JET YCOY
Newly Enlightened
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eneloop longevity
- Thread starter arjay
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arjay
Newly Enlightened
How do you measure internal resistance? Do I need a special device or something?
Random Guy
Enlightened
- Joined
- Jan 28, 2009
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- 205
Resistance is measured in ohms, not volts.
Mr Happy
Flashlight Enthusiast
The readings quoted by WDG would be the initial test voltages reported by the C9000 when you place a battery on charge. This voltage is proportional to the internal resistance of the cell and is a fairly good health indicator.
See above.
arjay
Newly Enlightened
Wow! that got me excited, I'm expecting a c9000 together with the eneloops I ordered which are due to arrive tomorrow. What else can this amazing charger do? recharge my car batteries?
Seems like I need to get my hands on more of those to keep my 180 eneloops happy and healthy(runs out and sells kidney!) 
I recently bought 8 "new" duraloops from a clown on the b/s/t forum. They turned out to be late 2007 manufacture. The capacity is about what WDG stated (1750-1850), but the voltage sag under load is pretty bad. They spend over half of their run time well below 1.2V with a 500mA load.
Comparing voltage to the various published charts, these cells most closely resemble charts for 5A loads rather than 500mA loads. I don't know if age is a factor or they are used/abused cells.
WDG
Enlightened
What he said!
I didn't even know the MH-C9000s gave this kind of information when I first got them. It was from reading through CPF that I discovered it, and how useful it is. Here's a page that gives a good explanation of what the numbers mean: Interpreting Maha MH-C9000 Impedance Check Voltage linked from TakeTheActive's TTA's Picks for Best Answers to Rechargeable Battery Questions
arjay
Newly Enlightened
Thanks for the links! seems like I need to do a lot of readings. I just got my c9000 and batteries today.
Wonder if I should do a capacity test on all of them just to see how consistent these eneloops are. I got 80 AA's and 20 AAA's all with the same production code thus were produced in the same batch. Has anybody performed a test like this with this big of a sample size?
fishinfool
Enlightened
Thanks for the links! seems like I need to do a lot of readings. I just got my c9000 and batteries today.
Wonder if I should do a capacity test on all of them just to see how consistent these eneloops are. I got 80 AA's and 20 AAA's all with the same production code thus were produced in the same batch. Has anybody performed a test like this with this big of a sample size?
If you have the time and/or just want to experiment like I do, then go for it. I have over a hundred eneloops and duraloops (accumulated over 8 months though), all of which I've done break-in's right out of the package, used them, charged, discharged and r/a'd them several times, and they all have produced very consistent numbers.
If you do a capacity test on all of them, I'd love to see the numbers just to compare them to mine. But since you have 100 eneloops I guess we'll see them numbers in about 3 weeks or so.
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arjay
Newly Enlightened
If you do a capacity test on all of them, I'd love to see the numbers just to compare them to mine. But since you have 100 eneloops I guess we'll see them numbers in about 3 weeks or so.
3 weeks? try 3 months. I plan to do discharge>break-in>discharge>break-in on each set to bring them to full capacity. 4days/setx25 =100days
now I can cut that in half if I can get my hands on another c9000 :naughty:
fishinfool
Enlightened
3 weeks? try 3 months. I plan to do discharge>break-in>discharge>break-in on each set to bring them to full capacity. 4days/setx25 =100days
When you mentioned doing a capacity test on all of them, I assumed you were just going to do an R/A but since you've explained it further, I guess we'll see you in 3 months. Just make sure to come up for air every now and then. :naughty: Good luck.
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Apollo Cree
Enlightened
They might call it something different around there. Maybe just a "Marine battery." Maybe someone who supplies parts for boats would have a better idea. A "gel cell" or "unspillable" battery might have some value as well.
You might even be better off with just a regular car battery. Realize that every time you give it a really deep discharge, you're shortening the lifetime. If you size it such that you only discharge it part way during an outage, it might work well enough, especially if you only do the deep discharge on rare occasions when you're really desperate. It will eventually go bad. Replace it when that happens.
If you can't get a good charger, you could just top it off after an outage and rig up some sort of real slow trickle charge circuit and check the water level frequently.
Consider it this way. An AA eneloop gives you about 2 watt hours. A car battery gives you about 500 watt hours. Consider the relative prices and the amount of work involved to charge the batteries.
You may also be able to hook the battery up to a car with jumper cables if you have a long outage and charge it that way.
By the way, be sure to put a fuse right at the battery terminals. Lots of amps, sparks and heat if you have wiring problems.
3 weeks? try 3 months. I plan to do discharge>break-in>discharge>break-in on each set to bring them to full capacity. 4days/setx25 =100days
And I thought my Break-In of 16 (for a TK40 - 1 set in the tube & 1 set ready) was tedious.
At one point I thought I had a close guesstimate of 1 hour into trickle charge at the end of the Maha break in.
tengc82
Newly Enlightened
You can get AW 18650s from Espinelli in Manila. Just behind Bangko Sentral ng Pilipinas (Central Bank of the Philippines). I think those are more reliable if you have good lights from reputable brands that run on dual CR123s. Longer lasting batts and higher power. Pretty good in a blackout. Sorry to hear about the electricity issue in Mindanao. Never knew it was that bad. The electricity in Manila is great although some people say expensive due to rising oil prices.
tengc82
Newly Enlightened
Wow! Nice to know there are Pinoys here in CPF! We should have a meet sometime to discuss our hobby. How many are based in Manila?
Wrend
Enlightened
In a pinch the C9000 will run nicely off of your car's 12VDC too.
I have a bunch of Eneloops and use them in series cell sets so that each cell within each set is always used in the same devices as the other cells within that set and has the same cycle life. I store them charged and just switch them in to a device when the set in it gets low. This way the cells within each set are charged at the same time as each other and have the same state of charged capacity even though they may have been in storage in my work room for a while.
Since getting the C9000, I do a slow discharge at 100mA, then a break in cycle on my new Eneloops (1900mAh for the AAs and 800mAh for the AAAs), then match them for capacity. I check the IR by their voltage measurements on my multimeter after they've been fully charged and rested for a few hours by comparing their "battery test" load voltage with their resting voltage. The MM measures down to 1mV, which is nice.
I also calculated the average capacity test variations of the different ports on my C9000 and use that to calculate even more accurate capacity results for the cells I test in it.
This probably isn't something the average user will want to do, but someone with 100 Eneloops might want to consider it.
My cells generally get used in rotation often enough so that I don't worry about doing extra charge and discharge cycles on them to keep them fresh. But in some devices that I use rarely, I like to do a full discharge and charge cycle on the cells about every 6 months when I think of it.
For general charging I charge the AAAs at 400mA and the AAs at the default 1000mA. I also let them go through the top off charge after the first charging phase is done to help balance them off, leaving them on the charger for a total of about 5 hours.
The nice thing about this kind of precision use, as an example: The 4 AAA Eneloops that I've been using for the last couple months on a daily basis in my TI-89 calculator all have the exact same voltage level down to the mV.
My two year old Eneloops (the oldest ones I have) have only lost about 1.1% of their capacity. They don't have more than about 50 cycles on them and have been used primarily in low drain rate transmitters, but they've been used at up to a 5A drain rate for a few minutes at a time in other devices, and were overcharged and got pretty hot on a dumb charge a few times.
...
Just noticed this thread is kind of old and was resurrected...
I have a bunch of Eneloops and use them in series cell sets so that each cell within each set is always used in the same devices as the other cells within that set and has the same cycle life. I store them charged and just switch them in to a device when the set in it gets low. This way the cells within each set are charged at the same time as each other and have the same state of charged capacity even though they may have been in storage in my work room for a while.
Since getting the C9000, I do a slow discharge at 100mA, then a break in cycle on my new Eneloops (1900mAh for the AAs and 800mAh for the AAAs), then match them for capacity. I check the IR by their voltage measurements on my multimeter after they've been fully charged and rested for a few hours by comparing their "battery test" load voltage with their resting voltage. The MM measures down to 1mV, which is nice.
I also calculated the average capacity test variations of the different ports on my C9000 and use that to calculate even more accurate capacity results for the cells I test in it.
This probably isn't something the average user will want to do, but someone with 100 Eneloops might want to consider it.
My cells generally get used in rotation often enough so that I don't worry about doing extra charge and discharge cycles on them to keep them fresh. But in some devices that I use rarely, I like to do a full discharge and charge cycle on the cells about every 6 months when I think of it.
For general charging I charge the AAAs at 400mA and the AAs at the default 1000mA. I also let them go through the top off charge after the first charging phase is done to help balance them off, leaving them on the charger for a total of about 5 hours.
The nice thing about this kind of precision use, as an example: The 4 AAA Eneloops that I've been using for the last couple months on a daily basis in my TI-89 calculator all have the exact same voltage level down to the mV.
My two year old Eneloops (the oldest ones I have) have only lost about 1.1% of their capacity. They don't have more than about 50 cycles on them and have been used primarily in low drain rate transmitters, but they've been used at up to a 5A drain rate for a few minutes at a time in other devices, and were overcharged and got pretty hot on a dumb charge a few times.
...
Just noticed this thread is kind of old and was resurrected...
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Bolster
Flashlight Enthusiast
...and another resurrection here in 2012. Worthy of it, since the thread documents historical Eneloop performance. I've been using the BI mode on my Maha C9000 to revive my cells and have observed:
2006-vintage Eneloop AAs average 1871 mAh capacity (for 12 cells)
2007-vintage .................................1942 mAh (for 2 cells)
2010-vintage .................................1986 mAh (for 9 cells)
2011-vintage .................................1954 mAh (for 4 cells).
None of these cells stored in refrigerator, and many of them were not sufficiently exercised (I had no Maha to refresh) until now. Many of them were in low-draw applications that would take years to deplete; some were in high-draw flashlights, and many others waiting around in the drawer to be used. So a mix of usages. Without regular R&A or BIM, these cells were not particularly well cared for.
2006-vintage Eneloop AAs average 1871 mAh capacity (for 12 cells)
2007-vintage .................................1942 mAh (for 2 cells)
2010-vintage .................................1986 mAh (for 9 cells)
2011-vintage .................................1954 mAh (for 4 cells).
None of these cells stored in refrigerator, and many of them were not sufficiently exercised (I had no Maha to refresh) until now. Many of them were in low-draw applications that would take years to deplete; some were in high-draw flashlights, and many others waiting around in the drawer to be used. So a mix of usages. Without regular R&A or BIM, these cells were not particularly well cared for.
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HighlanderNorth
Flashlight Enthusiast
What is R&A and BIM?
Shadowww
Banned
Refresh&Analyze (basically discharges & charges battery few times in a row) and Break-In Mode (charges battery at 1/10 of it's capacity for 16 hours, then complete discharge, then fast charge with dV termination)
Bolster
Flashlight Enthusiast
Minor point, but I think the second charge of BIM is also 16 hours. The whole process of a Maha BIM takes something like 39 hours.
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