GH2 GH2 external battery, making strange noises...

[Framerate]

I know there are some really clued-up people here when it comes to batteries, so I'd really appreciate some advice.

I bought an 8.4v Lithium Polymer battery to use with my GH2, via the offcial DCC8 coupler.

This is the battery: http://www.batteryonline.org.uk/showimage.php?products_id=EDC012SK

The specs are 8.4 volts, 2 amps, max 21Wh. The voltage after charging measured 8.9 volts across the DCC8 terminals.

I know it's not a very big capacity but it's small and light, and has an LED charge remaining function. It came with a selection of leads and adaptors, one of which was a perfect, polarity correct, fit for the DCC8 pigtail socket.

Charged it up - didn't get very hot, and then (after a quick prayer) plugged it into the GH2.

Everything was fine - the camera worked as per normal.

However, I was aware of a quiet 'fizzing' sound from the battery when the camera was powered on (but not recording)

Shooting video increased the battery noise to a louder 'fizz', intespersed with fairly high frequency whines of varying pitch. Hard to accurately describe it - but it was making noises

I've never owned any sort of rechargeable battery that made a noise under load - however, I've never owned a Lithium Polymer battery before, so I don't know if this is what they 'do'

I wasn't happy using it so I emailed the seller, who also advised against use, and said he'd consult 'his engineer'......

I've heard nothing for a couple of days and I'm on the point of returning it - but, if the noise is par for the course with Li-Poly batteries I'd certainly keep it because of the other advantages.

So - *do* Li-Poly battries make a noise when dischaging under load?, or is the thing about to explode?

Your advice gratefully received.

 

[Ed Kishel]

You just found a gh2 without the band issue, I wouldn't risk it
We use li-polymer batts at work and they are as quiet as a church mouse...

 

[Framerate]

You just found a gh2 without the band issue, I wouldn't risk it
We use li-polymer batts at work and they are as quiet as a church mouse...

Ah, thanks for that. It's pretty much what I suspected - but not having used a Li-Poly battery before I was a bit unsure whther the noises were part & parcel of the experience. I did, actually, think how ironic it wuld be if one of the only 10 'good' gh2's in the entire world got blown up by a dodgy third party battery :cheesy:

Back it goes - a shame, because it's a handy size, has the LED status check, and has all necessary leads and connectors in 'one box' solution.

I don't know whether to try another sample (or perhaps try Li-ion?) , or just kick the whole idea into touch. The seller seems to be having some difficulty consulting his 'engineer' about the issue - at least, he hasn't been in further contact despite another query from me.....

BTW to clarify, the noise can be heard quite clearly in a quiet room from about, say, 2 foot distance.

 

[adolgin]

Framerate, the batteries (Li-Pol or Li-Ion) can not make noise by themselfs as they are just that - several cells connected together, no "moving parts." The thing is Li-Ion/LiPol cells can not produce 8.4V, or 5V as chemically they are set to produce ~3.7V multiplied by a number of cells. So in case somebody needs 8.4V or any other fixed voltage, they integrate electronic circuits in the package capable of converting the cell voltage into the custom set 8.4V. If that circuit is cheaply made, it can make all kinds of noises that you hear. Btw good luck waiting for the "engineer" expanation who is somewhere in China probably

 

[aguia]

It sounds like components in the batt case are faulty. You mention an LED status light, there has to be a little board inside that has some caps on it and one of the caps is bad (capacitors can make noise). My guess is that its actually a 12v cel with a voltage converter that also has an LED on the same board, I say this because I built my own external batt for my AF100 that outputs both 7.2v and 12v with a similar setup. FWIW there have been a $hitload of bad capacitor stories originating in China over the past 5 years, the problem extends to things like computer motherboards for high-end HP workstations and such.

 

[Framerate]

It sounds like components in the batt case are faulty. You mention an LED status light, there has to be a little board inside that has some caps on it and one of the caps is bad (capacitors can make noise). My guess is that its actually a 12v cel with a voltage converter that also has an LED on the same board, I say this because I built my own external batt for my AF100 that outputs both 7.2v and 12v with a similar setup. FWIW there have been a $hitload of bad capacitor stories originating in China over the past 5 years, the problem extends to things like computer motherboards for high-end HP workstations and such.

@Aquia - Thanks very much - I hadn't entertained the possibility of it being 12 volts reduced to 8.4, but if that's the cheapest option (is it?) then I suppose that's wht they would do.

@Alex - thanks also for your input. I'm puzzled by the mention of 3.7 volts per cell for Li-Poly. I did some Wiki research which suggested that the most usual Li-Poly cells are 4.2 volts (which, coupled together would give the claimed 8.4 volts) obviously this is incorrect, and I'm more than happy to accept your own expertise.

What about Aquia's suggestion that it might be a 12 volt cell that's been converted down? The fully charged voltage measured 8.9 volts (which was what I relied upon to provide the slightly in excess of 8.4 volts required by the GH2 when used with the DC adaptor)

Although the extra voltage was neceesary for GH2 operation, I was slightly puzzled because I'd also read that Li-Poly batteries had a very tightly controlled charge and shouldn't be getting up to 8.9 volts. Obviously, if the battery *is* a 12 volt cell (as per Aquia's theory) then it would explain the 8.9 volts?

Either way, it seems to be getting riskier by the minute

 

[adolgin]

You are welcome. The cells are indeed 4.2V fully charged, dropping down to approximately 3V for the fully drained state. 3.7V is somewhat of a mid point in the slope. They could be using a 2 cell design with a voltage booster, or 3 cell design with a step down regulator. Both approaches will work. In any case without a voltage converting circuit there is no way to produce either 8.4 or 5V. Regards

 

[Phenixone]

I personally use the Dolgin plate made by @adolgin for my Panasonic batteries. Now my GH2 can use AF100 and HPX170 batteries. It is great!
It has an optional secondary output for my monitor andalso has a light to see the batt. charge and I swap batteries in no time. Love it!



PS: my rig changed a bit since. cables are not flying anymore and tape has been replaces by strong velcro.

http://dolgin.net/zen_dolgin/index.php?main_page=product_info&cPath=18&products_id=99

 

[Framerate]

You are welcome. The cells are indeed 4.2V fully charged, dropping down to approximately 3V for the fully drained state. 3.7V is somewhat of a mid point in the slope. They could be using a 2 cell design with a voltage booster, or 3 cell design with a step down regulator. Both approaches will work. In any case without a voltage converting circuit there is no way to produce either 8.4 or 5V. Regards

Thanks again.

By those figures it seems that, as the battery is producing 8.9 volts charged, they must be using more than two cells and stepping the voltage down (albeit innacurately)

Is it possible that they could have used only 2 cells, but that the charging process is not as controlled as it should be, resulting in the 8.9 volts?

Bottom line - assumng that it's a step down circuit that's producing the noise, how risky is it to use? (in your completely 'no guarantee' honest opinion, of course)