Old Production Takes From an Old Guy

Extending Rechargeable Battery Life

UPDATE 1-21-13: Having tried turning our chargers on and off out for about 6 months, I’m not convinced it helped us extend the life of our cells. In fact, it may have shortened them. I’ll leave this post online for those interested in the process, and I still think rotating them is a good idea. The timer power strip, however has been put to another use. END UPDATE

Though I’ve been using rechargeable batteries for almost 6 years now, I’m still learning the best way to maximize their life and run time. I am a firm believer in continuing education, and we try to monitor the life of our batteries, look at the data and feed that information back into our systems that get tweaked for better performance. 

As I said in my previous post about batteries, I was a little disappointed in the life I got of my first set of AAs. I don’t blame the manufacturer; I suspect we didn’t use them in a way to maximize their life. So we’ve made a few changes. These changes are based on our usage patterns, so consider them as principles we’re trying, not absolutes to follow.

Rotate

The first thing I did was to establish a rotation pattern for our batteries. We have 32 AAs in stock, and use 12-16 for a normal weekend. However, now that I have a team of volunteers who help set up on Saturday (and this includes getting batteries for the mic’s), I noticed that they would gravitate toward some of the chargers and leave the batteries on the other ones. I suspect this led to some of the batteries being used a lot more often than others. This would explain why I have 12 or so batteries from the original set that still work great, and others that are pretty much done for.

Based on our usage, I designated two chargers (they hold 8 batteries each) as Saturday and two as Sunday. That way, everyone always grabs the batteries out of the right chargers, and we don’t end up using the same ones for the whole weekend. To further randomize the rotation—and because we sometimes have to dip into the other set to accommodate all the mic’s, or because we don’t use them all—when I charge my AAAs for the stand lights, I pull all the AAs out, put them in a box, and randomly put them back in the chargers.

My theory is that this will average out the usage patterns for all the batteries to be roughly equal. While the Saturday on time is a little longer than Sunday, the fact that they get mixed up and put back in different day’s chargers should even that out.

Timing the Charging

My friend Dave Stagl pointed me in this direction; a timed power strip to turn on and off the chargers so they’re not sitting there trickling all week. A the time, it sounded like a good idea. As I’ve done more research, that is confirmed. It seems that NiMh batteries don’t like to be on a trickle charge all the time, as that can lead to over charging, or just lazy batteries. It is recommended to charge them, take them off the charger, then top them off before use. While I could do that, it’s a lot of work—and you know how much I like to automate things.

This power strip, made by GE and available at Amazon or your local home center, costs about $30. It can be programmed for seven days, which would be great if you had a mid-week service or rehearsal that you needed the batteries topped off for.

Enter the timed power strip. By setting the power strip to turn on at 5 PM on Friday and off at 5 PM Sunday, I have fully topped off batteries for the weekend, they fully top off on Sunday afternoon, then rest during the week. Of course it’s too soon to tell how this will extend the life, but based on my research, I’m hopeful.

Keep Refining

In the past, I recommended leaving the batteries on the charger all the time. I’m changing that stance based on new information and experience. This is not back-peddling or being wishy-washy; I’m simply committed to finding better ways to do everything. As new information becomes available, I update my position. I think that’s healthy.

Also, if you’re interested in learning more about rechargeable batteries, I encourage you to check out Battery University. There is a wealth (and I mean a wealth) of information there about battery technology, chemistry, charging, discharging, etc. It’s pretty impressive, really. And a hat tip to reader, Frank Dengel for making me aware of this resource. 

This post is brought to you by Horizon Battery, distributor of Ansmann rechargeable batteries and battery chargers. Used worldwide by Cirque du Soleil and over 25,000 schools, churches, theaters, and broadcast companies. We offer a free rechargeable evaluation for any church desiring to switch to money-saving,  planet-saving rechargeables. Tested and recommended by leading wireless mic manufacturers and tech directors. 

4 Comments

  1. bwebber1@gmail.com

    I am curious what you mean by "top off." I have an Ansmann charger and when you turn it on (or place a battery in it) it just refreshes the battery and re-charges (or so I thought). So wouldnt that actually mess you up because you are actually charging them twice as many times?

    A side note – I have been using the Ansmann batteries and charger for around 6 months now, and It is incredible the performance of the microphones on a rechargeable and is great how much money I have saved doing it.

  2. bwebber1@gmail.com

    I am curious what you mean by "top off." I have an Ansmann charger and when you turn it on (or place a battery in it) it just refreshes the battery and re-charges (or so I thought). So wouldnt that actually mess you up because you are actually charging them twice as many times?

    A side note – I have been using the Ansmann batteries and charger for around 6 months now, and It is incredible the performance of the microphones on a rechargeable and is great how much money I have saved doing it.

  3. dschliep@horizonbattery.com

    Brian – glad to hear the success you're having with the Ansmann charger/batteries.

    If I may respond to the above comment, when you use an Ansmann Energy 8+ or Energy 16 charger, the refresh/reconditioning cycle will address the "lazy" NiMH syndrome that Mike refers to in the above post.

    In our experience, leaving a cell in trickle charge for a few days to a week will not prematurely age the battery or reduce recycles. Over the past decade, we have tried both methods described above – using a timer or just placing the batteries on trickle. Our conclusion was: if you are using a refreshing charger (not simply a charge-discharge) there was no further benefit to stopping the trickle cycle.
    However, I do not recommend using a trickle charge for weeks-on-end.

    You actually bring up a valid point. Using a timer to "top-off" a cell does actually double the # of recycles you place the battery through in a week.

    I believe Mike touched on the most important aspect of battery maintenance — that being rotation. While it's always good to have some spare rechargeables ready to go, it's vitally important to rotate these cells into the mix.

    If I might add one other suggestion – by all means do not try to use a NiMH rechargeable in a similar way you would use an alkaline battery. By that, I mean It's not good to try to "stretch" the # of recycles by using the battery on say, Sunday and then again on Wednesday night. Although the AA's run-times exceed 12+ hours, and it may be possible to use a battery twice in the same week, the strain of the battery operating at lower capacity can produce diminished lifespan. This is probably the #1 cause of shortened life cycles.

    If you are not using a charger that automatically refresh/recondition the cells, then I would suggest running the manual charge/discharge cycle about once a month if you are using the batteries in a typical church setting. (1-3x weekly) A good rule of thumb is about every 8-10 cycles then run a manual charge/discharge cycle. For more information visit our Pro-Audio section and also our blog post on reconditioning battery chargers. Hope this helps!

  4. dschliep@horizonbattery.com

    Brian – glad to hear the success you're having with the Ansmann charger/batteries.

    If I may respond to the above comment, when you use an Ansmann Energy 8+ or Energy 16 charger, the refresh/reconditioning cycle will address the "lazy" NiMH syndrome that Mike refers to in the above post.

    In our experience, leaving a cell in trickle charge for a few days to a week will not prematurely age the battery or reduce recycles. Over the past decade, we have tried both methods described above – using a timer or just placing the batteries on trickle. Our conclusion was: if you are using a refreshing charger (not simply a charge-discharge) there was no further benefit to stopping the trickle cycle.
    However, I do not recommend using a trickle charge for weeks-on-end.

    You actually bring up a valid point. Using a timer to "top-off" a cell does actually double the # of recycles you place the battery through in a week.

    I believe Mike touched on the most important aspect of battery maintenance — that being rotation. While it's always good to have some spare rechargeables ready to go, it's vitally important to rotate these cells into the mix.

    If I might add one other suggestion – by all means do not try to use a NiMH rechargeable in a similar way you would use an alkaline battery. By that, I mean It's not good to try to "stretch" the # of recycles by using the battery on say, Sunday and then again on Wednesday night. Although the AA's run-times exceed 12+ hours, and it may be possible to use a battery twice in the same week, the strain of the battery operating at lower capacity can produce diminished lifespan. This is probably the #1 cause of shortened life cycles.

    If you are not using a charger that automatically refresh/recondition the cells, then I would suggest running the manual charge/discharge cycle about once a month if you are using the batteries in a typical church setting. (1-3x weekly) A good rule of thumb is about every 8-10 cycles then run a manual charge/discharge cycle. For more information visit our Pro-Audio section and also our blog post on reconditioning battery chargers. Hope this helps!

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