Reversed battery

Black Raven · Feb 12, 2016

I have a 2 watt blue laser that I accidentally installed the battery backwards and when I turned it on the laser did not power up and I noticed a burning electrical smell, I took the battery out and put it the right way and now the laser only gives off a dim light, I recharged the battery hoping that would help and it did slightly but no where near what this thing is capable of. What could have fried? Driver board or laser diode or both?

marcuspeh · Feb 13, 2016

Black Raven said:
I have a 2 watt blue laser that I accidentally installed the battery backwards and when I turned it on the laser did not power up and I noticed a burning electrical smell, I took the battery out and put it the right way and now the laser only gives off a dim light, I recharged the battery hoping that would help and it did slightly but no where near what this thing is capable of. What could have fried? Driver board or laser diode or both?

There's no way of knowing if it is the driver board or the diode. If you driver board has a reverse polarity protection, there is a chance that only the board is fried.

Black Raven · Feb 13, 2016

marcuspeh said:
There's no way of knowing if it is the driver board or the diode. If you driver board has a reverse polarity protection, there is a chance that only the board is fried.

Is it possible that even with reversed polarity protection a reversed battery could cause damage?

Benm · Feb 13, 2016

Not really, that's what reverse polarity protection in for

Then again many driver circuits have none since it 'costs' a bit of extra dropout voltage regardless of how you implement it. They often rely on a reversed battery not being able to make mechanical contact. That approach usually works well for things like AA batteries, but it may not work for all lithium cells.

InfinitusEquitas · Feb 13, 2016

Unfortunately you are now the proud owner of a dim blue light. Impossible to say without actually seeing it whether it's the diode, driver, or both that are damage. If it was laser from ebay/china, it's finished.

What kind of laser was it? Where did you get it?

Laser Chick · Feb 13, 2016

Hi Black Raven :wave:

Welcome to the forum

Bummer about your laser. That is almost word for word of a post from about a week ago.

Pman · Feb 13, 2016

I will add that putting in batteries the wrong way or using 2 when it is only supposed to have 1 is a VERY common issue and can happen to anyone if your attention isn't focused on it.
There are things you can do to help prevent it again such as using a label maker to label the laser or marking the inside of the back switch with a + or - and a 1 or 2 for which way the battery goes and how many it takes. You can also put the information on a slip of paper and slide it inside where the battery goes to remind you.

Laser Chick · Feb 13, 2016

All my laser but 2 of them have the battery go in - end first. I have put the batteries in backwards for both of those models being a creature of habit. I am lucky that the lasers have circuitry in them to protect against reverse polarity so that saved my butt both times!! :beer:

Black Raven · Feb 14, 2016

I just ordered a replacement driver with reversed polarity protection, I'll let you know if it fixes it, I also have a 2 watter coming from sci-fi lasers. I live in Ohio do you think that that will make it through US customs?

Laser Chick · Feb 14, 2016

Yes you should receive it no problem.

Black Raven · Feb 14, 2016

Sweet I can't wait

Benm · Feb 15, 2016

Putting in the batteries the wrong way is easy enough to do - especially with green lasers when they often go in the 'non intuitive way'. As long as you use batteries with 'nipples' contact can be mechanically avoided in such cases though.

Protecting a driver from swapped batteries is fairly easy - i usually only takes a mosfet and a resistor to do so without any significant insertion loss (as you would have from a diode).

Inserting 2 batteries instead of 1 is more difficult to deal with: if it's a buck regulator it might be just fine or run a bit hot, but a typical boost regulator cannot output a voltage lower than it's input (minus a skottky diode drop).

Hemlock_Mike · Feb 15, 2016

I mark my portables with a magic marker on the removable contact end.
RED dots or + OR a black marking.
HMike

GSS · Feb 15, 2016

What are reverse polarity batteries exactly i'm missing something when I google. Are they just a battery with out a positive nipple? I can't see them working on a internal 2 spring system.

Pi R Squared · Feb 15, 2016

GSS said:
What are reverse polarity batteries exactly i'm missing something when I google. Are they just a battery with out a positive nipple? I can't see them working on a internal 2 spring system.

I think you didn't carefully read the whole thread. There is no such thing as a reverse polarity battery. They are talking about accidentally inserting the batteries the wrong way. The batteries without the nipple are called "flat top", the ones with the nipple are called "button top".

Alan

GSS · Feb 15, 2016

Pi R Squared said:
I think you didn't carefully read the whole thread. There is no such thing as a reverse polarity battery. They are talking about accidentally inserting the batteries the wrong way. The batteries without the nipple are called "flat top", the ones with the nipple are called "button top".

Alan

Pi, I understood the thread "really teacher" my dog didn't eat my homework this time

I've seen ads or a least I think I have on batteries that say reverse polarity protection on top off "over charge or discharge" protection. Is a flat top just for spring to spring contact? I have to go back cause something Benn said about mechanical avoiding chance? I've been up since 2:00 maby I sleep posted:thinking:

Reversed battery

Black Raven

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Pman

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Laser Chick

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