Assembly Instructions for the CirKits Solar Charge Controller and Low Voltage Disconnect circuit (C) G. Forrest Cook Nov 24, 1997 Rev Mar 1, 1998 Before beginning with the assembly of the circuit board, it is a good idea to have the proper tools. A 35 Watt or similar size soldering iron and fine gauge resin core solder is a must. A good pair of needle nose pliers and small wire cutters are also necessary. Solder absorbing copper braid or a solder vacuum device are also useful for cleaning up solder bridges. Care should be taken to avoid overheating any of the parts, especially the semiconductors. If you are mounting the circuit board in a box, you may want to mark the four mounting holes using the circuit board as a template before you solder the parts on. If you do not have any experience soldering circuit boards, it may be a good idea to seek help from an experienced person to get you started with the process. Insert and solder the components in the following order, see the circuit board pictorial for parts locations. Parts sit on the side with white markings, solder on the opposite side. Resistors 1X 22 ohm resistor (red red black gold) at R21 3X 2.2K ohm resistor (red red red gold) at R6, R10, and R20 1X 39K ohm resistor (orange white orange gold) at R4 1X 47K ohm resistor (yellow purple orange gold) at R8 3X 1M ohm resistor (brown black green gold) at R9, R18, an R19 8X 100K ohm resistor (brown black yellow gold) at R1, R2, R3, R7, R14, R15, R16, R17 There is no component installed at location R5 due to a circuit change. Inductors 2X either a ferrite bead on a wire or a 22 ohm resistor with 3 turns of resistor lead wrapped over the resistor at L1 and L2. Diodes Be sure to observe polarity on all of the diodes. 1X 1N4004 (small black diode) at D4 1X 80SQ045 Schottky Diode (big black diode) at D1 9X 1N4148 (tiny glass diodes) at D5, D6, D7, D8, D9, D10, D11, D12, D13 Capacitors 2X 0.001uF (may be marked 102) at C9, C10 17X 0.1uF (may be marked 104) at C1, C2, C3, C4, C5, C6, C7, C8, C11, C12, C13, C14, C15, C16, C17, C18, C21 C23 4.7uF, not marked on the board, it will bridge pins 2 and 6 on top of the 741 op-amp, U2, - on pin 2, + on pin 6. See the ICs section below for more info on the placement of C23. Observe polarity with the two electrolytic capacitors, the - sign on capacitor goes opposite of + sign on circuit board. 2X 220uf at C20 and C22 Trimmer Potentiometers 4X 100K trimmers at R11, R12, R13, R22, screws towards board edge. Fuse 2X fuse clips at F1, install 10 Amp fuse before soldering. F2 is only used if the board is to be cut in half for individual circuits. Terminal Block 2X 3 pin terminal block at the back of the board, slide the pieces together before soldering. Solder the connector into the SP/BAT/LOAD terminals, do not use the terminals labeled BAT near C18, they are for the LVD circuit if the board is cut in half for seperate circuits. Transistor 1X 2N3906 at Q2, orient the flat side as shown on the board marking. LEDs Align the flat sides of the LEDs with the board markings. Red at D2, Green at D3. You may want to extend the LEDs to the front panel of a box with wires. Be sure to heat sink the LED leads while soldering, they are VERY heat sensitive. ICs Orient the ICs so the notches line up with the board markings. 2X 78L05 at U4, U6, orient as shown on the board pictorial. 1X 4011 at U3, ground your sparks, this part is static sensitive. 1X 741 at U2, solder C23(+) into the vacant R5 hole nearest U2, the capacitor can be bent sideways to sit on top of the R5 marking. C23(-) connects to U2 pin 2, next to the "C2" marking on the board, be careful not to overheat U2 when soldering to pin 2. 2X 1458 at U1, U5. These parts may be marked MC4558CP. --u-- Here are the pins numbers <1 8> of the op-amps as seen from <2 7> the tops of the 8 pin ICs. <3 6> <4 5> ----- MOSFETS 2X IRFZ34 at Q1, Q4, the metal tab should go towards the board edge. Install the heat sink on the transistors before soldering, see the schematic for a picture of the orientation. These parts are static sensitive, ground yourself. Switch Leads ON/OFF Switch The regular switch configuration for the LVD circuit is a DPDT switch, mount the switch on a box and wire the leads directly to the S1 pads on the circuit board in the same pattern as the back of the switch. Be careful soldering the switch leads, the plastic melts easily. ON/OFF Pushbutton You may want the LVD circuit to be controlled with pushbuttons. Also, some higher current loads may not switch on reliably with the DPDT switch arrangement. After adjustment, with if the load turns on momentarily then turns off change the switch to a pair of pushbutton switches. Connect the "on" pushbutton between the S1 pad on the lower right nearest C16 and the side of C16 nearest potentiometer R22. The "off" pushbutton should connect between the upper left pad for S1 and the side of R20 that is next to potentiometer R22. Equalize Switch An optional SPST equalize switch may be connected across potentiometer R12 between the center lead and the lead closest to the edge of the circuit board. The equalize switch is used as a manual control for occasionally overcharging the battery, turn the switch on during charging on occasion to bring up the voltage of the weaker cells. External connections Insert 16 gauge stranded wires into the terminal block and tighten the screws. Note that it is possible to damage the screws by overtightening. It is a good idea to use red wires for plus contacts and black wires for minus contacts. It is best to wire the terminal block with the permanent wires, the connectors may not stand up to repeated use. Inspection Clean excess flux from the bottom of the board, inspect for solder bridges and remove any that are found. Double check for correct orientation of ICs, transistors, diodes, and electrolytic capacitors before applying power. If you do have to replace a part, it is easier to cut the part on the board and unsolder the pins individually, this lessens damage to the board. Tune Up Follow the alignment instructions for setting the potentiometers. Assembly into box At this point, you should be ready to install the circuit in a box, a metal case is highly recommended. Drill all of the holes first, then install the board, LEDs, and switch or switches. Mount the board on tubular stand-offs. If you have problems getting your board to work, CirKits will repair and align the board, if it is considered by us to be repairable, for a cost of $25 plus parts, mail the board and a check or postal money order to CirKits. In the event that more money is required for parts, we will return a postcard to you requesting the amount.