# TANK_SENSOR_V1 ## Description Solar-powered single-cell LiFePO4 water-level transmitter with MPPT charging and protected panel input. ## Project Details - **Owner:** sirvi - **Created:** 8/22/2026 - **Last Updated:** 8/22/2026 - **Visibility:** Public ## Key Components ### D1 — [SS34](https://www.flux.ai/collinsemasi/ss34~qf.md) - Role: Reverse Polarity Protection - Role Details: Series SS34 40 V/3 A. REVIEW headroom: approximately 0.3-0.45 V forward drop at charge current adds to PTC drop - Manufacturer Name: NextGen Components Inc - Functional Group: Solar Input and Protection - Part Type: Diode - Datasheet URL: https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/5335/SMASS340000S34.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: SS34 **Pins:** - A [pin 2] - C [pin 1] ### D2 — [SMBJ18A-13-F](https://www.flux.ai/lcsc/smbj18a-13-f~uiys.md) - Role Details: REVIEW: provisional SMBJ18A, VRWM 18 V and max clamp 29.2 V; confirm solar-panel maximum Voc and surge profile before release - Functional Group: Solar Input and Protection - Product Info Url: https://lcsc.com/product-detail/TVS_DIODES_SMBJ18A-13-F_SMBJ18A-13-F_C135055.html - Manufacturer Name: DIODES(美台) - Role: Clamping - Part Type: TVS - Package or Case Code: SMB_L4.6-W3.6-LS5.3-RD - JLCPCB Part Class: Extended Part - Manufacturer Part Number: SMBJ18A-13-F - LCSC Part Number: C135055 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_Diodes-Incorporated-SMBJ18A-13-F_C135055.pdf **Pins:** - A [pin 2] - K [pin 1] ### D3 — [ZLLS350TA](https://www.flux.ai/lcsc/zlls350ta~vjrd.md) - Functional Group: Gate Drive and Power Stage - Manufacturer Name: DIODES(美台) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/1811122023_Diodes-Incorporated-ZLLS350TA_C139441.pdf - Role Details: U3 REGN to BTST high-side gate-drive bootstrap diode - Package or Case Code: SOD-523_L1.2-W0.8-LS1.6-RD - Manufacturer Part Number: ZLLS350TA - Product Info Url: https://lcsc.com/product-detail/Schottky-Barrier-Diodes-SBD_DIODES_ZLLS350TA_ZLLS350TA_C139441.html - LCSC Part Number: C139441 - JLCPCB Part Class: Extended Part - Part Type: Schottky Barrier Diodes (SBD) - Role: Bootstrapping **Pins:** - A [pin 2] - C [pin 1] ### F1 — [SMD1206P075TF/30](https://www.flux.ai/adrian95/smd1206p075tf30~aa.md) - LCSC Part Number: C46970778 - Role Details: 750 mA hold, 30 V PTC, about 90 mOhm initial resistance. REVIEW hot-ambient derating; at 0.5 A initial drop/loss is about 45 mV/22.5 mW - Manufacturer Part Number: SMD1206P075TF/30 - Datasheet URL: https://www.lcsc.com/datasheet/C46970778.pdf - Functional Group: Solar Input and Protection - License: https://creativecommons.org/licenses/by/4.0/ - Role: Protection - Manufacturer Name: RUILON - Part Type: Fuse **Pins:** - P1 [pin 1] - P2 [pin 2] ### F2 — [1206L100/33NR](https://www.flux.ai/adrian95/1206l10033nr~bzf.md) - Manufacturer Part Number: 1206L100/33NR - Functional Group: Battery 3.3V Regulator - Manufacturer Name: LUTE - Role Details: 1 A resettable fuse; protected single-cell LiFePO4 battery assumption. Do not bypass; BAT+ to F2 to BAT_FUSED. - Datasheet URL: https://www.lcsc.com/datasheet/C22435907.pdf - Current Rating: 1A - Part Type: Fuse - Role: Protection - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - P1 [pin 1] - P2 [pin 2] ### J1 — [1729128](https://www.flux.ai/adrian95/1729128~gmm.md) - Package or Case Code: 1729128 - Part Type: Connector - Datasheet URL: http://www.phoenixcontact.net/product/1729128 - Manufacturer Part Number: 1729128 - Role Details: Pin 1 SOLAR+, pin 2 GND; 5.08 mm screw terminal - Role: Input Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Phoenix Contact - Functional Group: Solar Input and Protection **Pins:** - 1 [pin 1] - 2 [pin 2] ### J2 — [1729128](https://www.flux.ai/adrian95/1729128~gmm.md) - Role Details: Pin 1 BAT+, pin 2 BAT-; single-cell LiFePO4 battery - Manufacturer Name: Phoenix Contact - License: https://creativecommons.org/licenses/by/4.0/ - Functional Group: Battery Interface - Package or Case Code: 1729128 - Part Type: Connector - Role: Battery Connector - Datasheet URL: http://www.phoenixcontact.net/product/1729128 - Manufacturer Part Number: 1729128 **Pins:** - 1 [pin 1] - 2 [pin 2] ### J3 — [Pin Header 01x04 2.54mm Vertical](https://www.flux.ai/adrian95/pin-header-01x04-254mm-vertical~l97.md) - Role Details: VREF, CHARGE_STATUS, CHARGE_DONE, GND - Role: Status Connector - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Functional Group: Status Interface **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] - Pin_4 [pin 4] ### J4 — [Pin Header 01x04 2.54mm Vertical](https://www.flux.ai/adrian95/pin-header-01x04-254mm-vertical~l97.md) - Role Details: Pin 1 3V3_SYS, pin 2 GND, pin 3 U0TXD, pin 4 U0RXD - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Role: Debug Connector - Functional Group: ESP32 Controller and Debug **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] - Pin_4 [pin 4] ### Q1 — [SI7288DP-T1-GE3](https://www.flux.ai/lcsc/si7288dp-t1-ge3~oj29.md) - Functional Group: Gate Drive and Power Stage - JLCPCB Part Class: Extended Part - LCSC Part Number: C126988 - Product Info Url: https://lcsc.com/product-detail/MOSFET_VISHAY_SI7288DP-T1-GE3_SI7288DP-T1-GE3_C126988.html - Role: Switching - Manufacturer Name: VISHAY(威世) - Role Details: High-side switch using both halves of dual Si7288DP in parallel; electrical choice verified. REVIEW Flux footprint naming/dimensions against official PowerPAK SO-8 land pattern before layout - Manufacturer Part Number: SI7288DP-T1-GE3 - Package or Case Code: DFN-8_L5.5-W5.2-P1.27-LS6.0-BR-EP2 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/1809191821_Vishay-Intertech-SI7288DP-T1-GE3_C126988.pdf - Part Type: MOSFETs **Pins:** - D1 [pin 6] - D1 [pin 6] - D2 [pin 5] - D2 [pin 5] - G1 [pin 2] - G2 [pin 4] - S1 [pin 1] - S2 [pin 3] ### Q2 — [SI7288DP-T1-GE3](https://www.flux.ai/lcsc/si7288dp-t1-ge3~oj29.md) - Part Type: MOSFETs - Role Details: Low-side switch using both halves of dual Si7288DP in parallel; electrical choice verified. REVIEW Flux footprint naming/dimensions against official PowerPAK SO-8 land pattern before layout - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/1809191821_Vishay-Intertech-SI7288DP-T1-GE3_C126988.pdf - Functional Group: Gate Drive and Power Stage - Manufacturer Name: VISHAY(威世) - Manufacturer Part Number: SI7288DP-T1-GE3 - Package or Case Code: DFN-8_L5.5-W5.2-P1.27-LS6.0-BR-EP2 - Product Info Url: https://lcsc.com/product-detail/MOSFET_VISHAY_SI7288DP-T1-GE3_SI7288DP-T1-GE3_C126988.html - JLCPCB Part Class: Extended Part - LCSC Part Number: C126988 - Role: Switching **Pins:** - D1 [pin 6] - D1 [pin 6] - D2 [pin 5] - D2 [pin 5] - G1 [pin 2] - G2 [pin 4] - S1 [pin 1] - S2 [pin 3] ### RT1 — [Semitec 103AT-2 Thermistor](https://www.flux.ai/reed-nowling/semitec-103at-2-thermistor~33.md) - Manufacturer Part Number: 103AT-2 - Functional Group: Battery Temperature Qualification - Datasheet URL: https://www.mouser.com/datasheet/2/362/semitec_atthermistor-1202913.pdf - Role: Sensing (Shunt) - Exclude from PCB: true - Manufacturer Name: Semitec - Role Details: 10 kOhm Semitec 103AT-2 NTC physically attached to battery; complete 5.23 kOhm/30.1 kOhm TS window network **Pins:** - undefined - undefined ### SW1 — [TS-1088-AR02016](https://www.flux.ai/lcsc/ts-1088-ar02016~e3n1.md) - Role: Human Interface - Functional Group: ESP32 Controller and Debug - Role Details: ESP32 RESET momentary normally-open button - Manufacturer Part Number: TS-1088-AR02016 - JLCPCB Part Class: Extended Part - LCSC Part Number: C720477 - Package or Case Code: SW-SMD_L3.9-W3.0-P4.45 - Manufacturer Name: XUNPU(讯普) - Product Info Url: https://lcsc.com/product-detail/Tactile-Switches_XUNPU-TS-1088-AR02016_C720477.html - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409302330_XUNPU-TS-1088-AR02016_C720477.pdf - Part Type: Tactile Switches **Pins:** - 1 [pin 1] - 2 [pin 2] ### SW2 — [TS-1088-AR02016](https://www.flux.ai/lcsc/ts-1088-ar02016~e3n1.md) - Manufacturer Name: XUNPU(讯普) - Package or Case Code: SW-SMD_L3.9-W3.0-P4.45 - Part Type: Tactile Switches - Role Details: ESP32 BOOT momentary normally-open button - Product Info Url: https://lcsc.com/product-detail/Tactile-Switches_XUNPU-TS-1088-AR02016_C720477.html - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409302330_XUNPU-TS-1088-AR02016_C720477.pdf - LCSC Part Number: C720477 - JLCPCB Part Class: Extended Part - Manufacturer Part Number: TS-1088-AR02016 - Role: Human Interface - Functional Group: ESP32 Controller and Debug **Pins:** - 1 [pin 1] - 2 [pin 2] ### TP_BAT — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: Measure protected post-fuse BAT_FUSED supply at U2 VIN - Functional Group: Battery 3.3V Regulator - Role: Test Point - Part Type: Test Point - Testpoint Size: 0.5 **Pins:** - P1 [pin 1] ### TP_GND — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: Test Point - Functional Group: Battery 3.3V Regulator - Role Details: Measure BAT- return; BAT- remains distinct from GND except existing explicit star link - Part Type: Test Point - Testpoint Size: 0.5 **Pins:** - P1 [pin 1] ### U2 — [TPS63900DSKR](https://www.flux.ai/lcsc/tps63900dskr~nuj5.md) - JLCPCB Part Class: Extended Part - Manufacturer Part Number: TPS63900DSKR - Part Type: DC-DC Converters - Manufacturer Name: TI(德州仪器) - Package or Case Code: WSON-10_L2.5-W2.5-W0.50-TL-EP - Role Details: TPS63900 buck-boost; SEL low and CFG3=16.2k set 3.3V. Protected 1-cell LiFePO4 assumption: 3.2V nominal, 3.6V full. - LCSC Part Number: C1518762 - Datasheet URL: https://www.lcsc.com/datasheet/C1518762.pdf?spm=wm.sxq.inf.ggs&lcsc_vid=FlVZVVIFFgBeVAVTT1BXUgFfEwJeVlBfEwVcAlMHRAQxVlNeR1RZUFZWRFFfUDsOAxUeFF5JWBYZEEoKFBINSQcJGk4dAgUUFAk%3D - Role: Power Regulation - Functional Group: Battery 3.3V Regulator **Pins:** - CFG1 [pin 3] - CFG2 [pin 4] - CFG3 [pin 5] - EN [pin 1] - EP [pin 11] - GND [pin 8] - LX1 [pin 9] - LX2 [pin 7] - SEL [pin 2] - VIN [pin 10] - VOUT [pin 6] ### U3 — [BQ24650RVAR](https://www.flux.ai/adrian95/bq24650rvar~aoc.md) - Role: Power Conversion - Role Details: BQ24650RVAR VQFN-16 plus exposed pad; 1S LiFePO4, 3.60 V, 0.5 A, protected-input MPPT 4.992 V - Functional Group: Solar Charger Controller - Manufacturer Name: Texas Instruments Inc. - Datasheet URL: https://www.ti.com/lit/ds/symlink/bq24650.pdf - Manufacturer Part Number: BQ24650RVAR - Part Type: Integrated Circuit - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - BTST [pin 16] - EP [pin 17] - GND [pin 11] - HIDRV [pin 15] - LODRV [pin 13] - MPPSET [pin 2] - PH [pin 14] - REGN [pin 12] - SRN [pin 9] - SRP [pin 10] - STAT1 [pin 3] - STAT2 [pin 5] - TERM_EN [pin 7] - TS [pin 4] - VCC [pin 1] - VFB [pin 8] - VREF [pin 6] ### U4 — ESP32-C3-MINI-1U - Manufacturer Name: Espressif - Part Type: Integrated Circuits - Manufacturer Part Number: ESP32-C3-MINI-1U - Role Details: ESP32-C3-MINI-1U external-antenna module. RF connector must remain mechanically accessible; reserve clearance for W.FL/MHF III/AMC mating plug and antenna cable. REVIEW: module exposes no GPIO11 pin, so requested GPIO11_SCL cannot be connected to U4. - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/user-uploaded/8a79ebf2fb98936a938265e9c18c20d846760bd4e6584855a80ccb05ae3a7053.pdf - Functional Group: ESP32 Controller and Debug - Role: Microcontroller **Pins:** - 3V3 [pin 3] - EN [pin 8] - EPAD [pin 49] - GND [pin 53] - GND [pin 41] - GND [pin 39] - GND [pin 14] - GND [pin 44] - GND [pin 50] - GND [pin 46] - GND [pin 1] - GND [pin 47] - GND [pin 43] - GND [pin 2] - GND [pin 45] - GND [pin 51] - GND [pin 37] - GND [pin 48] - GND [pin 36] - GND [pin 11] - GND [pin 52] - GND [pin 42] - GND [pin 40] - GND [pin 38] - IO0 [pin 12] - IO1 [pin 13] - IO10 [pin 16] - IO18 [pin 26] - IO19 [pin 27] - IO2 [pin 5] - IO3 [pin 6] - IO4 [pin 18] - IO5 [pin 19] - IO6 [pin 20] - IO7 [pin 21] - IO8 [pin 22] - IO9 [pin 23] - NC [pin 24] - NC [pin 7] - NC [pin 34] - NC [pin 35] - NC [pin 4] - NC [pin 17] - NC [pin 15] - NC [pin 25] - NC [pin 29] - NC [pin 10] - NC [pin 9] - NC [pin 28] - NC [pin 33] - NC [pin 32] - RXD0 [pin 30] - TXD0 [pin 31] ### U5 — [LIS2DW12TR](https://www.flux.ai/lcsc/lis2dw12tr~erve.md) - Role: Motion Sensor - Part Type: Motion Sensors - Accelerometers - Product Info Url: https://lcsc.com/product-detail/Motion-Sensors-Accelerometers_STMicroelectronics_LIS2DW12TR_LIS2DW12TR_C189624.html - LCSC Part Number: C189624 - Package or Case Code: LGA-12_L2.0-W2.0-P0.50-BL - JLCPCB Part Class: Extended Part - Manufacturer Name: ST(意法半导体) - Role Details: I2C accelerometer. CS tied high, SA0 tied GND (7-bit address 0x18), INT1 to GPIO3_MOTION_INT. REVIEW: GPIO11_SCL is pulled up and reaches U5 but cannot reach U4 because ESP32-C3-MINI-1U has no GPIO11 terminal. - Manufacturer Part Number: LIS2DW12TR - Sensor Type: Accelerometer (3-axis) - Termination: LGA - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/1810010032_STMicroelectronics-LIS2DW12TR_C189624.pdf - Functional Group: Motion Sensing **Pins:** - CS [pin 2] - GND [pin 8] - GND [pin 6] - INT1 [pin 12] - INT2 [pin 11] - NC [pin 5] - RES [pin 7] - SCL/SPC [pin 1] - SDA/SDI/SDO [pin 4] - SDO/SA0 [pin 3] - VDD [pin 9] - VDDIO [pin 10] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/sirvi/tanksensorv1~kv](https://www.flux.ai/sirvi/tanksensorv1~kv).* --- *Generated from [https://www.flux.ai/sirvi/tanksensorv1~kv](https://www.flux.ai/sirvi/tanksensorv1~kv)*