Checking the batteries may be an issue as I think they may be sealed up but I'll have a go.

The bit inside the seal is all soldered, so less likely to be causing an issue (but check the wire where it exits the package.

mudcow007

nope i didnt get the bottom of it to be honest

i have kinda retired the light as it was getting royally onto ones boobs, the way it would randomly go off

so any suggestions to suit it would be bloody marvellous

slowbike

mudcow007 wrote:

so any suggestions to suit it would be bloody marvellous

It's not a complicated light - as said above, changing modes is down to a quick interruption to power source - this is how the button works. So it's just a case of eliminating the cheap bits (connectors & wires) and then when that doesn't work it's likely to be the circuit board or the even light itself...at which point it's probably not worth going much further unless you're interested in circuit boards!

mudcow007

Righto, i will refit it to the bike an see how its behaving.

im sure someone will have a breakdown guide to how you take it to bits

cheers

daxplusplus

http://www.youtube.com/watch?v=GdI_vUiN38I- here you go 3 videos that take you through it 8)

slowbike

mudcow007 wrote:

im sure someone will have a breakdown guide to how you take it to bits

Hammer?

itboffin

Slowbike wrote:

I believe it's to do with short interruption to power - I had similar issue with my UltraFire torch - mine was fixed by shimming the battery with some paper to stop it breaking contact inside the housing.

So for an external battery pack you need to check that any and all connections are secure and sound.

+1 its usually this, most of the 16500 sized batteries are slightly different in size, i wrap gaff tape a couple of times around each once that ensures a snug fit.

daxplusplus

Bit of an update.

I don't think it's lose connections .. the mode changing just does not tie in with connections being disturbed.

For a day or so I wondered if it was due to water getting into the light units (and there is still a very slight chance that this is the cause).

However chief suspect at the moment is that the batteries themselves are dying .. the mode changing gets worse the longer I leave it between charges. I remember reading somewhere that the battery backs have a very simplistic design and that it can lead to uneven discharging of the batteries.

I will look into this and see if I can find out more.

slowbike

Have you sat it on the dining room table, turned on the lights and left it ...

All the time they're fitted to the bike you could be on loose connections ... putting the lights in a stable place with no physical movement will test that (although it won't totally help if the cables are heating up a bit ... !)

good luck ...

daxplusplus

I like your thinking but I'm not sure how hot the leds get and whether they might burn out .. I know with the cheaper torches that's a real possibility.

slowbike

really? I wouldn't think they'd get hot enough sat on the dining room table - unless you have the heating cranked up to 50°C - but ok, don't sit them on the dining room table - put them on the patio table ... outside ...

daxplusplus

Another update.

I tried leaving the lights on while off the bike. One of them got very hot, the other not at all. I simply switched them off, waited a while and tried again. Doing this I ran them for hours and hours.

One of them (the cool one) would occasional switch off the centre led but not change modes. The other one didn't change modes.

Put them back on the bike and the hot one started changing modes occasionally while out on rides. The one with the dodgey centre led never changed modes again. Maybe there was some moisture in it that the tests indoors drove out? It's been worked fine ever since.

The one that still changed modes out on the ride? Well back to vibrations being the probable cause and I had noticed that the bevel that changes the mode was quite loose and had too much movement. I tried tightening it up but no joy - it was already as tight as it would go. So I tried bodging with some electrical tape close to the bevel so that a certain amount of friction was introduced. This seems to be enough to have cured the random mode changing .. I've covered approx 300 miles since and no probs with mode changing anymore