you got a metr? If so, set notifications for certain voltage levels.
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No because it would add weight 
On the VX1 are 4 ledâs to monitor the battery level. When I hit hard cut-off (3.2V/cell) then there is 1 led left. I guess the VX1 is set to 3V/cell for empty battery. Does someone know if it vibrates then like if the remote battery is low? That would be great.
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i donât think so. It only vibrates on low remote battery.
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not sure if i would take vesc cutouts over 15g addedd weight 
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@rich get a Metr you will thank yourself, its amazing the data that it can tell you when riding and jumping.
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Yeah, the cut off should be current dependent with some filtering, there is not that much problem sagging the cells deeply under heavy load
The way I see is to set it low and when you feel it starting to loose too much power, stop riding and switch packs so it doesnât get a too low resting voltage
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Iâm considering to buy more cells and build a second equal pack so I can swap and donât have to drain the battery full empty. Beacuse an empty battery usually means going home if you have no spare.
Also it would be easy to switch if itâs the same size. But itâs a bit risky without knowing how the 12s2p performs. At least he price for Molicel is good at the moment.
I wanted to build a spare battery for my regular MTB as well but with 18650. Right now the VTC6 are twice as expensive which is ridiculous. 12s bricks of P42A are so huge compared to 18650
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My quarantine is over because my test today was negative. Now I am allowed to leave the flat, weather tomorrow: cold, snow and rain 
No problem because I have to build the battery 
.
I decided to not use the lipos anymore because they puffed once more so I definitely need the new battery if I want to ride. I took the electronics apart already.
12s 5Ah Lipo vs. 12s2p 8Ah Li-ion, quite impressing. More range plus smaller size
Without wires and BMS the P42A pack is even lighter than the lipo setup, curious about the final weightâŚ
Tomorrow night I can borrow a kweld for spot welding so I need to prepare some things. Already cut the nickel series connections. Right now I try to figure out how to do it with the 4 power wire connections.
I should buy a new truck. The axles are a tad bent from jumping 
the front truck is alright.
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Do you see that as a truck problem, or as a âonly someone jumping like me could do thisâ problem? 
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How do they compare for max current? Or will this not matter?
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Well⌠a combination of both
After bending some Trampa vertigo trucks with 12mm hollow axles I bought Infinity with 12mm solid steel axles but it didnât help.
Solid steel axle after abuse, no crashs.
IMO many trucks have a design flaw. The hanger is too narrow and the axles too long. Why the hell using a 20mm spacer which puts much more force on the axle where the wheel is mounted? Why not wider hanger, no spacer and shorter axle?
The Matrix II have hollow axles but no spacer and wider hanger , thatâs why itâs my first damaged truck of MBS and not the second or third.
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Well the lipo was 5Ah 30C so in theory rated for 150A.
The 12s2p is about 50A continious and 90A max.
50-60 battery amps are enough for this build but would not be enough for regular MTB.
The biggest difference is voltage sag. The Lipos sag 1.8V at 50A which is a good value, I guess the 12s2p will sag 5-6V at 50A. If I set hard cut off at 2.5V/cell and soft cut off at 3-3.1V/cell it shouldnât be a problem. Brake regen -19A for 2p.
For comparison on my MTB with VTC6 12s6p pack the voltage sag is 5V at 100A.
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Rich personally i would only replace the hanger if
A. it is causing issues with steering
B. is causing issues to your drive
and the point on having shorter axles and wide hangers is exactly what you need or replaceable axles
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You might wanna check if your wheel gear isnt rubbing against the mounting plate because of the bent axle
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Like the etoxx trucks? 
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True, I mean itâs rideable 
If you take a closer look you see that the gear drive is askew as well thanks to the non-precision hanger. Fortunately the bent axles match the angle of the gear drives almost perfectly.
I have 2 oil slick Matrix II but they are pretty useless so I would need black Matrix II.
Good point but it ainât, had one drive open last week and gonna open both next week again for swapping housings so I can check both sides.
I am a fucking idiot because I made a mistake while gluing the cells together and am quite pissed now. I use 2 fishpaper stripes between each serial group. I found out that I forgot 1 stripe on 2 groups and one group has double fishpaper WTF!
Fuck, right now I am thinking about if I take the risk or rip it apart. I slightly prefer to ignore it 
What can happen? If the heat shrink melts I would be in trouble but is that realistic? It probably would need way more than 200°C but then Iâm in trouble anyway. There is no rubbing so this is not a problem. Is there something else I donât see?
If I rip it apart in best case I most likely damage the shrink tubes and have naked cells. I donât know if this is what I want. Plus today Iâm going to get the kweld. DamnâŚ
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Youâre jumping on the board, Iâm pretty sure thatâs enough vibrations to slowly chip away at that cell wrap and short it over time. Without knowing what glue you used I donât know what the best way of taking it apart would be, but I would definitely add the missing fishpaper if I were you.
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Oh shitâŚ
Best way for sure would be to cut off the cell shrink on those cells and take the pack apart, than re shrink the cells and glue everything back together.
If thatâs not an option, I would press as minimum some more silicone between the cells to make the connection stronger.
Like there
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I have 18650 shrink tube but nothing for the 21700, checked all shrink tubes. So cutting the shrink is no option. I decided to fix the battery and just open the connection of the problem cell, at least that was the plan.
My nightmare startedâŚ
2 hours later but still strong
hours laterâŚ
My thumbs hurt like hell
Nothing is torn like a miracle but damaged the shrink tubes. At least no cuts at all and they are in one piece.
This time 3 stripes fishpaperâŚ
Funnily almost all paralell connections were still strong but I reinforced them all.
With a ton of glue I glued the pack together.
Finished just before sunrise
I donât know if the pack is safer than before after all the abuse
Got the kweld yesterday but my energy is gone⌠need a personal charger.
Conclusion of the night: need to buy 21700 shrink tubes and never ever repeat this shit again.
But the Pattex polymere glue is great, the connection is ultra strong and flexible. The consistency is more like sikaflex and not silicone but it doesnât dry out like sikaflex.
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Result is looking good.
Thumbs up!
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