18650 full charge voltage

[Superuser187]

Hello peeps...
I have a cheap 2 slot xtar charger that charges 500mah per battery...I like that it charges slow and serves me well cause cause I have 2 pairs of batteries Soo no problem charge slowly.....

The thing is when I check the voltage of fully charged 18650 batteries it shows 3.78volts and when I put on the mod shows 100% charge and all good...

But I see some people say their chargers have settings to choose charge to 4.1volts and I was wondering...does this charger not fully charge and I could get another and charge them to 4.1v and make batteries last longer???

And then the mod will still show 100% charge but just will just take longer time to go lower than that???
Cause I mean since the mod shows it's 100% already at 3.78volts

 

[Storm52]

You should be hitting 4.2 volts on full charge. How old are the batteries? Do you have a volt meter, besides the charger?

 

[Superuser187]

You should be hitting 4.2 volts on full charge. How old are the batteries? Do you have a volt meter, besides the charger?

They are both brand new batteries lg hg2 with QR code and vtc6 3000mah and I check the voltage with a voltmeter..

The charger is super basic xtar and has no screen just 2 slots and it's not adjustable to current or voltage of anything....I guess it's the charger I need to get another one if I want to take advantage of full capacity of batteries...
I don't feel like they don't last much but I wonder if it's bad for batteries to use them in that range hmmmm

 

[UncLeJunkLe]

If your charger says the batteries are fully charged, the charge should be 4.2 volts (but more likely just under that at 4.1x volts).

So if this is true (batts are charging to 4.2 volts) and your mod shows full charge, then your mod is wrong.

If your mod is right then..
- either your charger is faulty or
- your batteries will no long hold a full 4.2v charge (time for new batteries).

To find out for sure what's going on, check the "fully charged" batteries on a known, working multimeter (or some other meter). If you don;t have a multimeter, find a cheap one. You don't need anything fancy or expensive or ultra accurate. You just need a reasonable idea of what the "full charge" voltage is on the batteries so you can diagnose what the problem is. In the USA, we can get multimeters for as little as $7. Not good for commercial use, but sufficient for most hobbyists.

 

[Superuser187]

If your charger says the batteries are fully charged, the charge should be 4.2 volts (but more likely just under that at 4.1x volts).

So if this is true (batts are charging to 4.2 volts) and your mod shows full charge, then your mod is wrong.

If your mod is right then..
- either your charger is faulty or
- your batteries will no long hold a full 4.2v charge (time for new batteries).

To find out for sure what's going on, check the "fully charged" batteries on a known, working multimeter (or some other meter). If you don;t have a multimeter, find a cheap one. You don't need anything fancy or expensive or ultra accurate. You just need a reasonable idea of what the "full charge" voltage is on the batteries so you can diagnose what the problem is. In the USA, we can get multimeters for as little as $7. Not good for commercial use, but sufficient for most hobbyists.

That's the thing....the batteries are both new and since always was charging to 3.8v and the charger is also new...
I measure the volts with a multimeter that I know works good but I will check again with another multimeter I have to make sure the thing is not broken...
Soooo the mod shouldn't show 100% charge if my batteries are 3.8volts fully charged? Seems that multimeter shows wrong readings lol....I will go to my car I have a better multimeter there and test tomorrow morning to make sure...thanks peeps

 

[UncLeJunkLe]

That's the thing....the batteries are both new

It doesn't matter if your batteries are new. They could be defective or could be old stock that was stored improperly.

I measure the volts with a multimeter that I know works good

You never told us what voltage your multimeter showed?

Soooo the mod shouldn't show 100% charge if my batteries are 3.8volts fully charged?

All the mods I own only show full charge when battery is above 4.1x volts. Any other voltage and the mods will show less-than full charge. I guess mods are looking for a certain voltage level, not actual capacity of the battery. I would suspect that all mods are designed in this way, but I could be wrong.

Also, it might help to know what mod you are using (but ultimately what matters is what the actual full charge on your batteries is).

 

[UncLeJunkLe]

never mind, I guess it's safe assume your multi-meter is showing 3.78 volts. In that case I have no idea what's going on.

Yes, it could be a bad charger.
What charger (exact Xtar model please)?
Is it possible your specific model of charger is designed to only charge up to 3.8v? 3.78 is a long way off from 4.2 so it's either defective or it's designed to only charge up to 3.8 (assuming batts are not defective).

But this does not explain why the mod shows full charge at 3.78 volts. However, this is not as important as figuring out why the charger is only charging to 3.78 volts (in my opinion).

 

[Superuser187]

It doesn't matter if your batteries are new. They could be defective or could be old stock that was stored improperly.



You never told us what voltage your multimeter showed?



All the mods I own only show full charge when battery is above 4.1x volts. Any other voltage and the mods will show less-than full charge. I guess mods are looking for a certain voltage level, not actual capacity of the battery. I would suspect that all mods are designed in this way, but I could be wrong.

Also, it might help to know what mod you are using (but ultimately what matters is what the actual full charge on your batteries is).

I said my multimeter I have at home shows 3.78volts but that's a cheapo and old multimeter and since the mod shows full charge when I put the batteries inside then I guess my multi is broken
....bored to go to the car now and check with other multimeter I have but I will tomorrow and I bet it will show 4.1v now that u explain me....
My mod is a gen and the batteries are both bought 4 and 2 months ago and different brand
But as u said since the mod shows full then it's gonna be 4.1v or something...
And now I know this multimeter must go to the trash hahahaha
I BET I GOT FOOLED BY MY MULTIMETER

 

[VapingBillet]

Hi SuperUser187

Which Xtar charger do you have as there are many many different models, if for instance you have the WP2H this has a setting on the side "choose suitable voltage for battery" = 3.2v, 3.6v, 3.8v if this has been set to 3.6v it will fully charge the cells to 4.2v however on some displays of Xtar chargers it will display the setting you are using which may be what you are seeing, i.e 3.8v.

However standard now is 3.7v that is fully charged at 4.2. safest to use is 3.6v

I also would advise that I have never found the xtar chargers particularly accurate that I have owned, however this is just my experience.

 

[UncLeJunkLe]

I BET I GOT FOOLED BY MY MULTIMETER

Very possible.

bored to go to the car now and check with other multimeter I have but I will tomorrow

If you stop being lazy (you say "bored" ) we could know right now

Also, we still want to know exact model of charger. Look at sticker or embossing on bottom.

 

[Superuser187]

Hi SuperUser187

Which Xtar charger do you have as there are many many different models, if for instance you have the WP2H this has a setting on the side "choose suitable voltage for battery" = 3.2v, 3.6v, 3.8v if this has been set to 3.6v it will fully charge the cells to 4.2v however on some displays of Xtar chargers it will display the setting you are using which may be what you are seeing, i.e 3.8v.

However standard now is 3.7v that is fully charged at 4.2. safest to use is 3.6v

I also would advise that I have never found the xtar chargers particularly accurate that I have owned, however this is just my experience.

It's a cheapo xtar mc2 model name and has no switches or display..
I checked the back tho and sais 5v 1amp input and 4.2v 2x500mah output sooo that means it's default is 4.2v Soo I guess since my mod also shows full charge then my multi is broken that's why show 3.78v...this multi it's a cheapo that even few weeks ago was reading correctly but I guess it's time to trash....I have a good one tho for work sooo I will check tomorrow cause I am curious even tho I am pretty sure what it will show

 

[UncLeJunkLe]

I guess since my mom also shows full charge then my multi is broken.

 

[Superuser187]

Dammit u saw before I edit it hahahahhahaa

 

[VapingBillet]

It's a cheapo xtar mc2 model name and has no switches or display..
I checked the back tho and sais 5v 1amp input and 4.2v 2x500mah output sooo that means it's default is 4.2v Soo I guess since my mod also shows full charge then my multi is broken that's why show 3.78v...this multi it's a cheapo that even few weeks ago was reading correctly but I guess it's time to trash....I have a good one tho for work sooo I will check tomorrow cause I am curious even tho I am pretty sure what it will show

Yes looks like the multi then, yes please let us know, my curiosity cat has been fully killed!

 

[DaveP]

I agree on the multimeter reading incorrectly, but most mods will show low battery around 3.5v or so If you take them out and put them on the charger or read them with a VOM when the mod shows low battery.

 

[Superuser187]

I agree on the multimeter reading incorrectly, but most mods will show low battery around 3.5v or so If you take them out and put them on the charger or read them with a VOM when they show low battery.

Yeah that was what I was thinking like calibration of the batteries level on the software would still show 100% charge from 3.8v and up
But I checked batteries with my good multimeter and they show 4.15v soooo yeah I trashed the multimeter hahah

 

[Superuser187]

Yes looks like the multi then, yes please let us know, my curiosity cat has been fully killed!

*Drum roll
AAAAAAAND yes my multimeter was broken and I checked and it was 4.15v fully charged sooooooo I got FOOOOLED

 

[DaveP]

*Drum roll
AAAAAAAND yes my multimeter was broken and I checked and it was 4.15v fully charged sooooooo I got FOOOOLED

Before you buy a new meter, check the test leads and their contact sockets in the meter. Sometimes tarnish, dirt, weak contact springs in the leads, or corrosion can be the cause of low readings if the leads are resistive, especially with low voltages. You should get close to zero resistance when you set the meter on Rx1 resistance and short the leads together.

 

[UncLeJunkLe]

I wonder if a very weak battery could cause improper readings on a multimeter?

 

[Superuser187]

It was my first and the cheapest multimeter ever lol i had it for 15 years I think and just had it at home for simple readings like house batteries and that stuff....served me well...
I closeeeeeee myyyyyy eyeeeeeeeeees
Only for a moment and the moment's goneeeeeee

Duuuuuuuuuuust in the wind
My multi now is dust in the wiiiiiindddd

Ohhhhhhhh aaaaaaa aaaaaaaaa