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Old 02-09-11, 09:26 PM   #1
malux
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In Depth Gemini Titan battery testing

Hey all, this might be a breach of etiquette. If it is, please let me know. I did a long post reviewing the Gemini Titan here.

I'll summarize what I found. Basically, it's a nice light. Solidly built and easy to switch from mode to mode. I consistently saw run times very close to the advertised 4 hours on high Gemini claims (3hr 47 and 3hrs 58 minutes on high and total runtimes over 4 hrs).

One thing I noted was the time between the LED switching from Orange to Red was very brief (under a minute). Other than that, the light was very impressive.

I won't go everything here, hope the summary helps.
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Old 02-10-11, 08:26 AM   #2
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I noticed the same on my Titan. The warning indicator does change rather fast from orange to red when running in the Hi mode. Also if I am near the end of the battery capacity, I can turn off the unit while it is still green but comes back as yellow or red after turning it back on.

Other than that, it's been a month of useage on my Titan and everything is still fine. I still can get close to 4 hrs of runtime. I have pretty much retired my MS900 and put that on my backup MTB bike.
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Old 02-10-11, 09:08 AM   #3
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I'm glad my data is consistent with yours. Actually, your post inspired me to go all out on the battery testing. I plan on doing another test in another 90 days just to see how well the light and battery hold up.

In the meantime, i'm planning on getting a spectrometer to get accurate "brightness" measurements. I'm also thinking of putting together a side-by-side time-lapse video of a magicshine using the MS battery and a DIY NIMH battery holder I built.

I think lots of folks wonder how good NIMH batteries in the 2200-2900mah range are for the MS. I think a video would help.
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Old 02-10-11, 07:14 PM   #4
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I'm also seeing about 4 hrs of run time on mine on high. Haven't had any issues so far either.

Great write-up!

I wonder what the life of the light would be on low mode and on strobe mode.
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Old 02-10-11, 09:03 PM   #5
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Quote:
Originally Posted by NBYRDR View Post
I'm also seeing about 4 hrs of run time on mine on high. Haven't had any issues so far either.

Great write-up!

I wonder what the life of the light would be on low mode and on strobe mode.
I can do a run without collecting voltage and current data just to get times. I'll work on that and update the review. The voltage and current data take a long time to graph (i took samples every two seconds using photos of the DVMs)

I was also thinking of seeing how long the MS900 runs on the gemini battery.
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Old 02-11-11, 08:36 AM   #6
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The voltage and current data take a long time to graph (i took samples every two seconds using photos of the DVMs) I was also thinking of seeing how long the MS900 runs on the gemini battery.
I'll look forward to your tests. I recorded volatage and current about every 6 minutes and the "averaged" the values across the life of the tests.

Both my Dinotte batteries as well as the MS units from China and Geoman all supplied 27-30 watt/hours of power. The light heads used in my tests were using 2.7, 5.5 and 11 watts with respect to low medium and high setting. This produced about 2:40 runtime on high.

But what I don't know for sure is this: If I can "see" or count 30 watt hours of usage in testing a battery to low-voltage circuit cut off - does this mean the battery is rated at "30 watt/hours?" Or am I seeing the ~80% usage of a battery that could be rated at 36-37 watt hours.

I'm using the simple formula of: average current x average voltage x (minutes/60) = watt hour to express battery power in wH. I don't know if this "right" or not - but it seems to make sense.



MS lighthead running at 1.5A average
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