Eneloop Pro's going bad

[avihsnis]

nub diving in headfirst; i just ordered my first light on friday, the massdrop aaa cu 219c and was about 2 minutes away from pulling the trigger on the 4x aaa pro + charger kit before deciding to meander over here. think i'll go with the standard eneloops; thanks.

do people mod lights like these with voltage dividers to use with protected li-ion cells or is that a no-go for whatever reason my nubbiness is unaware of ?

 

[knucklegary]

Recently bought 4pk Pro for a Manker E03H arriving soon..
All four dated 06/20 tested at approx 14% right out of package, even tho states fully charged
I charged all to 100% on MiBoxer..
Now after 8hrs rest they test 75% with one cell down to 68%
Is this normal for these pro cells chemistry to lose charge (self discharge) while sitting idle ?
Thanks!

Edit: googled info.. appears all eneloops (NiMH) self discharge at approx 14% at room temperature.
Battery rotation is a must with this chemistry
Asked and answered :huh:

 

[chillinn]

Edit: googled info.. appears all eneloops (NiMH) self discharge at approx 14% at room temperature.
Battery rotation is a must with this chemistry
Asked and answered :huh:

That 14% may just be initially from termination voltage to resting voltage, 1.34V is about 13% lower than 1.54V. CPF user Katherine Alecia opened up an 18yo package of Eneloop AAA and the SoC was 1.3V. I opened up a 4yo package of same and the SoC was 1.32V. But these were standard Eneloop. While my experience is the Pro are a lot more fragile, I expect their LSD properties to be the same as standard.

 

[archimedes]

Are you all talking about capacity, or voltage

 

[ChrisGarrett]

Hi-Caps should discharge more than the standard LSD Eneloop/Fujitsus, but remember, Panasonic/FDK doesn't charge them up to 100% before packaging, but rather 70%-ish.

Chris

 

[knucklegary]

Arch, i was referring to capacity. I don't believe my batch received more than 33% charge from factory

After full at rest they are 1.3v, top off @1.51v charging rate 1a (automatic)

 

[archimedes]

Did you do a complete discharge-recharge-discharge capacity test cycle ?

As you likely know, for NiMH, it is difficult to estimate SoC from OCV.

 

[knucklegary]

You make a good point Arch

My Opus BT C3400 finally said good night irene. It was so troublesome, replacing worn out cooling fan and transformer once, I never replaced it. Thought to go with xtar dragon but never did. I felt these hobbyist chargers with test functions were more a novelty

Anyway, I tossed the Pros back in MiBoxer C4-12 and the bats are holding an even SoC

 

[archimedes]

You make a good point Arch

My Opus BT C3400 finally said good night irene. It was so troublesome, replacing worn out cooling fan and transformer once, I never replaced it. Thought to go with xtar dragon but never did. I felt these hobbyist chargers with test functions were more a novelty

Anyway, I tossed the Pros back in MiBoxer C4-12 and the bats are holding an even SoC

Haven't heard that phrase in a while, lol.

I have a couple XTAR chargers, seem pretty decent to me.

 

[knucklegary]

I own VC2 Plus 2 bay, excellent quality, and great customer service :twothumbs

 

[WalkIntoTheLight]

Arch, i was referring to capacity. I don't believe my batch received more than 33% charge from factory

After full at rest they are 1.3v, top off @1.51v charging rate 1a (automatic)

You can't use voltage to translate to capacity. Doesn't work that way.

You must do a proper full discharge test, using a charger that has a capacity measuring function.

I suspect your Eneloops are fine.

 

[knucklegary]

Yes I understand..

Tho, MiBoxer will measure mAh from state of battery to max full

All the new Pros, out of package, took 2000 mAh to fill-up

One cell a little more than the others but you're correct the eneloops are all fine

 

[WalkIntoTheLight]

Yes I understand..

Tho, MiBoxer will measure mAh from state of battery to max full

All the new Pros, out of package, took 2000 mAh to fill-up

One cell a little more than the others but you're correct the eneloops are all fine

No, you can't measure mAh from current state to full. Especially with NiMH batteries, which become very inefficient to charge near the end of the charge cycle. All you're measuring is how much mAh the charger is using. That tells you very little about how many mAh are actually being stored in the battery.

 

[knucklegary]

Copy that WIL.. it was the low SoC that had me concerned

Is it normal for new Pro NiMH right out of package to self discharge 2000 mAh, that was the question

I noticed how inefficient NiMH is towards end of charging. And can get warm, one cell hit 40c

Edit, early morning grammar I speak backwards

 

[WalkIntoTheLight]

Is it normal for new Pro NiMH right out of package to self discharge 2000 mAh, that was the question

First, Eneloops are not fully charged at the factory. They are packaged at about 75% charged.

Second, how do you know they were discharged 2000mAh? Unless you measured their remaining capacity, and then compared it to a measured full charge-discharge cycle, you can't know. It sounds like you're relying on what the charger puts in, to tell you what the capacity difference is. You can't rely on that, especially for NiMH.

Do you have a charger that measures discharge capacity? Have you tried that on a freshly opened package?

 

[knucklegary]

Dude relax, I am not disagreeing with you!

I think my new eneloops were factory charged much less. MiBoxer measured 2000mAh to full.. which made me think they were about 30%

Regardless, got xtar dragon back ordered from Illumin Supply. I'll play with the eneloops more when I get the charger

Nomo coffee for you!!

 

[archimedes]

I think we're all saying the same thing

 

[chillinn]

No, you can't measure mAh from current state to full. Especially with NiMH batteries, which become very inefficient to charge near the end of the charge cycle. All you're measuring is how much mAh the charger is using. That tells you very little about how many mAh are actually being stored in the battery.

I am going to say there are limits to everything, even this. I know my cells. resting SoC 1.34V, they're fully charged, 1.30V, less so, 1.26V, close to half capacity, 1.2V almost empty. I have seen this enough, I bet someone could map remaining capacity to those SoC's in Eneloop. I have read what you're saying over and over, but my experience is this is easily and academically solved with someone with time and a charger that can discharge the remaining capacity in a cell. I'll bet my bottom dollar remaining capacity maps right to a specific resting voltage. If one cell reads 1.26V and another cell reads the same, I'll bet they have precisely the same capacity remaining. These things are magical, but they aren't magic.

 

[WalkIntoTheLight]

I am going to say there are limits to everything, even this. I know my cells. resting SoC 1.34V, they're fully charged, 1.30V, less so, 1.26V, close to half capacity, 1.2V almost empty. I have seen this enough, I bet someone could map remaining capacity to those SoC's in Eneloop. I have read what you're saying over and over, but my experience is this is easily and academically solved with someone with time and a charger that can discharge the remaining capacity in a cell. I'll bet my bottom dollar remaining capacity maps right to a specific resting voltage. If one cell reads 1.26V and another cell reads the same, I'll bet they have precisely the same capacity remaining. These things are magical, but they aren't magic.

I agree with that, mostly. I think there may be some variation in resting voltage, depending on how hard the cell is drained, even after waiting awhile. But, yeah, Eneloops are pretty consistent. If you know your remaining capacity at a particular voltage, then it is probably very similar with all your Eneloops.

 

[batteryfever111]

Store Eneloop Pro batteries depleted is a good habit?

I see some people mention that they store the Eneloop Pro batteries discharged to prolong their health.
I was doing the opposite, stored them charged up, so I have fully charged batteries when I need them, as chargin up takes another 3h wait.

I have almost all first and second generation eneloop pros degraded. I don't think I used them much, maybe 50 cycles in their life at most.

I have a couple of sets of the latest Eneloop Pro generation, and would like to avoid they go bad while standing still.