Oh God My U2 blow up

Guys,yesterday I was watching Tv,and meantime I was reloading My U2.
Then,U2 didn't work anymore,and I found the batteries were in the wrong direction,I noticed the stimulatory smoke in My U2.
Now My U2 only can work in Level 1,2,&3;
Don't put the batteries in wrong direction,That's my lecture.

sorry to hear that! I hope you dont play with guns in front of the TV!

A professional flashlight of a couple hundred dollars can't prevent a reverse-polarity accident?

I don't think you can put bullets in a gun backwards...

EngrPaul said:

A professional flashlight of a couple hundred dollars can't prevent a reverse-polarity accident?

I don't think you can put bullets in a gun backwards...

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http://members.arstechnica.com/x/demandred/badbrochure.jpg

Sorry to hear about your U2.

I thought the spring contact at the head end was slightly recessed. It should offer mechanical reverse polarity protection. I wouldn't think you'd be able to make contact with the wrong end of the battery, unless that spring had been stretched out a little.

Try calling Surefire customer support and explain what happened.

What sort of batteries were you using? Have you modified your U2 in any way?
Seems like a call to SureFire is in order...

Al

Yes,My spring of U2 had been stretched out for use 18650.
It Seems I just lost the micro-chip,The Led is OK.

I live in China now,So I have contacted with SF service by E-mail and waiting for their respond now.

I don't think you can put bullets in a gun backwards...

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no, but carelessness can shoot out the TV!

:sick2: :green:

thank you for the tip!!! I know if doesn't help you but it helps me!!

i did the same spring move but never thought of the negatives

frankbyerswat said:

Yes,My spring of U2 had been stretched out for use 18650.
It Seems I just lost the micro-chip,The Led is OK.

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I'm glad to hear that My U2 died for something.

frankbyerswat said:

Yes,My spring of U2 had been stretched out for use 18650.
It Seems I just lost the micro-chip,The Led is OK.

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If you stretched the spring contact to the extent that the U2's ability to physically protect against reverse polarity was compromised I guess extra special care is needed when using aftermarket batteries.

Unless you think this still would have happened had you not stretched the spring and used SF123A batteries?

Al

Actually,I always believe SF is designed prefect,also in mico-chip,because mico-chip is heart of Led flashlight.
This time no doubt is my fault,But I hope it will help SF to improve their products.

Good Luck with your email to SureFire - I'm interested to find out what they say.

Al

Now I know why SF is not accept 18650 in new U2.
and I find out that there are no products can prevent reverse-polarity in design of micro-chip,SF can lead this as they alway do

A mechanical protection does not lead to loss of power. If I'm not mistaken, voltage polarity protection will result as a loss of voltage from the battery (across a diode).

Engrpaul,you're right,It must parallel one diode.
I hope there is another way.

I know that there are circuits that'll protect against reverse polarity they may be large though I know good battery chargers have them.

65535 said:

I know that there are circuits that'll protect against reverse polarity they may be large though I know good battery chargers have them.

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They generally add loss though - something thats fine in a battery charger but not a feature you want in a battery powered flashlight.

Surefire likely did think of reverse polarity protection and determined the positive spring length based on that. Without any mods the U2 does have reverse polarity protection with the cells its designed to operate from.