I've never watch Heroes. I hear it's a great series, and I recall the catch phrase from the early episodes—"Save the cheerleader, save the world." I have no idea what that means, but I have a great suggestion for you to not only save your church some serious coin, but also save the planet. Interested? Check out rechargeable batteries.
Now if you've been around this electronics thing for any length of time, you probably have bad experiences with rechargeable batteries. Ten years ago, they had very low voltage (compared to their alkaline counterparts), and didn't last long. Some devices, especially wireless mics, wouldn't even run on them. Well, that was then, this is now.
I was motivated to check out rechargeables last year when I was going over the budget I inherited from the previous Tech Director. It was a great budget, but I was stunned when I saw we were planning on spending over $2,500 on batteries for the year. $2,500! On batteries! Are you kidding? Nope, I did the math and sure enough, at our current rate of use, that's pretty close to where we were.
I did some research and came across Horizon Battery. They claimed to have put their batteries in hundreds of churches across the country. The are even used by Cirque de Soleil. That impressed me. So I did some research and read up on their line of batteries by Ansmann. As it turns out, a rechargeable Ansmann AA battery is rated for 2800 mwh (a measure of how much energy the battery will hold). A typical alkaline is rated at about 1800. They also make a 250 mah 9 volt batteries, and while not quite up to Alkaline levels, they will still power a wireless mic for several hours.
When I did the math, I discovered that I could convert our entire church (main ministry center, student and children's ministries) for less than $500. Conservatively, we stood to save nearly $2,000 the first year. So I took the plunge. After a year of use, we haven't looked back. I haven't had to order batteries for nearly 10 months. Once I figured out how many we needed to keep up with the use, the only problem we've had is that some people think they are disposable and throw them out when they go dead. Ongoing education is the key there—we've lost about 8-10 batteries to the trash.
Before I rolled them out in services, I did some testing. I found that a 250 mah 9V would power our Shure ULXP transmitters for nearly 4 hours. Amazingly, two 2700 mwh AA's would power our Shure SLX transmitters for over 10 hours. Not only did we not have to buy batteries anymore, but they lasted longer than the disposable ones!
In practice they have required a few changes to how we use batteries. We used to use one disposable in each wireless for rehearsals, then check it for Saturday night and if it was good, we kept it. We would then change it out on Sunday. Some weekends we would go through 10-12 batteries. Since the rechargeables don't last quite as long, we replace them before each service. I always hated doing this with disposables, because I knew that there was still capacity left, but we couldn't take a chance. Now, we toss them in the charger. They exhibit no memory effect that I can tell, and seem to hold a charge pretty well.
As for quantity, for the 9 volts, I took the maximum number of mics we might use in a service or program and doubled it. I figured that they would last as long as the charge cycle would take. So far that's worked out great. We use AA's in our student and children's ministries, and since they last so long, I have a few extras, but basically the batteries last the weekend, then we charge during the week. Horizon sells 10 bay chargers, so we can turn over a lot of batteries in a short time.
We did have one problem with a 10-bay 9V charger about 8 months after we bought it. Four of the bays stopped charging. I called Horizon, they sent me an RMA, and we had it back in about 2 weeks (which was about a week too long, but it didn't cost me anything). Overall their service was quite good.
My only caveat is that you have to train everyone to change the batteries before the service (especially the 9v ones). When the batteries go, they go quickly. We tried to push the limits with our ULXP series mics because they transmit battery voltage back to the receiver. Problem is if you have 2 bars on the meter, you have between 10-20 minutes before the mic shuts down. It will go from 2 bars to 0 in a minute or two. After having the worship leader's mic go out a few weeks in a row, we now just change it between every service.
The upside of making the switch was that I saved so much money on batteries that I was able to buy 3 more new wireless mics last year instead of throwing the money in the trash can. If you currently use AA batteries it's a complete no-brainer to go rechargeable. Get the new 2800 mwh batteries (about $15/4) and a 10 bay charger and you're all set. If you use 9V's and can be disciplined enough to change them often, it also makes great sense. You'll save a ton of money and keep a pile of batteries out of the landfill. As an added bonus, the NiMH rechargeable batteries are not considered hazardous waste like alkalines are. Like I said, save your budget and save the world. What's not to like?
It's been over 2 years now that I've been using these batteries and my enthusiasm has not waned. The still work great for us every weekend, and I've cut down the number of batteries we buy to a dozen or two per year (instead of 3 dozen a weekend). I will say now that having used both Ansmann's professional, rack-mount chargers and the more consumer-level desktop ones, that the pro chargers are the way to go. They are several times the cost, but charge much more reliably. The desktop ones have a habit of letting the batteries pop out of the charging bays, and you end up with partially charged (or not at all) batteries. While the pro series are not perfect, they are a lot better.
I've also found that rechargeable batteries self-discharge at a faster rate than new alkalines, so it's important to keep them in the charger. We made it a policy that when pulling batteries for a mic, you take them out of the charger, and immediately fill the empty slots in the charger with spares we keep in the drawer below. That way we always have 32 AAs (we have two 16 slot chargers) and 16 9vs (two 8 bay chargers) ready to go.
The usual disclaimer: I am in no way affiliated or compensated by Horizon Battery or Ansmann. I just really like their stuff.