Sennheiser L2015/BA2015 and standard AA NIMH

[Solstace]

Hi everyone

 

Thought I'd ask here first since I don't necessarily want us to be the first to try something like this...

 

Last year we bought a full set of BA2015's for our EW100 G3 sets. I didn't mind paying a little extra as I thought the charging control mechanisms built-in to the BA2015 packs would maintain a longer useful life. Predictably, less than a year on from purchase and deployment I've just got word of the first "live" failure of one of these packs. Showed green light when the mic was in the charger, full 3-bars when turned on, and died about 30mins into the gig.

 

On the one hand, I could send the dud back for warranty replacement, but it got me thinking... has anyone had success with:

 

1) Using the L2015 base-station chargers to charge standard NIMH AA's in the mics

2) Swapping out the cells in the BA2015 packs with standard NIMH cells?

 

Boss is suggesting calling Sennheiser. Having no desire to sit through yet another semi-automated call-handling system, I'm guessing that the first word of the response will begin with "N" and end with "O". And it won't be "Nando". :)

 

So - anyone done any hacking on these?

[jamesperrett]

Do you have a proper battery management policy (which includes logging the number of charges and fully discharging every pack every few weeks)? If so, Sennheiser ought to replace the pack as you will be able to show that it hasn't performed to spec (assuming you've done less than 1000 cycles with it). I'd contact Sennheiser anyway.

 

If you get no joy from Sennheiser, the packs look like they use standard Panasonic cells with some added management electronics so you can probably replace the cells but you may need to reset any data contained in the electronics.

 

James.

[Rob_Beech]

Phone Sennheiser regardless. If it's not performing as it should then it should be replaced. Do let us know how you go on. Specifically if you have any issues dealing with them.

 

Rob

 

 

Edit to add : mmmm Nandos......

Edited June 10, 2013 by Rob_Beech

[Solstace]

Hmm - will have to put this on hold for a while as more urgent (and important) things need dealing with first. I'll keep y'all posted. Here's where I got so far:

 

From having ripped the failed unit apart (out of frustration for the week that's been, if nothing else) - it's not a trivial swap to replace the cells. These are industrial AA cells with some extra bits soldered on, some kind of thermal cutout and extra sense terminal I think, with a plastic moulding around the lot. So I think I can say that just popping out and dropping any old high-street AA NIMH won't work. Still doable for us Pro's perhaps, but whether the outcome is worth the expenditure...

 

I also know ('coz I tried) that without the sense terminal working, 2 x conventional AA NIMH cells won't be charged by leaving the mic in the charging cradles. So at least I also know that if anyone drops a mic in the cradle with alkaline AA's then nothing will go "BANG"

 

Meanwhile I think I'll just order a replacement (they're only a 6-month warranty anyways according to our supplier) and deal with the more advanced hackery and actual phone-calls later...

 

C.

[gmbuth]

I can confirm your experience. We're using the BA2015 for our service in church and last week our 2nd batterypack died while live http://www.blue-room.org.uk/public/style_emoticons/default/mad.gif. Luckily we've a wired emergency mic but a failure is always inopportune.

Both batterpacks died within a year. We use the L2015 charger and recharge the battery every week two times. That means app. 150 charge cycles. The belt stays in the charger always (trickle charge).

 

The L2015 doesn't show an error in the charge process. It's also strange that this charger is fast-charging the batteries. This method is known for shortening the battery life! It would be great if the L2015 has the possibility to choose between fast or normal charging.

It charges with 700mAh while 150-200 would be much better (charge power app. 10% of the battery capacity).

 

I think we gonna use NI-MH batteries with a professional charging station where you can set the charge power and get an alert before the battery is end-of-life!

 

Interesting test: http://www.eventdv.net/Articles/News/Feature/In-the-Field-The-Sennheiser-ew100ENG-G3-Wireless-System-and-Rechargeable-Batteries-60879.htm

[amertahir]

Reviving this super-old thread hoping someone would get some benefit from my experiences. I was able to open up a replacement BA2015 battery pack and understand what is the extra chip/sensor they've used to make NIMH battery chargeable with the Sennheiser L 2015 charger. It turns out it's a pretty standard NTC 10K B 3950 1% Thermistor (like this one: https://www.ebay.com/itm/402635385350?hash=item5dbef06a06:g:E5kAAOSwqLlf9SNK) connected to battery's -ve terminal and the middle pin (metal contacts that lie between the two -ve spring tabs in the battery compartment) inside battery compartment. You can solder this thermistor between the -ve terminal (bottom one if the battery pack's +ve side is facing right from your view) and the middle pin (it's location described previously). The thermistor doesn't have any -ve or +ve terminals so it can be connected in any way. Then, you can put in any NIMH rechargeable batteries inside and be able to charge the microphone/bodypack with the Sennheiser L 2015 charging station.