Rechargeable AA Batteries for radio mics

[pumphouse]

I did search on here but didn't see anything relevant and reasonably recent.

I'd like to find a reasonably priced set of rechargeable AA batteries and chargers for use in Trantec S5.3 and Sennheiser beltpacks to reduce the recycling load on using disposable batteries that we get through quite fast in show weeks.

CPC do these.  Does anyone have any experience with them, or can you recommend another solution and supplier that has worked.

I know there are some potential issues with slightly lower voltages and  battery indications etc. but any experience-based advice on something that works would be welcomed.

Thanks in advance.

[Robin D]

How often are show weeks? We played with several different rechargeables years ago. Two sets were great during show week, but found that with two shows a year meaning no use, the deterioration was so high, they were next to useless after a year or so. 

I was in contact with the Varta importers at the time who advised that they need frequent use to remain viable. Keeping them on charge without use, would make matters even worse. 

Things may be better with lithium rechargeable but ensure you get the right charger. 

[pumphouse]

Show use is fairly sporadic - it goes in fits and starts.  I have a run of 3 shows in 6 weeks coming up but they they will likely be back in their box again until a 2 week run in January, then back in their box until March.  We're a bit better than 2 per year but definitely not every other week, so yes - good point about the usage.

The CPC product has a discharge cycle button that helps with cycling batteries that have been in long term storage - no idea how well this work though!

[DrV]

It strikes me that there would be room in the market for a custom 2xAA pack made up of a LiPo prismatic (pouch) cell with an integrated charger and a USB-C connector. You could store a lot of Watt-hours in a pack that size. Anyone know of such a product?

[richard_cooper]

To add to your list of things to be careful of, many rechargeable AAs are ever so slightly larger in diameter I can't remember if it was a problem with the Trantec packs, but it's a definitely a no go in Line6 transmitters, which were just too tight.

[cedd]

I use rechargeables regularly on my S5.3's and they've been pretty hassle-free. 

I initially bought Panasonic Eneloop, but have subsequently also bought Ikea's LADDA own brand (supposedly rebadged Eneloop if you believe the photography forums) and Amazon Basics own brand. All have been fine, and when I come round to my next bulk replacement I'll probably buy one set of Amazon and one of Ikea, so I've got a white and a green set for easy identification of the 2 sets. 

My chargers are Japcell 16 way ones, and again they've been great. 

[cedd]

2 minutes ago, richard_cooper said:

To add to your list of things to be careful of, many rechargeable AAs are ever so slightly larger in diameter I can't remember if it was a problem with the Trantec packs, but it's a definitely a no go in Line6 transmitters, which were just too tight.

Mine haven't had any problems. Whereas my Line6's have given me heaps of issues. I've now 3d printed my own battery bays, which are a bit more loose. Fiddly job to print, clean up and swap though so not something I really fancy marketing as a replacement part! 

[DavePallant]

I've looked at rechargables in the past but even just using 16 channels of Sennheiser it's 32 batteries. To keep my sanity I would need to recharge them all simultaneously and with a matinee and evening show there is not enough time between shows to recharge so for safety I would need two sets of batteries. Then overnight I might need to recharge two sets of batteries if I have matinees Friday and Saturday. On shows where I might be using 24 channels then we're up to 48 batteries per show and 96 needed to be kept track of and not mixed up.

If I were to go for it then 48 batteries in chargers plus 48 more batteries would be around £600 whereas I'm in the different situation from the original poster of being able to charge for the batteries I use which is usually around £60 for a week of rehearsals and shows.

[J Pearce]

We use Fischer Amps chargers and their NiMh batteries. We have 5 of the 16 way chargers, and around 250 batteries (AA and AAA) in our stock. We date mark the batteries into stock, older batteries get shuffled onto non-show-critical jobs, and duff batteries get disposed of. On shows we use coloured dot stickers to denote two sets of batteries. On a matinee day we charge the evening set during the matinee show, which achieves full charge before battery change is due. Tech rehearsal days tend to weed out the dodgy batteries, and they usually fade so needing to do an interval swap would be a flag to take that battery out of circulation. We store our batteries fully charged, but don't leave them on charge. 

The above is fairly industry standard, though there are other chargers and batteries out there.

Re voltage and indicators - some mics can be told they're using NiMh and adjust their indicators accordingly, on others it's just a matter of getting used to interpreting the readout correctly. More modern upmarket transmitters use integrated lithium based batteries that use their own chargers (Axxient, Senn 6000/9000 etc.) and provide very accurate battery life estimations.

[pumphouse]

47 minutes ago, cedd said:

I use rechargeables regularly on my S5.3's and they've been pretty hassle-free. 

I initially bought Panasonic Eneloop, but have subsequently also bought Ikea's LADDA own brand (supposedly rebadged Eneloop if you believe the photography forums) and Amazon Basics own brand. All have been fine, and when I come round to my next bulk replacement I'll probably buy one set of Amazon and one of Ikea, so I've got a white and a green set for easy identification of the 2 sets. 

My chargers are Japcell 16 way ones, and again they've been great. 

Thanks Cedd.  Are they the Ni-MH batteries then?  Sounds like they may be worth a try.

@DavePallant - I can charge for the batteries - this is more perhaps trying to improve my environmental footprint.  On the basis of your numbers if you charged the same amount for hire as for sale of the batteries you would have your money back in 10 show weeks, which isn't too bad a return period.

@J Pearce - The Fischer stuff looks great - I have seen this at another Theatre but may be a little on the toppy side price-wise for us.  Will think about it for sure though.

Thanks all for the input.

Edited September 20, 2023 by pumphouse
Updated to include reply to a more recent post.

[mnorwood]

23 minutes ago, richard_cooper said:

[...] many rechargeable AAs are ever so slightly larger in diameter [...] it's a definitely a no go in Line6 transmitters, which were just too tight.

It's also a no-go with the Audio-Technica beltpacks at one of the venues I run shows at. I reckon I could probably get my rechargeable AAs into them with the use of a small rubber mallet, and back out again with a set of pliers, but I really don't want do that! Mind you: I've also labelled all my batteries so I can identify/keep track of them, which doesn't help in that regard...

I have three sets of 32 batteries (96 in total, all Ni-MH), swapping after every other performance run (as each pair lasts 8+ hours), with each set being a different make (Eneloop, Ansmann, Ikea) and sourced from a different retailer (Battery Logic, CPC, Ikea). Each set is colour coded and each battery is numbered, so I know where each battery should be at any given time, and also to make sure the same batteries end up in the same beltpack night after night (so if there is a problem, it doesn't leapfrog around the cast).

Like cedd above, I also use JapCell's 16-way chargers (model BL-16000) and agree they work well. I also have some Technoline BL-700N 4-way chargers "at home", which have a built-in "test" function (charges and then discharges each battery at a constant rate, then spits out an approximation of that battery's capacity) the results of which I keep in a database (having each battery uniquely identifiable really helps here), and from which I get charts that highlight potential problems and (should eventually) show battery degradation over time.

As to passing the cost on to a group that's employing me to run sound for them (as I never hire or loan the batteries out to others): I roughly calculate how much it would have cost to have used single-use batteries, based on prices on CPC at the time of putting together the invoice, and charge them that. Thus, it's no more expensive for them than it would have been otherwise (and they get to feel good for being "Green").

[jamesperrett]

The CPC charger/cell combination makes no mention of whether the included cells are of the pre-charged type. These retain their charge for much longer than conventional NiMH cells. I've used GP Recyko pre-charged cells which seem to work fine - even if you wait a couple of months after recharging them before you use them again. I've also used the Amazon Basics cells which mention GP on the packaging so they may well be the same as the Recyko cells.

[richardash1981]

To back up @richard_cooper's point, I've got a set of those Ansmann 2500mAh AA batteries, and they are the biggest ones I have met - with the result that they don't fit in a lot of things! I don't think they were pre-charged.

I've had good results with GP Recyko (a little smaller) and GP ordinary (smaller again, fit anywhere a dry cell will) AA cells.

The test function charger sounds useful - I did the same thing with a resistor and a data logging multimeter (but it was tedious!), and life got a lot easier and more reliable once all the poor-performing AAs were eliminated and the remainder could be matched at similar capacities. It's amazing how little relationship there was between marked capacity and actual capacity after some years of use!

[paulears]

Radio mics and comms walkie talkies can easily integrate now quite reliably - and the differences seem to be just capacity rather than reliability.

The killer is the regime you have to follow. One set in use, one on the charger is risky, you also need another set if you do two shows in one day, but then a system to put one set on charge after second show, take them off, and put another set in the radios, and the charging time is longer than the gap between shows sometimes. I have to admit I have gone back to disposables simply because I had to get people to come in early just to do a better swap, and then sometimes stay late to let a set finish, rather than leave them on, charged, overnight. The thing I did do was colour code each set - red green and blue tape, and you'd be amazed how often I'd have one or two red ones in the blue set, and some blues in the green - no idea. Somehow a few flat ones always seem to get missed.

If you have a dedicated person to look after radios, this works fine - but for panto, with 70+ shows, recharging is just too risky we feel. It would be cheaper, but human error is the killer.

[mksound]

We’ve been using the Ikea LADDA AA’s for the last 18 months and find them great. We have a set of 84 as we would regularly use 30 channels of wireless for shows between Trantec, LD Systems and Line 6 mics (HH and BP). We get 2 shows out of a charge, with a full spare set. 

We have 2 16way Bonsai chargers bought from Amazon which have been great so far. 

The batteries themselves are a neat fit in most of the battery compartments but  haven’t found any that they won’t fit into.