View Full Version : Lithium Ion Battery - off topic

01-23-2012, 08:07 PM
I have a bit of an off-topic question....
I'm working on a PTZ camera project controlled by a prop chip for my shop. I have a few older sony digital cameras model: DCR-TRV30 and DCR-HC38.
Both of these cameras use lithium ion rechargeable battery's and I do not have the AC/DC power cable.
I need to power one of them with 110vac and was hoping I could simply use a regulated DC supply to power either one of them.
I found both of the cameras voltage input is 7.5vdc for the battery input and DC power input, but both battery and DC in connectors have 3-pins.
I slid some wire into the connectors and went ahead and tried using 7.5vdc to the +/-, but it powers on for 3 sec then displays "replace battery or AC adapter".
I'm assuming this is because nothing is connected to the 3rd pin.
I researched what I could, but info is limited... all I could find is that the 3rd pin on LiIon batterys is for a thermosensor.

Does anyone know how to power one of these 3-pin cameras using a regulated DC supply ?
guessing I need a specific voltage to the 3rd pin?

01-24-2012, 12:04 AM
This is most likely a thermistor connected to the negative or positive side of the battery. Measure the resistance of the thermistor on one of the batteries and use a resistor of similar value to jumper the pin to the negative or positive terminal. Then use an ac adapter with a 7.5-9VDC output.

A dead battery with the negative or positive contact insulated may also work. Still needs an ac adapter though.

Peter KG6LSE
01-24-2012, 02:55 AM
Welcome to SONY . All the consumer sony stuff has smart chips in it to Digitally talk to the cam or charger ..
So you cant just rig a Brick to it .
Here's what I did for a old TRV900. I used the batt and is PCB inside.
The cells are in series as to make 7.2 7.4 volts ,, so you need to apply your EXT DC where the cells used to be ...
and make some kind of voltage divider with OR use a LM reg to Fake a 3.2V ish per cell center tap ..

Peter .

01-24-2012, 03:42 AM
Details for the TRV30:
Resistance between the 3rd pin and negative of the battery input is 6.8k.
Resistance between the 3rd pin and negative of the AC adapter input is 2k.
Power meter on +/- of the Lith ion battery shows 8.4v... between the 3rd pin and negative is 3.5v.
When the battery is plugged into the camera (camera off) I get 8.1v from +/- on the AC adapter input plug, and 2.8v between the 3rd pin and negative of the AC adapter plug.

do the AC wall adapters from sony for directly powering the camera also have this chip inside them?
I do have a dead battery I can take apart... but it just seems odd they would put this same chip inside their AC adapters.
You can see the AC adapter input plug on the 3rd pic from the left, just between and below the illustrated "3" and "-".
Whadya think?

The + and - just bridge straight down through the circuit board to the batteries. There are no individual connectors from the PCB to each cell other than the bus line making them series.
So it should work if I disconnect the batteries from the PCB and connect the DC supply instead?
Is there a certain way to disconnect these? I know these batteries can be touchy

01-24-2012, 06:21 AM
I noticed the battery is wired a bit oddly.
I threw together a 3D model to illustrate it the best I can:

The batteries are connected in sets of 3 as illustrated, what isnt illustrated is that one set is upside down... so the top of one set of 3 is positive and the top of other set is negative.
Other than the '3rd pin' that runs vertical up the side, I do not see any connections from the bottom to the top.

Heres another with an attempt to show where the negative ends of the cells are.
Not exactly sure how to wire up a DC supply to replace the battery

Oh, this vertical connection does NOT directly connect to pin3.
The first pic in post 4 shows the vertical wire running up and connecting to the left of pin3

Loopy Byteloose
01-24-2012, 12:44 PM
When guessing voltages, it is better to bring the guess up in steps rather than risk an overvoltage - Overvoltage is what damages the ICs. So starting the third pin at something like 3 volts might be prudent and moving up slowly. The 7.5 volts seems about right. Often what is considered a 7.2 Lithium ion battery is set up to quit functioning at 7.2 volts and may take a charge up to nearly 9 volts. But there is no reason to go higher if 7.5 Volts works.

Peter KG6LSE
01-24-2012, 07:55 PM

FYI that is the digital pin
That ATMEL uses chip is why its a ""info lithuim" . it Comms Over that middle Pin .
master slave comms like in USB . the cam interrogates the bat for a ID then it tells the how much charge is max and min and what it is at right then .
Just like a laptop pack .

Great Idea in a "ideal " world . but it also makes the cam Very finicky with how it gets is power ..

As for the DC jack .. its about 8 V . enough overhead to full-charge the LI ION cells .
some where here I have its Pinout on my computer .. I want to say its not smart ! ( just DC ) ..

This is how your pack is now

Here is one way to fake the 3V needed to run the cam ....
I have NOT tested it to work . depending on how the 3V is sensed it( the bat PCB) may get confused .. The Diodes are to keep the smoke in .

any 1 Amp 1n400X should do .. the Reg is 3.3V .

Peter ....

01-24-2012, 08:48 PM
Thanks Peter, yes it is wired exactly like your first drawing.
So the main +/- in will be 7.5v, I have plenty of 1N4001 diodes, what should I use to get 3.3v on the middle pin? Maybe an LM317?
Or should I just use a resistor in voltage divider configuration to get 3.3v?

Peter KG6LSE
01-24-2012, 10:07 PM
See that is where depending on how its done to measure Batt life is gonna make one way better then the other .

the R/R is OK if its just sensing a "soft " voltage

but if its loading up the bottom batt with some kind of current . >10mA the Reg my just do better as it wont "sag" if the thing draws to much

Yup a 317 is OK.

a way to see how its senseing is follow the 3V tap trace to the 1st component it hits .. IF its a resistor and has a > 10 KΩ value or so
divider is alright . 1-3K OHM or so per R


02-16-2012, 11:01 AM
Ok finally got back to work on this...
I created the circuit as illustrated, but after wiring it up and connecting a multi-meter... I am only reading about 1vdc coming out of the circuit.
I have tried with 7.4vdc & 9vdc in, I get the same output regardless... the camera will not power on.

One thing that seems odd to me, is the middle pin on the LM317 really supposed to connect to ground?
Normally I would divide a resistor value by the 1.25v ref voltage to get the current output, and connect the resistor between the middle pin and output pin... I have never seen a schematic with the middle pin connected to a ground.

I have it wired up exactly as in the drawn schematic.
Using 1n4001 diodes, an LM317 and a 10uf 16v cap.

Any Idea why I am only getting about 1vdc?89619

02-16-2012, 01:56 PM
The LM317 connects to ground through the adjust resistor.

Peter KG6LSE
02-17-2012, 03:48 AM
that Middle pin is NOT the same as the middle tap point on the batt cells. its a Digital signal .. you HAVE to use the Batts PCB to make that cam turn on .. its Where the Cells Used to be is where you add your external Power .......
you have to fake the cells IN the bat back ..


02-17-2012, 07:03 PM
I have a digital 8 Sony TRV230E
I needed a larger battery power source and rather than pay for Sony's expensive accessories I made up a battery pack using ten NI Metal Hydride batterys and used a switched mode chip (National) diode, inductor, capacitor (few pounds) and plugged it into the standard camera power socket (not the battery connectors). Worked a treat without the battery in (with the battery in it happily charges it). The adapter for my camera is marked as 8.4v 1.5A so I adjusted the powersupply to give me 8.4v. I chopped of the camera connector from the power supply and attached it to my new power pack and .... well its still going after all these years.
Since Ni M Hi batteries in AA size can be got for about 1.50 and at 1.7 AHr (1700maH) this should give well over 2 AHr life (more than 3 times the original capacity). Note - charging multiple Li Ion batteries is no trivial task - think charge balancing, max current, max voltage etc, by comparison Ni M Hi are easy. Ok the result is bulky but.....

12-23-2012, 03:18 PM
Hey Guys,
Thought I would post an update on this since I did figure it out.
I found a very simple way to bypass the infolithium battery and can now power the camera with a brick/wallwart or other DC batteries.
Any DC supply from 6v to 7.5 works, I have not gone above 7.5v for fear of burning something out... the normal AC adapter supplies 8.4vdc so I imagine this to be the upper limit.

Trick is to use a combination of the AC input pins and battery input pins.
Looking at the AC adapter jack on the camera (where you plug in the sony power supply such as model ACL10A), there are 3 pins. One pin is on the bottom of the jack walls, the other 2 pins are on the top. The bottom pin is the positive, directly connect your new power source to this pin. Next you will connect the negative wire of your new power source to the negative battery terminal on the camera (see pic in post #10 above, the black wire is the negative battery terminal).
Finally, you need to jumper the negative connection you just made, to the third pin inside the AC adapter jack.
The third pin I am referring to is on the opposite side of where the positive pin is connected, so you will skip the pin in the middle.

Thats it! The camera powers up with no problem and does not give the error message I was getting in previous attempts.
Sorry, could not get a good picture of inside the AC jack.

12-23-2012, 06:23 PM
See that is where depending on how its done to measure Batt life is gonna make one way better then the other .

the R/R is OK if its just sensing a "soft " voltage

but if its loading up the bottom batt with some kind of current . >10mA the Reg my just do better as it wont "sag" if the thing draws to much

I think it might be quite complex to get this to work - the controller on the lithium pack has several roles.

Firstly it prevents the battery catching fire - that's its main function, and will cutout on over voltage, under voltage, over current or if
the two banks of cells are too imbalanced.

It also controls the charging of the cells (the middle tap is to ensure balanced charging and may take significant current
if the controller decides to charge the battery. It might also try to load each set of cells to judge their condition - without
the schematic of the battery controller its hard to know.

It is probably interrogated and directed by the camera (which will know if there is a DC charging plug inserted - the OP didn't
seem to have the right connector so the camera might not have thought there was power coming in and have failed-safe
by powering down when it saw a rise in voltage.

Trying to inject current at the battery terminals will likely fail because the controller needs to be convinced the battery voltage
and stage of charge match - it probably monitors current and voltage and time.

eBay for secondhand charger and cable??

12-23-2012, 07:05 PM
The problem is solved and is now operating on a stable voltage of 7.5v provided from an AC/DC switching supply.
My purpose was to power it from a 110vac wall outlet and completely eliminate dependency on any form of battery.... the lithium battery has already been properly disposed of.
Earlier attempts resulted in the camera recognizing it was not being powered from an InfoLithium battery or OEM Sony wall adapter and shutting itself down.
By wiring it in the configuration illustrated in post #14, the goal of using an alternate power source was accomplished.
By powering it this way, I am able to consolidate multiple power supplies into a single source for my project.