Charger polarity - how to tell?

[Gionnirocket]

Yes the photo was an example of a ac/brick/dc charger because ROAMERS asked about it -- it is an example of just one charger. It is for sale at amazon.
MThe one I have, as I have stated in the original post, does not have any markings (see pics)

Yes... and your answer was in post #2
Do you think anyone is going to magically know by looking at a connection with no markings?

 

[netrate]

I was reaching out because people on this forum are much more experience than I am (or ever will be) and I was hoping that they might have had an "insight" or other ideas I didn't think about. I don't think there is magic in that,. As a layperson, it would be quite easy for me to overlook something obvious or even not-so-obvious that an experienced person would know. When I reno'd my bathroom, I made many many many simple/stupid mistakes that another contractor with more experience would probably shake their head at, but alas that is the value of experience -- and that is why I came here and appreciate the help that is given.
An of course, I am a bit nervous about this too. Chargers are not cheap and I don't want to wreck a charger because I jump in like a bull in a china shop without doing my research and reaching out to the kind and helpful people here on the forum.

 

[Gionnirocket]

I was reaching out because people on this forum are much more experience than I am (or ever will be) and I was hoping that they might have had an "insight" or other ideas I didn't think about. I don't think there is magic in that,. As a layperson, it would be quite easy for me to overlook something obvious or even not-so-obvious that an experienced person would know. When I reno'd my bathroom, I made many many many simple/stupid mistakes that another contractor with more experience would probably shake their head at, but alas that is the value of experience -- and that is why I came here and appreciate the help that is given.

Sorry if I came across as harsh but it's either marked or it's not... It's really that simple.
And since you say it is all in Chinese, that means that it was not meant to be sold in the Americas at which point the only thing I would trust is a voltmeter.
I'd even verify voltage and monitor closely on the first few charges that it shuts down properly and doesn't over charge.

 

[AHicks]

I was reaching out because people on this forum are much more experience than I am (or ever will be) and I was hoping that they might have had an "insight" or other ideas I didn't think about. I don't think there is magic in that,. As a layperson, it would be quite easy for me to overlook something obvious or even not-so-obvious that an experienced person would know. When I reno'd my bathroom, I made many many many simple/stupid mistakes that another contractor with more experience would probably shake their head at, but alas that is the value of experience -- and that is why I came here and appreciate the help that is given.
An of course, I am a bit nervous about this too. Chargers are not cheap and I don't want to wreck a charger because I jump in like a bull in a china shop without doing my research and reaching out to the kind and helpful people here on the forum.

Nothing wrong with the questions you asked. It would seem that some may be forgetting that they asked some of the same questions when they were first getting their feet wet, and have forgotten those days. Keep asking any question you might have, just be patient with some of the guys who may have answered that same question hundreds of times....

Pays to maintain a little thick skin in places like this, and remember that replies made in print don't always come across the way they were intended. Pay off comes when somebody shares some of the experience you are looking for..... -Al

 

[netrate]

Thank you for the reply. You are willing to help and I appreciate that. Tonality is weird online, so no harm no foul.
I have read about the polarity issue many times and have even seen on Amazon when someone says "bought it, the polarity is wrong and blew out my charger". I am trying to avoid that. Right now I am familiarizing myself with my voltmeter to ensure I have the leads correct.

Right now, this setup work for continuity checking and when I am checking the voltage on the batteries. At the bottom LEFT of the voltmeter is a DC 10A slot and I am unsure about that part even though I haven't used it before. I am hoping the way I have it right now is the way I need to do the checking.

 

[AHicks]

Your voltmeter is able to read up to a 10 amp draw by putting the red lead in the left position. You have it in the correct position to read/measure volts. With the dial set where it's at you should be able to read up to 20 volts. If you want to read your battery voltage for instance, you would set the indicator on 200, to allow the volt meter to read up to 200v.

As far as polarity, USUALLY you will see a negative in front of the voltage if you have the leads reversed.

 

[netrate]

So on the voltmeter, red is ALWAYS positive, right?

 

[AHicks]

I think that's a pretty safe bet, yes.

 

[indianajo]

A simple cheap multimeter may be more user-friendly. Not many here are up to speed using resistors and components when a multimeter is so much easier. Thoughts? If polarity has reversed a multimeter will flag a - minus sign. Easy peasy! No?

My chargers shut down when there is no battery connected to them. Yours something special? Connect battery backwards, you may blow up charger. Resistor across pins makes charger work while you measure polarity.

 

[netrate]

This charger is still pumping out voltage when not connected to a battery using my multimeter. Yes I know that chargers can blow, so that is why I'm trying my hardest to figure this out first before charging the batteries

 

[netrate]

Success! Thank you team!

 

[tomjasz]

My chargers shut down when there is no battery connected to them. Yours something special? Connect battery backwards, you may blow up charger. Resistor across pins makes charger work while you measure polarity.

Again we're confusing comments. I use a MM to determine polarity. My and most MM's are reverse polarity "protected". If my + is on the negative outflow and - is on the plus out the voltage reading has a - MINUS sign. I then know I've reversed the polarity with my MM probes. I'm not understanding why a resistor is needed for this simple task.

 

[AHicks]

Again we're confusing comments. I use a MM to determine polarity. My and most MM's are reverse polarity "protected". If my + is on the negative outflow and - is on the plus out the voltage reading has a - MINUS sign. I then know I've reversed the polarity with my MM probes. I'm not understanding why a resistor is needed for this simple task.

I have seen chargers that will have zero output unless they see a load. I've never tried it, but a resistor might be mistaken for a load, allowing you to check polarity?

 

[netrate]

I don't have enough experience to chime in, but both chargers I have will show voltage even without a battery attached.

 

[Gionnirocket]

This thread is turning into a load... is that enough to trigger the charger

 

[netrate]

You can feel free to close this thread if necessary as my original problem is solved thanks to the people on the forum.

 

[tomjasz]

I have seen chargers that will have zero output unless they see a load. I've never tried it, but a resistor might be mistaken for a load, allowing you to check polarity?

Yes, that's true. A MM is useless to troubleshoot some. Thanks for the reminder!

 

[Gionnirocket]

Re

You can feel free to close this thread if necessary as my original problem is solved thanks to the people on the forum.

Really not a problem... I was just bored.... and as you can see, still am

 

[AHicks]

Re
Really not a problem... I was just bored.... and as you can see, still am

That being the case, been thinking about just what would happen putting a small resistor across a pair of say 2-3a charge leads. I'm thinking you would hear a snap, and see the smoke leaving it? I KNOW it's going to get hot pretty quickly.... I suppose if you had one big enough, it might survive?