# Zebralight let me down



## pipspeak (Sep 20, 2010)

First big test of my new ZL H501w last weekend camping in Yosemite and it let me down big time, but I'm curious if this is a classic ZL failure or something else. 

I had two freshly charged 2600mAh batteries and with both it exhibited the same behavior: after about ten minutes on medium or high, the light started a rapid flickering, sorta like a semi-strobe. In addition, the high would sometimes work, sometimes not (it would go low to medium then to slightly-less-than-medium instead of high). 

Basically the light became semi-useless to me -- brushing your teeth in the cold and dark with bears around while your light is doing a poor impression of a strobe is not much fun :candle: 

It was cold (low 40s) and the flickering started when the light was away from body warmth (outside of jacket, hanging in tent etc.) so I'm wondering if the temperature was something to do with it. Each time I took out the battery and replaced it, and the light worked fine for a while then exhibited the same annoying behavior.


----------



## Mr. Tone (Sep 20, 2010)

I really love my H501w, but that problem is the only thing that makes mine not perfect. Mine will do the flickering thing on high, too. My guess is that it is a problem with the regulation and the voltage of the battery. Mine never does it with batteries fresh off the charger. It will after it has been on high a while(10-20 minutes), or when the batteries have been sitting for a while. It is definitely annoying.


----------



## Armed_Forces (Sep 20, 2010)

You should NOT blame Zebralight for an end user battery problem! 

In mission critical situations one should never rely on rechargeable cells or at least always have quality primary backups. There's only one suitable primary cell and that's Lithium. Lucky for you, Energizer now makes a Lithium AA. While you're at it, get some Eneloops and test them for cold weather performance in the Zebralight because I'm betting they will perform better than the cells you're using now based on your stated capacity i.e. your cells are crap. Eneloops are LSD (low self discharge) and made to very high quality standards. That makes all the difference in the world of NiMH chemistry. A lithium AA primary will very likely trump the Eneloop in cold weather because of the differences in voltage between the cells but I haven't tested this. Make sure you come back and post an appropriately titled thread after you get this sorted.


----------



## Linger (Sep 20, 2010)

+1, sounds a lot like a poorly performing 2650ma battery. I can totally replicate that with a duracell 2650ma...but it goes away with eneloops.
Eneloops, nothing but, for rechargables. You sould try a primary cell before posting the problem is your light. I'd like you to consider editing your title if you find the issue was power supply.


----------



## pipspeak (Sep 20, 2010)

OK, I'll do a few tests with Li AA and a low-discharge Imedion cell. I did just try it at home with one of the rechargeables I used on the trip, and the light is still acting flaky. Will report back.


----------



## Sno4Life (Sep 20, 2010)

Just to add to what has been said, I have been using rayovac 4.0 LSD Ni- MH rechargeables, and they work great down to freezing. Any below and it's Lithium primaries all the way!


----------



## FroggyTaco (Sep 20, 2010)

I get the exact same flickering when my battery needs replacing in the 501 & 501w. 

Sounds like your 501 was trying to warn you.


----------



## bansuri (Sep 20, 2010)

I feel that the "No User Serviceable Parts Inside" assembly method ZL employs increases the chance of failure.
A connection that can't be cleaned is forever dead once it oxidizes or loosens up.
This opinion is based on my H50 which gets flakey switching issues until I pour a little alcohol down in it and let it get between the body and PC board, then it works fine for a while. I don't know if the head is pressed on or threaded but I can't tighten or loosen it to get a better connection.


----------



## Woods Walker (Sep 20, 2010)

pipspeak said:


> I had two freshly charged 2600mAh batteries.


 
I think that might be the issue. I had bad luck with 2500-2600 NiMH batteries in most of my lights. They just didn't hold a charge even for a short time. I would try some LSD NiMH or Lithium primaries. I bet everything will work out great as it did for me.


----------



## Mr Floppy (Sep 21, 2010)

I've had the same problem and it wasn't in cold weather. It does seem to be battery related. The batteries I used are sanyo 2700 NiMH, even fresh out of the packet ones. 

Easy fix for me though was to run them through a break-in charge on my C9000. Hasn't been a problem since. The other batteries I swap with only goes through the refresh-analyse cycle and that seems to fix it for a few charges. After the flickering moments, the analyse cycle would report the capacity of ~50-70% of their actual capacity, which is actually around 2400 so that's when I would book them for a break-in. So many batteries, just 4 slots.


----------



## Shorty66 (Sep 21, 2010)

YOu might just need to clean the contacts. That problem has been around several times and a little cleaning ahs helped most people.


----------



## amigafan2003 (Sep 21, 2010)

+1 on it being the batteries at fault.


----------



## purduephotog (Sep 21, 2010)

Discussions like this bother me- folks going back and forth about whether it is the batteries or the hardware.

Wouldn't a Variable Voltage supply (such as a benchtop unit) solve this discussion issue- set it to the target voltage and lower it until XXXX happens or is observed?


----------



## kevinm (Sep 21, 2010)

My guess is that the batteries you have are not good in the cold (or possibly at all). 

1. Test the Zebralight at room temp with those batteries. If it fails to work, try the light with some other batteries. If it works, go to 2. If it will not work with any battery you can find, your light is broken.

2. Place the Zebralight with one of the batteries you took with you in the freezer. Take it out when it is really cold and see if it works. If not, the batteries are not good in the cold. If it works, your batteries probably discharged to much before you used them. In both cases, take the batteries back and get Eneloops and Energizer lithiums.

Most batteries don't work well in the cold. I bring Energizer Ultimate lithiums for exactly this reason if I'm going into a cold cave. They are expensive (and I am cheap), but they ALWAYS work.

Kevin


----------



## Alan (Sep 21, 2010)

I have thrown away all of my Sanyo 2600ma NIMH cells since they don't hold charge more than a few days. Enelope is the only cell I use nowadays, extremely reliable.


----------



## srfreddy (Sep 21, 2010)

Armed_Forces said:


> In mission critical situations one should never rely on rechargeable cells or at least always have quality primary backups. There's only one suitable primary cell and that's Lithium. Lucky for you, Energizer now makes a Lithium AA. While you're at it, get some Eneloops and test them for cold weather performance in the Zebralight because I'm betting they will perform better than the cells you're using now based on your stated capacity i.e. your cells are crap.



Um.... Energizer has made Lithium AA's for many many years now lol...... :thinking: Their new lithium battery is a lower-end product, the Advanced Lithium. All Ni-mh's hate cold weather. Eneloops are certainly a better bet though. 
(first post xD)


----------



## strinq (Sep 22, 2010)

I actually can't wait to see what the TS found out...


----------



## Obijuan Kenobe (Sep 22, 2010)

I'll just chime in that NiMH batteries I use in my HAM radios are also very weak in cold weather. In fact, this is big deal in portable radio operating (which I like to do occasionally) such that you need to choose another battery type given colder weather. The stock NiMH batteries are great, but far from ideal for all conditions.

obi


----------



## Mr. Tone (Sep 22, 2010)

pipspeak said:


> OK, I'll do a few tests with Li AA and a low-discharge Imedion cell. I did just try it at home with one of the rechargeables I used on the trip, and the light is still acting flaky. Will report back.


 
While all the suggestions being made are good, it is not impossible that it is a problem with the light itself and not the batteries. 

Today I took my H501w and cleaned all contacts with rubbing alcohol. After it was dry I put freshly charged nimh cells in it to see what would happen. Mine does the flickering thing with every brand of NIMH that I have. That includes Eneloops, Energizer 2500, Kodak Pre-charged LSD, Rayovac Hybrid, and Northtech 2000ma LSD. 

These same batteries all perform flawlessly in all my other AA lights, including 2 Quark and 2 Q mini. All my batteries are charged and maintained by the Titanium Innovations AA/AAA 4 channel smart charger. Silverfox gave this charger great reviews. 

So I can say that my light, properly cleaned and with good, healthy, straight off the charger NIMH batteries(including Eneloop) does this flickering thing.

It is quite annoying but I still love the light.


----------



## kevinm (Sep 23, 2010)

Mr. Tone said:


> While all the suggestions being made are good, it is not impossible that it is a problem with the light itself and not the batteries.
> 
> Today I took my H501w and cleaned all contacts with rubbing alcohol. After it was dry I put freshly charged nimh cells in it to see what would happen. Mine does the flickering thing with every brand of NIMH that I have. That includes Eneloops, Energizer 2500, Kodak Pre-charged LSD, Rayovac Hybrid, and Northtech 2000ma LSD.
> 
> ...



Have you tried DeOxIt or some other such product? I have found (both in the lab and in home practice) rubbing alcohol to be far from ideal, particularly if you are using the normal brown bottle stuff.

And agreed, not impossible. But I doubt it.:nana:


----------



## Ventzy (Sep 23, 2010)

My expearince with ZebraLight H501w, is that this flickering, is beginning of troubles, after some weeks, headlamps stop to work. I have 6 pcs., of Zebralight H501W, and all of them failing in this way. But all they, was with old UI. I hope, that next generation (new UI), will be much more reliable. Now i have new 6 pcs., with new UI, and still don't have any problems...


----------



## Mr. Tone (Sep 23, 2010)

kevinm said:


> Have you tried DeOxIt or some other such product? I have found (both in the lab and in home practice) rubbing alcohol to be far from ideal, particularly if you are using the normal brown bottle stuff.
> 
> And agreed, not impossible. But I doubt it.:nana:


 
No, I don't have any DeOxIt. From what I hear around CPF I should get some. Does it clean and also prevent oxidation on aluminum? The bare aluminum on my Quarks oxidize like crazy.


----------



## Mr. Tone (Sep 23, 2010)

Last night I decided to try something else. I took a freshly charged Rayovac Hybrid and put it in the H501w and fully tightened the cap. I didn't turn it on but left it off until half an hour ago. It has been going strong on high since then with no flickering. I assume it is because of this. https://www.candlepowerforums.com/posts/2988412&postcount=25

I always unscrew the tailcap on it so this is a different approach. OP, try charging up one of your NIMH batteries and stick it in the light and fully tighten the cap. Let it sit overnight without turning it on and then try it the next day to see if it works without flickering. Let us know if you try it.


----------



## f22shift (Sep 23, 2010)

Linger said:


> +1, sounds a lot like a poorly performing 2650ma battery. I can totally replicate that with a duracell 2650ma...but it goes away with eneloops.
> Eneloops, nothing but, for rechargables. You sould try a primary cell before posting the problem is your light. I'd like you to consider editing your title if you find the issue was power supply.



yeah i agree with everyone else. the high capacity are not reliable at all and can develop high resistance and poor ability to retain a charge.

i can see an advantage of a remote battery pack in cold weather too. i think headlamps are more susceptible to cold temperatures because it's not hand held.


----------



## Gaffle (Oct 5, 2010)

f22shift said:


> i can see an advantage of a remote battery pack in cold weather too. i think headlamps are more susceptible to cold temperatures because it's not hand held.



That aluminium body just gets all of the heat sucked out of it in the cold, and its not getting a ton of heat from your forehead. There is one advantage to the remote battery pack, and there is another advantage to the less conducting plastic headlamps.


----------



## kiwicrunch (Oct 5, 2010)

I had a problem with similar behaviour in the past, and was equally disappointed. 

However it turns out that this simply caused by a dirty contact and easily fixed with a bit of sandpaper glued to the positive terminal of a battery. This was a year ago and I haven't experienced any problems since then.

Original post here https://www.candlepowerforums.com/posts/3120940&postcount=10


----------



## FroggyTaco (Oct 5, 2010)

Also a pencil eraser fits in the battery tube rather nicely as well.

Just clean the eraser on your jeans first for example.


----------



## tandem (Oct 6, 2010)

FroggyTaco said:


> Also a pencil eraser fits in the battery tube rather nicely as well.


:thumbsup:
I seem to recall cleaning contacts with an eraser way back in my very first electronics class. This would have been long before ARPANET begat the Internet, so we mostly had to figure things out for ourselves back then. Didn't always succeed at that, but at least an eraser worked well...


----------



## carrot (Oct 6, 2010)

Your anecdote speaks volumes about carrying a backup...


----------

