Lights going out

[RichardB]

I did an experiment recently to see what the burn time was on my Moon Meteor lights. I knew they would last me the length of my commute on the electric bike (approx. 55 minutes) but wandered if they would last long enough when I switch to human power in the Spring (I estimate it will take me about 1:15). What surprised me was what happened when they ran out of juice. With both lights (Meteor 200 and 250) they literally went out as if I had switched them off. Not gradually going dim like an incandescent bulb, but out in an instant. Is this an issue with LED lights generally? It's a concern to me, as 90% of my commute is along unlit lanes, and to be suddenly without light could be nasty. It happened to me once on a motorbike (main fuse blew) but I was able to slow the bike down and get off the road by using the indicators. There is obviously not that option on a bicycle. I got the second Moon as a spare, but it's no use in a bag or pocket if the main light is not going to give any warning when it runs out. I suppose I could have both on the bars, and start the second one half way into the journey. That might work. They both have a run time of 1:20 to 1:30 on full power, so I will probably be OK, but there's not much margin of error.

I was wondering if anyone else had this issue, and what they did about it?

 

[gbb]

Its a while since I enlightened myself re LED lights but IIRC, as the voltage drops, the draw on the battery spikes and can damage them. You'll maybe find the lights have some protection device that cuts them off at a specific point.
Also with some batteries, running them to dead flat can damage them.

Glad to be told otherwise, it is old info but may still hold true.

 

[RichardB]

You'll maybe find the lights have some protection device that cuts them off at a specific point.

Yes, that makes sense to me, and fits with the behaviour of the lights.

 

[summerdays]

It depends on the light, my Hope 1 does that, which can be a little disconcerting, my strategy is to have a second light and know I have to charge them regularly. So for me I need to charge the Hope weekly in the depths of winter where it generally is only actually dark for the last 10 mins of my homeward commute.

Other LED lights I have fade instead.

 

[RichardB]

At this time of year, I am in full dark both ways for the full commute. I have a regime of charging every day I use them, both ends, so running out of juice shouldn't be a problem. I think the ultimate solution will be a light with a 3-hour burn time, but that is unlikely to be as small and cute as the Moon. Swings and roundabouts.

 

[MickeyBlueEyes]

I've had my front light go out once on me (cable fault) but to be honest it's no great shakes as long as you have a back up. Unless you are bowling along at 40+ you can stop the bike in a few seconds. Either carry a spare light (or in my case a spare battery), or buy a light with a longer burn time.

 

[Globalti]

Don't your LED lights have a less powerful setting? In that mode they actually strobe extremely fast so power use is reduced considerably.

 

[MickeyBlueEyes]

I've just looked at the runtimes on the box from my Moon light. All values are "up to"
Constant beam:
Low: 6 lumen - 9 hrs
Standard: 12 lumen - 4 hrs 30
High: 25 lumen - 2 hrs 15
Overdrive: 50 lumen - 1 hr
10% flashing: 5 lumen - 20 hrs 40
50% flashing: 25 lumen - 4 hrs 25
100% flashing: 50 lumen - 2 hrs 10
Strobe: 10 lumen - 10 hrs 40

At constant beam on high you would get a couple of hours, that should do you?

 

[raleighnut]

It's the 'protection' circuit on the L-ion batteries that causes it, if the battery fully discharges it wrecks em.
Try getting a light that runs on 4 AA batteries and run that on NiCad or NiMh rechargables (or even Duracells)

EDIT - Try something like this, 80hrs runtime on Alkaline so should give 50-60 on rechargeables

 

[MossCommuter]

I carry a handful of these just in case

 

[furball]

I had a rear light from one of the respected light manufacturers that was very bright but the payback was very short battery life. The light would go out suddenly and I wasn't aware of this until there close passes.

 

[si_c]

One of the things I quite like about my fenix is that as the power drops, it steps down a light level to maximise run-time. I get about 2 hours from the full 1200 lumen, or 5 at 500. The other thing I like is that it uses 18650 batteries, so at this time of year I carry a set of spares with me, just in case.

 

[shouldbeinbed]

I.ditched a Hope 1 as that did it. I tend to favour USB chargeables now so can always top them up at work.

I have a couple.of chargers, home and work, for my magicshine clone as that burns its battery very quickly and I don't trust it to stay lit if I decide to ride a bit longer than anticipated

 

[tyred]

Fit a dynamo and be finished with all that nonsense.

 

[Lonestar]

No problems for me two hours in the dark and lights still going strong.

Spare 18650 batteries are there if needed plus a spare lamp.