All Rechargeables Are Not Created Equal!

[S4MadMan]

OK, I have a few different 1/2D rechargeable batteries sitting around and based on my naked eye, I could see a difference in the light output. So I decided to get more scientific and use a Streamlight SL-35X as the test bed and record the lux output for each battery. The results are amazing, there's a 5,500 Lux difference between the worst and best performing battery.

Can anybody explain to me the tremendous disparity? All the batteries were fully charged and I did each lux reading 3 times and came up with an average.

Test Flashlight: Streamlight SL-35X (with SL-20X body):

Does this mean MAG uses higher output rechargeable batteries? Please, enlighten me. /ubbthreads/images/graemlins/confused.gif

 

[MR Bulk]

??? I am not into incandescents, but I'll take a stab:

Perhaps the bulb amperage draw characteristics of the SL-35X are optimized to use the output characteristics of the MagCharger's batteries?

In other words have you tried a different set of combinations such as all batteries now running through the Mag, then all through the Zero, etc.? Lotsa-more work-a, but definitely providing a database more of the holes filled in.

 

[Bullzeyebill]

S4MadMan, which flashlight did you use for testing? SL35X uses full size D NiCd 5 cell stick. Did you use an SL 20X flashlight with a 35X lamp?

Bill

 

[S4MadMan]

[ QUOTE ]
Bullzeyebill said:
S4MadMan, which flashlight did you use for testing? SL35X uses full size D NiCd 5 cell stick. Did you use an SL 20X flashlight with a 35X lamp?

Bill

[/ QUOTE ]


Hi Bill, yes, I used a SL-35X reflector in a SL-20X body. Sorry for the confusion.

 

[Bullzeyebill]

S4MadMan, check the amperage draw at the flashlight tail threads and battery of each pattery pack to see what the draw is from each of them. Some how that magcharger battery pack is putting out more amps to light.

Bill

 

[koala]

Why don't you choose ONLY 1 bulb and run it with different sets of batteries?

Vince.

 

[S4MadMan]

[ QUOTE ]
koala said:
Why don't you choose ONLY 1 bulb and run it with different sets of batteries?

Vince.

[/ QUOTE ]

That's EXACTLY what I did; only run 1 bulb. I did everything the same except switch batteries. Please re-read my original post, the only flashlight I used was an SL-20X with a SL-35X lamp.

 

[billw]

Are all your 6V batteries really 6V (5 cells?) or are some
of them 4-cell packs (really only 5V.) you see this often
in 9V "transistor" batteries: some say "for use in 9V
applications" but they're only 7.2V. 8.4V are also available,
but rarer. Likewise, many retail "D" recharagble cells are
C-sized batteries in a D-sized case (ie AH rating of the Ds
is the same as for the Cs.)

BillW

 

[S4MadMan]

Bill, yes, all straight out-of-the-box 6.0Volt, 5 cell 1/2Ds, unaltered in anyway.

The MAG rechargeable battery is incredible!

 

[koala]

opps sorry, reading too fast..
Could this be the internal resistance of the cells?

 

[illumiGeek]

Are they sealed packs, or individual cells? If they are packs, then my guess would be a variances in internal resistance due to the contruction of the packs (tabbed and spot welded, tabbed and soldered, not tabbed, etc.).

Also, are these all around the same age? Even rechargable batteries get weaker with age (use).

 

[Doug Owen]

[ QUOTE ]
S4MadMan said:

Does this mean MAG uses higher output rechargeable batteries? Please, enlighten me.

[/ QUOTE ]

In a way, yes. They're NiCd and I suspect the others are NiMH?

And someone around here was just asking 'why would anyone want NiCd when they could have NiMH?'.......

Doug Owen

 

[Brock]

And for really good info on AA cells check out
http://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM

 

[Ginseng]

The PowerStream 1/2Ds are nicads.

I'm afraid that to shed some more light on the situation you'll have to do the other edge of the matrix. That is, run different bulbs with a single battery pack. Otherwise, there just aren't enough knowns to allow extraction of the unknowns. All the things noted above could be factors. Was your PS batt grouping made of loose cells? If so, you also need to be scupulous about contact cleanliness.

Wilkey

 

[S4MadMan]

IllumiGeek: good points, my Powerstreams are not sealed packs but I have electrical taped them together. All the batteries are new.

Ginseng: I did not "scrupulously" clean the contacts on the PSs. I will do so, thanks!

 

[Ginseng]

No, I mean "scupulous". As in...oh, forget it. /ubbthreads/images/graemlins/wink.gif

Wilkey

 

[S4MadMan]

[ QUOTE ]
Ginseng said:
No, I mean "scupulous". As in...oh, forget it. /ubbthreads/images/graemlins/wink.gif

Wilkey

[/ QUOTE ]

LOL!!! /ubbthreads/images/graemlins/grin.gif

 

[ChrisA]

[ QUOTE ]
Could this be the internal resistance of the cells?

[/ QUOTE ]

Yes. NiCads have even lower internal resistance than NiMHs...

Chris

 

[Bullzeyebill]

Again, check amp drain of each battery pack in SL20X with 35X bulb/reflector.

Bill

 

[eluminator]

Did you measure the voltage of the cells?

Rechargeable cells will suffer from "voltage depression" if left sitting around for many months. The cure is to run them through a few charge/discharge cycles. Severely discharging the cells causes the same symptom, though it might not be the same disease. They tell me that overcharging will also do this.

To be honest, I have no proof that leaving them around causes "voltage depression". I do know that newly purchased batteries often show a considerably lower voltage than normal after charging. I attribute this to "laying around". I suppose I can't rule out other causes. Maybe riding around in the back of a UPS truck somehow does this. /ubbthreads/images/graemlins/smile.gif

Saying a cell is "fully charged" means nothing regarding it's voltage. That just means the charger detected the negative voltage change that tells it to terminate the charge.

Allowing cells to sit around for months also causes the crystal size to increase, which increases the internal resistance, as well as reducing the "effective" capacity. High temperature storage and charging in very slow chargers do this too. A few charge/discharge cycles in a good pulse charger should fix this too. My "proof" here is this link:
http://www.resrchintl.com/memory_effects.html

I also agree that cleaning the battery contacts can make a big difference, especially at this current draw.