HDS AA option?

[LouRoy]

Ty_Bower,

I have a printout of the old chart dated June 4, 2005. It lists the runtimes for 60 lumens, 60 lumens XR, and 42 lumens. Your figures are exactly what the chart shows. It shows the 42 lumens model should get 60 minutes runtime with Li-ion batteries and 80 minutes with a Duracell (and 75 minutes with Surefire, 55 minutes with BatteryStation primary batteries). Turbodog's actual runtimes make me wonder if the chart is correct.

It is too late tonight, but I will post the entire old chart tomorrow if anyone is interested.

 

[John N]

If I understand you, you're saying your b42 gets 17 min on max?

If so, then here's my guesses:

No, I don't have a B42. It was just a WAG based on the runtimes that HDS previously had on their web site. Gosh, I can't wait for Henry to post the updated runtimes...

-john

 

[turbodog]

If you guys remember, Henry did post somewhere that he needed to revise the runtimes.


I have yet to see a unit that didn't make 20 min on max. I also am not hearing of problems with the primary level runtime.

If you're using the light on max a lot, you're likely to run into heat problems way before the battery dies.

If you need 60 lumens on 2x123, buy an L4.

I'd say that the thermal limitations of the hds lights are their only weakness, as I see it.

 

[John N]

I have yet to see a unit that didn't make 20 min on max. I also am not hearing of problems with the primary level runtime.

It sounds like the orginal poster is suggest his doesn't make 25 mins.

If you're using the light on max a lot, you're likely to run into heat problems way before the battery dies.

But of course, you probably have hit the issue. His battery probably isn't dying - his light is stepping down due to thermal issues.

If you need 60 lumens on 2x123, buy an L4.

Is that because it really doesn't get as hot, or just that they don't protect the LED as well as the HDS does?

Does the U60 at 42 lumens get as hot as a B42 at 42 lumens?

-john

 

[joema]

...I will post the entire old chart tomorrow if anyone is interested.

Here it is:

 

[turbodog]

A 60 model should not get as hot as a 42, when run at 42 (level 2). This is because of the better emitter. But, the 42 runs a lot cooler than the 60 anyway, so it's hard to tell the difference.


I think the original poster's NOT hitting an overtemp problem. I think the air cooling is an UNDERtemp problem for the battery. Silverfox has clearly shown that primary 123 (and r123s also) perform better at temps 90F and above, not to exceed safe limits of course.

The L4 gets to COOKING temperatures. I have measured mine at 165F at least. They provide NO overtemp protection. But I don't see that as a problem. It shortens life, but you'll outgrown it before it dies anyway. And SF's got a lifetime warranty if you still have it when it goes up in smoke.

 

[turbodog]

The chart predates the 42xr model I notice.

There's also a big difference between brands of cells.

 

[John N]

I think the original poster's NOT hitting an overtemp problem. I think the air cooling is an UNDERtemp problem for the battery. Silverfox has clearly shown that primary 123 (and r123s also) perform better at temps 90F and above, not to exceed safe limits of course.

Nick, is your light cold, warm or hot to the touch 3/4 of the way into your ride?

There's also a big difference between brands of cells.

What brand batteries are you using?

-john

 

[leukos]

Here it is:

According to this chart, my 100 minute runtime in high mode (B42GT w/ R123) doesn't seem so far fetched.

 

[PeLu]

Yes, but at high-ish drain rates the lower internal resistance sort of evens the score.

Yes, a little bit, but mainly the LiIOn cell's capacity does much less suffer from higher loads than a primary cell's.

I use some 750 mah rechargeable li-ion cells, and 900 mah are available.

There had been 900mAh cells which gave shorter runtime at the highest level than a 750mAh cell which is more suited to higher loads.
So you should look for cells which had been proven to perform well under high load conditions (and avoid protected cells for that reason).

BTW, could this thread be moved to the approbriate forum?

 

[turbodog]

According to this chart, my 100 minute runtime in high mode (B42GT w/ R123) doesn't seem so far fetched.

No offense, but I have a really hard time believing this time is accurate.

I figure that:

1. you missed a stepdown during the runtime check

2. your light is not running at max (eg. has a problem)

3. or you got a really, really good led. And by that I mean the upper 1% of 1%. This seems not likely since all lights are calibrated.


Look at it this way. If 20 min is considered minimum, with maybe 30 being average (and this is for a b42, not a 42xr), then 100 is so far out there on a standard distribution curve as to be unbelievable.

So speaking from a probability standpoint, I'd say that option 1 or 2 is more likely.

How many times have you checked the runtime? How was it conducted? The runtime checks I did were in a dark room, and I watched the light actively the WHOLE time. And no, I didn't have anything else better to do.

 

[leukos]

Turbodog, PM sent.