Longevity for Eneloop batteries

**psoo** · 09-16-2018, 08:27 AM

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I have been using Eneloop AA rechargeable batteries for my Pentaxes for several years with no problems till recently. After my batteries had become discharged while shooting with my K50, I recharged them with an "Energizer" charger. This is supposed to shut down after the charging is complete. However, it did not shut down and I found that after about half a day the batteries were feeling very warm. I removed the batteries and later put them back into my camera and began more picture taking. I found that the batteries discharged very quickly indicating that they were not fully charged and/or faulty. Is this typical of all rechargeable batteries when they reach end-of-life? Could the charger be faulty? I welcome your comments.

Penview52 · 09-16-2018, 08:50 AM

Rechargeable batteries like Ni MH can attain 1.2 volts when new but this voltage can not be attained after thousands of recharging. Metal fatigue can be the cause why batteries will not charge well no matter how long you charge it. The only way to get the full charge is buy a new batteries.

TonyW · 09-16-2018, 09:41 AM

Originally posted by psoo

I have been using Eneloop AA rechargeable batteries for my Pentaxes for several years with no problems till recently. After my batteries had become discharged while shooting with my K50, I recharged them with an "Energizer" charger. This is supposed to shut down after the charging is complete. However, it did not shut down and I found that after about half a day the batteries were feeling very warm. I removed the batteries and later put them back into my camera and began more picture taking. I found that the batteries discharged very quickly indicating that they were not fully charged and/or faulty. Is this typical of all rechargeable batteries when they reach end-of-life? Could the charger be faulty? I welcome your comments.

They can certainly get quite warm and the fast drain could be down to age, but could also be coupled to the charger.

Perhaps you may wish to consider a better charger, one that allows for a charge discharge cycle- assuming that the Energiser charger is it of that type. It is possible that a full charge discharge cycle may rejuvenate them

I particularly like these from the Maha range
Chargers - 8-Cell Chargers - Maha Energy

Some basic Eneloop info
eneloop Technologies - Panasonic

leekil · 09-16-2018, 09:41 AM

In my experience, the failure case for rechargeable batteries is that the charger indicates an error. I have a PowerEx charger, and it will flash the light by the battery when it can't charge it. I don't know what the similar behavior on an Energizer charger would be. My charger charges each battery individually, so you can tell which one has a problem. Potentially if your charger does not do that, one bad battery in the batch could be preventing any charging form happening?

Not a Number · 09-16-2018, 10:10 AM

How many years is several? Three years or more? I think you've done well and it is probably time to buy a new set. The Maha chargers have a break-in cycle that can often revive batteries that won't charge on lesser chargers. But if the battery it too far gone there is no hope. I have a couple AAAs that are beyond hope.

What kills the batteries mostly is overheating/overcharging and leaving the deeply discharged for periods of time.

Everything you could possibly want to know about Eneloops (and associated chargers):
Eneloop 101 (The #1 Eneloop Guide) with best deals, tests and win free..

E-man · 09-16-2018, 10:47 AM

I have some Eneloops that are well over a decade old that are still going strong. I've always charged them in the Eneloop charger they came with. Interestingly, any non-Eneloop batteries I've tried to charge in the Eneloop charger registered an error with the flashing LED.

As a side note, I've found similar performance with AmazonBasics low self discharge rechargeables. It may be apocryphal, but I've heard it said they're actually Eneloops in disguise.

Penview52 · 09-16-2018, 10:52 AM

The attached info gives the idea why rechargeable batteries deteriorating after many years of use.

Attached Images

C_Jones · 09-16-2018, 02:10 PM - **1 Like**

I have a Centech Digital Multimeter. I test my rechargeable batteries with it. Below is a shortcut to a similar one on EBay. I got mine at Harbor Freight.

Cen-Tech 69096 Digital MultiMeter Electronic Volt Tester Electrical Testing Tool | eBay

Below is another offer for a similar model (less cost).

https://www.ebay.com/itm/CENTECH-7-Function-Digital-Multimeter-Meter-69096-9....c100010.m2109

---------- Post added 09-16-18 at 05:36 PM ----------

Also, a shortcut to a video is below about using the Centech multimeter if you need it. Note that it can also measure DC voltage (setting #20 for small batteries under DCV on dial of meter), and that rechargeable batteries will have different readings than non-rechargeable.

You Tube

**RKKS08** · 09-16-2018, 03:04 PM

In the old days, with a good charger you could leave the batteries for days in the charger. When chargng was complete, such a charger would care for self discharging by occasionally give a short charge impuls.

But now, with normal and low self-discharging batteries, the charger cannot easily distinguish between these two types. Intelligent chargers could occasionally use a longer charging pulse and measure the delta current, but I am not sure whether this is really implemented.
I probably ruined a couple of batteries by leaving them permanently in the charger, after a couple of days they may have got over-loaded.

With normal (not low self-discharging) NMh and in the past with NiCd batteries, this never was a problem.

**Joseph464** · 09-16-2018, 04:59 PM

I use AA Eneloops for my K-r and use an Energizer charger. The batteries take forever to fully charge. They do get warm. It takes so long it's not worth my attention to keep track of the hours, so I charge them overnight. I always have one set in the camera and a backup set in my camera bag. After three years, the batteries show no sign of diminished capacity. I've learned that care has to be taken to make sure all 4 batteries are seeded properly in the charger, and resist pulling them away from the AC current before the green light goes off.

C_Jones · 09-16-2018, 05:22 PM

If I have left my EBL batteries in my charger for several hours and the green light does not show yet I check them with my multimeter, and if they show near full charge I sometimes just stop charging at that point.

Not a Number · 09-16-2018, 07:47 PM

The Maha chargers can distinguish between NiMH, NiCD and other batteries by testing the impedance. According to their FAQ batteries can be left in C9000 charger indefinitely (note: not all chargers have this function):

Quote:

Can I leave batteries in the charger? Does the charger keep the
batteries topped off?

Upon completing the charge, the MH-C9000 goes to a very slow charge
current (less than 10 mA) to keep the battery topped off. This "trickle
charge" stops only when the batteries are removed. It is okay to keep
the batteries in the charger as the batteries will always be ready for
use. However, exercise common sense when keeping appliances constantly
plugged in the wall.

Testing battery voltage without a load doesn't tell you much. A battery with diminished capacity can show a decent voltage but drop drastically as soon as a load is put on it.

**psoo** · 09-16-2018, 07:54 PM

Originally posted by Not a Number

How many years is several? Three years or more? I think you've done well and it is probably time to buy a new set. The Maha chargers have a break-in cycle that can often revive batteries that won't charge on lesser chargers. But if the battery it too far gone there is no hope. I have a couple AAAs that are beyond hope.

What kills the batteries mostly is overheating/overcharging and leaving the deeply discharged for periods of time.

Everything you could possibly want to know about Eneloops (and associated chargers):
Eneloop 101 (The #1 Eneloop Guide) with best deals, tests and win free..

I think that my batteries are about 5 years old. They are often left for months without recharging and when I use them I usually see that they have partly discharged. I guess that the batteries are ready for replacement but maybe the charger is also faulty. I have another charger so I will retire the Energizer and use the other one. Hope this will fix my problem.

**psoo** · 09-17-2018, 08:03 AM

Originally posted by Joseph464

I use AA Eneloops for my K-r and use an Energizer charger. The batteries take forever to fully charge. They do get warm. It takes so long it's not worth my attention to keep track of the hours, so I charge them overnight. I always have one set in the camera and a backup set in my camera bag. After three years, the batteries show no sign of diminished capacity. I've learned that care has to be taken to make sure all 4 batteries are seeded properly in the charger, and resist pulling them away from the AC current before the green light goes off.

Hi Joseph, you operate your batteries and camera just like I do. As I mentioned above, I also used an Energizer charger, and my Eleloops took hours and hours to charge. The batteries also got very warm. I am now using an Enercell charger made in China. I think I purchased it as an inexpensive package with non-Eneloop batteries. This charger does not increase the battery temperature anywhere near that for the Energizer charger. However, it also does not seem to switch off even after charging overnight and I can't tell whether the batteries are fully or partially changed. As far as batteries in general are concerned, the descriptions on the store packages usually state that they can be recharged 1000--2000 times. This must have been estimated from carefully controlled laboratory conditions and not under field conditions where batteries are not ideally treated. I suppose that every few years, one should buy new Eneloops to play it safe.

**RKKS08** · 09-17-2018, 10:03 AM - **1 Like**

Originally posted by Not a Number

The Maha chargers can distinguish between NiMH, NiCD and other batteries by testing the impedance.

Modern IC controlled chargers which handle each cell individually use a sawtooth pulse, measuring delta current and voltage with each pulse. So they can decide when a cell is fully loaded without knowing what kind of cell it is. With a full cycle (discharge+charge) this also gives a picture of the health status of the cell.
Deeply discharged (unresponding) cells would first need a current-limited constant voltage till the cell starts to respond; then (after a pause) the pulse loading may get a try. My chargers cannot do this automatically, but I several times successfully revived cells which the intelligent loader marked as dead, by using an old simple (constant voltage) loader first.

09-16-2018, 10:47 AM	#6
E-man Veteran Member Join Date: Aug 2012 Posts: 678	I have some Eneloops that are well over a decade old that are still going strong. I've always charged them in the Eneloop charger they came with. Interestingly, any non-Eneloop batteries I've tried to charge in the Eneloop charger registered an error with the flashing LED. As a side note, I've found similar performance with AmazonBasics low self discharge rechargeables. It may be apocryphal, but I've heard it said they're actually Eneloops in disguise. Last edited by E-man; 09-16-2018 at 11:00 AM.

09-16-2018, 03:04 PM	#9
RKKS08 Site Supporter Join Date: Mar 2010 Location: Frankfurt am Main Posts: 1,241	In the old days, with a good charger you could leave the batteries for days in the charger. When chargng was complete, such a charger would care for self discharging by occasionally give a short charge impuls. But now, with normal and low self-discharging batteries, the charger cannot easily distinguish between these two types. Intelligent chargers could occasionally use a longer charging pulse and measure the delta current, but I am not sure whether this is really implemented. I probably ruined a couple of batteries by leaving them permanently in the charger, after a couple of days they may have got over-loaded. With normal (not low self-discharging) NMh and in the past with NiCd batteries, this never was a problem. Last edited by RKKS08; 09-16-2018 at 03:05 PM. Reason: Typing

09-16-2018, 07:47 PM	#12
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	The Maha chargers can distinguish between NiMH, NiCD and other batteries by testing the impedance. According to their FAQ batteries can be left in C9000 charger indefinitely (note: not all chargers have this function): Quote: Can I leave batteries in the charger? Does the charger keep the batteries topped off? Upon completing the charge, the MH-C9000 goes to a very slow charge current (less than 10 mA) to keep the battery topped off. This "trickle charge" stops only when the batteries are removed. It is okay to keep the batteries in the charger as the batteries will always be ready for use. However, exercise common sense when keeping appliances constantly plugged in the wall. Testing battery voltage without a load doesn't tell you much. A battery with diminished capacity can show a decent voltage but drop drastically as soon as a load is put on it. Last edited by Not a Number; 09-16-2018 at 08:09 PM.

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09-16-2018, 08:27 AM	#1
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 485	Longevity for Eneloop batteries Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here. I have been using Eneloop AA rechargeable batteries for my Pentaxes for several years with no problems till recently. After my batteries had become discharged while shooting with my K50, I recharged them with an "Energizer" charger. This is supposed to shut down after the charging is complete. However, it did not shut down and I found that after about half a day the batteries were feeling very warm. I removed the batteries and later put them back into my camera and began more picture taking. I found that the batteries discharged very quickly indicating that they were not fully charged and/or faulty. Is this typical of all rechargeable batteries when they reach end-of-life? Could the charger be faulty? I welcome your comments.

09-16-2018, 08:50 AM	#2
Penview52 Veteran Member Join Date: Apr 2017 Photos: Albums Posts: 327	Rechargeable batteries like Ni MH can attain 1.2 volts when new but this voltage can not be attained after thousands of recharging. Metal fatigue can be the cause why batteries will not charge well no matter how long you charge it. The only way to get the full charge is buy a new batteries.

09-16-2018, 09:41 AM	#3
TonyW Veteran Member Join Date: Feb 2016 Posts: 706	Originally posted by psoo I have been using Eneloop AA rechargeable batteries for my Pentaxes for several years with no problems till recently. After my batteries had become discharged while shooting with my K50, I recharged them with an "Energizer" charger. This is supposed to shut down after the charging is complete. However, it did not shut down and I found that after about half a day the batteries were feeling very warm. I removed the batteries and later put them back into my camera and began more picture taking. I found that the batteries discharged very quickly indicating that they were not fully charged and/or faulty. Is this typical of all rechargeable batteries when they reach end-of-life? Could the charger be faulty? I welcome your comments. They can certainly get quite warm and the fast drain could be down to age, but could also be coupled to the charger. Perhaps you may wish to consider a better charger, one that allows for a charge discharge cycle- assuming that the Energiser charger is it of that type. It is possible that a full charge discharge cycle may rejuvenate them I particularly like these from the Maha range Chargers - 8-Cell Chargers - Maha Energy Some basic Eneloop info eneloop Technologies - Panasonic

09-16-2018, 09:41 AM	#4
leekil Pentaxian Join Date: May 2016 Photos: Albums Posts: 2,003	In my experience, the failure case for rechargeable batteries is that the charger indicates an error. I have a PowerEx charger, and it will flash the light by the battery when it can't charge it. I don't know what the similar behavior on an Energizer charger would be. My charger charges each battery individually, so you can tell which one has a problem. Potentially if your charger does not do that, one bad battery in the batch could be preventing any charging form happening?

09-16-2018, 10:10 AM	#5
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	How many years is several? Three years or more? I think you've done well and it is probably time to buy a new set. The Maha chargers have a break-in cycle that can often revive batteries that won't charge on lesser chargers. But if the battery it too far gone there is no hope. I have a couple AAAs that are beyond hope. What kills the batteries mostly is overheating/overcharging and leaving the deeply discharged for periods of time. Everything you could possibly want to know about Eneloops (and associated chargers): Eneloop 101 (The #1 Eneloop Guide) with best deals, tests and win free..

09-16-2018, 10:52 AM	#7
Penview52 Veteran Member Join Date: Apr 2017 Photos: Albums Posts: 327	The attached info gives the idea why rechargeable batteries deteriorating after many years of use. Attached Images

09-16-2018, 04:59 PM	#10
Joseph464 Site Supporter Join Date: Mar 2016 Location: Dartmouth, Nova Scotia, Canada Photos: Gallery \| Albums Posts: 164	I use AA Eneloops for my K-r and use an Energizer charger. The batteries take forever to fully charge. They do get warm. It takes so long it's not worth my attention to keep track of the hours, so I charge them overnight. I always have one set in the camera and a backup set in my camera bag. After three years, the batteries show no sign of diminished capacity. I've learned that care has to be taken to make sure all 4 batteries are seeded properly in the charger, and resist pulling them away from the AC current before the green light goes off.

09-16-2018, 05:22 PM	#11
C_Jones Pentaxian Join Date: Sep 2012 Location: NY Photos: Gallery \| Albums Posts: 6,086	If I have left my EBL batteries in my charger for several hours and the green light does not show yet I check them with my multimeter, and if they show near full charge I sometimes just stop charging at that point.

09-16-2018, 07:54 PM	#13
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 485 Original Poster	Originally posted by Not a Number How many years is several? Three years or more? I think you've done well and it is probably time to buy a new set. The Maha chargers have a break-in cycle that can often revive batteries that won't charge on lesser chargers. But if the battery it too far gone there is no hope. I have a couple AAAs that are beyond hope. What kills the batteries mostly is overheating/overcharging and leaving the deeply discharged for periods of time. Everything you could possibly want to know about Eneloops (and associated chargers): Eneloop 101 (The #1 Eneloop Guide) with best deals, tests and win free.. I think that my batteries are about 5 years old. They are often left for months without recharging and when I use them I usually see that they have partly discharged. I guess that the batteries are ready for replacement but maybe the charger is also faulty. I have another charger so I will retire the Energizer and use the other one. Hope this will fix my problem.

09-17-2018, 08:03 AM	#14
psoo Site Supporter Join Date: Jan 2012 Location: Long Island, NY Posts: 485 Original Poster	Originally posted by Joseph464 I use AA Eneloops for my K-r and use an Energizer charger. The batteries take forever to fully charge. They do get warm. It takes so long it's not worth my attention to keep track of the hours, so I charge them overnight. I always have one set in the camera and a backup set in my camera bag. After three years, the batteries show no sign of diminished capacity. I've learned that care has to be taken to make sure all 4 batteries are seeded properly in the charger, and resist pulling them away from the AC current before the green light goes off. Hi Joseph, you operate your batteries and camera just like I do. As I mentioned above, I also used an Energizer charger, and my Eleloops took hours and hours to charge. The batteries also got very warm. I am now using an Enercell charger made in China. I think I purchased it as an inexpensive package with non-Eneloop batteries. This charger does not increase the battery temperature anywhere near that for the Energizer charger. However, it also does not seem to switch off even after charging overnight and I can't tell whether the batteries are fully or partially changed. As far as batteries in general are concerned, the descriptions on the store packages usually state that they can be recharged 1000--2000 times. This must have been estimated from carefully controlled laboratory conditions and not under field conditions where batteries are not ideally treated. I suppose that every few years, one should buy new Eneloops to play it safe.

09-17-2018, 10:03 AM - 1 Like	#15
RKKS08 Site Supporter Join Date: Mar 2010 Location: Frankfurt am Main Posts: 1,241	Originally posted by Not a Number The Maha chargers can distinguish between NiMH, NiCD and other batteries by testing the impedance. Modern IC controlled chargers which handle each cell individually use a sawtooth pulse, measuring delta current and voltage with each pulse. So they can decide when a cell is fully loaded without knowing what kind of cell it is. With a full cycle (discharge+charge) this also gives a picture of the health status of the cell. Deeply discharged (unresponding) cells would first need a current-limited constant voltage till the cell starts to respond; then (after a pause) the pulse loading may get a try. My chargers cannot do this automatically, but I several times successfully revived cells which the intelligent loader marked as dead, by using an old simple (constant voltage) loader first.