Skip to end of metadata
Go to start of metadata

You are viewing an old version of this page. View the current version.

Compare with Current View Page History

« Previous Version 4 Next »

  • Wire the MPPTs in series instead of having high current traces on solar sense.

    • Reduces parasitic impedance

    • Reduces the number of high current rated connectors and wires required.

  • Cheaper isolators

    • Current SPI isolators have a built-in power isolator as well, which is convenient but it’s more expensive than an external voltage isolator.

    • Ideally, the MPPT would power the isolated side directly from the array.

  • Use ADCs with SPI or an MPPT with I2C?

    • Only 1 type of isolator would be required.

  • Non-automotive relay?

    • Current relay is labelled on Digikey as “automotive”, but the datasheet doesn’t mention anything about automotive certifications.

    • There are much cheaper “non-automotive“ relays on Digikey that consume less power (as far as I know, the relay driver circuit on solar sense has not worked).

  • If the PCB is smaller, it might be cheaper to have a 4 layer PCB, rather than a 2 layer PCB with 2 oz copper.

  • Increase the resistance values for I2C pull-ups? Can choose to sacrifice on the I2C bus speed in favour of lower power consumption with higher resistance. Will need to confirm that pull-ups are compatible with all I2C devices on the bus (to be done after all parts are finalized). Power savings may be negligible.

  • Adjust current-limiting resistor values for LED2 and LED3? A lot more current flows through LED2 even though it is the same part as LED3. Possibly more/less current is necessary.

  • As per note on Thermal Management sheet: Need to replace caps with more appropriate size for noise filtration on long temperature sense lines.

  • Possibly redesign relay circuit as it has been problematic in the previous iteration.

  • Make power rail test points in more convenient locations on the PCB (away from LEDs and other test points)

  • List of components that need to be re-examined and possibly replaced. Numberings correspond to BOM

    • 14. D2: DIODE ZENER 6.2V 5W DO214AA (min qty is 3000)

    • 17. D6: DIODE ZENER 15V 500MW SOD523 (not in stock)

    • 18. F1: FUSE 12 A 600VAC/DC KLM-12 (expensive)

    • 19. K1: RELAY AUTOMOTIVE SPST 15A 12V (expensive)

    • 31. Q1: MOSFET N-CH 250V 64A TO263-3 (weird vendor, unknown min qty)

    • 52. U1, U4_1-6: IC ADC MCP3427 10MSOP (not in stock)

    • 56. U6_1-6: IC DGTL ISOL 2500VRMS 2CH I2C 8SOIC (not in stock)

    • 57. U7_1-6: IC DGTL ISO 5KV 4CH GE (not in stock)

    • 58. U8: ACS722LLCTR-10AB-T (not in stock)

    • 61. U11: IC OP AMP DUAL GP RR 10MHZ 8-VSSOP (not in stock)

    • 63. U13: IC GATE NAND 1CH-2-IN (sus vendors?)

  • No labels