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Old Jan 12, 2012, 11:54 AM
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The definite Guide to Power connectors, charging, and other power related questions

#16 Camera

Since the same questions keep coming up on a regular basis, I'll try and clarify things in this guide. I have intentionally avoided using technical jargon where possible. The guide is designed as a reference for the most common power-related questions and is thus fairly long. However, I hope you will find the answer to your question.

This post will be kept up to date.

A #16 keychain camera will run about 40-45 minutes from a new fully charged internal battery. Recording in cold weather will drastically reduce the recording time.
Since you can't physically turn the battery off, the battery will always drain in order to keep the clock running. I don't know how long it will take to completely drain the battery, but I would expect a year, most probably much longer.
The camera can be configured either manually by editing an ASCII text file or much more conveniently by using the Nr16Setup program (see post #11).
Recording without sound will give longer recording times. Likewise, recording with a video data rate of 10mb/s will decrease the recording times. The recording indicator (flashing LED while recording) has no noticeable effect on the recording times. The recording indicator can be turned on or off in the configuration utility / text file.
The camera always records "clips" of a given length. The clip lengths can be set in the configuration utility / text file (see above). After the camera has written a clip, it will automatically create and record a new clip. This procedure will be repeated until the battery reaches a given threshold (runs out of power) or the flash card is full. If the camera is configured for loop recording, the oldest clips will be overwritten and recording will continue until there is no more internal or external power. Normally, there is a 2-3 second "gap" between clips.

Internal battery
The internal battery is a lithium polymer cell (LIPO), which, when fully charged, has a capacity of 4.2V. The camera will turn off when the battery voltage reaches approx. 3.5V.
The battery is user replaceable and comes with a tiny 2-pin connector. Instructions for replacing the battery can be found in the "Simple Instructions" manual (User Guide) supplied in pdf form by the manufacturer or downloaded here.
Since a connected external USB power supply will always supply more power than the camera functions require, the internal LIPO will be charged even when using the camera in Disk Mode, Webcam Mode, or Recording.
Battery protection circuitry is built into the camera. For this reason you should not replace the internal battery with another type of battery (for example Li-Ion). It is, however, possible to connect an external LIPO 1S battery in place of the internal battery but it should be recharged using an external charger.
The built-in charger circuitry is designed to charge a 250mAh LIPO. A depleted battery will take between 2 and 2.5 hours to fully charge with the camera turned off. The green LED will be extinguished when the battery is fully charged. It is safe to assume the battery is fully charged after 2.5 hours even if the green LED is still lit.
You should never connect a second battery in series. Doing so will destroy your camera because the voltage is the sum of all the battery volts.
You should also not connect batteries in parallel unless they have been properly "balanced" by an external charger. If the cells are not at the same state of charge, the higher charged cell(s) will try to charge the lower charged cell(s) with no current limit. This could damage the cells and cause dangerous overheating of cells and wiring.
If you replace the internal battery with another source of power (battery, charger, etc.) the supplied voltage must not exceed 4.2V (5V is not permitted on the battery connector). Doing so may initially work but will over-stress other components and will most likely lead to premature camera failure. If you must connect a 5V supply to the battery connector, then use a small diode (e.g. 1N4001) wired in series in the positive line. This will drop the voltage by about 0.7V. You obviously have to connect the diode correctly or no current will flow!

Using an external single cell LIPO in place of the internal battery
Some users my prefer to use a larger single cell LIPO in place of the standard one. This is possible so long the internal battery is never connected at the same time. "might" made a useful modification by incorporating a tiny switch into the camera casing in order to select the internal or the external LIPO cell. You should note, however, that charging a larger battery will take a very long time. Also remember that every time you disconnect the battery from the board, even very, very briefly, the internal clock will be reset. This will also occur if you use a switch because the power is briefly interrupted while you switch from one battery to the other.

The USB cable
A standard USB cable has +5V connected to pin #1 of the camera's USB socket and -V (ground / earth) connected to pin #5 of the camera's USB socket.
In V1 and V2 cameras the two center wires (Pin #2 and Pin #3) are the data lines and are only used when the camera is connected to a computer. They are not used when the camera is connected to an external power source such as car battery charger, external wall charger (mains charger), external USB power pack etc.
The camera "tests" the data wires to determine the connection type. Pin #4, which is sometimes called Pin x, is not used on V1 cameras.
V3 cameras (from ~January 2014) use a different cable. When pin #4 is shorted to pin #5 the data wires are used for A/V out where Pin #2 is Video Out and Pin #3 is Audio Out. Audio Out is only used in playback mode.
A word of caution for #11 owners: The first, prototype, versions of the #16 had Pin #4 connected to ground (earth). If a #11 cable was used, the cable was shorted! Owners of the #11 should double-check they only use standard USB cables and not the #11 special cable. All V1 "production" cameras should come with Pin #4 disconnected. On V2 cameras, Pin #4 is used for the video-out signal. If you use the #11 special cable you will destroy your V2 or V3 camera!
Picture of a V1 camera provided by Tom.

Picture showing the correct wiring for a standard USB charging cable for Hardware V1 and V2 cameras only. The data wires are not necessary if the cable is only used for charging.

Quick Note:
Pin #2 and #3 are the standard data lines. On V2 cameras, Pin #4 at the mini USB end is used for the video-out signal. The mini USB plug is standard. Only pin #4 is non-standard because the pin is not used in the USB specification. The video-out connection requires pin #4 (Video-Out) and pin #5 (GND). Charging and/or external power requires pin #1 (+5V) and pin #5 (GND)

The latest V3 cameras (Hardware V3 ~January 2014) use the same pin connections as the Mobius Action Cam:

Charging only, using a standard USB charger
When charging, the green LED will be on.
When fully charged, the green LED will be off.
The camera can be charged by any standard *USB source. This includes:
USB mains adapters (wall adapters), e.g. mobile phone chargers, navigation chargers, USB chargers, etc.
USB standard car battery chargers.
USB backup batteries designed to power/charge mobile phones, navigation devices, etc.
USB computer connection.
* Not all USB devices can supply enough current to charge the internal battery. Most mobile phones etc. will NOT be able to charge the battery. Surprisingly, even an iPad cannot charge or connect to the camera.

Simultaneous Charging and Recording using standard USB cables/adapters
The cable can be connected to any USB power source as long as the power source can supply 5 Volts under load. Note: Some USB hubs do not supply enough current. If the USB hub can't supply a nominal voltage under load, the camera will run on the internal battery which will be flat before the battery has a chance to charge!
When powering from the computer, the recording must be started before connecting the USB.
When powering from an external USB power source, the cable can be connected at any time, e.g. when the camera is turned off, before starting the recording, during the recording.

Using external power it is possible to record up to 10 hours of continuous video (many clips created automatically) using a 32GB micro SD card. A 64GB micro SDXC card, formatted as FAT32, will give you up to 20 hours! (see instruction manual integrated into the setup program).
I highly recommend the Just Mobile Gum Pro PP-08 (see picture below), but any other USB high power external battery power packs will also work.

The current draw was measured by wszim in post #1270 on the original thread.
When the camera is turned off, the RTC and processor draws about 120μA. I find this difficult to believe, but have also verified the value on my ammeter.
When the camera is turned on, but in standby mode, the camera consumes about 120mA.
When the camera is recording, the camera draws between 220mA and 300mA.
When the camera is off and charging, the current draw is 120mA.
When the camera is in removable storage mode, the charging current is less than 20mA. This translates to a VERY LONG charging time (maybe 17hours?) if the battery is flat!
When the camera is in Motion Detect standby mode (waiting for movement), the current draw is approx 130mA. A new battery will need recharging after about 86 minutes.
In order to protect the battery, the camera will stop recording and turn off when the voltage falls below approx. 3.5V.

The above figures are not definite, but serve as a guide.

Using the camera with only external USB power (internal battery disconnected)
The camera can be used without the external battery connected. Remember that the RTC (Real Time Clock) will be reset every time the external USB power is removed.
The camera requires an absolute minimum of 4.18V to operate correctly. This value may vary with the type of card used. I would think 4.3V would be a safer figure.
Using a 5V supply, the current required is at a minimum 220mA.

It is not possible to power the camera without an internal battery using 4 AA/AAA cells unless they are connected directly. Most commercially available cheap so-called "USB Backup" units which use 4 AA/AAA cells incorporate a primitive reverse-protection diode which reduces the available voltage, under load, to approx. 4.1V (4 x 1.2V - 0.7V voltage drop).

More expensive units may incorporate step-up electronics which ensure an accurate 5V (+/- 5%), but at the cost of power.

It is not a good idea to use 4 AA/AAA cells if you want to power the #16 directly without an internal battery, unless the output is regulated to 5V. Dedicated USB power packs or 5V converters designed to output 5V are the much better choice. Even with an internal battery installed, I cannot recommend using 4 AA/AAA cells as external power. I have stated this many, many times. Of course there are exceptions.

A word of WARNING
External power should be a nominal 5V. Fractionally higher voltages (such as from a fully charged 4 cell NiMH battery pack) can be tolerated without undue stress of the camera components

RC electric plane models - Warning
It is not recommended to plug the camera into a spare channel on the receiver. This may work, but it may also cause complete shutdown of the external electronics. If the voltage supplied to the camera's USB port is in excess of 5V (5%) there is also the risk of over stressing the camera's circuitry.
When recording, the camera draws as much power as a mini servo... and a bit higher when also outputting composite video for FPV. If the receiver is being powered by a separate battery, then the solution may work as long as the battery can handle the extra current. If the receiver is being powered by a linear BEC circuit on the motor ESC, adding the camera to that circuit may overload it and cause it to go into thermal shutdown, which in that case would mean total loss of control and a crash scenario!
If you must use a spare channel on the receiver, the complete electrical circuit needs to be taken into account and no components should become warmer than usual.

Here are some commercial external USB battery powered chargers
You cannot use a battery box with only 3 AAA / 3 AA batteries unless it incorporates step-up electronics to output 5V.
3 Batteries can only supply about 3.6V, but the camera requires a minimum of approx. 4.7V constant voltage. It will not charge or record when the voltage falls below approx. 4.3V.
A word of warning. Some 'Intelligent' power packs have recently appeared on the market that shut down when the current draw drops below 50mA! Don't use these chargers - they will most likely not work correctly and may even cause damage to your camera. A power pack that automatically turns off defeats the whole idea of using external power!

This is the cheapest, about $4-$5 on eBay
At first, I was not at all satisfied with the results using AAA rechargeable. I could only record up to 68 minutes using 1000 mAh batteries. Tom had told us that he obtained 123 minutes recording on his #11 camera using only 800 mAh batteries.
In my battery case there was a reverse-protection diode. After removing the diode I obtained much better results, but still not as good as Tom.
Further investigation, or better said, more testing, showed that after each test I could record for longer periods! It turns out that it is necessary to fully charge and then completely discharge the new batteries about 10 times using a good quality charger. My charger indicates the voltage of each cell as well as the percentage of charge. I believe a visual display is important. My other chargers do not have this.
Also, the total recording time appears to depend on the size of the memory card.
Four fully charged and conditioned AAA 800 mAh cells should be capable of providing a total recording time from between 1hr. 30mins. up to 3hrs. 50mins, where 2hrs. 30mins. seems to be a good average.
My charger takes just over 4 hours to fully charge the depleted cells. Faster chargers are available.
It is very important that you remove the reverse protection diode, if one is installed. Failing to do so will decrease the total recording time drastically to max. 68 mins.

Cost about $30 in 2009 on eBay

Expensive, but by far the best. Costs more than $45. Can also be found on eBay. A real power horse!

Price about $17 (without the camera) sold on eBay by the #16 camera stores. I have not tested the battery pack. If the seller does not list the battery pack separately, I suggest you ask for the price. #16 sellers are very obliging!

Car Charger (optional)
The optional car charger converts 12V DC into 5V DC. The center pin is the +5V and one of the connectors on the side is Ground (Earth). Any standard USB cable can be used together with the car charger.
If the car charger electronics are used with or without the casing to power the camera from a different 12V power source (external 3S lipo packs, for example), then the circuit will work well, but is probably too large to be practical.
Any 12V - 15V DC sources which need to be converted to 5V must go thru the car charger electronics (or similar regulator). You must NEVER bypass these electronics or apply 12V directly to the camera - doing so will destroy the camera.

Tom made his own 4 cell AAA External Battery Pack for the #11 camera. Use a standard USB cable instead of the "special" cable used by the #11. He added an LED to a standard battery holder. You can view his post here.

Here's a real "quicky" using 4 AA cells done by a1242629. Once again, use a standard USB cable instead of the "special" cable used by the #11.

DIY 3S LiPo Voltage Converter
bouzx6r has posted a simple method of converting a cheap car battery charger (see above picture) into a 3S LiPo-to-5V voltage converter. His idea may not be as small and compact as commercially available devices, but it's most probably just as good or even better. Click here for the original link with pictures.
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Last edited by Isoprop; Sep 24, 2014 at 10:41 AM.
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