Battery charging question

[Bravoroni]

Hi Guys,

So I originally had a nitecore i8 charger that I used to charge 8 x 18650 batteries. After using it for a few days I started noticing that it made a weird ticking noise and got VERY hot on the bottom. Needless to say this made me quite uncomfortable.

So I exchanged it for a Xtar VC8. So far it’s been amazing. No ticking or weird noises and it doesn’t get hot. It also comes with a nice screen that shows you some details about your batteries. This is what leads me to my question.

I noticed when charging my batteries most of them show as roughly 3.7v but others show as 4.1v. Also the longer they charge the higher the number goes. Is this normal? Sorry I’m a total idiot when it comes to batteries and voltages etc. If anyone could clue me in i would be very great full!

Thanks

 

[WorksForMe]

Yes,that's normal. As you use a battery the voltage slowly drops. Then when you charge it, the voltage should go back up to about 4.2V.

 

[mimöschen]

When a standard 18650 has been fully charged its voltage is 4.2V.
For each puff you take, the cell gets drained and its voltage decreases.
When your mod shows that the 18650 is empty, its voltage will most likely be at around 3.4-3.2V, depending on the cut-off voltage of your mod.

A fully charged 18650 will lose voltage over time even when sitting idle.
They don't like to be stored for extensive amounts of time fully charged, because the chemicals inside decompose a lot faster that way.
To keep unused cells in good shape for as long as possible, store them at room temperature with a charge of 3.4-3.8V.

If you ever let an 18650s voltage drop below 2V (some even 2.5V), get rid of it, because it has taken permanent damage and the risk of critical failure increases significantly.

 

[zoiDman]

...

I noticed when charging my batteries most of them show as roughly 3.7v but others show as 4.1v. Also the longer they charge the higher the number goes. Is this normal? Sorry I’m a total idiot when it comes to batteries and voltages etc. If anyone could clue me in i would be very great full!

Thanks View attachment 947381

Everything you have Described using your Xtar VC8 sounds Normal.

A Charger (or the Batteries being charged) should Never get Hot. Warm to the Touch is Normal. But Not Hot.

The Increase of Voltage you are seeing is the Actual Charging Process. Think of your Batteries like Tank of Gas in your Car. As you use your car, you consume the Gas in the Tank. The Same thing happens when you use a Battery. As you use it, you consume the Voltage in the Battery.

And charging is just like filling up your Car's Tank at the Gas Station.

A Fully Charged 18650 Battery has 4.2 Volts. And a Regulated Mod will usually stop working when the Battery Drops to about 3.0 Volts of so. So when you go to Charge an 18650 Battery, you can think of it as just like going to the Gas Station. Where 3.0 Volts is a Gas Tank on Empty. And 4.2 Volts is Completely Filled Tank.

 

[Hawise]

The others have covered the voltage issue, but your picture indicates that you might find some advice in another area useful - battery selection. Here's a quick overview:

1. Stick to batteries from the 'big 4' (or Molicel): that's Sony/ Murata, Samsung, LG and Sanyo/ Panasonic.
2. Pick a battery model with an appropriate CDR (you may already have done this, or not. We'll be happy to explain what this means and how to do it if you could use more details.)
3. Buy all your batteries from a reliable vendor. There's a list of good vendors (and generally good batteries, although you still need to check the CDRs) on Mooch's Recommended Batteries chart.

If you'd like more information, ask and it will be provided. Good call on the charger, by the way - one of the first rules of battery safety is noticing when something weird's happening and doing something about it!

 

[Bravoroni]

The others have covered the voltage issue, but your picture indicates that you might find some advice in another area useful - battery selection. Here's a quick overview:

1. Stick to batteries from the 'big 4' (or Molicel): that's Sony/ Murata, Samsung, LG and Sanyo/ Panasonic.
2. Pick a battery model with an appropriate CDR (you may already have done this, or not. We'll be happy to explain what this means and how to do it if you could use more details.)
3. Buy all your batteries from a reliable vendor. There's a list of good vendors (and generally good batteries, although you still need to check the CDRs) on Mooch's Recommended Batteries chart.

If you'd like more information, ask and it will be provided. Good call on the charger, by the way - one of the first rules of battery safety is noticing when something weird's happening and doing something about it!

Hey thanks for the reply. Yes I would love any input you have. As far as I know all the batteries I’m using are from good manufacturers? The guy at my local vape shop said they are Sony, Panasonic and LG (2 of them RE wrapped by other companies)

 

[Hawise]

Hey thanks for the reply. Yes I would love any input you have. As far as I know all the batteries I’m using are from good manufacturers? The guy at my local vape shop said they are Sony, Panasonic and LG (2 of them RE wrapped by other companies)

Rewraps are a good place to start. There are two issues with rewraps:

1. Say LG produces a run of HG2's (a good model for many vapers). Not all of the batteries will perform the same way. They'll test them and categorize them as A bin, B bin, C bin. The best ones (A's) they'll sell under their own name as HG2s. The B's they might sell as a lower-rated model. C's could be sold off to resellers and not formally labeled as LG's. They're generally the ones rewrappers end up with. The thing is, they're the ones that didn't meet the criteria to be proper HG2s, and we don't know what criteria they did meet. Provided you're not using your cells at the limit, they may work perfectly well for you. Or they may not.
2. This one's an even more serious problem. The rewrappers managed to get a hold of a big batch of C bin HG2s. They've sold them for a while, and people have tested them and got a decent idea of how they work. But now they're running low or running out, and there aren't any HG2's about. So they get what they can - perhaps a batch of dodgy China manufactures from a factory without appropriate quality (and safety) controls, or more C bin batteries but of a battery model that isn't as suitable for vaping. And they slap the same label on them. There's no way to be sure what's under the label of a rewrap. They can and do switch sources regularly, taking advantage of whatever's available.

And that's why it's best to stick with the actual name brands, not rewraps. Of course, that still leaves the issue of counterfeits. That's why we generally recommend the reliable vendors on the chart I linked to in the previous post. Vape shops and places like Amazon, eBay and Alibaba should be avoided as far as batteries are concerned. The vape shops are often well-intentioned, but battery supply lines are super complicated (manufacturers absolutely will not sell to vapers) and it's too easy to be taken in by counterfeiters. The reliable vendors in the list aren't immune to problems, but they tend to be big purchasers with more reliable supply lines, many spot check their shipments, and when something slips by and purchasers report unexpected battery behavior, they have a track record of checking things out properly and, if a problem is confirmed, notifying other customers who got batteries from that batch and replacing them (the batteries, not the customers).

That's it for now. I'll be back with the promised battery selection advice shortly, but I'm grappling with a heat wave at the moment and need to go stick my head into a bucket of ice water. Did you know it was possible to encounter temperatures of positive 37 degrees Celsius? I've only ever met a 37 with a minus in front of it. (Note to all from warmer climes: I know I'm a wimp, but would you be much better at -44?)

 

[zoiDman]

...

That's it for now. I'll be back with the promised battery selection advice shortly, but I'm grappling with a heat wave at the moment and need to go stick my head into a bucket of ice water. Did you know it was possible to encounter temperatures of positive 37 degrees Celsius? I've only ever met a 37 with a minus in front of it. (Note to all from warmer climes: I know I'm a wimp, but would you be much better at -44?)

The Heat is Unreal.

Never seen it So Hot So Far North on the West Coast.

 

[Hawise]

Hey thanks for the reply. Yes I would love any input you have.

And here's my rundown on the battery selection process:

Background: Batteries have two key metrics: CDR (Continuous Discharge Rating), measured in amps, and capacity, generally measured in mAh. CDR tells you what wattage you can use it at while the capacity gives you an idea of how long it will last between charges.

1. Find out what CDR you need. The calculation is:

(Your maximum wattage) ÷ (The number of batteries in your mod) ÷ 3

So, if you were to vape at up to 70 watts on a two battery mod, it would be:

70 watts ÷ 2 ÷ 3 = 11.7 amps

However, if you were vaping that way on a one battery mod, it would be:

70 watts ÷ 1 ÷ 3 = 23.3 amps

2. Find a battery with at least that CDR

• If at all possible, make sure it's a Sony/Murata, Sanyo/Panasonic (they only make 18650s suitable for very low wattage vapers), Samsung, LG, or Molicel.
• Check that Mooch's testing confirms the CDR. A number of vendors aren't entirely accurate with CDRs, or list 'temperature limited CDRs' which are valid for some uses but should only be used with some very expensive equipment to monitor the cell's internal temperature.
• The easiest way to find a good battery is to pick one from Mooch's Recommended Batteries list. There are other good battery models, but the list offers a shortcut for identifying common vaping batteries. CDRs and capacity are included on the list to help you pick what you need.
• General practice is to choose the battery with the highest capacity that meets your CDR needs. However, if you often vape near the limits of the CDR you need, you will usually get better performance from a higher CDR battery with a lower capacity. Basically, the official capacity becomes less meaningful as you approach the CDR.

3. Buy your batteries from one of Mooch's reliable vendors (who can be found on the blue row near the bottom of the Recommended list linked to in the previous step)

• The reliable vendors list is the best way we have at the moment of reducing the risks of getting a counterfeit.

Two more things to mention:

1. You may be wondering why I refer to Mooch so often. He's our resident battery guru. After working in the industry for many years he's now dedicating part of his time to performing comprehensive testing of the batteries used for vaping, so he has more and better information about the batteries we use than anyone else.

2. When talking about rewrappers, I forgot to mention that most of them are mildly to horrifically dishonest about CDRs on the batteries they rewrap. Some have claimed their 18650s have a CDR of 70 when the practical limit with current technology seems to be about 30. Also, anything described as a CDR 'pulse' rating should be ignored. Pulse ratings are meaningless.

Anyway, good luck, and feel free to ask any questions you may have. I like rambling about batteries.

 

[Ed Brown]

(Your maximum wattage) ÷ (The number of batteries in your mod) ÷ 3

So in this calculation, are you using the 3 to represent the voltage? (Volts x Amps = Watts, so Watts/volts = Amps). Is 3 appropriate for a regulated mod?

For an unregulated mod it would be appropriate to use 4 or 4.2 or even 3.7 because the max amps are achieved when the battery is fully charged. As the battery drains the amps go down.

It may make sense though to use 3 for a regulated mod, because the regulated mod tries to maintain the same watts, so it takes more and more from the battery as it drains. Am I thinking correctly?

 

[UncLeJunkLe]

For regulated mod
Battery Amp Draw / Drain Calculator - Vaping Hardware

For both regulated & mechanical
Battery drain | Steam Engine | free vaping calculators

 

[Hawise]

So in this calculation, are you using the 3 to represent the voltage? (Volts x Amps = Watts, so Watts/volts = Amps). Is 3 appropriate for a regulated mod?

For an unregulated mod it would be appropriate to use 4 or 4.2 or even 3.7 because the max amps are achieved when the battery is fully charged. As the battery drains the amps go down.

It may make sense though to use 3 for a regulated mod, because the regulated mod tries to maintain the same watts, so it takes more and more from the battery as it drains. Am I thinking correctly?

You've got it. When determining CDR, you need to calculate the max amps, so that's a fully charged battery for an unregulated mod and a fully (or as far as it gets - the low battery cutoff) discharged battery for a regulated mod. The cutoff is usually 3.2 - 3.4 volts, and we drop it to 3 to account for running the board and general inefficiency.