Lowest Battery Usage Limit

[Ketsuban]

When I first started getting into APVs, I was using IMR 2500mah 35amp 3.7V batteries. I use similar ones still with the same specs. My boyfriend at the time and my friend both said not to let it get down below 3.7, we were doing unregulated. .2ohms

I just got a new XCube II which does have a battery shutoff point. Is it safe for me to let my battery get down to that point using the cube? I still had about 1/3 of the life when I put them on the charger, with only 3.63V in them and kinda freaked out a little, lol.

 

[93gc40]

Yes it's safe.. You can run a battery down below 3 volts before damaging the battery. Most cut-offs are in the 3.2-3.5 volt range. 1. to keep you from going too low and 2. to keep vapor production from degrading too much.

 

[MorpheusPA]

Seconded! It's fine to use your batteries to the cutoff point (as long as that point is 3.0 volts or above for the most delicate batteries, 2.5 volts for much of what's used today). The battery has enough overhead at 3.2 volts or so to stay off the charger for quite some time as well.

It'll be better for overall battery life to recharge around 3.7 volts, but if you're in a spot where that's inconvenient, don't worry about it. Our batteries are there to serve us, not the other way around--and a "full" discharge in a regulated mod won't harm your battery in the slightest. It just doesn't give you the advantage of extended lifespan past the spec.

 

[tj99959]

Most battery spec sheets will tell you what the minimum voltage is. (Normally 2.9v)

With your old mechanical mod you would think that the performance falls off a cliff at about 3.6v is why your friends suggested what they did.
So their suggestion was about performance than about safety.

 

[Devn]

With regulated mods they have their own chip that thinks for you. Depending on your chip, it will tell you to recharge the batteries at a certain voltage. Some are 3.2v, some are higher at 3.6v. Recharge back up to 4.2v and you're set.

 

[Rossum]

What people tend to forget with these cut-off voltages is that you're looking at "no load" voltages. IMO, what should be looked at is the voltage the battery is capable of producing under load, which will be less. How much less? That depends on the load. Most regulated mods do look at this, so I wouldn't worry about it much when using a regulated mod.

 

[zoiDman]

Good Point Rossum.

Also, how much does one Shorten the Lifespan of a Rechargeable Battery by doing Frequent Deep Discharges?

 

[MorpheusPA]

Good Point Rossum.

Also, how much does one Shorten the Lifespan of a Rechargeable Battery by doing Frequent Deep Discharges?

From the specified life (from the specs of Samsung and LG, anyway), not at all. They're specifically tested under deep discharge conditions to the lowest acceptable voltage. The reported lifespan is generally determined under moderately harsh conditions of midrange discharge, fast charge, and the full stroke of voltage from 4.2 to 2.5 (or whatever the lowest is).

However, you can outperform the spec by being gentle. Slower charging produces less heat, which ages the battery more slowly. Lower discharge rates (which vapers aren't good at!) decrease heat produced and age the battery more slowly.

Discharging the battery to 50% and recharging at that point will, theoretically, quadruple the number of charges you get out of it--overall, doubling cell life--if all else is equal and your usage doesn't outright damage the battery (ours generally doesn't if you have a good battery and know the limits from Mooch's reviews).

 

[Froth]

You'll be fine running them down to 3.6V or even lower honestly, I've run my Samsung 25R's down to cut-off voltage dozens of times(which is around 2.7-2.9V) and they don't seem to mind. Batteries are cheap insurance to me, due to the quantity I purchase and good pricing I pay less than $5 per battery and because of that I bin all of mine at 150 charge cycles regardless of the type of use or perceived amount of useful life left in the battery, honestly it's just not worth the hassle to ensure I'm getting the utmost life and charge cycles out of my batteries when they cost less than a pack of smokes each.

 

[AzPlumber]

Good Point Rossum.

Also, how much does one Shorten the Lifespan of a Rechargeable Battery by doing Frequent Deep Discharges?

You also need to look at lost vape time when short cycling. You will extend the cycle life of a battery with short cycling but will lose vape time with each cycle.

 

[suprtrkr]

Most of my regulated mods have a cutoff point in the 3.4 to 3.5 volt range. I always run them down that low, and have experienced no problems.

 

[Caterpiller]

When I loaded the manufacturer settings provided by Evolv for the Efusion DNA 200, into Escribe, I notice that their battery cut off wa set at about 3.0v.

I changed it to 3.5v as I was more comfortable with this setting.

Does anyone know if Lipo packs general run lower before cut off?

 

[VNeil]

The only hard numbers I've seen on relative recycle life verses discharge amount is here: http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

Table 2 suggests that if you discharge only to 50% you will get 600-750 full charge equivalent cycles, as compared to 300-500 for full discharge (for their tested samples). If you discharge only 25% you should get 500-625 full effective charge cycles.

If you only discharge 10% (frequent topping off) you get about 375-470, or fairly close to the 100% deep discharge life. This all suggests that recharging at about 50% charge remaining will maximize the battery life.

 

[MorpheusPA]

Yeah, as a general rule, shallow discharge is always to your advantage (but it's best to your advantage around 50%).

I always stress that the batteries serve us, not the other way around. Yesterday, I deep discharged. I had to be at the movie theater very early to get a seat for the new Star Wars flick, then went to a family dinner. By the time I got home, my box was flashing at me.

That's fine, no harm done, it's just that this one discharge counts as a full cycle instead of the normal quarter cycle I use when discharging by half.

Most mods also have a cutoff well above the rock bottom, so they're only discharging 80-95% anyway and giving you a small advantage on cycle life.