Did anyone tried to run the cables from battery to esc under an MTB board?
What do you use for protection?
(Both esc box and batteries are on top but I want to avoid the cable crossing the binding or under the foott)
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@rafaelinmissouri has done this with some sheets to protect the cablesā¦
Use a ti sheet! Sparks when your clearance falls short.
Didnāt @poastoast mount the cables on his awd this way?
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and how do you cut Titanium?
I was thinking aluminum sheets for ease of use, or half corrugated pipe for electrical cables (hard plastic) but that would be a nightmare to cut maybe?
i use printed foot pads just tall enough to allow cable to run in them, no more no less
printed tunnel to get the cables from the battery box to thw outside
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I used sheets of abs
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My original plan was to do the same: extending phase and sensor wires, but Iām afraid to make such a big hole on the board, plus the extra work (and materials I donāt have at hand i.e what is the 6 pin connector for the sensors that seems not to be standard jst?).
Is this solution going to be much better for Voltage spikes? Other reasons (beside rationalize everything in one place)?
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The reason I did it is just to not have anything on the standing surface.
I donāt use bindings.
And I like the esc and battery in the same box.
Having the esc in the rear is probably a more robust design. Where you just extended the battery wires and not every thing else.
I have two set ups like this with the long octopus legs and they have held up fine and the motors still come up sensored.
So I am happy with it.
@tomiboi had a really clean underbelly protector he can hopefully share here too.
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Better? Yes.
But we donāt know by how much. It depends on the wire lengths and positions, amount of current flowing, how close your ESC is operating to its rated max voltage, and other things.
Depending on the setup the battery wires could possibly be extended by a lot with zero issues. For other setups the battery wires might already be too long and badly stressing the ESC.
But it is a ābest practiceā to lengthen the phase+sensor wires instead of the battery wires. The longer the battery wires, the higher the voltage of the spikes the ESC has to deal with at its input.
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Just want to show off My newest battery build!
20s2p p42a split pack
18s2p in the rear, 2s2p in the front.
For my newest vesc onewheel build!
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Do you guys know what this yellow material is in between the cells? I keep seeing it in battery packs and I am looking to use it in the future. I believe itās a dialectic barrier made out of a polyimide film or something but thatās my best guess. Also if I shouldnāt use it, is there a better material that I could use?
Thank you in advance!
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FR4/fiberglass board.
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Working on trying to rehab this pack from my brotherās Ecomobl ET 12s3p 21700 board. He let it sit for a year+ (was at a full-ish charge, then trickled down from there). He reported that when he charged it up and used it, heād only get a handful of miles out of it. Charged again and it charges really quickly, and same thingā¦ short range. I suspected the BMS was stopping charge once one out of balance group hit 4.2v, with the rest lower.
Tested with multimeter. None of the voltages were below 3.5v, but ranged up to 4.186v. Tried plugging in the stock charger as a first step to see if it would self-balance. Left it for a few days but no dice. I bought a JBD smart BMS and got it installed to monitor values easier. This was the first reading from it.
0.682 delta could definitely be improved. Lowest cell was around 3.5v so I set the static balance threshold to 3.5v to let it try and settle down the higher cells over the course of a week+. The delta shrunk to 0.5xx but was painfully slow. I ended up rigging up my Xtar VC8 Plus cell charger with a dummy 21700 cell I printed, and bent some nickel tabs and soldered wires on to the pos and neg, terminating in a 2-wire JST so I could charge cells manually/individually through the BMS harness (thanks for the help @TheBoardGarage). After triple checking polarity and such, I took the time to get all cells up to around 4.0x volts.
0.066 delta was much better. I let it static balance for a day or so to get down to 0.05x and put it on the boardās charger to charge to full.
That brings me to today. Charged to full, but I looked and cell 11 is triggering over voltage protection because itās hitting 4.24-4.25 volts when on the charger.
I wanted to get thoughts, advice, etc on what to do at this point. Trying to save this pack was really more of a personal challenge for me, but Iām not going to bother if itās a lost cause and/or hazard.
Look at that pgroup for a broken weld. If nothing is obvious or you want more proof before disassembling- Balance it again and do another discharge cycle while carefully monitoring that group, i suspect one of the welds on that p group is broken and that is making that group charge and discharge faster but it is still early to judge
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sendcutsend will cut titanium sheets and/or press break it for you fwiw, iāve used their services before.
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Iāll check that out and see if I can locate any loosened up welds
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Are you saying to replace the FR4 with fiberglass tape in between the cells? Also do you know if the FR4 comes with double sided adhesive or would I have to buy some adhesive to put on it. If so, do you have any recommendations?