Sennheiser G3 Wireless Lav & Rechargeable Batteries

little bobby

little bobby

Well-known member
Has anyone else had a bad experience using the Eneloop rechargeable batteries with the Sennheiser G3 Wireless Lav transmitter and receiver?

My boss wanted to "cut back" on the amount of consumables I use and bought me some Eneloops. I now seem to get lots of interference hits and static using the setup. I have tried changing the frequencies to something different, made sure that no one had the transmitter near their cell phone, and even turned off my phone when I was running camera. I never had this problem before when using other batteries and I'm running out of theories as to why this would be happening.

Any ideas or experience with this?
 
This is a common problem. The lower voltage of the rechargables gives poorer performance. Rechargables are not a good idea for the G3. Your boss will save a lot more money by not being cheap and using the right product for the application. There have been threads on this topic before.

We use G3s on live television broadcast. We go through bucket loads of batteries. We use a fresh set of batteries for each show no matter how much/little they get used.
 
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Thanks Paul. I have a big pack of the Duracell ProCells on order as this is what I was using before with no issue.
 
Makes sense, rechargeables do have a lower voltage (typically 1.2V) than regular 1.5V alkalines.
However I cannot discern any audible difference or interference issues.. of coarse in my case, the units are gain staged properly and frequencies carefully selected based on the latest FCC info.
 
If someone overly tightens the screw on cap that holds the audio plug they can turn the jack and cause the internal wires to cross and touch causing intermittent interference. Happened on my G3. $65 for Sennheiser to fix.
 
Not only is the terminal voltage lower, they confuse the power meter. They show good battery then change to "danger Will Robinson" in just a few minutes. I think I used around 5000 AAs last year and if rechargeables had been reliable I'd have used them. They can work if you have a very rigid recharging system, plenty of spares and a numbering system that let's you record lifespan, recharges and usage. Who has time to track battery use like this? Batteries are just another consumable cost just like tapes and cards. Some people have always reused them with all the disadvantages that has.
 
Whenever anyone come to me and says they are having problems with their G2 or G3 radio mic's I always ask if they are using rechargeable batteries and most of the time it is the low voltage that is causing the problem.

Radio mic's can be problem for reception at at the best of times so to add yet another potential failure is vey short sighted and will cost you way more in time wasted waiting for a interference free take.
 
little bobby said:
Has anyone else had a bad experience using the Eneloop rechargeable batteries with the Sennheiser G3 Wireless Lav transmitter and receiver?

My boss wanted to "cut back" on the amount of consumables I use and bought me some Eneloops. I now seem to get lots of interference hits and static using the setup. I have tried changing the frequencies to something different, made sure that no one had the transmitter near their cell phone, and even turned off my phone when I was running camera. I never had this problem before when using other batteries and I'm running out of theories as to why this would be happening.

Any ideas or experience with this?
Click to expand...

Sennheiser has a special rechargeable battery pack for the G3 - this is different from the dry-cell battery pack and talks to the transmitter/receiver in a different way from the dry cell pack - it also has a special charger.

Using normal rechargeables with a lower starting voltage will mean that the transmitter/receiver will draw power in a different way and the end-point voltage will come much quicker.
 
At £65 for one battery, and £120 for the charger - that's serious money. Just having two for each pack is expensive. They don't do a multi charger that I'm aware of so if you need to charge 12 batteries between shows then you need six chargers. So that's £1500 for a power system that assumes you have time to recharge. If you want a spare battery for each receiver, that puts the cost up to over two grand! Fair enough - I've got a lot of them, but two batteries and a charger comes to £250. Break even comes at 500 charges - I wonder how many charge cycles the cells are rated for?
 
Thanks for the help guys. Looks like the Eneloops will be put into my wireless keyboard and mouse instead of my wireless mics.
 
Yes, with 1.2V rechargeable batteries, the batt. meter and low batt. warning indicators are not very accurate, so if one is not used to a regimented numbered battery charge/replacement system, I would also recommend good quality non-rechargeable batts.
But as I previously stated, audio and reception differences are negligible.. in my professional opinion.. though I have not done any scientific tests.. and don't have time to do so in the foreseeable future. But that would be a good task for John to conduct if he has the time and inclination to do so thank-you.
 
I've never detected a quality change in the audio as terminal voltage drops. Rf output is usually the first to suffer, so rechargeables just mean a very rapid death at the end instead of the more gentle voltage tail-off we get with ordinary batteries.
 
On the other hand, the new Duracell 'Quantum' (Hi-Density Core™) alkalines seem to have a long run-time in my SD-302. I got 20 AAs on sale for 12.99 at the local Shoprite. (N/E US burbs supermarket chain) Again, no scientific price= ma/hr. evaluation. However.. Larry Fisher, Pres. of Lectrosonics concurs with my finding and performed an actual test.
 
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The other possibility is to buy the cords that power the G3's, and then plug them into your master power supply. You have to wire them. $62 or so.
 
There's not a lot of difference between alkaline batteries... I get >10hrs G2 run out of semi-generic ~$10, 100-per-pack "Utilitech" AA's from Lowe's, so I've never seen a need to spend more on premium name-brand batteries.

The exception are the clearly Chinese-slave-labor manufactured varieties which are noticeably lighter-weight than your average AA alkaline... they may work, but voltage on them is unreliable and lifespan is nearly non-existent.

Never had any luck with standard rechargeables in anything other than toys and remotes.
 
My own theatre rule is one show - one set of batteries, then give the half empty ones to the crew, cast and anyone who wants them. Using the for two shows is risky. Both G2 and G3 run batteries down when switched off. Not badly, but there is current flowing when switched off.
 
Sennheiser specifes 'Two AA size batteries, 1.5V'. That rules out rechargables. They also specify a nominal voltage of 2.4 volts for the two batteries.

The nominal voltage of an alkaline is 1.5V x 2 = 3.0 volts (plenty of margin)
The nominal voltage of a rechargable Ni-cad is 1.2V x 2 = 2.4 volts (no margin)
The nominal voltage of a rechargable Ni-Mh is 1.2V x 2 = 2.4 volts (no margin)

I looked at some discharge curves and actually, I don't see a problem with the rechargables supporting the 2.4 V nominal voltage with the Sennheiser current draw. But the proof is in the peformance.
 
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