The Trampa / VESC battery systems

Depends on where you live. This is the price with 20% UK VAT. If you live in the US, you buy without VAT, but there might be some import tax. The other point is: When your cells degrade after a certain time of use, you only need new cells and they get cheaper and cheaper these day. Next benefit is possibility to travel and take out the cells for a flight. You also have the benefit of a proper BMS with CAN link into the ESC.
And if one cell goes wonky, this pack is so easy to get fixed. Insert a new cell and you sorted the matter for sub 10 dollar.

That’s what can make a pack like this great to use over the years.
What’s the recommended procedure for integrating the new cell into the pack? Bring the new cell to the same voltage as the others in its p-group, install it in the pack, and then slowly charge the pack and monitor voltages to make sure all is okay?

The new cell should match the other cells in the pack. Same type and roughly same wear/age.
You can also swap the entire P-group to make sure all cells are equally good.
You would charge the new cell to a very similar voltage, or discharge the pack to a similar voltage.
Once the voltage is matched, you swap the cell.

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Quite a few fuses in the 25A 1206 size range, varying from slow to fast blow.

https://www.mouser.com/Circuit-Protection/Fuses/Surface-Mount-Fuses/_/N-ba8gu?P=1yycdebZ1z0x87h

My point being that I wouldn’t be worried about finding the right fuse if i needed to replace one.

Very nice box but I’m not sure I would want the VESCs in the battery box. I was leaning more towards an VESC enclosure above the trucks to keep the motor and sensor wires short.

Actually long battery leads are worse than long phase leads, the spike from the impedance of the battery can toast an ESC and I’m pretty sure that’s the root of ABS_overcurrent errors

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I mean if I ever do a eMTB again I kind of just want to do a long top mount enclosure in the center, like a 12x6 vertical array with the ESCs at the end

Ok, that’s interesting. Didn’t know that, my esc experience is limited. I thought the current peaks would be higher into the motors and have more problems with inductance. Also heard the sensor cables could be sensitive to crosstalk/noise. Most eMTBs I have seen were the other way. Seems easier to just route the battery cables over the bindings.

I’m gathering parts for a street carver but might switch to a top mount battery as it might be more fun for me. A battery box with out spot welding sounds pretty cool. Carving a big channel in the deck, not so much.

It’s inductance of the battery and its wiring to the ESC that causes the voltage spikes.
Since the inductance of the coils of a motor is already huge (compared to the wiring) the motor wiring length isn’t as big an issue. Keep the motor phase wires short though to decrease power loss from the resistance of the motor wires.

When placing the ESC, choose shorter battery wires over shorter motor wires.

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Ah, thanks. It would be interesting to me to measure this. I’ve got the equipment (scopes and probes), just not sure the best way to put full load on the motors on a bench?

I also have an e-load that I could pulse the batteries with. That might be interesting way around that.

Wondering does the different length of negative and positive wire from the battery to the ESC causes any issues.

So, should - and + leads be same length, does it matter at all?

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I would think that minor differences wouldn’t be a problem but, let’s say, a one foot difference could be an issue. Mismatched lengths means the battery wires are not kept close together and that increases the inductance of the wires. When then becomes a problem depends on the actual inductance of the pack and wiring and how close the voltage spikes come to the ESC’s limit.

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Pics of blood or didn’t happen.

Sensor wires are not the future. ASS is the future.

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I like BMS butts and I cannot lie? I’m confused…

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Last time I checked, my esk8 never got me any ASS :confused:

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If anything I’ve gotten less since I started esk8 :frowning:

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Isn’t ASS technically always in the past…unless we’re walking backwards? :thinking:

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Not sure what ASS is but i can tell you decent sensorless sinewave controllers that make vescs with sensors look stupid already exist. The ARC200 was one of them.

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ASS is like their new HFI but better

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