Best charge rate for 30Q Battery?

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Joshk
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Best charge rate for 30Q Battery?

I’ve been charging my Samsung INR18650-30Q at 1.0 amps. It might be time for a new habit. What rate do you charge your 30Q at?

techieman33
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I charge mine at 1 amp because that’s as high as my charger will go. You should be safe at 2 – 3 amps. I can’t find the spec for the 30q off hand but the LG HG2 is supposed to max at 4 amps, and the Sony VCT6 at 5 amps. Charging at the higher amperages can decrease the battery life, so it’s probably not worth it to charger higher than 1 – 2 amps unless you really need that battery charged right that second.

Joshk
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Thanks techieman33. So you agree I can push them more.
If someone could explain the C stuff and how it relates to charge speed, that would be great.
I also think I found the spec sheet that says 1.5 amp standard, 4 amp max.

atbglenn
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I charge all my 18650’s at 1 amp. 26650’s at 2 amps

sac02
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Joshk wrote:
… If someone could explain the C stuff and how it relates to charge speed, that would be great …

C-rates are relative to the capacity of the battery, where 1C=the capacity of the battery.

  • For a 3000mAh 30Q, 1C = 3A, 2C=6A, 0.5C=1.5A, etc.
  • For a 2500mAh 25R, 1C = 2.5A, 2C=5A, 0.5C=1.25A, etc.
  • For a 12000mAh LiPo, 1C=12A, 2C=24A, or 25C=300A (LiPo can do these high Amps)

Honestly I have no f’ing clue why this system exists. It sure seems a LOT easier to just state charge/discharge rates directly in Amps, instead of this convoluted C-rate system.

Speed4goal
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I charge between .5-1 amp I usually have enough spares don’t need to charge at 2 amps. If I’m hard on my batteries during discharge I don’t see the need to run them hard while charging. Its easier on the battery. Better life cycles. The rated life is usually at the worse conditions. Like 4 amp charge and 20 amp discharge 250-300 cycles to 70% you can extend by staying around a amp or less charging.

I read something on xstars website or somewhere they are on how their 26650s have 500 cycle life. But if you charge them at .25 amps it increases up to 750 life cycle

Jerommel
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sac02 wrote:
Joshk wrote:
… If someone could explain the C stuff and how it relates to charge speed, that would be great …

C-rates are relative to the capacity of the battery, where 1C=the capacity of the battery.

  • For a 3000mAh 30Q, 1C = 3A, 2C=6A, 0.5C=1.5A, etc.
  • For a 2500mAh 25R, 1C = 2.5A, 2C=5A, 0.5C=1.25A, etc.
  • For a 12000mAh LiPo, 1C=12A, 2C=24A, or 25C=300A (LiPo can do these high Amps)

Honestly I have no f’ing clue why this system exists. It sure seems a LOT easier to just state charge/discharge rates directly in Amps, instead of this convoluted C-rate system.


+1

It’s stupid.

[edit]
Hmmm… actually it does make sense, because you can parallel cells with the same C regardless of their capacity.

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EasyB
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From the 30Q datasheet: 1.5A is the standard charge, and 4A is the rapid charge rate.
https://www.imrbatteries.com/content/samsung_30Q.pdf

The C-rating system makes sense for Li ion batteries (and many other battery types) because, for a given chemistry, a cell’s discharge (and charge) rate capability is roughly proportional to its capacity. This is because as capacity is increased the surface area of the electrode is increased which leads to lower internal resistance and more rate capability. For example, with two Li ion cells of the same type, one 100mAh capacity and the other 5000mAh, you know they will have similar characteristics (like amount of voltage sag) at the same C-rating. If the max discharge rate for this chemistry is, say, 10C, the small cell can discharge at 1A and the big cell can discharge at 50A.

kiriba-ru
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Please dont forget that most known high-amp cells were made for power tools, that have 30-45 minutes fast chargers (charge current 1.5-2.0C). I have some 13Q cells from 8-10 years old tool batteries, they were discharged with 8-10Amp load and charged with 4Amp (3C) several hundred times (300-500 full cycles) and half of this cells still have about 1000mAh capacity.
Charging with high current is similar to discharging with high current, if cell has big internal resistance it will get hot and degrade fast, but if you use brand high-discharge rate cell you can easy charge them with half of declared continious discharge rate and this rate will be still safety IMO.

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EasyB
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kiriba-ru wrote:
Please dont forget that most known high-amp cells were made for power tools, that have 30-45 minutes fast chargers (charge current 1.5-2.0C). I have some 13Q cells from 8-10 years old tool batteries, they were discharged with 8-10Amp load and charged with 4Amp (3C) several hundred times (300-500 full cycles) and half of this cells still have about 1000mAh capacity. Charging with high current is similar to discharging with high current, if cell has big internal resistance it will get hot and degrade fast, but if you use brand high-discharge rate cell you can easy charge them with half of declared continious discharge rate and this rate will be still safety IMO.

For some cells high charge rates very quickly degrade capacity (like to 65% in 100 cycles). It is not just the heat produced by the IR; Li ions cannot intercalate into the graphite anode quickly enough during charge and end up plating instead. Cells like the Sanyo GA and Samsung 35E are particularly susceptible to this.

Some explanation and cycle life testing here:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=68556&sid=2a46a50...

ven
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All my cells are at 1a if 18650, some when charging 2 at a time are done at 1.5a(usually vape cells in pairs).

Generally
26650@2a
18650@1a sometimes 1.5a
16650@1a
18350 and 16340@0.5a
14500@0.5a
10440@0.3a
10180@0.1a

Eneloops
AA@1a
AAA@0.5a

leaftye
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18650’s at 500mA. That’s what most of my chargers default to. I almost always plan ahead and have the time to allow 500mA to complete, and going to a faster charging current only has downsides. Occasionally I do have a reason to charge a large number of batteries more quickly, and when using all my chargers isn’t enough, I’ll kick the current up to 1C where possible. I have about a dozen chargers for lithium ion batteries, and can charge close to 50 cylindrical cells simultaneously, not counting using hobby chargers.

Eneloop/Duraloop AA’s at 700mA on my LaCrosse that can’t go any higher, and 1A on others. AAA’s are charged at 200 or 300mA.

The low mode should be lower.

Reviews: Efan IMR18350 700mAh 10.5A, <a href="http://

bella-headlight
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To be perfectly honest good quality Li-ions are so cheap I am not that interested in pampering them to get a few extra cycles out of them.
Having said that my most used chargers (Lii-500“s) charge at max 1A per cell & I have an XSTAR SV2 Rocket that charges 2 cells at 2A so my 18650“s tend to get 1A & my 26650“s 2A if only charging 2 cells or if I want 4 × 26650“s charged at once they will go into 2 x Lii-500“s at 1A per cell.
I may well get another Rocket if a good deal comes up so that I can charge 4 × 26650“s at 2A each Smile

Ian

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leaftye wrote:
18650’s at 500mA. That’s what most of my chargers default to.

But they default to this irrespective of if it’s a 3400 mah 18650 or a 700 mah AAA … I don’t think it’s any indication of the best charge rate for a given battery …

Personally I consider 1C to be a happy medium between reasonable charge times / battery life and learnt this way before getting onto torches from flying RC Planes / drones with Lipo’s for many years

Joshk
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Thanks to everyone, I’ve read it all and appreciate it Smile I think 1.5 amp is my new overnight setting, with the balls to set it to 3 amp if I am in a hurry. Since I am often just topping them off I expect it would only be at 3 amp for a short time before CV mode kicks in. And I agree, I would rather enjoy using them than charge slowly for a few more life cycles at their EOL.

leaftye
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Witterings wrote:
leaftye wrote:
18650’s at 500mA. That’s what most of my chargers default to.

But they default to this irrespective of if it’s a 3400 mah 18650 or a 700 mah AAA … I don’t think it’s any indication of the best charge rate for a given battery …

Personally I consider 1C to be a happy medium between reasonable charge times / battery life and learnt this way before getting onto torches from flying RC Planes / drones with Lipo’s for many years

Yes, that is the default. For AAA’s and smaller lithium ion batteries, I lower the current, and really because I don’t trust the stability of these smaller sizes, particularly smaller lithium ion batteries due to issues I’ve had with 14500’s in the past. My best charge rate is the easy charge rate. Ideally my chargers would have programmable defaults so I could dedicate them to certain cells, so I have to take more time on smaller batteries. Almost every time I throw a battery on the charger, charging faster has no benefits for me, and slight negatives. When I absolutely need to charge quickly, and none of my other hundreds of 18650’s are charged sufficiently, I crank up the current even if it means increased battery wear.

The low mode should be lower.

Reviews: Efan IMR18350 700mAh 10.5A, <a href="http://

hellokittyhk
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I charge my batteries as I need em so i charge at 2C or higher.

dekozn
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I charge 18650’s at 1A, 0.5A takes to long for me to stay around the charger although I have some old cells I do charge at 0.5A but I find it annoying. With my opus I charge em at 700mA when I got the time for it. I find it a nice compromise.

Pete7874
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Based on the specs, it looks like charging the 30Q cells at 2 Amp shouldn’t be much of an issue, maybe at the expense of very slightly diminished life/capacity.

If I ever acquire a faster charger, I won’t hesitate to charge them at 2A. For now I’m stuck at 1A.

rizky_p
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i charge mine regularly at 2A i dont mind losing life cycle they are cheap anyways but 3A when i am in hurry, i tried 4A but the cells got rather hot.
I could charge up to 8A (30Q max charging is 4A based on spec) and charge 8 18650(4S2P) at the same time if i want to but 3A is warm enough for the batteries and i dont usually need charging that fast.

Charging @4A as 4s pack.

Jon-LiionWholesale
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Doing battery testing here we charge 30Q’s at 3A and over a handful of charges haven’t seen degradation. Of course over the long term you’ll see a little bit more degradation.

Samsung publishes that charging the entire battery at 4A you get 98% of the capacity that you get charging at 1.5A.

All of Samsung’s cycle life testing is done with charging at 4A so I can’t imagine it causes that huge of a difference in long term cycle life because if it did they’d probably want to publish cycle life with more normal charges.

At the same time, if you have time to charge at a lower charge rate it can never hurt.

rizky_p
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that is good to know, but the heat generated @4A charging 30Q rather disconcerting though.

Jon-LiionWholesale wrote:
Doing battery testing here we charge 30Q’s at 3A and over a handful of charges haven’t seen degradation. Of course over the long term you’ll see a little bit more degradation.

Samsung publishes that charging the entire battery at 4A you get 98% of the capacity that you get charging at 1.5A.

All of Samsung’s cycle life testing is done with charging at 4A so I can’t imagine it causes that huge of a difference in long term cycle life because if it did they’d probably want to publish cycle life with more normal charges.

At the same time, if you have time to charge at a lower charge rate it can never hurt.

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I normally just charge my 18650s and 26650s at 500mA. I’m rarely in any type of rush so I just throw them on the charger earlier in the day if I know I’m going to want fully charged batteries that night. I also figure that it’s easier on both the batteries and the charger. So, when I do charge at 1A or higher it feels super fast to me.

Litefighter
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SoCalTiger wrote:
I normally just charge my 18650s and 26650s at 500mA.

Ditto for me and overnight charging while rotating cells.

snakebite
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especially since they will age out before we wear them out.
that said i also charge all 18650 at 1a and 26650 at 2a.
i have plenty of spares so no rush.

bella-headlight wrote:
To be perfectly honest good quality Li-ions are so cheap I am not that interested in pampering them to get a few extra cycles out of them.
Having said that my most used chargers (Lii-500“s) charge at max 1A per cell & I have an XSTAR SV2 Rocket that charges 2 cells at 2A so my 18650“s tend to get 1A & my 26650“s 2A if only charging 2 cells or if I want 4 × 26650“s charged at once they will go into 2 x Lii-500“s at 1A per cell.
I may well get another Rocket if a good deal comes up so that I can charge 4 × 26650“s at 2A each Smile
ssschen
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Bought my very first batch of 30Q batteries. Put them on the LiitoKala Lii-500 for "NOR Test", more than 6 hours later, they are all terminated on between 3.6 and 3.8V, when I was expecting them to terminate close to 4.2V. Just want to make sure this is not normal???

Pete7874
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If the “End” display is blinking, then they are still charging back up. And if so, what you’re seeing is the current charging voltage, not final. Once the “End” display stops blinking, this will be an indication that the re-charging has finished and you should see voltage close to 4.22.

yuhsin91123
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I have SC4 charger and my 30Q charged up to 4.20 evenly.

ssschen
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Pete7874 wrote:
If the “End” display is blinking, then they are still charging back up. And if so, what you’re seeing is the current charging voltage, not final. Once the “End” display stops blinking, this will be an indication that the re-charging has finished and you should see voltage close to 4.22.

I didn’t realise the “End” blinking display means it has not finished. Crappppppppppp! Now I got to do it all over again. Back in the charger all of them go. Facepalm

Pete7874
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ssschen wrote:
Pete7874 wrote:
If the “End” display is blinking, then they are still charging back up. And if so, what you’re seeing is the current charging voltage, not final. Once the “End” display stops blinking, this will be an indication that the re-charging has finished and you should see voltage close to 4.22.

I didn’t realise the “End” blinking display means it has not finished. Crappppppppppp! Now I got to do it all over again. Back in the charger all of them go. Facepalm


But you already got your result (capacity), so all you need to do is just top them off at this point. No need to run the whole NOR Test again.
FreeMagenta
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For an example how different charge/discharge currents can affect battery life, look here: https://batteryworkshop.msfc.nasa.gov/presentations/Perf_Safe_Test_Panas...

Unfortunately it isn’t for 30Qs but gives a rough image how does it look .

I keep my cells around 3,90V and charge with 0.5A if I can plan in advance. If a fast charge is reqired, I use 2 amps. In extreme situations I can charge with 4Afrom hobby charger.

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