Battery causes tach light to blow? - XDTalk Forums - Your HS2000/SA-XD Information Source!

vtachrn · 05-08-2008, 10:33 PM

I have seveal rather cheap 7.2v flash lights that I was given a while back. They take the CR123A battery (3v). I have been using them alot around the house and the batteries are rather spendy to replace.

I ordered some rechargable Lithium Ion 3.0V CR123A 1000mAH batteries. When I put them in any of the flash lights, the bulb blows. What the heck? I have the regular Lithium Ion batteries that you can get at any store in the light and it works great, use these new rechargables and the light blows. I did hook up a multimeter and checked the voltage and the rechargable batteris and they are 3.0v, both of them produce 7.2 volts. The bulb in all the lights are matched to the correct 7.2 volts.

Any clue?

Ride the Lightning · 05-09-2008, 06:37 AM

I used to have a 19.2V Craftsman work light that did that. After lots of blown bulbs, lots of money spent replacing them, and lots of research, I discovered that they were simply 18V bulbs that were relabeled. Some batteries ramp up to peak voltage faster than others, and some will momentarily even go peak at a higher voltage and then drop a little bit. One of those is probably your issue. You could probably fix it by wiring a capacitor or inductor into the circuit somehow, it's been a while since I took electrical science, so I don't remember which you would need. Just something to buffer the initial voltage that the bulb sees.

The Tengu · 05-09-2008, 07:00 AM

RCR123 batteries are not 3.0v, they are typically ~3.6v but when they are fresh off of the charger they are 4.0-4.2v and then drop down to 3.6-3.7v after a short use.

**Majk** · 05-09-2008, 07:11 AM

You need to have a bleed down bulb if you want to use the flashlight right away. If you let the batteries sit for a minimum of 2 hours you shouldn't have any problems as they will come back down.

I've got a blackbear flashlight that will do that if I don't use the bleed down bulb.

vtachrn · 05-09-2008, 07:55 AM

Quote:

Originally Posted by The Tengu

RCR123 batteries are not 3.0v, they are typically ~3.6v but when they are fresh off of the charger they are 4.0-4.2v and then drop down to 3.6-3.7v after a short use.

Thanks for the input. The light was blowing, when I was using the batteries right off the charger. The issue is how to get them to drop down in voltage, without damaging something else....

rimfire · 05-11-2008, 05:19 PM

Quote:

Originally Posted by The Tengu

RCR123 batteries are not 3.0v, they are typically ~3.6v but when they are fresh off of the charger they are 4.0-4.2v and then drop down to 3.6-3.7v after a short use.

This is exactly why streamlight does not recommend them

Streamlight - FAQ
Q: Can I use rechargeable CR123 batteries in any of the Streamlight flashlights?
A: No. Streamlight products are optimized and the components can be damaged or destroyed by the use of anything other than the recommended battery type. The use of improper or substandard lithium batteries can be especially dangerous.

05-08-2008, 10:33 PM	#1
vtachrn XDTalk Member Join Date: Oct 2007 Posts: 77	Battery causes tach light to blow? I have seveal rather cheap 7.2v flash lights that I was given a while back. They take the CR123A battery (3v). I have been using them alot around the house and the batteries are rather spendy to replace. I ordered some rechargable Lithium Ion 3.0V CR123A 1000mAH batteries. When I put them in any of the flash lights, the bulb blows. What the heck? I have the regular Lithium Ion batteries that you can get at any store in the light and it works great, use these new rechargables and the light blows. I did hook up a multimeter and checked the voltage and the rechargable batteris and they are 3.0v, both of them produce 7.2 volts. The bulb in all the lights are matched to the correct 7.2 volts. Any clue?

05-09-2008, 07:00 AM	#3
The Tengu XDTalk 1K Member Join Date: Apr 2003 Location: Memphis, TN Posts: 1,569	RCR123 batteries are not 3.0v, they are typically ~3.6v but when they are fresh off of the charger they are 4.0-4.2v and then drop down to 3.6-3.7v after a short use. __________________ The militia of the United States consists of all able-bodied males at least 17 years of age and, except as provided in section 313 of title 32, under 45 years of age who are, or who have made a declaration of intention to become, citizens of the United States and of female citizens of the United States who are members of the National Guard. United States Code, Title 10, section 311, paragraph (a)

05-09-2008, 07:11 AM	#4
Majk XDTalk 2K Member Join Date: Oct 2004 Location: Nebraska Posts: 2,437	You need to have a bleed down bulb if you want to use the flashlight right away. If you let the batteries sit for a minimum of 2 hours you shouldn't have any problems as they will come back down. I've got a blackbear flashlight that will do that if I don't use the bleed down bulb. __________________ --------------------------------------------------------- majkthreads National Prayer Day May 1st, 2008 Psalm 28:7 "The Lord is my strength and shield; my heart trusts in Him, and I am helped."

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05-09-2008, 06:37 AM	#2
Ride the Lightning XDTalk 500 Member Join Date: Feb 2008 Posts: 533	I used to have a 19.2V Craftsman work light that did that. After lots of blown bulbs, lots of money spent replacing them, and lots of research, I discovered that they were simply 18V bulbs that were relabeled. Some batteries ramp up to peak voltage faster than others, and some will momentarily even go peak at a higher voltage and then drop a little bit. One of those is probably your issue. You could probably fix it by wiring a capacitor or inductor into the circuit somehow, it's been a while since I took electrical science, so I don't remember which you would need. Just something to buffer the initial voltage that the bulb sees.