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SRHS Ecomarathon schematic notes Posted on February 06, 2020 07:43:39.

SRHS Ecomarathon Schematic Part List
CJ 2/6/2020

Known issues noted with a *, and questions with a ?. A material list with make, model, source, price and data sheets is probably required to pass technical inspection; generating this list may uncover more issues.

Components:

1. Fuses:
* F1 “Main”: 75VDC 10A; currently 30A, needs to be lowered to 15A
* F2 “Precharge”: 75VDC 3A; was 0.5A but would blow if someone accidentally hit the horn button while starting.
* F3 “DCDC In”: 75VDC 5A; new
F4 “On”: 25VDC 0.5A
F5 “”Horn”: 25V 3A

2. Switches:
? S1 “Main”: 75VDC 15A latching; what is make/model/rating? If upgrade needed can use 15A circuit breaker and eliminate F1.
? S2 “Start”: 75VDC 0.5A momentary; what is make/model/rating?
S3 “Kill int”: 25VDC 0.5A latching
S4 “Kill ext”: 25VDC 0.5A latching
S5 “On”: 25VDC 0.5A latching
* S6 “Power”: Omron G9EB-1-B-DC12 250VDC 25A contacts SPST NO sealed relay with 12VDC 72 ohm coil draws 167 mA; currently only 28VDC, need to upgrade; need to purchase for $117, https://www.mouser.com/ProductDetail/Omron-Electronics/G9EB-1-B-DC12?qs=M6j53hjKB4%2FPynp4bjS9BQ%3D%3D
S7 “Dead Man”: 25V 0.5A momentary, part of modified Curtis Potbox X3
S8 “Horn: 25V 3A momentary

3. Resistors, all through-hole:
R1 “Precharge”: 5K 2W
R2 “Accel pot”: 0 to 5K 3-wire, part of Curtis Potbox X3
* R3 “10A Lim”: 5K; need to add
R4 “Tau”: 100
R5 “Gate”: 33

4. Capacitors, all through-hole:
* C1 “Res1”: 1000u 100V; what is ripple current spec? How much ripple is needed?
* C2 “Res2”: 0.1u 25V; need to add
* C3 “Tau”: 0.1u 25V; what is ripple current spec? with no per charge it will see 12 mA.
C4 “Filt”: 0.01u 25V

5. Diodes, all through-hole:
D1 “Freewheel”: Vishay V2100SG 100V 20A
D2 “Relay coil suppression”: 1N4001
D3 “Hi potbox”: 1N4001
D4 “Lo potbox”: 1N4001

6. Power transistor Q1: Fairchild FDP060AN08A0 75V 80A 6milliohm through-hole

7. Integrated circuit U1: NE555 timer through-hole, socketed

Mechanical Parts:

8. PC board:
? MP1 through-hole perforated; dimensions?

9. Heat sinks:
MP2 power FET
MP3 freewheel diode

10. Terminal strips:
? Power MP4: 100VDC 15A; what is make/model/rating?

Assemblies:

11. Battery pack X1: BatterySpace custom 48V 10A 672Wh 14x4 LG MJ-1 LiFePO4 with cell bank V and module T BMS cutoff

* Battery order doc says 5 strings not 4, did that change? Needs 10A cell current protection or ~500W, is this too weak? Test vehicle with added R3 10A limiting resistor and determine if 0-20 MPH acceleration is adequate. Also need to figure out how to measure speed, maybe a bicycle speedometer? If not enough power, ideal would be 2x14 20A 7 Ah cells; if so then change F1 and S1 to 25A D1 to 30A.

12. DCDC Converter X2: Kohree B0756T983Q (rebadged Tobsun THJ4812C240Z) 48V in 12V 20A with 20A cutoff out no soft start, hence needs precharge, waterproof; could be as low as 4A

13. Pot Box X3: Modified Curtis PB6 with high side resistor wire added; contains S7 and R2 listed above

14. Motor Control Board:
? X4: contains R3, R4, R5, C2, C3, C4, D2, D3, U1, MP1, MP2 and MP3 mentioned above; please send bottom wire picture to post

15. Motor:
? X5: DC brushed 48V 1000W; did you get the ZXTDR U-TD010 from Amazon?

16. Horn
? X6: 12V 2A; which horn do you have?

Other items not shown on diagram:

17. Other terminal blocks

18. Wires: insulated - I think most are 300V, 12 gage for 10A power circuits, able to upgrade to 20A, but better than 14 ga due to less voltage drop and more efficiency. Low power should be 16 or 18 gage, no smaller for durability. Choose wire colors and add color and gage to drawing: red, yellow and orange typically used for power, black or green typically ground, blue, green, white or purple for signals. Suggest easy to obtain automotive wire from O’Reilly Auto Parts.

19. Wire terminations: use preferably ring, but quick disconnect or bullet OK. Do not use fork, they can slip out after slight loosening. Use yellow for 12 ga, blue for 16 ga. red for 18 ga

20. Fasteners to attach components to mounting board: screws, flat washers, lock washers (use everywhere including adding thin ones for terminal strips, vehicles shake things loose), nuts - lock nuts can eliminate lock washers