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Selected the Cooper Bussman XEV10-20-T for its fuse rating of 20A which will protect against short circuits but not interrupt normal operation. Wiring must be sized according to this fuse - must be capable of >20A. Using the Chassis Wiring value from this table:https://www.powerstream.com/Wire_Size.htm, >16AWG wire will work (22A). We will go with 14AWG (32A) for a bit of a safety factor for all of the fuse derating conditions if it is readily available and not too much more expensive. ORANGE wiring for the high voltage will be used, with black and red heatshrink to specify the polarity.
We will need to find a place to purchase this fuse.
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- Charge Input +
- Output (Motor Controller) +
- Output (Precharge / DC-DC) +
- Common GND Side -
- Secondary contactor to emulate the coil sense contactor, coil wired in parallel with main contactor
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We should be able to manually turn the battery on or off. Should be rated for at least 20A, probably more for a safety factor. Should also be satisfying to turn on - big switches are nice.
This switch will be inline with positive side of the battery.
Switches such as this seem to be a problem finding - check this video for the importance of choosing a properly rated switch: https://hackaday.com/2018/07/24/a-dramatic-demo-of-ac-versus-dc-switching/
So instead of finding a switch rated for the proper currents, since our relays are rated for the voltages and currents, we will provide a manual way to remove power from the coils. A switch will be wired in series with every relay coil. These switches will be used (https://www.amazon.ca/gp/product/B07M5GGXTV/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1)
The BMS kill switch (connected to the BMS Carrier board) will be this switch: https://www.amazon.ca/gp/product/B07GT4KK7R/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Current Sense
Should we have the option of switching in a larger current sense resistor to measure the current more accurately - then we might not have to change current set points when switching code as the reading scales according to the resistor chosen.
We have a couple extra current sense resistors around the bay, so we should use one of these.
We need to figure out the model numbers of the connector and the crimps and wire gauges used for the connection to the current sense housing.
Connectors + Cables
- 12V Input - Molex Ultrafit, 2 pin, +/- consistent with the rest of the boards, 22AWG
- CAN - 2 ports, with BMS carrier in Daisy Chain Config - Molex Duraclik 2 pin, consistent with the rest of the boards, 22AWG
- Charge Input - 2-pin Molex MX150L, 14AWG
- Power Output - 2-pin Molex MX150L, 14AWG