Last time, I explained the test parameters, the setup and listed the batteries under test. Go back and read that post if you want to see the test conditions (yes, I had the battery meters set correctly to match the chemistry of the batteries). Today it’s time for the results show. Based on the traffic on Twitter last week, this could be more eagerly anticipated than the American Idol results show. And we’ll get to the results right after the break. I’m kidding. Sit down, Ryan.
So let’s get right to it, since you’ve probably already looked at the graph (can someone figure out a way to reveal a graphic only after the reader has reached a certain point in the post?). The bottom line, the ProCells lost. Big time. In fact, the worst rechargeable battery beat the mighty ProCell by an hour and fifteen minutes. The best rechargeables outlasted the ProCell by three and a quarter hours. Surprised? Actually I am too.
Quite frankly, I’m most surprised at how long all of the batteries ran. I set the test up so I could have audio driving the mics for about seven hours. I figured most of the batteries would be dead by then. Surprise! All but one of the NiMh batteries were still at 4 bars at 7 hours (the MaxE was at 3) and the ProCell was at 1. Since I had to set the stage for our mid-week bible study, I set the mics in our audio storage room and let the test go until the batteries all died. Much to my surprise that last two shut down at a staggering 14 hours! Let’s look at the graphs... By the way, the red line is the point where the mic switched off. Once a data point drops below the line, the mic is no longer transmitting.
I took data points at 15 minute intervals; I figured that would be enough resolution for live work. If you try to cut battery life closer than that, you’re braver than I (or just crazy, not sure...). Based on this graph, a few things are pretty clear. First, any of the batteries are more than capable of safely keeping a mic running for 2-3 church services. Second, there are three tiers of batteries here. The top contenders are the Ansmann 2850, the Sanyo 2700 and the Powerex 2700. The middle ground is occupied by the low self-discharge Eneloop and Max-E; no surprise, they’re rated at 2000 mAh and 2500 mAh respectively. The bottom rung in performance is clearly the ProCell.
Another thing that becomes clear is how different the discharge curves are between chemistries. The Alkaline drops off in a very linear fashion; it looks pretty much like a staircase. The top NiMh batteries drop slightly off full voltage quickly but then stay there for a long, long time before plummeting off the cliff. The low self-discharge batteries are sort of a middle ground. I have a lot more to say about these characteristics, but I’ll wait until Friday.
Since it’s a bit difficult to see how each battery actually performed, let’s take a look at each graph individually, starting with the top batteries, in alphabetical order.
As predicted by Robb MacTavish on Twitter, the PowerEx was a top contender. Though only rated at 2700, it bested the Ansmann 2850 (though 45 minutes is pretty academic). One of the things I like about the PowerEx is that it held at 4 bars for a solid 10 hours! It also took 4 more hours to drop to 0, meaning you have a lot of warning to change out. I would have no qualms about using these in a service, or for three in a row.
The Sanyo actually performed a little better than the PowerEx but since S comes after P, it’s listed second. Like the PowerEx, it held at 4 bars for nearly 11 hours. In fact, the ProCell was dead before the Sanyo dropped below 4 bars. How about that? Again, there was ample warning on the meter before it died. But it’s probably good practice to change them out at 3-4 bars anyway.
I was kind of surprised that the Ansmann didn’t outperform the lower capacity Sanyo and PowerEx. David Shliep of Horizon Batteries advised me that the batteries should be conditioned a few times for maximum capacity. I ran them through 3 cycles on the charger; perhaps they need a few more. Still they held at 4 bars for 8 hours which would be amazing if the Sanyo and PowerEx contenders weren’t in the ring. And 13.25 hours overall is pretty respectable.
Though low self-discharge batteries aren’t really needed for wireless mic use (you should always pull from the charger and back fill the charger), I was curious about how they would hold up. The Max-E dropped off a little more like an alkaline battery, with each stop on the meter getting a little shorter. Holding at 4 bars for 5 hours, and taking another 6 hours to go totally dead, these wouldn’t be a bad choice. But I think there are better (and more cost-effective) solutions here.
I’ll admit it, the Eneloops were my favorite going in; they outperform anything I’ve tried in my DSLR. Their specialty is delivering high current and discharging predictably even under high loads. Though they dropped dead 30 minutes before the Max-E, I would rather have Eneloops in my mics. Why? Because they held at 4 bars for 2 hours longer than the Max-E. You get fair warning when they’re going to go (change them at 3 bars). They held up well considering their capacity is 700 mAh less than the top performers. However, for wireless mics, I’ll stick with the regular Sanyos.
Pulling up the rear is the old standard, the ProCell. If it weren't for every other battery in this test, nearly 10 hours of life would be pretty impressive. In fact, it's about what the UR2 is rated for. But since the top batteries beat it by 4 hours, it's less impressive. The thing the ProCell has going for it is it's very even and predictable discharge curve. And at about 40 cents, it's about 12% the cost of the Sanyo 2700. On the other hand, I'm pretty sure I can get 8 charge cycles out of the Sanyo, after which I'm making money. Also, keep in mind that Cirque du Soleil uses rechargeable batteries (Ansmann 2850s to be exact) because they last longer than alkaline batteries. Guess that makes their audio guys as brave as the performers.
During the testing, I was Twittering throughout the day. While some were interested to see the data, many were not convinced. Some suggested the batteries wouldn’t hold up for more than a few months. So I’m doing two things: First, I’ll be using these batteries in our services and keeping track of them. I’m marking them and will repeat this test with the exact same batteries every six months for the next several years. Second, to shortcut those results, I grabbed a few Ansmann 2700’s that I bought in 2006 for my DSLR.
These batteries have not been treated kindly. I have no idea how many cycles they have on them, but I have used them heavily, then left them in a drawer until they were almost completely dead, charged them at rates higher than recommended, then left them for dead again. To see how old, mistreated batteries would hold up, I threw them in the charger overnight then repeated the test under nearly identical conditions. Here’s what happened.
I had no idea what to expect, but the results surprised me anyway. The voltage drop happened quickly, but then it stayed at 2 bars forever. In fact, I got tired and went home, cutting the test off at 13 hours. The mic was still running at 1 bar. My guess is it would have been dead in another 30 minutes or less so I didn’t mind shutting down the test. Like the previous day, I had 7 hours of music time to drive the audio components. Then we had a school district choir on stage for the final 6 hours, so there was some audio hitting the mic. And it still beat a brand new ProCell. This battery might make me nervous in a wireless mic because it would seem 2 bars wouldn't last long. But that would be an incorrect assumption. It ran for 10 hours at two bars. And I was really nervous, after 4 years of use, I wouldn't mind replacing it.
This post is insanely long, so I’ll save my conclusions for another post. Don’t worry, I have a lot more to say on this matter...
Thanks to our sponsors
I would be remiss if I didn't mention two companies that made this test possible; Horizon Battery and Thomas Distributing. Both sent a variety of batteries and chargers in for the test. I've purchased from both companies in the past and heartily recommend them. David Schliep from Horizon was especially helpful. Also, in the interest of full disclosure and in accordance with new Federal guidelines, I'm required to tell you that Thomas Distributing gave me some batteries and two chargers for this test. That in no way affected the results, or my opinion of the batteries or chargers. I call them like I see them, and I have in the past purchased the same or similar equipment from Thomas.