While we offer battery replacement as a service in our workshop at Ambient, we know that some of you would like to perform the replacement yourself. Here you go.
Be aware that general mechanical skills are required for the procedure. If you need help with a specific step, do not hesitate to contact Ambient support (support@ambient.de) for further assistance.
The NanoLockit uses a 3.7V Li-40B battery with a capacity of around 650 to 750mAh. The size is approx. 5.2mm height x 31mm width x 39mm length. When sourcing a battery, you can vary the capacity but stay away from unknown fishy brands and ridiculously high advertised capacities.
You will need a new front label for the NanoLockit. The front label can be bought from any Ambient dealer and is also available in our web shop. The Ambient part number is A02778 | NL-FB
You can also purchase a complete battery replacement kit from Ambient or any Ambient dealer. The kit includes a genuine battery with pre-attached wires as well as a front label.
Further required tools:
- Soldering iron
- T6 Torx or 1.3mm hex screw driver, depending on the Nano revision
- A Spanner for the notched 5-pin nut like the Lemo DCH.91.121.PA. (Makeshift tools like pliers can scratch the nut and the housing. You have been warned.)
Disassemble the housing to gain access to the battery
- Remove the front label first. Heat the label up with hot air for best results, then use a small (2mm) flat head screw driver to pry the label up at the edge. The best spot to do that is at the LED lens so you don't scratch the anodized housing.
- Remove the three screws beneath (1.3mm hex on older units and T6 Torx on later units) and loosen the 5-pin nut.
- Now you can separate the housing parts carefully. There are three small rubber O rings at the screw holes, so make sure not to lose those. The PCB remains in the front half and the battery is tacked in the rear half with double sided tape.
Replacing the battery
- Pry out the old battery from the housing
- If you have bought the Ambient Replacement kit (if not, check the next step), unsolder the wires on the on the board and discard the old battery and wires. Solder the new battery to the contacts on the board. The contact layout differs slightly depending on the NanoLockit revision. In any case, double-check the polarity! Reversing the polarity of the battery can damage the board! Also make sure not to short the wires during soldering. The batteries have an internal short circuit protection and should shut off in such a case. But you don't necessarily need to find out if it works.
- If you have bought a new battery elsewhere, unsolder the wires on the old battery and not on the board. Solder the new battery to the wires. Double-check the polarity! Plus = red, Minus = black. The thermistor contact in the middle is not used. Reversing the polarity on the battery can damage the board!
- Place the new battery in the housing. Either reuse the original tape or get a new piece of double-sided tape to tack it to the back.
Reassembling the NanoLockit
- Make sure to thoroughly clean the surface of the housing face from any glue residues that may still be left from the old front label. Depending on how well the sticker removal went, there may be a lot. Use alcohol or solvent to clean, but do so without the PCB inside the housing. Otherwise, the chemicals and glue residues might damage the board or the buttons!
- Make sure that the inner nut of the 5-pin connector does sit correctly (approximately flush with the PCB edge). Otherwise, the buttons will not be aligned properly in the housing and can jam when being pressed. Newer NanoLockits (starting with serial NLE…) do have a fixed collar on the 5-pin connector.
- Insert the screws and secure them in place with the three O rings. Put the two housing parts together and tighten the screws and the 5-pin nut. After tightening the nut, check if all three buttons work properly.
- If everything is cool, install a new front label (Ambient p/n A02778 | NL-FB). Simply align the three holes in the sticker with the button recesses for a perfect first-try fit.
Calibrating the battery
The NanoLockit requires a calibration routine in order to learn the new battery’s capacity. This is due to a small percentage of the battery capacity being preserved for maintaining the Real Time Clock (RTC). We need to remove the threshold and let the battery fully deplete one time.
If this step is skipped, runtime may be unexpectedly short.
- With a Micro USB cable, connect the NanoLockit to a Mac or PC with the LockitToolbox installed. While you are at it, feel free to update the firmware to the latest version. In case you don’t have it yet, the LockitToolbox can be found here: https://ambient.de/en/downloads
- Disable the RTC threshold in the LockitToolbox. The option can be found in the advanced settings, after selecting your Nano in the connected devices list.
- Fully charge the battery. Remove the NanoLockit from the USB cable, power it up and let it run completely dry. This will take approximately 35 hours, so go get some sleep in the meantime.
- When the Nano finally has powered down, connect the Nano to the Toolbox again and enable the RTC threshold again.
- You may choose to perform another runtime test to confirm that the resulting runtime is within specs. A fresh battery should at least last for 24 hours with the RTC buffer enabled.
Congratulations! You have survived the battery replacement
and restored your NanoLockit to its former glory.