Voyage Systems: Megan and Minnie

Vendor Corner (SERIOUS)
121

Are the CAN bus chips on Minnie more resilient than what we hear about MakerX ones?

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122

@DerelictRobot you seemed pretty clued up on whatā€™s happening with our maker X bbq can chips. Could a Minnie be a safer way of running 4wd or do we just run the risk of blowing up the Minnie instead?

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123

I canā€™t see how adding an extra component on CAN is gonna help or hinder a poor component choice from maker x. Just make sure your escs both power on at once

124

Maybe the Minnie can handle the current inrush on the can lineā€¦

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125

thatā€™s not how that works.

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126

All earsā€¦ Iā€™m always down for not learning the hard way :call_me_hand:

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127

However isnā€™t Daisy chaining the can line a bad idea anyway? Whatā€™s the can impedence on that line with the Minnie in circuit? Does it drop to 40? Or does it become end of 2 lines?

128

thatā€™s how canbus works

3 Likes
129

Is there a 120ohm resistor in the Minnie?

130

thatā€™s a question for creator, not me

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131

Pretty sure you want the total resistance on the can line to be 120ohms, ie 60ohms on first node and 60ohms on last node in CANBus chain.

132

Yeah 120ohm resistors in parallel at each end for stability and to prevent signal reflection. Just wondering how itā€™s running in this situation.

133

What about connecting a tvs diode in parallel?

134

Do you know how it works? Or just that it doesnā€™t?

135

There is, but it is disabled by default. To enable it, you need to solder this bridge. In practice I have never seen this actually make any difference.

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136

Ah cool :+1:. Still a good wiring practice to follow or place to start if there was an issue.

Did you ever have any issues with voltage spikes causing damage on the original metr?

137

Jbd do sell a uart to canbus module so this could work with it?
https://a.aliexpress.com/_mND3KPk

138

Hard to tell. It definitely wouldnā€™t work out of the box. It would require some work at our end at the very least and we would need technical docs for the UART-CAN module, which I canā€™t see on AliExpress.

Last but not least, even if we did make it work, thereā€™s only one UART port on the LLT, which is used by the BT module. So if you used it to connect to the CAN bus instead, you would no longer be able to connect to the BMS with the mobile app.

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139

On the newer generation of JBD bms (OEM of LLT), ble is built in and there is a spare uart port

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6 Likes
140

Still with an always on Bluetooth that drains your pack?

1 Like