Radio mics / rechargeable batteries

[Shez]

This is a topic that crops up now & again so I thought I'd share my most recent experiences. It's long bothered me the quantity of batteries that I go through for radio mics in a run of a musical or panto. I've tried rechargeables on occasion before but only on a small scale. I decided that this panto would be the time to switch over completely.

 

I use a mix of Senn G2 and L6 V75 mics; the G2 battery compartments will accommodate any battery that I've ever tried but the L6 is just that bit tighter and the majority of recharcheables I've tried don't physically fit. I begged / borrowed / bought a few different makes & models to try out. I've seen suggestions of Amazon brand and other badged types but was keen to use one that I know I can get hold of consistently. A change of 0.2mm diameter would I'm sure not even be noticed by most suppliers or users but that would scupper me! The winner was the Eneloop 1900mAh NiMH - it fits easily in the beltpacks and in my tests, runs for at least eight hours. I already had a 10 way Annsman charger but bought a couple of Technoline BL700N chargers too - seems very well rated and has selectable charging current - useful for gentle overnight or rapid between-show charging.

 

The run is now over and I'm pleased to report 100% success. I bought enough batteries for all the packs plus a couple of spares but not enough to run alternate sets on alternate shows. This made the charging regime slightly more complex than it perhaps needed to be but this was a trial run after all. The battery gauges on the packs were unsurprisingly less accurate than one would expect from alkalines but not wildly so; it was reassuring to know that I could expect at least eight hours regardless of what it suggested was remaining. Oddly one pack always suggested considerably less remaining time than the others but still ran for the same amount of time on a full charge.

 

If you've been umm-ing and aah-ing about making the change, I can recommend these particular batteries - they do a fine job and I'm happy to now not have a big box of part used batteries to deal with. And my environmental conscience is a little more clear than it used to be!

[Simon Lewis]

Shez,

 

Many thanks for the review - it's most helpful! Would either of the chargers be suitable for leaving with batteries on 'trickle charge' pretty much permanently? I have a number of church installs where ideally they would place the 'used' batteries in the charger after a Sunday service, then take them out again a week later...

It's a little lazy, I know, but some users need to operate that way!

 

Simon

[paulears]

I had a sneak into the A2's area and our state of play is this.

[cedd]

Futurist Fire

 

 

Following the above (local hire company destroyed by fire) I'm super careful about how I dispose of my old AA's. The fire was thought to have started in a box of AA's that had been removed from radio mics and were waiting to be disposed of. A box not too dissimilar to the ones pictured in Paul's photo. I don't know if it was a chance shorting by other batteries or if it was a faulty/damaged cell, but since that fire all of my used AA's sit in plastic boxes bought from a firearms dealer. They are designed for single shells and are divided in to compartments that hold a load of AA's on end without touching perfectly. Each battery is isolated and protected.

 

However a move to rechargeable batteries removes the risk of a fire from used batteries (but arguably adds one from the charger itself.

 

Thanks for your thoughts Shez. I'm now actively looking at getting some.

Can I ask, did you find the Amazon ones to be a different size? I'm reading lots of stuff (mainly on camera forums) saying the Amazon ones are rebadged Eneloop's, but I'm also not too keen to believe everything I read on the internet! Did you buy any Amazon ones to try and if so, did they fit the Line6's ok?

 

One regular issue I have is power being switched off overnight. One regular venue has an elderly caretaker who passionately switches off everything with a light on "just in case". Others have switched tech power to front of house that goes off once the crew go home.

I'm considering building a mini "charger UPS" made up of a pair of 16 way chargers (with 12V wall warts) powered by (directly or via a changeover relay) a pair of 12V alarm batteries capable of supplying enough current to do a full charge. It'll be a chunky box but no larger than my current box full of ready-to-use AA's and will ensure I always have charged batteries no matter what the venue do.

[MarkPAman]

The winner was the Eneloop 1900mAh NiMH

This is the info I needed, thanks very much!

I recently did some tests with Line6 V70 & V75 handhelds. The batteries are the Amazon 2000mAh - which I suspect would never come out of my belt packs if I forced them in, but are fine in the hand held mics. I have an ELB charger (also from Amazon) which, individually, charges 10 AA/AAA & 2 9V.

 

As Shez noted, the level meters don't read that well, tending to start at around 6 hours and rapidly dropping to about 2 hours during the first hour or so. However, from there, they level off, and all continued working fine up to 8 hours, at which point I stopped the test. But as I was testing 6 mics, and at the moment, can only charge 10 batteries at once, I took the mic with the highest reading home for to observe for another 6 hours, and it was still showing 0:40 at the end of 14 hours.

 

I've now repeated the 8 hour test 4 times, with some sets being used for gigs in between, and the results are consistent. So I'll probably now get some of those Eneloop ones, another charger, and start using rechargeables all the time.

 

Guess I could try some AAAs for my hand torch too, or would the initial drop be a problem?

[Shez]

Would either of the chargers be suitable for leaving with batteries on 'trickle charge' pretty much permanently? I have a number of church installs where ideally they would place the 'used' batteries in the charger after a Sunday service, then take them out again a week later...

Any "intelligent" charger should be OK with that in theory. Once they sense the battery has reached full charge, they drop to a trickle of ~20mA which is supposedly OK indefinitely. I'd feel a little wary of leaving them week after week like that but I have no specific reason why. How about a timer plug (weekly, not 24 hour) that would only power them on Sundays? They'd be fully charged by midnight Sunday, off for the rest of the week and then back on for trickle top up midnight Saturday so they'll be visibly full when taken out. Or whatever timings suit. I've seen solar chargers too - a week between uses should be long enough to slowly charge up again even with typical British weather!

 

Can I ask, did you find the Amazon ones to be a different size? I'm reading lots of stuff (mainly on camera forums) saying the Amazon ones are rebadged Eneloop's, but I'm also not too keen to believe everything I read on the internet! Did you buy any Amazon ones to try and if so, did they fit the Line6's ok?

I didn't actually try the Amazon ones - the current ones might be fine but if they change what's in the packaging next month, you never know what you'll get. Hence preferring to stay away from badged. Mark's comment above suggests they may not be a good fit though.

 

I'm considering building a mini "charger UPS" made up of a pair of 16 way chargers (with 12V wall warts) powered by (directly or via a changeover relay) a pair of 12V alarm batteries capable of supplying enough current to do a full charge.

I'm sure I spotted some chargers capable of being powered by a standard USB connection - a 5v power bank of some kind might be useful there?

 

The remaining time indications I saw in testing were as follows:

(Roughly averaged across all the packs)

Start - 8'20

1 hour - 7'00

2 hours - 6'40

3 hours - 6'00

4 hours - 5'20

5 hours - 5'00

6 hours - 4'40

7 hours - 4'00

8 hours - 2'40

9 hours - off

[sunray]

/>Any 'intelligent' charger should be OK with that in theory. Once they sense the battery has reached full charge, they drop to a trickle of ~20mA which is supposedly OK indefinitely. I'd feel a little wary of leaving them week after week like that but I have no specific reason why.

In the 80's I had around 100 AA's and built constant current chargers capable of charging upto 20 each.

 

A vertical plastic tube with a fixed contact at the bottom and a carefully cut slot at the bottom allowed the batteries to be pushed out.

The tube had flat batteries dropped into the top and a big piece of brass on a flying lead sitting on top of them.

 

The chargers were permanently powered and so simple that my 6 yo daughter soon learnt it was a good permanent supply of batteries if she followed the rules and did use them.

 

Of course this was in the days of nicads...

[Jivemaster]

The nice bit about the batteries is that the old AAs were NiCad so had a disposal issue, and usually struggled to get 500mAH inside, while NiMH usually gives much more capacity in the same size can.

[ninjadingle]

Simon, for your "lazy" users have you considered a Sennheiser L2015 with BA2015's? We use these all over our campus and would easily work for your application. G2 300/500 or G3 packs can be dropped straight into the charger without removing the batteries - lazy enough??

[sunray]

The nice bit about the batteries is that the old AAs were NiCad so had a disposal issue, and usually struggled to get 500mAH inside, while NiMH usually gives much more capacity in the same size can.

Really?

The earliest versions may possibly have been 500mA but I don't think I ever had anything less than 1AH.

My first foray into NiMh was for a tiny LCD tv which used as a video monitor while setting up AV systems. Battery life was short at around 1/2 - 3/4 hour on NiCad or 1.5H on Duracells so I purchase 2 sets (12) of 2000mAH NiMh which I used exclusively for this tv, Ooh about 3/4H. Within a dozen charges I found battery life getting shorter to the point I bought a battery analyser to try to balance the set of 6 each time and soon started discarding failing cells. The warranty on them was a farce.Since then I find NiMh do not have the consistency or reliability of NiCad and certainly discovered I can't leave them on trickle charge as it shortens their life. And Shelf life of charged NiMh's if much shorter than NiCad, I now find myself 'charging to order' and keeping a stock of alkaline's rather than trying to maintain a stock of charged batteries.

[Shez]

And Shelf life of charged NiMh's if much shorter than NiCad, I now find myself 'charging to order' and keeping a stock of alkaline's rather than trying to maintain a stock of charged batteries.

Whilst looking around at different options, I did see some cells claiming only a few % drop in charge after 12 months. I'll always charge shortly before use but perhaps technology is getting better in that regard? Those Eneloops claim 70% capacity remaining after 5 years!

[Jivemaster]

Early nicads were certainly 500mAH and that only when new, "PP3" nicads were 80mAH. Both seem to have improved by about three times since then.

[sunray]

Whilst looking around at different options, I did see some cells claiming only a few % drop in charge after 12 months.

If you do find some that can actually read the spec they are supposed to adhere to then please let me know please. My experience is far different from that spec.

I used to take a spare set of nicads for the camera when I went on holiday, in case I used the first set. I now take a charger with me as I know 3 sets will not be enough.

Ah well that's progress.

[revbobuk]

Shez,

 

Many thanks for the review - it's most helpful! Would either of the chargers be suitable for leaving with batteries on 'trickle charge' pretty much permanently? I have a number of church installs where ideally they would place the 'used' batteries in the charger after a Sunday service, then take them out again a week later...

It's a little lazy, I know, but some users need to operate that way!

 

Simon

 

Simon - that's exactly the regime we're implementing. Again using eneloop, and I'm using the Lidl smart charger, which works really well. So far we're about three months in, and no problems yet. Batteries come out of the mics and into the charger after every service, and stay on charge for a week. We've also got the same system going for 9v block batteries, as we have a couple of mics that use those. Users have mastered the system fine - only had one week where someone put a non-rechargeable battery in the charger!

[Simon Lewis]

That is useful to know! Many thanks for confirming....