Battery Regulator Assembly
Battery assembly requires soldering several surface mount components. The person doing the assembly is assumed to be skilled with a soldering iron and familiar with soldering 0402 sized components. If you aren't, find somebody who is or keep the temperature on low, don't get frustrated, and lets get started. The battery is considered easier to assemble than the controller daughterboard and is a good place to start if you are rusty.
The Bill of Materials (BOM) available on GitHub provides a component listing necessary for complete regulator assembly. Please refer to the latest version here. It is advised to order at least enough parts for 1 more regulator than you need. This will provide the necessary margin in case a part is damaged during assembly.
|Step 1: Solder 0402 resistors (R4, R6) and verify correct installation with multimeter. These parts are very small and can be hard to work with. Get them out of the way first.|
|Step 2: Install remaining resistors R1 - R7.|
|Step 3: Install C1, C2, C7, D1, M1.|
|Step 4: Install L1, make sure gap between contacts on the underside of the inductor lines up properly with the gap in the copper below.|
|Step 5: Install D1.|
|Step 6: Install C3, this must be installed as close to the center of the board as possible. There is very little tolerance between this component and the shell.|
|Step 7: Install C4, C5, C6, these components also have very little clearance with the shell, it is best to tack down one side of each of the three caps then with the shell determine if any of the caps need to be slightly relocated to fit. Once well placed, solder down both sides of the cap well.|
|Step 8: Install S1, the pins on this device must be bent over 90 degrees to resemble a Right Angle component. We found it necessary to run copper wires from the bottom to secure this component in place. Held only by solder this part will break off, it is recommended to secure it down with epoxy.|
|Switch before Right Angle Bending|
|Step 9: Install J1 and J2, these parts require precise placement otherwise the battery will not make contact. It is recommended to use the battery for sizing but be sure and do not let the battery contact the regulator! We have not tested it yet!|
Review all of the solder joints visually, make sure joints look clean and shiny, this is a good point to clean off flux etc. Rather than electrically testing the board thoroughly, a good visual check will suffice to save time. Best catch poor connections now!
If the visual checks look ok, check the resistance between ground and Vin, the resistance should be on the order of a megaohm.
Measure the connection between the positive battery contact and Vin, toggle the switch and verify switching between open and closed circuit.
The resistance between ground and Vout should also be on the order of a megaohm. Because of the large capacitance on Vin and Vout the resistance will float around a bit, we are just checking for shorts.
I recommend probing around further and verify things aren't shorting where they should not be. These are the key things to check however.
Connect the positive and negative battery contacts to a power supply. Set the supply to between 6.5v and 8v. Measure the voltage on Vout and toggle the switch, in one position you should see about 14.5V, with 100mV or so of noise. When the switch is in the off position Vout should discharge down to Gnd.
The regulator has now been tested and can be integrated into the shell. The power supply has been used in the place of the battery. If the PSU worked then the battery will work as well.