Ye Olde Rechargeable Battery Conundrum

[Chris Chapman]

Getting ready to roll on my Fall musical and ordered some new/replacement rechargeable batteries from Horizon.

What's the current feeling about pro-quality rechargables and leaving them in the chargers vs. once charged into storage? These are going from rehearsal/performance right back into charges and then cycling for about 2 weeks of sound rehearsal/tech/dress/performances.

The bigger issue is when I come off of this show, should they just cook and be ready at a moments notice at the cost of the long term viability of the battery?

Thoughts?

 

[themuzicman]

I don't quite get the question, but I'll take a stab at answering it...

The standard on most every NYC production are the Maha Powerex AA and AAA batteries and the Maha MH-C800S charger. We have two sets per show. One set is always in the wireless during a show, and one set is always on the chargers. The set in the wireless stays there overnight after the show in order to fully discharge. The set in the chargers is soft-charged every night (3 to 4 hour full deplete and full power-up). The next day before the show you swap the good batteries into the gear, the used batteries into the chargers and you are ready to go. Generally the night before a dark day we do a hard cycle on the batteries which takes about 8 hours.

In tech you you use two sets and don't worry about soft cycling. Morning session of tech gets one set, the other set charges, you swap at dinner break, and do your evening session. The chargers take around 2 hours to charge the batteries up.

I generally replace my rechargeable battery sets once a year, but they can go for 3+ years on 8 show weeks + rehearsals without issue.

Between productions we do not keep them in the chargers. If we need things at a moments notice I have two or three chargers of AA set up in my workbox (16-24 batteries) so we have those. We have a stash of AA, AAA, and 9V Alkalines to draw from until we can get rechargeables set up and ready to go, but generally anticipating needs keeps the use of Alkaline batteries to a minimum.

 

[SteveB]

"The standard on most every NYC production"

Kind of a broad statement. Big place that New York. In Brooklyn (which as BTW, is part of NYC still), we gave up on rechargeables a while back, especially for wireless microphones and simply use regulars. Even my ETC WRFR, which is supposed to use rechargeables, sucks with them. Duracells typically but I admit that possibly the software on the ETC unit might suck at managing batteries.

 

[Chris Chapman]

I don't quite get the question, but I'll take a stab at answering it...

The standard on most every NYC production are the Maha Powerex AA and AAA batteries and the Maha MH-C800S charger. We have two sets per show. One set is always in the wireless during a show, and one set is always on the chargers. The set in the wireless stays there overnight after the show in order to fully discharge. The set in the chargers is soft-charged every night (3 to 4 hour full deplete and full power-up). The next day before the show you swap the good batteries into the gear, the used batteries into the chargers and you are ready to go. Generally the night before a dark day we do a hard cycle on the batteries which takes about 8 hours.

In tech you you use two sets and don't worry about soft cycling. Morning session of tech gets one set, the other set charges, you swap at dinner break, and do your evening session. The chargers take around 2 hours to charge the batteries up.

I generally replace my rechargeable battery sets once a year, but they can go for 3+ years on 8 show weeks + rehearsals without issue.

Between productions we do not keep them in the chargers. If we need things at a moments notice I have two or three chargers of AA set up in my workbox (16-24 batteries) so we have those. We have a stash of AA, AAA, and 9V Alkalines to draw from until we can get rechargeables set up and ready to go, but generally anticipating needs keeps the use of Alkaline batteries to a minimum.

The issue for me is when I come off the show, but am in a soft wireless mic setting where I don't need live mics for 2-3 weeks. I'm looking at long term impact of cooking on chargers.

 

[BobHealey]

Community theater, so employ a very large grain of sodium chloride, but we've had very good luck with the powerex immedions. We get 6+ hours on a single charge with SLX body packs, and they don't mind being stored for 6-8 weeks between 2 weeks of heavy use. OEM claims only 15% self-dishcarge/year but we haven't tested this. We had used the standard powerex, but the self-discharge eventually rendered them unchargable after about 2-3 seasons. The only immedions we've had die were ones facilities stole for use in the automated sinks and were left in until they were stone dead.

 

[themuzicman]

"The standard on most every NYC production"

Kind of a broad statement. Big place that New York.

I'll rephrase to every single Broadway and Off-Broadway show and all the musical tours I have worked on in the last 6 years have used nothing but Powerex.

As for the original question of keeping them on chargers full-time...once you're done with them, just pack them up. I velcro all my chargers to a piece of wood, throw a power strip at the top, and flip the power strip off between productions. Every rechargeable has a certain rate of self-discharge. If you're worried about that, keep them on the chargers, but even after 2 to 3 weeks you'll still have 3/4 of the charge left and all you need to do is throw them on the chargers for like half an hour.

 

[MrX]

I've used the Maha/PowerEx Imedions for many years now, and even after having the batteries sitting unused for 6 months or more, they still have a decent charge in them when I pull them out.
The charger is a critical part of the equation, and for longest lifespan of the battery, they need to be slow-charged with smart charger like the MH-80x so they don't heat up or get over-charged.

 

[MikeJ]

I guess it depends on your frequency of use. Duracell Procells are only $0.32 each, even at online retail prices. So that's 64 cents per mic, per show, and those batteries could probably also be used for two rehearsal days, depending on length.

If you are a school with a show budget, and its only 12 mics for a week of rehearsals 4 times a year, we are talking less than $200/yr in batteries. I would just buy the procells. Yeah I know save the whales, and all that, but....

 

[Jay Ashworth]

Several notes, in no particular order:

1) Higher-rating NiMH's (say, about 2000mAh and up) start to get *really* intolerant of drops; they short the plates through the electrolyte, and the battery is dead. Any drop at all.

2) You're not going to *get* the rated mAh out of any cell, because what you can use depends on the minimum usable voltage of the *gear*, and that's guaranteed to be higher than the MUV of the *battery* -- I remember how surprised I was when I got some 2450s for my digital camera, and the nice LaCrosse charger with individual mAh meters, and it could only get 1950 into them from camera 'dead' to charger 'full'. Took me a while to figure it out.

3) NiCd and NiMH have a chemistry voltage of 1.25-1.3VDC nominal, noticeably lower than the 1.5VDC of alkalines. That can have a negative effect on the operation of the gear, depending on how picky it is, AND it will also reduce the amount of power you can get out of the cells, since the battery 'full' to MUV is a shorter distance.

 

[gafftaper]

I run a high school PAC. I have Senn EW100 3G wireless gear and Sure IEM's. About 2 years ago, I switched over to rechargeables. I have Panasonic Enloop Pro AA batteries being charged on Tenergy TN160 chargers (all from Amazon). I keep about 30 in stock, and we use 24 of them for about 9 hours on Sundays for my Church rental (they get charged between morning and evening services but probably don't need it). They get put on the charger at the end of the day and sometime later in the week when I walk past the booth, I pull them off. Sometimes they are on a day, sometimes it's most of the week. When you add in school musicals and other random uses, they get used and charged around 130 times a year. In 2 years, I've had 4 or 5 go bad and stop recharging. I've used them in back to back shows without charging in between. I'm VERY happy with the decision to switch to rechargeables. They probably cost about the same as buying Alkalines, but I love the convenience of never having to worry about anything or go out to buy more. They are always there, ready to go.

 

[BillESC]

I use just Duracell ProCell's, with them costing under $ .50 each I see no reason to go re-chargeable.

 

[MrX]

Several notes, in no particular order:

1) Higher-rating NiMH's (say, about 2000mAh and up) start to get *really* intolerant of drops; they short the plates through the electrolyte, and the battery is dead. Any drop at all.

I've heard this as well, but never experienced it. All my cells are ~2500mAh and have dropped several with no ill effects. Might depend on the manufacturer. Have you personally witnessed this issue? If so, with what brand of batteries?
I use PowerEx and Eneloop.

2) You're not going to *get* the rated mAh out of any cell, because what you can use depends on the minimum usable voltage of the *gear*, and that's guaranteed to be higher than the MUV of the *battery* -- I remember how surprised I was when I got some 2450s for my digital camera, and the nice LaCrosse charger with individual mAh meters, and it could only get 1950 into them from camera 'dead' to charger 'full'. Took me a while to figure it out.

Again, might depend on the manufacturer. My batteries start at close to or even above their rating after being broken in (2-5 charge/discharge cycles) and degrade slowly over usage.

3) NiCd and NiMH have a chemistry voltage of 1.25-1.3VDC nominal, noticeably lower than the 1.5VDC of alkalines. That can have a negative effect on the operation of the gear, depending on how picky it is, AND it will also reduce the amount of power you can get out of the cells, since the battery 'full' to MUV is a shorter distance.

What gear have you seen this "negative effect"? I find that rechargeable AA in most wireless gear last LONGER than alkaline AA batteries. Of course, most modern wireless gear use DC-DC converters so they don't care what the battery voltage is as long as it's above 1v or so. Please give some examples of equipment where modern quality NiMh AA rechargeables do not work as well as Alkalines.

 

[gafftaper]

I use just Duracell ProCell's, with them costing under $ .50 each I see no reason to go re-chargeable.

I spent a lot of years using the Costco AA's. They are dirt cheap and work great. Never had an issue with them and felt the same way Bill. Why spend the money on rechargeables, they are so cheap. However, once I went rechargeable I new I would never go back. There's a convenience factor of ALWAYS having a full set of batteries in house. Not having to deal with the paperwork of buying batteries all the time. With the cost of the good charger and the batteries there's a good chance I'm not saving much if any money, but I love the fact I never have to go to the store. They are just there. About 3 times a year I buy a few more to keep the stock up from the occasional lost or dead battery. But it's so easy.

 

[BillESC]

I buy my Procells by the gross. My current stock is dated: Use by March 2022

 

[gafftaper]

I buy my Procells by the gross. My current stock is dated: Use by March 2022

Well there's that.

 

[themuzicman]

With the cost of the good charger and the batteries there's a good chance I'm not saving much if any money, but I love the fact I never have to go to the store.

Did some quick math, assuming that $.50 price on ProCells. A Powerex Set costs $23/8 and $39 for the charger. With a total cost of $62, that's the equivalent of 124 ProCells. If you use all 8 at least 16 times in the year, you have broken even on the set.

An average show of mine has 24 wireless, each using 2x AA, and 8 wireless intercom packs, each using 6x AA 8 shows a week. That's a total of 96 AA batteries. I would need 12 sets, for a total cost of $738. Comparative ProCell cost @ $.50 would be $384 a week. The rechargeable pay for themselves in just about two weeks, and saves me a fair amount of money the rest of the year, and more importantly, puts a lot less junk in landfills the rest of the year - more so on larger shows.

 

[MrX]

There's no question whatsoever that good rechargeables (and chargers) will be cheaper in the long run. The Imedions I'm using now I have had running for almost 8 years and still have not lost 10% of their capacity and are used for over 200 shows per year. 8 Procells/show x 200 shows x 8 years (so far) is $6,400.00. Contrast that to 16 Imedions and 2 chargers ($100 or so). I'm sure I'll get another 2-4 years more out of the Imedions. It's literally a no-brainer if you maintain the batteries.

 

[Scarrgo]

I have all 9v Mics, anyone find a good rechargeable 9v? I go thru 600-800 per year at almost $1 each(Duracell Procell),
I would really like to not have to dump that many batteries into the recycle every year....

Sean...


*changed amount used...

 

[FMEng]

Powerex makes them in 8.4 and 9.6 volt versions.

 

[Scarrgo]

The Powerex offer 8.4v 300mAh and the 9.6v 230mAh, Which would one recommend, I have shure ULX's line of hand/body paks...

and doing some reading on the shure site, they recommend a brand iPower that offers a 9v 700mAh Li-polymer.

any thoughts?

Thanks for your time...

Sean...