Stenlight issues

[mattcaves]

A couple of days ago I got my stenlight out of storage after a couple of years of not caving. I charged the battery and turned it on expecting to see the bright light I was used to. Unfortunately, it was about as bright as a mini mag flashlight. One of the leds is about half as bright as the other. Both leds have a yellow hue to them. I have discharged and recharged the battery a couple of times and nothing has changed. The battery pack measures 8.2-8.4 volts. I have tried emailing stenlight, but have not received a response yet. Anyone have any idea what the problem could be?

[dutchcontractor]

I don't know much about Sten Lights but batteries in general tend to go bad when left unused/uncharged for long periods of time. You probably need a new battery.

[mattcaves]

The battery is holding a charge of 8.4 volts. The lamp only need 7.2 to come on at full intensity. I could be wrong, but I don't think the battery is bad.

[paul]

The battery is holding a charge of 8.4 volts. The lamp only need 7.2 to come on at full intensity. I could be wrong, but I don't think the battery is bad.

It's not just Voltage, Current also matters. Connect 2 of those batteries in series and you'll have 16.8 Volts. Now try using that to get your car started...

[mattcaves]

Connect 2 of those batteries in series and you'll have 16.8 Volts. Now try using that to get your car started...

That might be extremely helpful if I were trying to start a car...

I've received a reply from the good folks at stenlight. Their only suggestion is to upgrade the leds. They have not suggested that the battery is the issue. Does anyone here have any experience with having their sten upgraded?

[Anonymous_Coward]

I had mine upgraded in 2010. It is a much superior light now.

[BrianFrank]

Connect 2 of those batteries in series and you'll have 16.8 Volts. Now try using that to get your car started...

That might be extremely helpful if I were trying to start a car...
I've received a reply from the good folks at stenlight. Their only suggestion is to upgrade the leds. They have not suggested that the battery is the issue. Does anyone here have any experience with having their sten upgraded?

Paul's point was that under load (which is when your lights are on, not a voltmeter) is the true test of a batteries capability. You may have a car battery that shows 12-14 volts so you would think it would start the engine. But, it won't if the battery is damaged and it can't produce the amps or current the starter demands. Your lights are drawing a lot more current than a simple voltmeter. Batteries do not like sitting without being charged for an extended period of time as it deteriorates their cells.

[mattcaves]

Under load the battery reads 7.9 volts. The battery is working properly. When I use a fresh 9 volt battery the lamp has the same problem. One led is fairly bright, the other about half as bright. It is consistent through all four settings. According to the stenlight specs it should run for at least a couple of minutes on turbo with a fresh 9 volt battery. The problem is in the lamp itself. Anyone else seen this problem?

[BrianFrank]

Under load the battery reads 7.9 volts. The battery is working properly. When I use a fresh 9 volt battery the lamp has the same problem. One led is fairly bright, the other about half as bright. It is consistent through all four settings. According to the stenlight specs it should run for at least a couple of minutes on turbo with a fresh 9 volt battery. The problem is in the lamp itself. Anyone else seen this problem?

I stand corrected.

[LukeM]

I have seen much cheaper lights react to water damage with the same exact symptoms that you describe. Perhaps some corrosion or short has occurred somewhere, though it seems unlikely given the protection from the elements that the Sten has.

[Evan G]

I have seen much cheaper lights react to water damage with the same exact symptoms that you describe. Perhaps some corrosion or short has occurred somewhere, though it seems unlikely given the protection from the elements that the Sten has.

I have found condensation in my sten after a trip & this does sound like a case of corrosion on the ingratiated circuit board. Remember the Sten is water-resistant up to 25 feet not waterproof: http://www.stenlight.com/fact-sheet.htm

[slaybalj]

I've had the exact same problem. In fact, while caving at convention, one of the other people on the trip thought the second LED was an incandescent light. I had similar circumstances too - I'd just gone caving again after a 2.5 year hiatus.. I got the same response from Sten : 40$ to replace the LED or 90$ to upgrade. Though frankly, I don't really want to pay for a repair when I have no confidence that the repair would stand up to the minimal use I give it. Esp. since I think there's a good chance it actually broke while it was under warranty and I just didn't realize it. In its current state, on low power it'll output as much light as a cheapie hardware store headlamp and on turbo, it'll still impress anyone that hasn't seen a properly working sten in action. I honestly expected it to hold up better.

Laura

[kevinm]

Either you had a short or the light was left on and got too hot. It sounds like one of your LED's is fried, and those are the two most common causes. When one gets fried, it has a very high forward voltage, resulting in a weak total output. I'd either upgrade the LED's or upgrade the headlamp.

Kevin

[Jon]

I would get the upgrade, the $90 is about what you'd spend on a light of lesser quality. Corrosion may be a factor, in the connection or inside...I'd send the light and the battery back to Sten and ask for a QUOTE to make it all good. You might ask for the frosted optics. By the way battery info from Sten is below. I know apparently the battery is not the issue but the info is good. By the way if the battery is marginal you might look into their waterproof cased one.....They may not respond the fastest to respond but they have always been fair with me...try this person David.Niemi@stensat.org

Li Ion batteries are limited as much by their age than by the number of charge-discharge cycles; within 5 years they will typically have reduced capacity. The most important factors for the life of Li Ion batteries is to avoid storing them at high temperatures. Storing Li Ion batteries at 100% charge also reduces their life, especially if they are left on the charger for more than a few days or charged frequently without using them. For long-term storage we recommend keeping them in a refrigerator (or at least a cool location), and storing them only half-charged (near 7.5 volts open circuit).
Unlike nickel-cadmium batteries, fully discharging and recharging Lithium Ion batteries is not helpful. Li Ion batteries can be recharged reliably and directly from any state of charge as long as they are near room temperature.
The most vulnerable part of the LG723 battery, as with most devices with built-in cables, is the spot where the cable attaches to the rest of the battery. The battery is designed to be quite durable if treated properly. Avoid bending the cable tightly backwards; if you need to bend it, bend it gently around the end of the battery and across the other side.

[Mudduck]

While I dont own a sten, I have had to disassemble several lights with a problem similar to the OP. The wonderful thing about corrosion is that it can occur anywhere and cause current limiting anywhere along the line. Also surface corrosion on the board can wreak havoc on a regulator. I've found most of the time with other lights once its cleaned off everything goes back to normal. I'd pop the cover (lense or other applicable access) and look over the internal connections and board.