Old Production Takes From an Old Guy

Rechargeable Batteries: Year 2


Battery-graph-1-year-later.jpg

These were the results of the 1-year test.

OK, the title of this post might be a little misleading. I had actually indented to do multi-year tests to see how the rechargeable batteries in heavy rotation would hold up over the years. However, the answer is this; not quite as well as I had hoped. In fact, we got about 22 months out of the batteries before they were not performing to level that I was comfortable with. To be fair, some of the batteries are still going strong, but others have thrown in the towel. So I’ve replaced my entire stock.

And right away, all the naysayers will jump in and say, “Ha! I told you rechargeables were a bad idea!” Not so fast, cowboy. I’ll come back to that in a minute; first let me lay out the timeline. 

In January of 2010, I started buying chargers and batteries. By March, we had switched over completely to rechargeable batteries, which is also when I did my first round of tests. Those batteries were used every weekend and at mid-week, and as a group, performed exceptionally well. We did have one or two cells go bad, and those were replaced. Those cells got us through Easter, Christmas, and another Easter, not to mention outside events and other special services. 

Last fall, I started noticing that some of the cells began to drop off in capacity. I never had a mic die during a service, but I started seeing them drop down lower than I was comfortable with. Some batteries would end the second service on Sunday at 1 bar, which I didn’t like. I marked those batteries, tried re-conditioning them, but eventually decided that it was time to replace them. So in late November, I ordered a new set of 32 batteries and retired the old ones. 

Now, let’s do some math. We used the original batteries for about 22 months. We used to go through approximately 36 ProCells a week between weekends and mid-week. So here’s how it breaks down:

22 Months = 95 Weekends/Mid-Week (weeks)

95 Weeks x 36 batteries/week = 3,420 Batteries (if we used ProCells)

3,420 batteries x $0.32/ea = $1,094.40

So, if we had stuck with ProCells, we would have used roughly $1,000 worth of disposable batteries in that time frame. When I bought new batteries in November, I spent about $120 including shipping. Now it’s true I do have a few hundred dollars in charger cost, plus the original set of batteries. But on the high side, I’ve spent less than $500 on everything including chargers in the last 2 years. And now that the chargers are paid for, I can plan on about $120 in new batteries every two budget years.

But wait, there’s more! We also use AAA powered LED music stand lights every week. We have about a dozen of them in rotation, and we typically use about 6 on any given weekend. Those take 3 AAAs apiece. I also switched those over to rechargeable batteries about the same time. Only with those, I use low self-discharge (Ansmann Max-E) batteries so they don’t need to live on the charger all week. Let’s do some more math.

6 Stand Lights/week x 3 AAAs x 95 weeks = 1,710 AAA batteries

1,710 AAAs x $0.39 = $666.90 (I knew disposables were evil!)

Now there’s another $550 or so in savings (I have about $100 in Max-E AAAs). And those batteries are still going strong. I found that I can get about 3 weekends worth of service from those batteries in those lights. So, every three weeks, I pull my AAs out of the chargers, and charge up the AAAs. It takes about 10 minutes of my time, and we save $500/year. Not too bad. 

And this doesn’t count the community room, which I’ve also switched to rechargeable batteries. There is an event using a wireless mic over there almost every day, and they are on the same set of batteries they’ve had for nearly two years. Because the event times are shorter, a decrease in run time hasn’t been as big of a deal. Still, I may have to drop another $25 and get a new set of 8 AAs over there in the next month or so.

Earlier I mentioned that the performance was dropping off past where I was comfortable. I’m often asked, “When do you replace the rechargeable batteries?” The answer for me is, when I’m not comfortable any more. If I start seeing the cells drop down below 2 bars regularly after a service (when they used to hold at 4), it’s time to swap them out. Basically I’m replacing my rechargeable batteries when their weekly performance drops just below the level of a ProCell. 

How long that takes for you will depend on how you use them. I know people who use them far more often than I do, who will have to replace them more often, but when you do the math, you still come out way ahead.

Remember, those ProCells were going in the trash when they got down to 2-3 bars. With a rechargeable, you throw it on the charger. So it still works out. 

If you’re still on the fence, I encourage you to do the math. Figure out what you are really using now, and what the payback is. I can almost guarantee you the result will be savings when you switch. And we already know that rechargeables in good condition will outlast ProCells anyway by 30-50% and at end of life they are still on par; so there is really nothing to loose.

Next week, I’ll share my current strategies for (hopefully) lengthening the life of my rechargeable batteries.

Have you made the switch yet? If so, what is your experience? If not, what are you waiting for?

Today’s post is brought to you by Elite Core Audio. Elite Core Audio features a premium USA built 16 channel personal monitor mixing system built for the rigors of the road. For Personal Mixing Systems, Snakes, and Cases, visit Elite Core Audio.

12 Comments

  1. cmcglynn@colonialchurch.org

    MIke,

    We made the switch about a year and half ago. AA's for Shure IEM's and 9V for Shure ULXP's. I have been using the 9V without any trouble. However, I have been trading them out after each service for a level of comfort. The AA's for IEM's deteriorated faster because we were transmitting at high power for the first year and have since lowered the power level and increase the run time on a single charge.

    So far I have been very happy and not having to think about battery stock is huge deal for me since my job is not just in Tech Arts. These batteries are worthwhile investment that every church should consider. And the guys at Horizon Battery are the only place one should buy from. Ansmann's are the way to go!

    -Charlie

  2. cmcglynn@colonialchurch.org

    MIke,

    We made the switch about a year and half ago. AA's for Shure IEM's and 9V for Shure ULXP's. I have been using the 9V without any trouble. However, I have been trading them out after each service for a level of comfort. The AA's for IEM's deteriorated faster because we were transmitting at high power for the first year and have since lowered the power level and increase the run time on a single charge.

    So far I have been very happy and not having to think about battery stock is huge deal for me since my job is not just in Tech Arts. These batteries are worthwhile investment that every church should consider. And the guys at Horizon Battery are the only place one should buy from. Ansmann's are the way to go!

    -Charlie

  3. jliechty200@gmail.com

    We switched to Ansmann rechargeable AAs when we switched to Sennheiser EW 300 G3 wireless last summer. Before that, we were wireless-less, and before that – before the 700 MHz cutoff date – we had these totally top-shelf awesome Nady units that ran forever on super-affordable 9V batteries (sorry, I'll stop before I slay myself with sarcasm).

    With only three mics, our battery needs are limited, so I rotate through six out of a pool of twelve batteries each week. So far, the batteries have been very reliable. I'm still unsure of what the best policy is for running the reconditioning cycle on the charger. Should the refreshing only be done when the batteries start feeling weak, or would it make good preventative maintenance if done at a regular interval?

  4. jliechty200@gmail.com

    We switched to Ansmann rechargeable AAs when we switched to Sennheiser EW 300 G3 wireless last summer. Before that, we were wireless-less, and before that – before the 700 MHz cutoff date – we had these totally top-shelf awesome Nady units that ran forever on super-affordable 9V batteries (sorry, I'll stop before I slay myself with sarcasm).

    With only three mics, our battery needs are limited, so I rotate through six out of a pool of twelve batteries each week. So far, the batteries have been very reliable. I'm still unsure of what the best policy is for running the reconditioning cycle on the charger. Should the refreshing only be done when the batteries start feeling weak, or would it make good preventative maintenance if done at a regular interval?

  5. Mark

    Great post. You make a really good case and this issue comes up for us about every 12 months (budget time).
    We tried this a few years ago as we had 6 AAA-powered Samson wireless mics, 2 AA powered Sennheiser EW100 lavs, and various 9V packs for instruments. The biggest problems we had were with process and people, not technology.
    * When NiMH batteries died during some event during the week, people would just throw them away. (interestingly, they seem compelled to leave discharged disposables laying where they fall 🙂 )
    * When people finished using mics, they would "forget" to put batteries back on the charger so they were dead when needed next
    Any tips on how to keep all the users on the same page with regard to battery care and feeding?

  6. frank.dengel@gmx.net

    Hi Mike,

    Thanks for your post!
    I want to share the experiences we have made at our church here in Germany.

    Back in 2007 we purchased new Sennheiser EW 500 G2 wireless systems and equipped them in 2008 with Sanyo Eneloop AA's.

    My personal hobby are RC cars and RC models, so I had a lot of experience with rechargeable batteries, how to treat them and how to get the most out of them 🙂
    So I did a lot of testing with the Eneloop's when we started using them in our wireless systems.

    First I used a computerized power supply to measure the power consumption of the transmitters according to their voltage levels (1,5 volt of a fully charged rechargeable down to 0,9 of an empty one) and their switch off voltage (which was happily 0,9 volt, which is also the lowest point you should discharge a NiMH battery to).

    Second test was to find out, at which voltage levels the transmitter battery meter changes bars.

    The third test I did with my computer controlled charger. I discharged the Eneloop's at the given mA rate by the transmitter I figured out in test 1. With the discharge curve I then could pretty accurate determine the possible hours of use and how long the transmitter will run on each bar of the battery meter.
    To sum it up, it ran about 11 hours in our configuration, which was more than enough for two Sunday morning services.

    For recharging we use a small 4 bay charger/discharger with display. We don't leave the Eneloops in the charger for various reasons.

    First one, NiMH batteries usually don't have the so called memory effect, but still can get lazy over time. Because of the different chemistry compared to NiCD batteries they absolutely don't like overcharging. Which happens if they stay in the charger the whole time.
    This will cost you lifetime.
    Second reason is, that Eneloops really have no big self discharge. That means they can be stored for one, two or four weeks and there is no big difference in capacity compared to a fresh charged one.

    We now used the Eneloops for four years and there is no measurable loss in capacity.
    I measure them on a yearly basis in my computer charger to see, if the charge and discharge curve vary over time, to find defect or bad ones.
    The sorted out ones will then be used in our translation receivers, which also use AA, and only run in one service.

    For all who want to know more about rechargeables and how to handle them right to get a long lifetime, see http://batteryuniversity.com

    For me, the only difficulty in using rechargeables is the non linear batter meter of the transmitter. Only a few manufacturer have rechargeable capable meters.
    But one the other hand it's very difficult to set a battery meter to the discharge curve of a rechargeable. Maybe the only correct way would be to measure the mAh that have been used in relation to the total mAh of the battery used…

    So far my two cents…
    If you want to know more, let me know…

  7. frank.dengel@gmx.net

    Hi Mike,

    Thanks for your post!
    I want to share the experiences we have made at our church here in Germany.

    Back in 2007 we purchased new Sennheiser EW 500 G2 wireless systems and equipped them in 2008 with Sanyo Eneloop AA's.

    My personal hobby are RC cars and RC models, so I had a lot of experience with rechargeable batteries, how to treat them and how to get the most out of them 🙂
    So I did a lot of testing with the Eneloop's when we started using them in our wireless systems.

    First I used a computerized power supply to measure the power consumption of the transmitters according to their voltage levels (1,5 volt of a fully charged rechargeable down to 0,9 of an empty one) and their switch off voltage (which was happily 0,9 volt, which is also the lowest point you should discharge a NiMH battery to).

    Second test was to find out, at which voltage levels the transmitter battery meter changes bars.

    The third test I did with my computer controlled charger. I discharged the Eneloop's at the given mA rate by the transmitter I figured out in test 1. With the discharge curve I then could pretty accurate determine the possible hours of use and how long the transmitter will run on each bar of the battery meter.
    To sum it up, it ran about 11 hours in our configuration, which was more than enough for two Sunday morning services.

    For recharging we use a small 4 bay charger/discharger with display. We don't leave the Eneloops in the charger for various reasons.

    First one, NiMH batteries usually don't have the so called memory effect, but still can get lazy over time. Because of the different chemistry compared to NiCD batteries they absolutely don't like overcharging. Which happens if they stay in the charger the whole time.
    This will cost you lifetime.
    Second reason is, that Eneloops really have no big self discharge. That means they can be stored for one, two or four weeks and there is no big difference in capacity compared to a fresh charged one.

    We now used the Eneloops for four years and there is no measurable loss in capacity.
    I measure them on a yearly basis in my computer charger to see, if the charge and discharge curve vary over time, to find defect or bad ones.
    The sorted out ones will then be used in our translation receivers, which also use AA, and only run in one service.

    For all who want to know more about rechargeables and how to handle them right to get a long lifetime, see http://batteryuniversity.com

    For me, the only difficulty in using rechargeables is the non linear batter meter of the transmitter. Only a few manufacturer have rechargeable capable meters.
    But one the other hand it's very difficult to set a battery meter to the discharge curve of a rechargeable. Maybe the only correct way would be to measure the mAh that have been used in relation to the total mAh of the battery used…

    So far my two cents…
    If you want to know more, let me know…

  8. Chris Wyllie

    Hey Mike,

    I was on the fence until I read through this. We only have 4 handheld Sennheiser's and I wasn't sure it'd really be worth it for us. Thanks for helping!

  9. Simmomar@yahoo.com

    Great write up! Thanks for picking up where you left off in 2010 trending over time how this played out for you. We went to rechargeables a few weeks ago with our wireless pickups and monitors. I pushed for them sheerly out of a desire to be steward like about waste and the environment, regardless of long term cost implications. But already we are seeing the return on the investment. I can get through 3 1/2 hours of rehearsal on Thursday and still have enough for 1 hour on Sunday morning. If you have a worship band, please encourage them to pursue rechargeables. It can help reduce our costs, and it better serves the Lord to use His resources wisely. Peace and thanks.

  10. Simmomar@yahoo.com

    Great write up! Thanks for picking up where you left off in 2010 trending over time how this played out for you. We went to rechargeables a few weeks ago with our wireless pickups and monitors. I pushed for them sheerly out of a desire to be steward like about waste and the environment, regardless of long term cost implications. But already we are seeing the return on the investment. I can get through 3 1/2 hours of rehearsal on Thursday and still have enough for 1 hour on Sunday morning. If you have a worship band, please encourage them to pursue rechargeables. It can help reduce our costs, and it better serves the Lord to use His resources wisely. Peace and thanks.

  11. mike@churchtecharts.org

    Thanks, Mark. Rechargeable batters are a great way to save money, save the planet and lower your stress level. I'm completely sold on them. You still have to keep an eye on the battery level meter, but generally speaking, we get plenty of run time out of them now.

    mike

  12. mike@churchtecharts.org

    Thanks, Mark. Rechargeable batters are a great way to save money, save the planet and lower your stress level. I'm completely sold on them. You still have to keep an eye on the battery level meter, but generally speaking, we get plenty of run time out of them now.

    mike

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