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Throwing a little light on the subject
#21
Unfortunately I have seen many of these through work. A lot of the batteries available have no protection at all, particularly LiPos. The resistors used are generally located in the light head. These types of light use direct drive current from the battery and the resistor is used to drop the voltage so the LED is not damaged. The worst ones for this are the lights where switching between the light levels switches in more LEDs (ie 1 LED for low, 2 for med and 3 for high).

If you get the packs from reliable sources like Batteryspace etc then they will be protected otherwise some are and most aren't (even if there is a circuit board inside this is often just printed tracks to the individual cells).

Things are improving though and you are right that lots have been sold but a significant amount have had problems. Most have not ended in explosion but a lot of the battery packs have failed and when they have I can almost guarantee you that if cut open one of the cells will have vented/blown.

I have had 3 high quality packs fail on me in the last 5 years. 1 where I accidentally reversed the polarity. It was only connected for around 2 seconds but continued to heat over a couple of minutes until it caught fire and eventually exploded. 2 others have had cells blow where the cell casing expands but does not rupture.

In work we have had a few actually explode while charging using the cheap wall chargers. One of these went so violently it destroyed the machined aluminium housing it was in. The best one though was when one chap tried to charge an M1 lithium battery (imagine a Li ion pack the size of a breeze block). Unfortunately the M1 is a primary battery and cannot be charged!! That went with enough force to destroy a lorry.

My advice would be to invest in either a proper balance charger (around £50 for a decent one) or buy a good quality battery from a reputable source like batteryspace (again likely to cost around £50)
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#22
Bearing in mind these light heads are so cheap, when you factor in 50 quid for a good battery the set up is still a bargain.

Jon, can you link to a good battery for us?
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#23
I was thinking the same thing Blackers...

The lights can be bought batteryless, so they could still be a bargain. But I've looked at battery space and don't really know what I'm looking at.
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#24
A replacement battery for my old Light & Motion Stella180 is over £90! That's why i haven't replaced it and have been tempted by the cheaper lights, but not if they could burn the house down! Jon, have you had a look inside the battery and head of the Chinese Magicshine coppies you can usually find on ebay for around £30? A number of Sketchy members have them and TMK are still going strong.
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#25
I havent seen inside all the light variants but have had about 10 different ones apart over the last couple of years. About half had a switched mode drive circuit a couple had resistors and one had the battery wired directly to the LED Confusedhock: . None of the lights had a low voltage cut off. A lot of good information can be found on the candlelightpower forum.

Let me know what voltage your battery is and I will see what is available. You might be lucky and have an 8.4v NiMH in which case you will be fine using it as you are and the packs are cheap when they need replacing. I have seen quite a few recently which are sold as Lithium Ion but when opened are actually NiMH cells. I think the Chinese folks have realised the batteries were the main point of failure and are reverting back to more reliable technologies.

Treehugger, buying spares from the manufacturers is expensive. You could get a generic battery but may have to cut off and replace the L&M propriety connectors.
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#26
Yep would definitely have to cut the connector off.
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#27
Having a look around the adverts suggest the batteries are 8.4V lithium. These are in fact 7.4V packs. The higher voltage rate is a bit of a con by the sellers to make them sound better than they are by increasing the battery Watt hour. The peak voltage is 4.2V hence the 2S packs (two cells in series) are advertised as 8.4V. In reality the nominal voltage for the cell is 3.7V and all reputable resellers will be advertising them as 7.4V packs.

A couple of options for replacements are:

<!-- m --><a class="postlink" href="http://www.mtbbatteries.co.uk/">http://www.mtbbatteries.co.uk/</a><!-- m --> . This guy is a small UK seller (called Smudge on singletrack) and his work and backup is excellent.

Another option is to use cheaper hard cased LiPo batteries and chargers for the RC industry (this is what I use) such as:

<!-- m --><a class="postlink" href="http://www.ebay.co.uk/itm/Turnigy-Zippy-5400mah-2s-7-4v-50c-60c-Hard-Case-Lipo-Battery-HPI-Traxxas-Tamiya-/141389030477?pt=UK_ToysGames_RadioControlled_JN&var=&hash=item20eb71644d">http://www.ebay.co.uk/itm/Turnigy-Zippy ... 20eb71644d</a><!-- m -->

Stick to well known manufacturers such as Turnigy and Overlander. Avoid the cheapy chinese brands (Zippy, Volts, Vapex etc) like the plague . Only use hard case LiPo's for MTB.

Good balance charger:

<!-- m --><a class="postlink" href="http://www.ebay.co.uk/itm/Imax-B6-LCD-Screen-RC-Lipo-NiMh-Li-io-n-LiFe-Battery-LiPro-Balance-Charger-UK-/350817215639?pt=UK_ToysGames_RadioControlled_JN&hash=item51ae55e497">http://www.ebay.co.uk/itm/Imax-B6-LCD-S ... 51ae55e497</a><!-- m -->
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#28
Quote:Yep would definitely have to cut the connector off.

Have a chat to the guys at mtbbatteries. They do replacement batteries for all the main brands or can replace the cells in your current pack. Would likely be around the 50 pound mark I would think.
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#29
Jon Wrote:
Quote:Yep would definitely have to cut the connector off.

Have a chat to the guys at mtbbatteries. They do replacement batteries for all the main brands or can replace the cells in your current pack. Would likely be around the 50 pound mark I would think.
Thanks mate, will give them a bell.
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#30
Plenty of good advice there Jon.

One thing not mentioned is the type of light and the spread.

I find the cheap lights have a very harsh white/blue light and that they tend to have a very bright hotspot.

Neither of these things suits me, I like a softer yellow light that allows me to see depth better and I like to have a good peripheral spread of light.



I get that £15 is cheap and it is great to start getting people out but they are just that... please do invest in the balance charger and charging bag.
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