Improve run time of cheap head lamp?

Hi all,

I recently purchased a few of these head lamps from theBay for use when camping. At $10 each (I bid on them at 90c and no one else made a bid :thumbsup they were too good to turn down. They are pretty much perfect for what I want.

I mate of mine did the same and got the chance to use it before me and noted that they chew through their 3xAAA power supply very quickly even on low mode.

Without replacing the LED itself, and trying to keep the closed up device as stock as possible, how could I go about improving the battery life?

Obviously a good set of batteries would help - higher capacity would be best. Maybe a small efficient driver (I would LOVE to get rid of the strobe mode...the most useless/annoying mode in existence). would help a bit. I can't imagine the cheap driver in there now being very efficient.

Not much else really I guess?

Here's a photo of the guts of the light:


As you can see the board is 'unique' to say the least. Also there is a size-able gap between the back of the battery holder and the back of the LED PCB. I reckon you could fit a small driver in there. I'll have to take it apart again to check the actual size.

So anyway...a little random. Guess I should first ask is it even worth it!?

Hope to hear from someone.

Peace.

- Matt

You could try using 3 10440 li-ion's and modifying the battery holder so they are all connected parallel. Would give you 3 times the mah rating of just one of the li-ion's. The driver should handle the 4.2v (fully charged) voltage just fine. Batterys are about 7.00 a set from dx. Charger for the li-ion about 10.00 to 12.00 at dx. Buy three sets and save more.

It is hard to tell just from seeing one side of the board but I am guessing it may only have a linear regulator driver. You may be able to change out an smd resistor to change the light output level(s) thus increasing runtime at the expense of brightness. That and/or possibly putting a resistor inline prior to the whole circuit to reduce power would be about all that will help short of changing out the driver and/or LEDs themselves for more efficient ones.
Would it be worth it? If removing a resistor and replacing it would do the trick for you.... sure, if not I would say swapping driver would start to add a possible lot to the cost of it and not knowing the full extend of the headlamp I would vaguely say.... no.

True words Lynx. I think moderator007's suggestion is probably the best bet. Bit of added expense but the light is really good for our purposes (especially with the zoom device removed - give good flood that way).

I might try find somewhere else that sells 10440 as opposed to DX. Our trip is in 4 weeks and i'm still waiting on some other drivers (unrelated) that I ordered 2 months ago :S

Mattaus said:

True words Lynx. I think moderator007's suggestion is probably the best bet. Bit of added expense but the light is really good for our purposes (especially with the zoom device removed - give good flood that way).

I might try find somewhere else that sells 10440 as opposed to DX. Our trip is in 4 weeks and i'm still waiting on some other drivers (unrelated) that I ordered 2 months ago :S

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Unless the headlamp is exceptional quality I wouldn't go with the 10440 solution myself. You may gain some runtime but the hassle of trying to mod springs and contacts to take 3 10440 batteries in parallel could be harder than you think and having to charge 3 of them each time the set are depleted will either require 3 separate charge cycles or configuring a charger. This will also make it where you cannot use standard AAAs any more in that light without reversing the changes you made. It would be easier to just buy L92 energizer lithium AAAs instead and get some nimh LSD cells and carry spares. Use up the nimh cells and keep the lithiums for backup.

Unless the headlamp is exceptional quality

Click to expand...

Definitely not. It was just exceptionally cheap and perfect for my desired application.

hassle of trying to mod springs and contacts

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The springs and contracts are mounted on little tin plates that slide in and out with ease. It would be actually very easy to mod this to run in parallel.

I'm going to try and modify them and see how it goes. I spoke to a friend of mine earlier today and he has some of the 10440's so I won't have to make a purchase just to see if it works. Also the way I will modify it, it will be reversible so if it does go **** up I can revert the whole configuration back to it's stock state.

win-win

Mattaus said:

Definitely not. It was just exceptionally cheap and perfect for my desired application.

The springs and contracts are mounted on little tin plates that slide in and out with ease. It would be actually very easy to mod this to run in parallel.

I'm going to try and modify them and see how it goes. I spoke to a friend of mine earlier today and he has some of the 10440's so I won't have to make a purchase just to see if it works. Also the way I will modify it, it will be reversible so if it does go **** up I can revert the whole configuration back to it's stock state.

win-win

Click to expand...

Be interesting to know the increase in runtime for the hassle of dealing with 10440s et all. The one thing about lithium and nimh batteries is runtime will be more level in light output and can possibly be shorter in some sense compared to alkaline batteries since when they deplete the voltage goes from 1.5v+ to 1.1v before 90%+ is used up while lithium and nimh will not swing that far in voltage.

It will come down to which set of batterys has more energy. Now that i have had more time to thank about this, i dont think there is any 10440's out there with a high enough capacity that will make a difference. The dx 10440 has only 350 mah as tested by a reviewer. This will be almost the exact same energy in the aaa's. If you can find (true capacity) 600 or above capacity 10440's then your run time will be almost double the aaa's. It may be the best option to buy a new driver with less watts as mentioned, Sacrificing brightness.

If you made or bought a external belt battery pack wired in with some larger batterys would be the way to improve your run time greatly. 18650's would work great for this.

Bugger. I didn't even think of the rechargeable batteries being lower capacity. Shows how much I know about batteries! I might have to consider an external pack but that reduces the suitability of the head lamp some what. Might just see what the biggest battery I can fit in the case with slight modification is.

EDIT: a 17mm PCB based driver would be the abosult perfect fit for this light. That leaves enough room in the case to almost fit 2 sub-C size batteries.

I might jsut give this a miss and buy a shed load of AAA alkalines.

A length of Radio Shack hobby wire leading down to a 3 D cell holder that you could put on your belt would give you orders of magnitude more runtime, and at the same price point as the headlamp..

Something like this could possible fit your headlamp. Should give you about twice the run time. I dont know if it will fit . You will have to measure. You will probably have to buy a hobby charger to charge it.

I think the easiest and cost effecient would be to change the driver, sacrificing brightness. There's just not that many cheap options on such a small battery compartment. Unless you go external pack.

Too big

However I am having some other battery solution problems for a different light and I may need to purchase a hobby charger for that, so Li batteries are not totally out of the question.