Rechargeable batteries. Let’s consider the facts.
Are rechargeable batteries a practical solution for the Mobile DJ. Let’s get technical on this.
After spending years going through and trashing 8, 12, 16 batters per wedding. I was admitedly a bit concerned. I was going through an awful lot of batteries especially with my use of my In Ear Monitors and my ceremonies and sometimes even receptions we requiring more and more use of batters. NiCad batteries are simply not good to dispose of. And it seems that there was a lot of money that was going down the drain.
But are rechargeable batteries any good. I remember over the years people complaining about how quickly they would discharge,. That they didn’t stack up to your typical Nickel Cadmium batters you get off the shelf. But I had heard of some batters that worth the look, the Panasonic eneloop pro.
So let’s compare the two. Will the rechargeable battery hold up to long term use? Not only for the need for the day, but after multiple uses over months or years using them.
Are rechargeable batteries a practical solution for the Mobile DJ? Let’s get technical on this.
Specifics and equipment
For this experiment, I am putting in the ring the Duracell ProCell, probably one of the most used batteries in the event space vs the Panasonic eneloop pro. These are batteries that provide about the same milliamp-hour ratings, the Procell at 2500 mAh and the eneloop pro with a minimum of 2450 mAh and a top end of 2550 mAh. These eneloop pros are also about I year old with about 35 charging cycles since I bought them. Some are used a bit unevenly although I do try my best to mix up batteries every chance I get to try to evenly distribute the wear on them.
To charge these batteries I invested in a Tenergy RN162 8-bay charger. This unit allows you to charge Nickel Metal Hydride and Nickel Cadmium batteries. The envelops are Nickel Metal Hydride variants and they are listed as Low Self Discharge” batteries that are ideal for high drain devices like camera flashes, flashlights, and the like.
They are listed to be rechargeable up to 500 times and maintain an 85% charge for one year. Well, we can put that to the test because I now have had my batteries for about one year now. More on that when we get to the numbers.
So in this test, I am going to be using three different devices. The Sennheiser SKM 100 G3 microphone, the Sennheiser SK 100 lav pack, and the Sennheiser EK 300 IEM pack. I am going to do an initial test run of 8 rechargeable batteries to get an initial baseline running for 7 hours. This is the typical runtime one would use, and then I am going to do a six-on-six test. 6 rechargeable batteries in a mic, lav pack, and IEM pack versus the same 3 devices with the ProCell batteries and run them till I start to see batteries in a low battery indicator state.
I am taking measurements with this LIUMY Oscilloscope Multimeter. It’s a great multimeter under $80 that can also test if you are running a pure sine wave, modified sine wave, or square wave from your power sources. This came in real handy with my UPS testing. Kinda handy.
The first run
So one of the first things I am going to do is to check what the stored capacity of the eneloop batteries is. And when I test the batteries out, to my surprise, they are only charged to an average 49-50%. Now I remember that the last time I used them was about two weeks prior so I was a bit surprised that the capacity had drained to half. I honestly expected closer to 60% or more. But I went ahead and charged them, and they capped out at 71-72%.
Now according to Panasonic, the eneloop will hold up to 85% of its charge for up to one year. Calculating total state of charge by this equation:
(v – 1.1) *2
This is a very oversimplified measurement, but it still gives us a pretty decent ballpark of how much battery life one has in their batteries.
So for my first test, I decided to go with all rechargeable. Just to get a baseline load to expect in my comparison test. I decided to charge up my batteries but let them sit for a short while to bring a more typical scenario of charging say the night before. I ran the test for 7 hours, which is 1 hour more than a typical event. The results are pretty much what I have experienced over the years. Nothing fell short during those 7 hours. After taking measurements we started with an average across all batteries of 67.4% and ended with an average of 27.5%.
Rechargeable v. NiCad. FIGHT!
My second run is where I wanted to compete with the ProCell NiCads so I compared a mic, a lav pack, and an IEM running each battery type. When I tested the ProCells I was a little shocked to find they were “overcharged” to 102.2%. NiCads are good in storing energy for a long period so I wasn’t surprised that there was consistency across all measurements out of the box.
This test I ran for 10 hours when I started to see both microphones blink to indicate that a low battery condition existed. And honestly when the dust settled the results were surprising. The first hour of discharge shows a greater drop on the Nicads. As time marched on at the home stretch many of the eneloop pros had slightly higher measurements than their NiCad counterparts.
The one place where the NiCads shows a bit of staying power was the IEM packs. While there is less draw with the unit itself, you could go a bit further with a NiCad and an IEM pack where the rechargeable outperformed all the other batteries by the 9th hour.
The TLDR of this all. The eneloop pros can hang with the NiCads, and even in some cases exceed in long runtimes. What makes it even more interesting is that these are 1-year-old eneloop pros. I am curious what a fresh set of batteries would produce. But we want real-world testing and lets face it, you are buying rechargeable batteries to have them hang around for a bit.
When cost matters
Now onto cost. So when I originally bought my eneloop pros they cost 64.11 for a package of 16. That puts it about 4.00/battery. When I bought a new box of ProCells that cost 20.43 for a package of 48. That puts the batter at under $0.43 per battery. Since once you do the math it takes less than 10 events to get your return on investment. And these ProCells are rated for 500 cycles. So if you truly get 500 cycles out of them the cost difference per batter is $212.81 vs $4.00.
If you are going to own recharges how well do they hold up to the vigors of use? I would put my experience as excellent for the battery itself, but the label casing as a bit of a mixed bag. I have a few that are peeling from the tops but they can simply be removed. The negative is more of the surface is exposed, but in practical terms, it should not be an issue.
I do recommend you get a battery holder just to keep them together. They are pretty inexpensive and adds a level of organization to the whole thing.
Rechargeables FTW: Well at least the eneloop pro
So now that I’ve lived with my rechargeable batteries for a year, what is my conclusion? I did initially question them when I would charge my batteries but then see that I would go from “three bars” to “two bars” pretty quickly. I never ran out of power with them but always wondered what was up. Now I know that the batteries drain pretty quickly when stored, and while I always charged my batteries 1-2 nights before an event now I know that the extra charge would net me about 1 more hour of use from them versus having them sit around for a good while. This is of course with batteries that are used, a fresher set might have a little more capacity to give.
Given the cost savings and the fact that they hold their own against a NiCad, even if you only use them for 1 year of use, it is well worth it. I plan to keep these going till I am getting less than 7 hours of capacity which hopefully will be many more years of use. The eneloop pro gets an enthusiastic thumbs up for me.