Cree T6 battery died suddenly

[robjh]

I've used cheap Chinese Cree T6-style lights for a few years with few problems, until today.
The battery was fully charged up only a couple of days ago, and was working fine when I went out this morning. I turned it off, then tried to turn it back on an hour or so later and it was completely dead.

It's definitely the battery, as the light works OK when switched to a different battery.
The battery won't charge either - it is as if the charger doesn't recognise that anything has been connected.
I've had batteries gradually lose their lifespan before, but not known a sudden death like this.

Is there anything I can try to investigate/fix the problem, or do I just shrug it off as a risk of buying cheap sh*t and learn the lesson for the future?

The battery was sold as a 'rechargeable 8.4v 6400mAh battery pack' for Cree XML 3xT6 LED 4200Lm light, and looked something like this

 

[mrbikerboy73]

I'd shrug it off and buy another myself. I've got one of those lights from eBay and although it's very good, I don't reckon the battery will last more than a couple of years. They are so cheap though, it's worth buying another I think. Your post has prompted me into buying a spare battery so thank you!

 

[fossyant]

C&B Seen for replacement chargers and batteries. UK stuff, good service.

 

[shouldbeinbed]

C&B are more costly and proper rubberised cover.

I've just ordered a spare cheap and cheerful battery pack from Amazon for £7.

My current one died like yours this time last year, I dismantled it, refixed the connections and sealed it all up in duck tape & its been OK this winter but doesn't hold its charge quite as long as it did.

 

[robjh]

C&B are more costly and proper rubberised cover.

I've just ordered a spare cheap and cheerful battery pack from Amazon for £7.

My current one died like yours this time last year, I dismantled it, refixed the connections and sealed it all up in duck tape & its been OK this winter but doesn't hold its charge quite as long as it did.

Well, it's working again now. It may be because I resorted to throwing it onto a hard surface, or may not, but I think the most likely thing is a dodgy connection inside the battery pack which could account for the sudden complete death, and equally sudden revival. I'd better make sure to keep a backup battery with me.

 

[Cubist]

Well, it's working again now. It may be because I resorted to throwing it onto a hard surface, or may not, but I think the most likely thing is a dodgy connection inside the battery pack which could account for the sudden complete death, and equally sudden revival. I'd better make sure to keep a backup battery with me.

In which case be very, very careful how you charge it. In fact, scrub that and bin it. They tend to be recycled laptop batteries, and if they are behaving inconsistently there could well be a short. Charge it in a biscuit tin in the garage if you must, but check your house insurance is up to date.

 

[cyberknight]

I have found those batteries need to be stored with a certain amount of charge over long periods and need topping up, iam bad at this as i forget which shortens the lifespan of the pack.
I normally buy a new pack every year, for around a tenner i cant really moan.

 

[The_Weekend_Report_Guy]

I had this happened to me a few months back with a similar light.. And like someone else mention it was a short or miss connection.. I like to Fix, break stuff so I got a utility knife and took it apart where I knew the short was.... found that the wire was broken.. reattached the wire and used silicone to water prove it... and lots of electrical tape to reinforce the weak points...

Problem solved..! But I still got another light and battery as a spare... Actually have 3 extra ones that I am trying to sell for £20 each.. (check the for sale area if interested)

Good luck !!

 

[Nigelnaturist]

I have had one since Nov 2012 and one from late 2013, and both are still holding charge well, or least seem to I don't usually ride long in the dark 1hr tops, and most of my night riding recently has been on lit roads, so its a bit difficult to say for sure.

 

[gbb]

I have found those batteries need to be stored with a certain amount of charge over long periods and need topping up, iam bad at this as i forget which shortens the lifespan of the pack.
I normally buy a new pack every year, for around a tenner i cant really moan.

The difference may be the quality of the batteries themselves. Tenner for pack is really quite cheap.
My Enix (i think thats the name) pack cost a fair bit 5 years ago.
Last year hardly got any cycling in at all. I grabbed it out of the cupboard where it'd been for the best part of a year, put there in an unknown state of charge....put it on the bike, it worked instantly and continued to do so for over an hour. Very impressive. (mind mine is a 4 x 18650 cell 15v setup)

 

[robjh]

The battery pack has suddenly died again, as it did before (see top of thread).

I took the casing off the pack to see if I could identify any loose connections. I couldn't, the connections in there all looked firmly fixed on.
However, I was surprised to see that only 2 out of the 4 batteries appear to be connected together in any way. The end casing was plastic so it can't have played any role in connecting to the second set of batteries.
In these pictures, the top pair have no visible connections to the others. This doesn't seem right to me - am I missing something?

If I'm right then this is more evidence that I've bought a piece of cheap crap.

 

[fossyant]

The battery pack has suddenly died again, as it did before (see top of thread).

I took the casing off the pack to see if I could identify any loose connections. I couldn't, the connections in there all looked firmly fixed on.
However, I was surprised to see that only 2 out of the 4 batteries appear to be connected together in any way. The end casing was plastic so it can't have played any role in connecting to the second set of batteries.
In these pictures, the top pair have no visible connections to the others. This doesn't seem right to me - am I missing something?
View attachment 115833 View attachment 115834
If I'm right then this is more evidence that I've bought a piece of cheap crap.

Those may well be a dodgy pack. All 4 should be connected. Don't get the connectors short circuited in that state, it will go up in a poof of smoke.

I've split 2 old packs where a cell or two dies. I have a specific charger for those, and it can identify a dead pack. I've salvaged 4 batteries from 2 dead bike light packs, and continue to use these in Ultrafire Torches.