Charging and when to replace batteries

[Violetti Usva]

I'm curious how often I should replace batteries.

I'm currently using 5 LG HB6's for my mech mods and I've read not to charge fully to 4.2V so I take them out of the charger (Xtar VC4) when they're at 4.2 on the dial but before the light changes green to indicate full charge.

With my current mechanical set-ups I run batteries down between 3.6 and 3.8V before recharging. Is this too often for optimal battery life?

I've had these 5 on a rota for a while now and wonder when I should replace them. While I know the capacity for 4.2 down to 2.5V (IIRC the cut-off point) I don't know what capacity I should be expecting from charging 3.7-4.2V etc and if this is even a good indicator of how alive a battery is. I don't think any of the batteries are "hitting any less hard" as its often put.

 

[DaveP]

Depending on the coil in your atomizer you might be able to use batteries with high MAW ratings and lower Amp ratings and get longer vape time. What resistance is your typical coil in your mech?

Replace your batteries when vape time is noticeably shorter.

Charging to cutoff isn't going to hurt your batteries. You can expect a year or more of good vape time on the HB6 charging them when the vape on your mech starts to drop off. My chargers don't usually go to 4.2v. When I measure voltage after charging they are usually at 4.1v to 4.15v.

With a variable voltage mod I vape to cutoff and then charge. With a mech you can judge when the vape is weak and look at voltage once you take them out. Vape quality drops off quickly once the battery voltage is below 3.7v. At 3.3v they suddenly drop quickly. The nominal voltage for an 18650 is 3.7v.

Here's one of Mooch's tests on the HB6. The red line on top is the HB6. It's a great battery for high amp applications, but you might get more vape time on a mech with a Sony VTC6 or a Samsung 30Q. At 3.7v to 4.2v you aren't pulling high amps. Look for batteries with high MAH ratings and a 10A or better current rating. You will get longer vape time.

The Sony VTC6 will give you 3000mah at 15A. The HB6 is 1500mah with a 30A max rating. On a mech you might vape twice as long on the Sony VTC6.

 

[Violetti Usva]

Edited with updates since this morning:

I almost only use mech mods and these questions are specific for them. I do have some Sony something or others in my regulated devices that last much longer. 0.15 is my usual build so I'll be sticking to the LG HB6's I think. I'm not worried about how often I recharge, only whether or not using them down further might extend their overall life. I know 1500mah is the batteries capacity down to 2.5V but I don't ever use this rota of HB6's past 3.6V. Since this morning I've seen reads between 250 and 600mah.

"Replace your batteries when vape time is noticeably shorter" - I won't notice because they're on a rota, 5 batteries slowly getting worse (presumably).

I think perhaps if I write down the voltage estimate when I plug it in and the mah when its finished I could use that as an estimate of their diminish in capacity down to 3.6-3.8V. In this case, is there a specific limit i.e if 3.7V to full charge is only 15mahs it's useless (hyperbolic of course).



I have always been confused by one thing with that graph - lets say I'm using 0.14ohm coils for mathematic "ease" on a hypothetical-mech-mod with no other sources of voltage drop.

With a full battery (4.2V) these coils would pull 30amps (126W) but the voltage drops instantly to 3.45V, which would only pull 24.6amps. This amperage has a voltage drop to 3.55V.

3.45V, 0.14Ohm --> 85W
3.45V, 30amps --> 103W
3.55V, 0.14Ohm --> 90W
3.55V, 30amps --> 106W
3.55V, 24.6amps --> 87W

...what on earth is my initial wattage?


(also, I have seen all of mooch's 18650 graphs and try to keep up to date )

 

[madstabber]

Edited with updates since this morning:

I almost only use mech mods and these questions are specific for them. I do have some Sony something or others in my regulated devices that last much longer. 0.15 is my usual build so I'll be sticking to the LG HB6's I think. I'm not worried about how often I recharge, only whether or not using them down further might extend their overall life. I know 1500mah is the batteries capacity down to 2.5V but I don't ever use this rota of HB6's past 3.6V. Since this morning I've seen reads between 250 and 600mah.

"Replace your batteries when vape time is noticeably shorter" - I won't notice because they're on a rota, 5 batteries slowly getting worse (presumably).

I think perhaps if I write down the voltage estimate when I plug it in and the mah when its finished I could use that as an estimate of their diminish in capacity down to 3.6-3.8V. In this case, is there a specific limit i.e if 3.7V to full charge is only 15mahs it's useless (hyperbolic of course).



I have always been confused by one thing with that graph - lets say I'm using 0.14ohm coils for mathematic "ease" on a hypothetical-mech-mod with no other sources of voltage drop.

With a full battery (4.2V) these coils would pull 30amps (126W) but the voltage drops instantly to 3.45V, which would only pull 24.6amps. This amperage has a voltage drop to 3.55V.

3.45V, 0.14Ohm --> 85W
3.45V, 30amps --> 103W
3.55V, 0.14Ohm --> 90W
3.55V, 30amps --> 106W
3.55V, 24.6amps --> 87W

...what on earth is my initial wattage?


(also, I have seen all of mooch's 18650 graphs and try to keep up to date )

I have the liitokala lii-500 and it’s an analyzing charger. So I can run a test to find out how many mah my batteries are capable of. This can come in handy to find out if I want to toss them or not. I got mine for fasttech for around $25-$30 I think so they aren’t expensive. The other charger with these capabilities that I know of is the Opus BT-3100. It is a little more but still pretty inexpensive. I think you should get one to help you out.

 

[rob33]

I just keep it simple and match my batteries and build to last all day. If I can't match that up it's time for new batteries.

 

[Violetti Usva]

madstabber that does sound very useful but not something I can fork out for right now!

 

[AzPlumber]

imo you're over thinking it, replace them when they no longer hold a decent charge and vape time per cycle becomes frustrating.

Short cycling (charging) will extend battery life but also means less vape time per cycle, only you can determine if it is worth it.

 

[Baditude]

I applaud your diligence and interest in your battery safety practices. However, as AzPlumber suggested you are probably over thinking it.

I don't particularly see a need to pull your batteries off of the charger before they reach the full 4.2 volts. My Xtar VP4 leaves my batteries between 4.1 4.16 volts when finished charging. It's the older "trickle" chargers that you might want to keep an eye on.

Short cycle charging will extend your battery life, but at what price in obsessive compulsiveness? Again, nothing wrong with that, just seems "a little extreme" to me.

As batteries naturally age, they lose their mAh capacity. As they lose their mAh capacity, they also lose their amp rating. The harder a battery is used (or abused), the faster it will "age" or degrade. So your 30 amp battery may only be a 15 amp battery way down the road. There's no easy way to find a battery's amp rating, but you can find the battery's capacity with some chargers. Using one of these chargers could give you a good idea of how much your batteries have aged or degraded over time.

You're using the "best" batteries (brand and model) for the way you vape. I assume you keep a close eye on the wraps and insulator rings. You're not misusing/abusing your batteries by pushing them at or over their amp limit (0.15 ohm has an amp draw of 28 amps), although you don't have much of a safety margin.

I'm assuming that you've already seen Mooch's blog and videos, but for the benefit of those readers who haven't:

• When should you replace a battery?How can we extend the life of our batteries?

• How can we extend the life of our batteries?

 

[DaveP]

I have always been confused by one thing with that graph - lets say I'm using 0.14ohm coils for mathematic "ease" on a hypothetical-mech-mod with no other sources of voltage drop.
With a full battery (4.2V) these coils would pull 30amps (126W) but the voltage drops instantly to 3.45V, which would only pull 24.6amps. This amperage has a voltage drop to 3.55V.

3.45V, 0.14Ohm --> 85W
3.45V, 30amps --> 103W
3.55V, 0.14Ohm --> 90W
3.55V, 30amps --> 106W
3.55V, 24.6amps --> 87W

You aren't considering using a .14 ohm coil on a mech, are you? Most would agree that's a dangerous setup. You did say that your example was hypothetical. Just wondering.

Mechs are usually Tootle Puffer devices that run under 20W.

 

[Violetti Usva]

Using LG HB6's in a mech I usually go for 0.15-0.17, but wouldn't consider 0.14 a problem with these or a certain few other batteries. One of my Reload clones has a triple coil build ohming out at 0.14 and produces the best flavour I've ever had - just drains the batteries too fast to be usable out of the house for long.

 

[DaveP]

Using LG HB6's in a mech I usually go for 0.15-0.17, but wouldn't consider 0.14 a problem with these or a certain few other batteries. One of my Reload clones has a triple coil build ohming out at 0.14 and produces the best flavour I've ever had - just drains the batteries too fast to be usable out of the house for long.

Steam Engine rates your .14 ohm coil at 30A and 126 watts on a freshly charged 4.2v lithium cell. I'd consider raising the coil resistance to a safe range or going to an electronic mod with safety devices that shut the vape down if you exceed safe limits. The best 18650 batteries top stop at 30A and that's pushing them hard on a mech. Mechs are unforgiving. You don't want a battery failure.

Play around here and see where you'd be safe.
Ohm's law | Steam Engine | free vaping calculators

 

[Baditude]

Using LG HB6's in a mech I usually go for 0.15-0.17, but wouldn't consider 0.14 a problem with these or a certain few other batteries. One of my Reload clones has a triple coil build ohming out at 0.14 and produces the best flavour I've ever had - just drains the batteries too fast to be usable out of the house for long.

Steam Engine rates your .14 ohm coil at 30A and 126 watts on a freshly charged 4.2v lithium cell. I'd consider raising the coil resistance to a safe range or going to an electronic mod with safety devices that shut the vape down if you exceed safe limits. The best 18650 batteries top stop at 30A and that's pushing them hard on a mech. Mechs are unforgiving. You don't want a battery failure.

I have to agree with DaveP. Your "amp draw" is the same as your "amp limit" with a 30 amp battery using 0.14 ohm resistance. You're pushing your batteries hard, up to their manufacturer's limit. You think that might be why your batteries drain too fast? Is "produces the best flavour I've ever had" worth the risk of pushing a battery to its limit in a mech mod?

Using batteries that hard causes them to age/deteriorate prematurely. As a battery ages/deteriorates, it loses mAh capacity and its current rating. So that 30 amp battery will soon be a 15 amp battery. Are you going to be able to determine when that happens?

Everyone is free to set their own safety parameters. Just try not to end up like this unfortunate fellow. First vape related death

 

[DaveP]

What Baditude said.

That, and you'd probably need to look at a mech that will use 26650 batteries to vape at the levels you described and be safer. Not all 26650 cells will deliver more than 30A. Shop carefully. As MAH rises, amp capacity generally falls. There's a tradeoff for high amperage. 26650 mechs start at prices under $30.

Top 5 26650 Mechanical Mod Clones | Best Vape Deals

Mooch's 26650 battery testing shows some 26650's that will satisfy your needs.
26650 Battery Bench Test Results and New Ratings Table

Be Safe!

 

[Violetti Usva]

I have to agree with DaveP. Your "amp draw" is the same as your "amp limit" with a 30 amp battery using 0.14 ohm resistance. You're pushing your batteries hard, up to their manufacturer's limit. You think that might be why your batteries drain too fast? Is "produces the best flavour I've ever had" worth the risk of pushing a battery to its limit in a mech mod?

I know that is why my batteries drain fast, it's an annoyance I'm currently accepting

Using batteries that hard causes them to age/deteriorate prematurely. As a battery ages/deteriorates, it loses mAh capacity and its current rating. So that 30 amp battery will soon be a 15 amp battery. Are you going to be able to determine when that happens?

Trying to figure out how to determine the loss of current rating is what I've been asking, in an incredibly waffley way I'll admit.

That, and you'd probably need to look at a mech that will use 26650 batteries to vape at the levels you described and be safer. Not all 26650 cells will deliver more than 30A. Shop carefully. As MAH rises, amp capacity generally falls. There's a tradeoff for high amperage. 26650 mechs start at prices under $30

They're so huge that I can't see myself using them - I am looking for a nice 21700 mech though

 

[Baditude]

Trying to figure out how to determine the loss of current rating is what I've been asking

To the best of my knowledge, there is no commercially available device to measure a battery's amp rating.

If I'm not mistaken, Mooch does a calculation based on performance and temperature measurements from his test lab to calculate his amp rating. It's a similar process that the manufacturer uses when they designate their amp rating.

The above battery charger will give a good ball park figure on a battery's capacity. You could use the results of that to estimate the loss in amp rating.

 

[DaveP]

Trying to figure out how to determine the loss of current rating is what I've been asking, in an incredibly waffley way I'll admit.

Batteries are generally good for a year or more if they aren't pushed to the limit. Rotating cells increases usable life. I have batteries that still provide long vape times that are 2 and 3 years old, but I vape at 10W. The more you stress them the quicker they die. High drain and heat are the chief enemies of L-ion cells.

 

[Violetti Usva]

I've started making a spreadsheet so I can graph out my batteries capacities!