Battery question.

[jkmtwo]

I stopped smoking about 6 months ago, I started on a junky gas station kit, that lasted for 2 weeks or so, and then I moved on to the ego t, and since then I havent touched a cig. Recently, I have wanted something with a little more kick, so I purchased the Provari, I love it, but I have just one question. I have read different places that Li-ion bats are ready to be recharged anywhere from 3.5v to 3.8v, is this true? And does this hold for IMR batts as well?

I know this is probably a stupid question, or has been asked a billion times, if you know the answer, feel free to educate me, thanks.

 

[Traver]

Li-ion bats charge to 4.2 volts. Some people only charge them to 3.8 or so because that improves their lifespan. Of course if you only charge them to 80 or 90 percent they won't go as long between charges. They can be recharged any time they are below 4.2 and should not be drained below 3.2.

 

[jkmtwo]

I think I worded that wrong but it looks as though you answered my question lol

 

[jkmtwo]

Oh and thanks

 

[dearme]

I never have figured out how that would save batteries. If you charge them at 3.8, you would have more recharge cycles and I thought battery life was related to the number of cycles. It seems to me you would be lowering the length of life.......although I do this as well, but more for convenience. I always change my batteries in all 3 PVs every day in the afternoon so they have time to totally recharge before I go to bed. I know they are not anywhere close to being at 3.8 as I rotate the PVs all day..........

 

[Rocketman]

I think the cycle life issue is for Li-ion cells charged over 4.10 volts.
Maybe an extra 5% charge gained by charging to 4.20 volts, and life shortened maybe 10%.
Charge to 4.23 volts and cut life by maybe 30%.
Charge to 3.8 volts and you are giving up 30% of the charge and not really improving life.

Life cycle figures are also reduced by hitting the cell with heavy loads (like vaping?). I doubt a vaper will be able to "baby" a Li-ion cell to hit 2000 cycles. If you see 300 cycles consider yourself lucky.

If you are using $10 cells, and a $10 charger you could be wasting a whole dollar (per cell) by charging to 4.20 volts

 

[yzer]

Optimally, the more common 3.7VDC Li-ion batteries (ICR) should be charged to 4.17VDC. Charging higher than 4.20 compromises the lifespan of the battery. The two charger types I have both charge to 4.17V but if the battery is left on the charger for several hours after the charging light turns green the charge voltage may slowly rise, approaching 4.20V. This is due to a float voltage produced by many chargers after the charging light turns green. Built-in circuity of protected Li-ion batteries will trip off to prevent overcharging by cutting off the charge voltage from the charger somewhere around 4.25V or above.

There are some Li-ion battery chargers out there that will charge Li-ion batteries to 4.20V. These chargers cut safety margins a little closer than the 4.17V to please customers who want that last .3V of charge from their batteries and want to see that 4.20V visible on their little DMMs.

The over-discharge protection circuit of a protected Li-ion battery trips at 2.50-2.75V and may prevent the battery from being charged again.

Li-ion batteries may be recharged anytime the battery voltage measures from 2.75 to 4.16 volts without ill-effects. In practice it makes little sense to charge a 3.7V battery if the voltage is higher than 3.8V.

I run protected Li-ion 14650s right down to less than 3.2V on my E-Power 14650. This is the voltage at which the battery fails to fire a LR carto.

IMR batteries are different than the ICR batteries discussed above. IMR batteries have higher drain rates and smaller capacity ratings than ICR. IMR batteries feature "safer" chemistry than ICR but unlike ICR: lack any protection against external short circuits. For longest service life IMR batteries should never be discharged below 3.5V.

 

[dearme]

Gosh, I'm glad I don't worry about battery life. I would drive myself crazy. I'll just stick with my roughly every 24 hours, knowing that I could go another 24 hours if something came up, or my battery charger died. I have 6 AW IMRs 1600mah so I figure I could go almost 2 weeks and still get a new charger in plenty of time if I limited myself to only 1 PV at a time.......LOL

 

[yzer]

Everyone must find a battery solution that suits them best. A few PVs out there require IMR batteries because of high current draw from a limited battery size.

I get 1.5 days from a protected 14650 ICR battery. Since I have a handful of them I only need to charge batteries once a week: on the weekend. I can charge up to five 14650s at a time.

 

[jkmtwo]

Thanks Yzer, you nailed it on the head, I meant to say discharge. I think that the Provari taps out at about 3.3 or so, but a friend of mine said he didn't think that I should wait that long and change out before that, but he is on familiar with non imr batts, and all the info I can find usually doesn't address imrs.

Just the same I have been draining them to about 3.5v and then and then changing them out.

 

[Traver]

If you really want to know about batteries try here.

Lithium-based Batteries Information

 

[WillyB]

.... I run protected Li-ion 14650s right down to less than 3.2V on my E-Power 14650. This is the voltage at which the battery fails to fire a LR carto.

IMR batteries are different than the ICR batteries discussed above. IMR batteries have higher drain rates and smaller capacity ratings than ICR. IMR batteries feature "safer" chemistry than ICR but unlike ICR: lack any protection against external short circuits. For longest service life IMR batteries should never be discharged below 3.5V.

I'll just deal with your last point. That IMRs "lack any protection against external short circuits" is incorrect. Time you did some homework. Unprotected Li-Ions and IMRs are in fact provided with short circuit protection. It's under the positive terminal.

Most commercial, cylindrical lithium-ion cell design are equipped with a positive thermal coefficient (PTC) current limiting switch to provide hazard protection against short circuits external to the cell. This device, shown in Figure 1, is thin annulus consisting of a specially irradiated polyethylene laminated with a metal on both sides [1]. When exposed to an overcurrent situation, this normally conductive polymer heats up and changes phases to become several orders of magnitude more resistive. Once the short is removed, the PTC cools down and returns to its electrically conductive state. This device has been a very effective method of providing reliable short circuit protection in low voltage battery assemblies