Eneloop voltage question.

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Steve P.
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Eneloop voltage question.

Hi everybody! I've been a lurker since last Summer, but decided to join last week.

I tried the search feature but couldn't find an answer to my question. What should my voltage be hot off the charger? How long does it take for the voltage to "settle down" after being pulled off the charger and what should that voltage be?

Also, can somebody list the voltages say from full charge down to what would be considered empty? I'm used to dealing with 18650's.

Thanks!

Steve P.

 

 

 

T.H.Cone
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Well, Steve, While I use Eneloops myself, all I know is the battery says 1.2 volts and that an alkaline should be 1.5 volts.  Both facts I'm sure you are aware of.  What you might not be aware of is the fact that I am the Welcoming Committee, so welcome to BLF!  All kidding aside, one of the really smart guys will be here in a minute to answer your question.

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Don't be confused, my Username has been changed from "Cone" to "T.H.Cone".  I'm still the same clown.

JohnnyBravo
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Hi and Welcome Steve P.  I'm somewhat new here as well.  I bought quite a few 10 packs of AA and AAA of the newer (1500 cycle) versions at Costco recently.  Just $19.99 for a 10 pack w/ plastic storage cases too!  I usually get around 1.44 volts right off the charger.  Then maybe a day or few days later, they seem to settle down to around 1.37 or so.  Hope that helps Bro!  PS.  I usually notice diminished quality around 1.10-1.15 volts, so that's when I charge them up again.

"Better to have it and not need it; than to need it and not have it." and, "I have more than I need, but not as many as I want."

scaru
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First of all welcome to BLF. My charger generally terminates charge right around the 1.45 mark but depending on the battery this can vary. After a few days they generally will be around 1.38 for me. 

 

Here a graph of eneloop discharge is at different rates. (Credit to Silverfox over at the other forum)

Different lights will pull different amounts of current but most of mine will pull somewhere between 1 and 3 amps so I will focus on the 2 amp discharge. For that one it started at approximately 1.37 volts and then by the end of its discharge was down to .9 volts. 

Hope this helps but I'm sure someone more experienced will jump in. :)-->HKJ

BetweenRides
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Hello and Welcome to BLF, Steve!

Confirming above. Usually AA's charge to right around 1.449 almost every time. Settle in to around 1.39-1.41 after a week or so.

Steve P.
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Thanks for the quick reply and the warm welcome! It sounds like my cells are terminating properly. I'm using the Sony BCG-34HLD charger I picked up based on the test in the charger forum and it seems to work great on all 4 channels. Soooo....when my cells reach .9 to 1.0 volts I should consider them empty? Sounds good to me. I just picked up an Eagle Tac P20 A2 MII as a backup to my Eagle Tac T20 C2 MII. I carry both of them when I'm on my bassboat. I got it for 49 bucks shipped. Normally 65 bucks.

Cone, I'm in south Jersey right now! I'm doing some inspection work at the Hope Creek Nuclear plant......

 

 

scaru
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Yep. However I would recommend not running them down that far because as I understand that shortens the batteries life. (cycles not mah) However considering they're rated for 1500 cycles if you recharge them once a week they would last 28 years. (1500/52) So you probably don't need to worry. Wow I just disproved myself. Wink Nice lights btw. Smile

Steve P.
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Scaru,

I was really surprised at how little difference there is between the P20 and the T20. The P20 is an XPG-R5 at 300 emitter lumens and the T20 is an XML-T6 at 720 emitter lumens. They're almost the same. When I get home, I need to go test them out because I get the feeling that the P20 might out throw the T20. The T20 is realistically good out to maybe 75 yards, regardless of what Eagle Tac claims. It suits my needs tho because I need a flooder at the boat ramp. If I want to "reach out and touch somebody" I get out my Solarforce 2X18650 with the Masterpiece 1 R2 thrower head on it. That thing must throw a good 300 to 350 yards, but I haven't done any scientific testing. Later!

T.H.Cone
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Steve P. wrote:

Cone, I'm in south Jersey right now! I'm doing some inspection work at the Hope Creek Nuclear plant...... 

Really?  You're not a diver, are you?

fidem, prae caeteris omnibus praeter honestatem

 

 

Don't be confused, my Username has been changed from "Cone" to "T.H.Cone".  I'm still the same clown.

Steve P.
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Nope, are you working there?

T.H.Cone
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No, but I do work around power plants and other similar infrastructure, You know, fun places that require FR coveralls, dialectric boots, TWIC cards, and other fun stuff depending on the day.

fidem, prae caeteris omnibus praeter honestatem

 

 

Don't be confused, my Username has been changed from "Cone" to "T.H.Cone".  I'm still the same clown.

fishinfool
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Aloha and welcome to BLF Steve P.!

Don wrote:

"But as I said long ago, you are more likely to be killed by a dead fish dropped by a seagull in the Sahara Desert than by a lithium ion

HKJ
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Here is a charge curve for a eneloop, the terminates is around 1.53 volt, but it drops to 1.45 volt in a short time.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

kreisler
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HKJ, you got the i4 V2 charger!!?

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HKJ
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kreisler wrote:
HKJ, you got the i4 V2 charger!!?

Yes and I am nearly finished with testing. Generally I does fine on LiIon, but I wonder about the termination on NiMH, it does not look like -dv/dt.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

BetweenRides
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Thanks, HKJ, always fascinating to see your graphs. I was charging a few AAA eneloops overnight anyway, so thought I'd post readings off my dmm:

1.502 - off the charger
1.495 - 5 minutes
1.490 - 10 minutes
1.488 - 15 minutes
1.485 - 20 minutes
1.482 - 25 minutes
1.480 - 30 minutes
1.475 - 45 minutes

Steve P.
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Now I'm clear on termination voltage and where it settles down to. Also, .9 volts is considered "EMPTY", correct? What is the suggested voltage reading where I say, hey, I need to charge these things? I guess I'm asking what's the minimum voltage I should normally run these down to?
scaru
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Yeah .9 volts should be considered empty. 

scaru wrote:

Yep. However I would recommend not running them down that far because as I understand that shortens the batteries life. (cycles not mah) However considering they're rated for 1500 cycles if you recharge them once a week they would last 28 years. (1500/52) So you probably don't need to worry. Wow I just disproved myself. Wink Nice lights btw. Smile

raccoon city
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Welcome to BLF, Steve P.

kreisler
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anyone feel free to correct me if smarta$$ me talks bull$hit but here's my take anyway...

Steve P. wrote:
Now I'm clear on termination voltage and where it settles down to. Also, .9 volts is considered "EMPTY", correct? What is the suggested voltage reading where I say, hey, I need to charge these things? I guess I'm asking what's the minimum voltage I should normally run these down to?

For example we're talking of Eneloops 800mAh AAA: then the very lowest you can get (e.g. after 850mAh discharged capacity) UNDER LOAD is 0.8V (~0.81-0.82V, typically it's more like 0.83V).

this is UNDER LOAD.

let this Eneloop cell rest for 2 3 hours, or 23 hours or whatever. the voltage will recover (but the cell is still empty of course!) to, say, 1.10V minimum. This voltage is called "resting voltage", "voltage at rest", or i call it "offline voltage (at rest)". Believe me, you will NEVER find an Eneloop at rest, which has your quoted "0.9V". At rest, the Eneloop (if it is 100.1% depleted) will have at least 1.10V.

What does the C9000 do? It discharges (slowly) down to 0.9000V (cell is maybe 95% empty by then) and then let it rest for 1 or 2 hours. during that time (e.g. the 2.0 hours) the cell recovers to 1.2000V (pretty much exact this number). In other words, a NiMH cell with 1.20V resting voltage is considered "empty" by the C9000. The truth is, it's possible to quench out even more capacity (with electronic gadgets or flashlights with superlow current draw) such that the resting voltage approaches the 1.10V. If you do this hardcore overdischarging too often, you probably hurt the Eneloop cell in some way ("aging") although i cant confirm this because Eneloop cells tolerate all kinds of abuse.

*If* you do find Eneloops at rest which show 0.80 or 0.90V on your DMM, then your DMM is either is kaput, or i will call you a liar haha or your the first Eneloop owner in the world who managed to produce such a resting voltage state, world-premiere!! (the probability that your Eneloop cell is broken and that be the reason why you get such an otherwise impossible DMM reading is practically zero because Eneloops are robust in many respects.)

In summary, if you know that your Eneloop cells are okay (not broken), then at discharged state (e.g. up to 850mAh discharged for Eneloop AAA) and at rest, you will never see 0.8, 0.9 or 1.0V. Never. 1.10V is the lowest you could measure. More typical voltages are between 1.16 and 1.20V; if your DMM reads 1.20V (at rest) or lower, then it's time (and not too late yet! Smile ) to recharge the cell.

hope this helpz.

 

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Vieplis
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kreisler wrote:

...at rest, you will never see 0.8, 0.9 or 1.0V.

I think this is bullshit. I don't have any eneloops, but it is just a NiMH cell; I have measured 0.9 or so on a NiMH cell.

Imagine you measure your empty 1.1V cell every day; the voltage eventually will go to 0V. Gradually. 

kreisler
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Vieplis wrote:
I think this is bullshit. I don't have any eneloops, but it is just a NiMH cell; I have measured 0.9 or so on a NiMH cell.

Imagine you measure your empty 1.1V cell every day; the voltage eventually will go to 0V. Gradually. 

thanks for your opinion Wink

ive been doing EXTENSIVE runtime testing on Eneloops on Hi, Med, and Lo. More than anybody else on cpf or blf, believe me. When a 800mAh Eneloop AAA is TOTALLY depleted (99.x%) say in Moonlight mode and you take it off the charger, the cell shows 0.8xV (e.g. 0.82V) and it would recover very slowly to 1.1xV (e.g. 1.14V) within 24 hours.

Well, we're talking about practical situations: i dont know what happens with the resting voltage of the original Sanyo Eneloop (t = 0.1sec, V(t) = 0.83V; t = 1day, V(t) = 1.14V) if you let it rest even longer, say t = 5 yrs, V(t) = ?.??V.

I own super expensive NiMH LSD cells (Varta LSD, 4€ apiece AAA), and they show a TOTALLY DIFFERENT discharge behavior and other behavior which means that Eneloops are indeed VERY SPECIAL cells in every regard.

Probably true, after 5 or 15 yrs the Eneloop cell (if stored at depleted state) is dead. kaput. and it then eventually has to cross the 0.9V mark haha.

In any case if nobody else did as much extensive testing of Eneloop cells in their depleted (and totally depleted) state, then my word be da truth until someone comes up with youtube video proving the opposite.. Silly

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Vieplis
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(I think it would not be years). Just add a little discharge, less than your moonlight mode. If you can get the cell from 1.2V to 1.1V, you can also get it to 1.0 or 0.9 or 0.8, just use less current. You could even connect the cell to a stable 0.8V, then disconnect a week later. I think it would stay at 0.8V then.

The cell should not be dead, if discharged to 0V. Polarity reversal is what kills them.

 

kreisler
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good info, thanks!!

 

i dont have much knowledge about batteries but i did much observing of my Eneloop cells and since the OP was asking about practical info or typical situations, i was able to give helpful info. Typically, people do *not* discharge their cells further than after dimming has begun (~0.90V under load; the C9000 cut off mark) and even less people do runtime tests on Lo, super Lo or Moonlight modes, especially not on their expensive Eneloop cells. The 3rd gen Eneloops keep their charge even longer and that makes this discussion harder because any normal user who buys them (to use them of course!, for normal purposes!! and not testing runtimes on Moonlight mode) would not measure resting voltages below 1.15V.

Eneloops are very special, that's all i wanted to convey. Wink

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What type of voltmeter does the OP have?  Before joining BLF, I'd just check my batteries using the dedicated battery test function of my $5 HarborFreight meter (link), which @ 370milliOhms, should be 4.0mA for 1.5V and 25mA for 9V batteries.  Example, new alkalines start at 4.3mA, and I charge my LSDs to 4.0mA;  MiniMaglite Incans stop working at 3.6mA; my wireless mouse can further drain them to 2.8mA, which is when I consider them dead.  I used to just leave my batteries(rayovac hybrid LSD) in the smart charger (rayovac PS3) for 5-6 hrs, but after joining BLF, I've been measuring voltages more often, stopping my charge at 1.42v/4.0mA at 2hrs.  Without a Maha or LaCrosse hobby charger, I've never needed to measure volts and I didn't see anyone here mentioning such methods. 

HKJ's post12 graph show that LSD will plateau at ~1.42V for 4-5hrs?  while still charging and increasing the capacity(mAh) linearly up until the last (5th) hour in his charger?  Since the termination voltage on that graph is actually a range of 1.45-1.53V, So does this mean I cannot use Voltage alone in my decision to stop charging the LSD?  In my example, going by HKJ's graph, stopping my charge at 2hrs/1.42v/4.0mA my LSD could have only 1/3 capacity?  I thought capacity and voltage was a pretty straightforward linear relationship until HKJ's graph and all this talk made me question my methods.  Question is relevant only to people who don't have a Maha or LaCrosse hobby chargers, like OP and myself.  Smile

HKJ
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AAx3 wrote:
HKJ's post12 graph show that LSD will plateau at ~1.42V for 4-5hrs?  while still charging and increasing the capacity(mAh) linearly up until the last (5th) hour in his charger?  Since the termination voltage on that graph is actually a range of 1.45-1.53V, So does this mean I cannot use Voltage alone in my decision to stop charging the LSD?  In my example, going by HKJ's graph, stopping my charge at 2hrs/1.42v/4.0mA my LSD could have only 1/3 capacity?  I thought capacity and voltage was a pretty straightforward linear relationship until HKJ's graph and all this talk made me question my methods.  Question is relevant only to people who don't have a Maha or LaCrosse hobby chargers, like OP and myself.  :)

NiMH and NiCD requires a special termination method, and cannot be stopped on voltage alone.

Here you have a correct charge curve from the old SysMax charger (V1):

The "pulses" in the curve is has nothing to do with it, but is because my measuring time interval matches the chargers pulsing.

Look at the voltage curve, it peeks and then starts to drop. When it starts to drop is the correct time to stop charging, but it only has to drop a few mV! The method is called -dv/dt.

Any smart charger uses this algorithm, but often supplements with a absolute voltage and a temperature backup.

Another way to charge is to use a low current (1/10 marked capacity) for 12 to 16 hours, this works fine if the battery is empty.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Steve P.
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AAx3 wrote:

What type of voltmeter does the OP have?  Before joining BLF, I'd just check my batteries using the dedicated battery test function of my $5 HarborFreight meter (link), which @ 370milliOhms, should be 4.0mA for 1.5V and 25mA for 9V batteries.  Example, new alkalines start at 4.3mA, and I charge my LSDs to 4.0mA;  MiniMaglite Incans stop working at 3.6mA; my wireless mouse can further drain them to 2.8mA, which is when I consider them dead.  I used to just leave my batteries(rayovac hybrid LSD) in the smart charger (rayovac PS3) for 5-6 hrs, but after joining BLF, I've been measuring voltages more often, stopping my charge at 1.42v/4.0mA at 2hrs.  Without a Maha or LaCrosse hobby charger, I've never needed to measure volts and I didn't see anyone here mentioning such methods. 

HKJ's post12 graph show that LSD will plateau at ~1.42V for 4-5hrs?  while still charging and increasing the capacity(mAh) linearly up until the last (5th) hour in his charger?  Since the termination voltage on that graph is actually a range of 1.45-1.53V, So does this mean I cannot use Voltage alone in my decision to stop charging the LSD?  In my example, going by HKJ's graph, stopping my charge at 2hrs/1.42v/4.0mA my LSD could have only 1/3 capacity?  I thought capacity and voltage was a pretty straightforward linear relationship until HKJ's graph and all this talk made me question my methods.  Question is relevant only to people who don't have a Maha or LaCrosse hobby chargers, like OP and myself.  Smile

 

http://www.service.kleintools.com/Tools/PRD/Category/Multimeters%20TESTE...

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Wow I forgot about the bounce ...That's the way they know when batteries are fully charged .. The voltage rises and then it drops off when the battery is full .... the charger senses this and stops charging .

a battery bounce

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Exactly. That is when one know"s the "top off" is done. When batt reaches highest voltage (during top off stage) and then drops.

Keith

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Vieplis wrote:

kreisler wrote:

...at rest, you will never see 0.8, 0.9 or 1.0V.

 I don't have any eneloops, but

Get some Eneloops and come back. My Eneloops behave as kreisler stated,

Keith

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budynabuick wrote:

SHEESH

Get some Eneloops and come back. My Eneloops behave as kreisler stated,

Keith

lol Keith

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