# who knows LiIon SONY US17670GR energytec???



## Flashing-Bernie (May 24, 2006)

I already posted my question "incandescent" but I think here is the more appropriate sub forum:

does anybody here know, if lion cells "sony us17670gr energytec" (they are green, if that hint helps)? can they handle the current drawn from a P91???

I purchased two of them some weeks ago but I'm not quite sure if I can drop them into my SF 9P (with A19 extender, of course. which I havn't got yet... ). 

What happens if they are too weak? will they melt or leak out and spoil my 9P?

Is there a simple way to test the cells without putting them into my 9P?

does anyone have advice?

thanks,
bernhard


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## Flashing-Bernie (May 28, 2006)

...obviously no one ???

is there  with information on these recharcheables??


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## SilverFox (May 28, 2006)

Hello Bernie,

I believe those are somewhere around 1200-1500 mAh cells. Li-Ion cells are rated at 1.5 - 2C for current draw, so that would put you at 2.4 - 3.0 amps at 2C. If the P91 draws more than that, it is not suggested to use that sized cell.

Under higher loads, the batteries will heat up and the lamp will not burn at full brightness. When the batteries exceed 140-160F, permanent damage is done and you may run into problems the next time you charge your batteries back up.

To test, you need something like the West Mountain Radio CBA II. You also need to know the start up current draw and sustained current draw for the P91. You can dial those parameters into the CBA II and see where the voltage drops to and monitor the temperature under those loads. This is relatively simple for me, but your mileage may vary. The hardest part is determining the start up current draw.

Perhaps you can get us started by telling us what the rated capacity of the batteries are and how much current your light is drawing... 

Tom


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## dulridge (May 28, 2006)

Flashing-Bernie said:


> ...obviously no one ???
> 
> is there  with information on these recharcheables??



Not a lot - I went looking when I pulled them out of the battery pack of a dead Toshiba laptop. All of the cells were OK to my surprise. I have pulled 1.6A out of one for about 20 mins with no trouble. I have dischared one to a measured 1.6V and then recharged it - I would not now attempt this as I reckon I was lucky not to have started a fire on recharging it.

I've no idea what power that lamp assembly pulls though. According to the battery pack I pulled them from (3S3P) they are rated at 1500mAh. They work very well in Golston 7W LED torches at about 1/4 the brightness of 2xCR123. With an incandescent lamp the lower voltage compared to 2xRCR123 is likely to render them useless as most of the light output will be in the far infra-red. Assuming the battery assebly is producing something like the rated voltage and the current draw isn't over 1.5A I'd reckon you'd be OK. If it is over the rated voltage lamp life is apt to be short.

Sony cells appear to have a good reputation.


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## Flashing-Bernie (May 29, 2006)

thanks so far!

these cells have 1500mAh and a Surefire P91 lamp assembly draws 2.46A (2.7A on 2 Li-Ions) according to this CPF-thread.

Some sources in CPF say that 17670s from AW will manage the current of a P91. but I really don't know if there are significant differences between the mentioned sony cells and those of AW.

Bernhard


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## SilverFox (May 29, 2006)

Hello Bernie,

The information you have dug up indicates that they should work fine during the steady state run. The only problem that may arise is during start up. The first few milliseconds during start up see currents that can be 2X to 3X the steady run current. This often trips any protection circuit that the cells may have. If your cells are unprotected, there does not appear to be a problem.

You can find comments by people who have to double or triple click their lights to get them to turn on. The reason for this is that the initial turn on current is higher than their cells (with protection circuits) can provide. The brief current flow, until the protection circuit trips, allows a slight warming of the filament which reduces the current needed to get it to "glow."

With unprotected cells you run the risk of dropping low in voltage during start up, if the cells are at a low state of charge when you turn the light on. Fortunately Li-Ion cells do not have to be run down and prefer to be frequently charged up, so this would only be a concern if you need to use the light for an extended period of time.

It sounds like it should work, so now you have to decide if you want to give it a try.

Tom


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## Flashing-Bernie (May 30, 2006)

Hi Tom,

thanks for your clear and informative description. I always was wondering why some people write about double and triple clicks to start. now I understand, thanks!

these cells seem to be unprotected (according to the seller's information).

I'll try it as soon as the primary cells get empty which I have in my SF 9P right now.

Bernhard


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## LEDite (Jun 2, 2006)

Bernie;

I use lots of those 1500 mah Sony cells.

They will handle 3 amps. They do have a pressure cutout that will disable the cell if you draw significantly more current.

Larry Cobb


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