Old Production Takes From an Old Guy

Rechargeable Batteries: The 1 Year Test

Last year, I wrote a series on rechargeable batteries. I’ve long been a proponent of them, having started using them in wireless mics in 2006. In that series of posts, I did some pretty extensive testing to see exactly how long two modern, NiMh AA batteries would run a Shure UHF-R mic with an SM58 capsule on it (with music played through a wedge to simulate the mic processing audio). I compared the run time to a brand new Duracell ProCell (considered the standard for alkaline–aka disposable–batteries). I expected the NiMh batteries to hold their own against the ProCell, as I’ve had good experience with them for years. What I did not expect is for the ProCells to be completely trounced by the rechargeable cells.

In that test, the best NiMh cells ran for 14 hours before the mic switched off. The ProCell only managed 9.75 hours before going dead. So not only do rechargeable batteries save you a bunch of money, they also run longer than a ProCell (by over 4 hours!). Faced with that clear and decisive victory, many people made the switch. However, some remained unconvinced. “Let’s see how they hold up in a year,” was a comment I heard often. So here we are, one year later. This time, I pulled three sets of NiMh batteries from our regular stock. These are batteries we’ve been using every week for a year. I have no idea how many cycles are on each one, because we have more stock than we actually need. I can tell you we don’t baby them, nor do we abuse them. They’ve always been charged at the soft charge setting (500 mah), and we always pull straight from the charger.

Last time around, I tested two low self-discharge chemistries, the Ansmann Max-E and the Sanyo Eneloop. Neither provided the runtime of the higher capacity NiMh batteries, but they both outlasted the ProCell. As I don’t see any compelling reason to use low self-discharge batteries in wireless mics, I’ve pulled them from our stock and didn’t re-test. I have the charger capacity to always fill mics from the charger and suggest that to everyone. I do use Eneloops at home, however, and they’re fantastic. But let’s get on to the results, shall we?

UPDATE 3/18/11:

It was pointed out that I did not include model numbers for the batteries in question. So here goes: Ansmann 2850 mAh, PowerEx 2700 mAh, Sanyo 2700 mAh. All are NiMh chemistry.

END UPDATE.

Battery Testing Graph

I think this speaks for itself. Click for a larger version

Results

As you can see from the chart, the ProCells once again lost. Big time. This time, we got 8.5 hours out of a fresh set of ProCells, while the worst NiMh battery ran over 12.5 hours. Just as importantly, the “fall off the cliff” point (as indicate by the vertical red lines) is 7 hours for the ProCell and 11.25 hours for all three NiMh batteries. I define “fall off the cliff” as the point where you really should replace the battery as the life declines very rapidly after this point. Interestingly, last year, the Sanyo ran the longest at 14 hours (beating the Ansmann by 45 minutes); this year however, the tables turned and the Ansmann outlasted Sanyo by well over an hour.

It’s also interesting that all three NiMh batteries fall off the cliff at roughly the same point, however the Ansmann lands a little softer, giving you a little more time to get them changed. Now, with that said, quibbling over the last hour of run time in the scope of a total run time of 14 hours is rather academic. And I don’t recommend you push them this far anyway, you’re really asking for trouble after about 8-9 hours with any of them. Again, it’s interesting to note that the Ansmann indicated 3 bars far longer than the rest of them, which is consistent to what we observe each weekend.

In Use

In our use, we battery up the mics around 12:30 on Saturday, and power them off at 6:45 or so. Most of the time, the mics are reading 3 bars, though the Ansmanns tend to be reading 4 at that point. When we use them in our PSM900 IEMs, we rarely see them report less than 4 at the end of the day. Sundays are similar, though the runtime is shorter.

We’ve gotten pretty confident in the run time of these batteries; to the point where we really don’t spend much time thinking about it. Sure, I have Workbench open at FOH and glance over occasionally, but it’s more to make sure they’re all turned on; I rarely consider the battery gauge. For me, that’s a big benefit of using the rechargeable batteries; I just don’t think about them anymore. When I’m at FOH, I’d much rather spend my time thinking about the mix than wondering whether my batteries are going to hold out for one more song (and I’ve been in that boat far too many times with ProCells).

Other Observations

Last time around, I gave the nod to PowerEx batteries as the winner, though I acknowledged the other two as being so close that it really doesn’t matter. A year of use has changed my mind. We have a bunch of all three batteries, but we use the Ansmann more than the others most of the time. This is for a few reasons. First, the Sanyos are bigger than the others and don’t fit well in the UR2s. We have to pull them out, and that’s caused some degradation of the plastic wrap on the outside. Some of them are really coming apart. The PowerEx are also breaking down a little bit, and again are slightly bigger than the Ansmanns. They come out of the mics better than the Sanyos, but the smaller Ansmanns fit the best. Overall, the Ansmann cells are holding up very well, both in charge capacity and physically. We have had two Ansmann batteries short out internally, however. I’m not sure what caused this; the vocalist noticed the mic heating up, so we pulled the cells and found a clear dark line on the top of the cell. This happened twice in the first 6 months of operation, and hasn’t been repeated. We assume we got a few bad cells, because I’ve used at least 150 Ansmann batteries over the years and these are only two to ever go bad.

As I’ve said over and over, we’re saving a ton of money every year on batteries; at least $1,000 and probably more. Given that it cost us less than $300 to get into it, it’s a pretty fair bargain. I expect the batteries to last 5 years before we have to replace them, our savings is pretty significant. It’s also considerably more environmentally friendly to not dump thousands of used AAs in the trash every year. We use them and don’t think about it, which I really like.

I’m not sure how you could remain unconvinced about the effectiveness of rechargeable batteries at this point, but in case you are, we’ll revisit these same cells a year from now and see how they’re doing. Until then, I’m going to find something else to spend that $1,000 on. Maybe some new mics…

34 Comments

  1. pblosser03@gmail.com

    Great posts on the benefits of rechargeable batteries and how long they can last. Even if you do only get one good year out of them, you’re still saving a ton of money.

    Some of our wireless still uses 9v, so I have some of the Powerex 300 NiMh batteries, and ours died after after a year of being used at least twice every week. I didn’t really have any spares, so those were used a lot over that year.

    I have changed most of our AA battery usage over to Eneloops, mainly because we use them for things other than wireless mics (2-way-radios, child-care beepers, etc..) and I wanted to have a standard battery for everything. Some of those non-wireless-mic things work for weeks without needing to change batteries. I haven’t had them for very long, so it will be interesting to see how long those last.

  2. pblosser03@gmail.com

    Great posts on the benefits of rechargeable batteries and how long they can last. Even if you do only get one good year out of them, you’re still saving a ton of money.

    Some of our wireless still uses 9v, so I have some of the Powerex 300 NiMh batteries, and ours died after after a year of being used at least twice every week. I didn’t really have any spares, so those were used a lot over that year.

    I have changed most of our AA battery usage over to Eneloops, mainly because we use them for things other than wireless mics (2-way-radios, child-care beepers, etc..) and I wanted to have a standard battery for everything. Some of those non-wireless-mic things work for weeks without needing to change batteries. I haven’t had them for very long, so it will be interesting to see how long those last.

  3. bivar@haugdal.com

    Hi.

    Do you use the 2100mAh or the 2500mAh version of the Ansmann Max-e batteries?

    I really enjoy your podcasts and your website by the way.

    God bless you.

  4. bivar@haugdal.com

    Hi.

    Do you use the 2100mAh or the 2500mAh version of the Ansmann Max-e batteries?

    I really enjoy your podcasts and your website by the way.

    God bless you.

  5. mike@churchtecharts.org

    Bjørn,
    The Max-e batteries are great cells, but I prefer the higher runtime and capacity of the regular NiMh ones. The 2500 mAh Max-es are new and I’ve not had time to try them yet. However, as we have sufficient charging capacity to always go straight from charger to mic, low self-discharge hasn’t been a need for us.

    I don’t think the 2500 mAh version would be a bad choice, but I prefer the 2850s.
    mike

  6. mike@churchtecharts.org

    Bjørn,
    The Max-e batteries are great cells, but I prefer the higher runtime and capacity of the regular NiMh ones. The 2500 mAh Max-es are new and I’ve not had time to try them yet. However, as we have sufficient charging capacity to always go straight from charger to mic, low self-discharge hasn’t been a need for us.

    I don’t think the 2500 mAh version would be a bad choice, but I prefer the 2850s.
    mike

  7. bivar@haugdal.com

    Thanks Mike.

    I misread your article, thought you used the maxe. Sorry. Thanks for your answer.

    Bjørn Ivar

  8. bivar@haugdal.com

    Thanks Mike.

    I misread your article, thought you used the maxe. Sorry. Thanks for your answer.

    Bjørn Ivar

  9. robalan1@ix.netcom.com

    Thanks so much for doing these tests. I pushed our system onto rechargeables in the early 2000’s (when all our stuff used 9V’s) and have had no regrets, but typically kept quiet about it because most techs I’ve met will scream heresy if they find out you depend on rechargeables for church services. It’s nice to see someone in the real world doing fair testing.

    I was disappointed that the LSD batteries were not included in this follow up. I understand the reason, but it would have been nice because I want to know how LSD chemistry behaves over time compared with the high-capacity type. Many claims and suspicions argue that LSD chemistry offers a longer overall lifespan than traditional cells, but I have never seen proof of this. I do not expect you to redo your intensive testing, but it would have been useful to have included some year-old Eneloops from home with the caveat that they are not in the same usage pattern as the others. That may not be scientific, but I cannot find similar tests elsewhere that include “old” batteries. In fact, I was extremely happy that you tested your old Ansmann 2700’s in your test last year. Virtually everyone tests brand new cells, so it’s hard to know how these things degrade after time and abuse. I suspect that companies are forced to trade lifespan for capacity or other immediate concerns. The new Eneloops are now rated for 1500 recharge cycles, but does this actually improve overall lifespan or is it just a lab result? It’s hard to know.

    You mention that you expect to receive 5 years of service from your batteries, but I doubt this will be possible. My own experience suggests that batteries more than 3 years old start showing weird behaviors and must be tested, matched, and refreshed in a suitable charger to keep them in operation. Regardless of my experiences, however, the 1-year degradation in both the voltage “plateau” and overall capacity indicates that these batteries may barely keep up with Procells after about 3 years. NiMH batteries seem to lose their ability to maintain a high voltage as they degrade and this means fewer bars on your mics after shorter periods of time. Obviously, it’s okay if they “only” match Procells as that’s plenty good enough, but I suspect that your team is going to lose trust in the cells at some point before 5 years are up. I realize that you aren’t going to keep using the batteries to meet some arbitrary deadline, but will replace them whenever you deem necessary, but I’m just saying that 5 years is a long time.

    It’s likely that a routine “refresh” cycle on all of your batteries would be beneficial to measuring and maintaining performance. This only needs to be done once a year or so, IMO. My church doesn’t have a high-tech charger, so I take batteries home to do this. This allows me to catch bad cells before they cause a disruption and to measure capacity trends.

    Thanks again for these excellent tests using real world equipment. Great stuff!!

  10. robalan1@ix.netcom.com

    Thanks so much for doing these tests. I pushed our system onto rechargeables in the early 2000’s (when all our stuff used 9V’s) and have had no regrets, but typically kept quiet about it because most techs I’ve met will scream heresy if they find out you depend on rechargeables for church services. It’s nice to see someone in the real world doing fair testing.

    I was disappointed that the LSD batteries were not included in this follow up. I understand the reason, but it would have been nice because I want to know how LSD chemistry behaves over time compared with the high-capacity type. Many claims and suspicions argue that LSD chemistry offers a longer overall lifespan than traditional cells, but I have never seen proof of this. I do not expect you to redo your intensive testing, but it would have been useful to have included some year-old Eneloops from home with the caveat that they are not in the same usage pattern as the others. That may not be scientific, but I cannot find similar tests elsewhere that include “old” batteries. In fact, I was extremely happy that you tested your old Ansmann 2700’s in your test last year. Virtually everyone tests brand new cells, so it’s hard to know how these things degrade after time and abuse. I suspect that companies are forced to trade lifespan for capacity or other immediate concerns. The new Eneloops are now rated for 1500 recharge cycles, but does this actually improve overall lifespan or is it just a lab result? It’s hard to know.

    You mention that you expect to receive 5 years of service from your batteries, but I doubt this will be possible. My own experience suggests that batteries more than 3 years old start showing weird behaviors and must be tested, matched, and refreshed in a suitable charger to keep them in operation. Regardless of my experiences, however, the 1-year degradation in both the voltage “plateau” and overall capacity indicates that these batteries may barely keep up with Procells after about 3 years. NiMH batteries seem to lose their ability to maintain a high voltage as they degrade and this means fewer bars on your mics after shorter periods of time. Obviously, it’s okay if they “only” match Procells as that’s plenty good enough, but I suspect that your team is going to lose trust in the cells at some point before 5 years are up. I realize that you aren’t going to keep using the batteries to meet some arbitrary deadline, but will replace them whenever you deem necessary, but I’m just saying that 5 years is a long time.

    It’s likely that a routine “refresh” cycle on all of your batteries would be beneficial to measuring and maintaining performance. This only needs to be done once a year or so, IMO. My church doesn’t have a high-tech charger, so I take batteries home to do this. This allows me to catch bad cells before they cause a disruption and to measure capacity trends.

    Thanks again for these excellent tests using real world equipment. Great stuff!!

  11. robalan1@ix.netcom.com

    I trust that your most recent report is the most accurate, but I want to mention that last year you said the Ansmanns were the largest and most difficult to get out and that both the Powerex and Sanyos were “normal” AA sized and easier to remove. These mentions were found at http://www.churchtecharts.org/archives/1716 . After a year you report the opposite and the Powerex and Sanyos are being damaged.

    This “size” issue is very important for this type of equipment as the batteries are exchanged so often. In fact, it seems to have taken many years before the equipment manufacturers have taken this into consideration when designing the gear. Even our most recent wireless system, which is our primary and most trusted headset, requires a knife blade or screwdriver in order to remove the batteries. I assume this is done on purpose so that users can’t knock the batteries out, but they made no accommodation to the folks that have to get them out after each use. However, some brands do better and are easier to work with.

    I’m sure you’re tired of my ranting, but it may be useful to note the exact model of batteries in question when making your charts. This is simple to determine if we look at last year’s test, but if people stumble upon this page in a search engine (like how I found last year’s test) then they may want to know which batteries are being tested. I’ll shut up now. Thanks again.

  12. robalan1@ix.netcom.com

    I trust that your most recent report is the most accurate, but I want to mention that last year you said the Ansmanns were the largest and most difficult to get out and that both the Powerex and Sanyos were “normal” AA sized and easier to remove. These mentions were found at http://www.churchtecharts.org/archives/1716 . After a year you report the opposite and the Powerex and Sanyos are being damaged.

    This “size” issue is very important for this type of equipment as the batteries are exchanged so often. In fact, it seems to have taken many years before the equipment manufacturers have taken this into consideration when designing the gear. Even our most recent wireless system, which is our primary and most trusted headset, requires a knife blade or screwdriver in order to remove the batteries. I assume this is done on purpose so that users can’t knock the batteries out, but they made no accommodation to the folks that have to get them out after each use. However, some brands do better and are easier to work with.

    I’m sure you’re tired of my ranting, but it may be useful to note the exact model of batteries in question when making your charts. This is simple to determine if we look at last year’s test, but if people stumble upon this page in a search engine (like how I found last year’s test) then they may want to know which batteries are being tested. I’ll shut up now. Thanks again.

  13. jlukesalter1@gmail.com

    Hey Mike.

    Once again a brilliant resource to pass around the tech department. Just a quick one…

    How often is your charger powered? Is it on a socket which is powered 24/7/52? Or on a circuit with a break so it’s on when the system is on?

    Cheers

    J Luke

  14. jlukesalter1@gmail.com

    Hey Mike.

    Once again a brilliant resource to pass around the tech department. Just a quick one…

    How often is your charger powered? Is it on a socket which is powered 24/7/52? Or on a circuit with a break so it’s on when the system is on?

    Cheers

    J Luke

  15. mike@churchtecharts.org

    We keep our batteries on charge 24/7. When they’re in trickle charge mode, they use comparatively little power, so we just leave them running.
    mike

  16. mike@churchtecharts.org

    We keep our batteries on charge 24/7. When they’re in trickle charge mode, they use comparatively little power, so we just leave them running.
    mike

  17. blanton-lewis@aminternational.org

    Since Peter B mentioned it, as far as 9v are concerned, we’ve used the LiPo 500mAh batts from Thomas Distributing and they’ve been great.

    Just got some PSM900 so good to know that the NiMH work well in those. I wish the Ansmann charger wasn’t so bulky though. Is that the one you’re using, or the Maha? Or …?

  18. blanton-lewis@aminternational.org

    Since Peter B mentioned it, as far as 9v are concerned, we’ve used the LiPo 500mAh batts from Thomas Distributing and they’ve been great.

    Just got some PSM900 so good to know that the NiMH work well in those. I wish the Ansmann charger wasn’t so bulky though. Is that the one you’re using, or the Maha? Or …?

  19. terryf@bereanbaptist.com

    Hey Mike,

    The Ansmann site has two 2850’s the “MAH” and the “MAH Digital”. What’s the difference. Should I get one over the other?

    Thanks,

    TF

  20. terryf@bereanbaptist.com

    Hey Mike,

    The Ansmann site has two 2850’s the “MAH” and the “MAH Digital”. What’s the difference. Should I get one over the other?

    Thanks,

    TF

  21. terryf@bereanbaptist.com

    ….never mind. Horizon only sells the regular MAH and that’s what you mentioned above. The “regular” ones.

  22. terryf@bereanbaptist.com

    ….never mind. Horizon only sells the regular MAH and that’s what you mentioned above. The “regular” ones.

  23. elishalyx@gmail.com

    hey Mike,

    quick question. my church uses 9Vs in our ULX stuff did you have any experience with rechargeable 9Vs?

    Elisha

  24. elishalyx@gmail.com

    hey Mike,

    quick question. my church uses 9Vs in our ULX stuff did you have any experience with rechargeable 9Vs?

    Elisha

  25. mike@churchtecharts.org

    Elisha,
    Yes, I started off using Ansmann 9V batteries 6 years ago. I’ve used their http://www.horizonbattery.com/rechargeable-batteries/9v-250-mah-rechargeable-batteries-by-ansmann.html“ rel=”nofollow”>250 mAh batteries and 10 station chargers. They work quite well, though the run time is no where near that of the AA batteries. With ULX, you should expect to get 4-5 hours of run time; I would change them after 2 services. Test that theory to be sure.

    I know other people (I’ve not used them myself) who have been having good success with the http://www.thomasdistributing.com/iPOWER-9-Volt-500mAh-Lithium-Polymer-Rechargeable-Batteries_p_275.html“ rel=”nofollow”>iPower Lithium Polymer batteries. They’re a good bit more expensive, but they have double the capacity. From what I hear, the number of charge/discharge cycles is significantly less than the Ansmann. So it all depends on what you value.

    Note too you can’t charge Lithium Polymer batteries with the same chargers you’d use for NiMh batteries (the NiMh chargers will destroy them). So make your choice and stick with a chemistry.

    mike

  26. mike@churchtecharts.org

    Elisha,
    Yes, I started off using Ansmann 9V batteries 6 years ago. I’ve used their http://www.horizonbattery.com/rechargeable-batteries/9v-250-mah-rechargeable-batteries-by-ansmann.html“ rel=”nofollow”>250 mAh batteries and 10 station chargers. They work quite well, though the run time is no where near that of the AA batteries. With ULX, you should expect to get 4-5 hours of run time; I would change them after 2 services. Test that theory to be sure.

    I know other people (I’ve not used them myself) who have been having good success with the http://www.thomasdistributing.com/iPOWER-9-Volt-500mAh-Lithium-Polymer-Rechargeable-Batteries_p_275.html“ rel=”nofollow”>iPower Lithium Polymer batteries. They’re a good bit more expensive, but they have double the capacity. From what I hear, the number of charge/discharge cycles is significantly less than the Ansmann. So it all depends on what you value.

    Note too you can’t charge Lithium Polymer batteries with the same chargers you’d use for NiMh batteries (the NiMh chargers will destroy them). So make your choice and stick with a chemistry.

    mike

  27. mike@churchtecharts.org

    Terry,
    FYI, mAh stands for milli-amp hours; it’s a measure of capacity.

    mike

  28. mike@churchtecharts.org

    Terry,
    FYI, mAh stands for milli-amp hours; it’s a measure of capacity.

    mike

  29. mike@churchtecharts.org

    Ron,
    I went back and re-read that post and indeed note that. It’s odd, because today, the Sanyos are easily the largest in diameter and are very difficult to get in and out of the UR2 transmitters. The PowerEx can be a bit sticky, but the Ansmann, while larger than an alkaline, do slide in and out reasonably well. I have no explanation for this other than to theorize that the PowerEx and Sanyo batteries have swollen slightly due to the charge/discharge cycles.

    As for the overall life of the cells, it will indeed be interesting. When I tested the 2700s last year, they held up quite well, despite being 5 years old. I would use them in a mic without worry (at least for our normal 5-6 hour usage pattern). One thing that has been interesting is to see how the cells hold up, and to develop a pattern of yearly testing. It’s always good to know how long to expect the batteries to run, and what their discharge curves are. By testing them each year, we’ll keep up with that. I’m still optimistic of getting 5 years out of them, but even if we don’t the cost savings are significant.

    mike

  30. mike@churchtecharts.org

    Ron,
    I went back and re-read that post and indeed note that. It’s odd, because today, the Sanyos are easily the largest in diameter and are very difficult to get in and out of the UR2 transmitters. The PowerEx can be a bit sticky, but the Ansmann, while larger than an alkaline, do slide in and out reasonably well. I have no explanation for this other than to theorize that the PowerEx and Sanyo batteries have swollen slightly due to the charge/discharge cycles.

    As for the overall life of the cells, it will indeed be interesting. When I tested the 2700s last year, they held up quite well, despite being 5 years old. I would use them in a mic without worry (at least for our normal 5-6 hour usage pattern). One thing that has been interesting is to see how the cells hold up, and to develop a pattern of yearly testing. It’s always good to know how long to expect the batteries to run, and what their discharge curves are. By testing them each year, we’ll keep up with that. I’m still optimistic of getting 5 years out of them, but even if we don’t the cost savings are significant.

    mike

  31. owenmorgan@proclaimers.com

    do you have any problems with voltage inconsistency leading to strange behaviour with wireless gear?

  32. owenmorgan@proclaimers.com

    do you have any problems with voltage inconsistency leading to strange behaviour with wireless gear?

  33. mike@churchtecharts.org

    Owen,
    We have not seen anything like that. A friend of mine had some issues with an AT handheld, but it turned out to be a bad transmitter. Once it was repaired, everything was fine. What kind of issues are you having?
    mike

  34. mike@churchtecharts.org

    Owen,
    We have not seen anything like that. A friend of mine had some issues with an AT handheld, but it turned out to be a bad transmitter. Once it was repaired, everything was fine. What kind of issues are you having?
    mike

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