JUMPINATOR II | MBS DW II | E-TOXX | lightweight MTB

Good to see you back on track Rich!

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Thanks man!
the pic looks great but highly illegal :laughing:

There is something similar not far from my home, maybe I try it on a sunday someday. Once I had a barbecue there and police came because someone called them. I have to be quick and the same you should do, haha.

No but I would not jump or even ride with them. Just for safety reasons.
My general problem with the Matrix II (metal baseplate) which I own is that the kingpin nuts get loose all the time. I have this with 3 of 4 trucks which means re-tighten the nut(s) one or several times during a ride.

Gracias :grin:
Can’t wait for more sessions

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Yeah Im not sure I can reach the cool parts. The digging site is closed for good, so they made a few paths for pedestrians. Not sure I can ride on those without pissing people off lol. In any case there are bike trails along the edge. And bout the trucks, imma try them carefully at first lets see how they hold up.

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Set the date and count me in! :smiley:

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Same! Hoping to finish my mountainboard soon and then we just need some nice weather.

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One of my trucks I only have to tighten once every few months but on the oilslicks, it used to be every ride and I could feel them when they got loose again.

Apparently the 2 in matrix 2 stands for use 2 lock nuts

Hasn’t gotten loose again since adding this guy back in January.

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Hell yeah! We should do a groupshred near Maastricht, I found a local electric mountainboard guy why can guide us around the trails :smirk:

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:joy:
That’s what I do as well but it doesn’t help much.
Last time in dirt park I accidentally dropped the outer nut during re-tightening. Like a miracle it was gone and I couldn’t find it anymore. I gave up searching and also one nut is better than none so I continued but there was a strange sound from one motor and I thought it is damaged. Well it was just the missing nut which sticked to the can and touched the hanger a bit on every rotation. That was funny.

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:rofl: Had that same thing happen.

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I am in quarantine again because a work colleague is covid positive and I had closer contact the last days including celebrating my birthday with loads of alcohol wearing no mask. My test yesterday was negative but I have to repeat it on tuesday otherwise my quarantine will be extended. So with luck I’m free on wednesday.

Locked at home and a bit sad because I can’t ride so what to do? Make future rides better with swappable batteries :grin:

Time to finally build the 12s2p P42A pack which I wanted to finish last year already. Not a power horse but I need it light, curious how the battery performs at 30-60A.

Going with this layout

I glued the 2 parallel cells with CA glue before to make things much easier. I’m tired of sikaflex and trying a flexible neutral cure polymere glue without any acid instead.

I use an old credit card to remove/form the joint

Because of the CA glue the complete 6s packs can be done at once. After adding polymere glue to one side I turned the cells over and did the second side. Then I glued the 2p packs together and then glued the outer joints. Finished.

Before you scream WHERE IS THE FISHPAPER… of course I used it :laughing:
2 stripes between all series packs. This way it can be properly glued together and is still safe.

Well, not the prettiest but should be bulletproof. The consistency of the glue is awesome and it smells like in the woods. In 24 hours I’ll see if it glues as good as it smells.

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Don’t smell too much of it or you might see some stars :rofl:

But for real a 24 cell lightweight power pack sounds incredible. Very interested in your thoughts.

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Thanks for reminding me to check the current fragrance :grin:
Instead of the fresh scent of the forest, it now smells like an air mattress :man_shrugging:

Unfortunately the light weight 12s2p is heavier than the current 5Ah lipo setup but hey it’s 8Ah for about the same price and safer. My only concern is voltage sag, hope it’s not more than 5-6V.

One very interesting thing regarding tires I recognized, they last forever on this build. This is because I don’t really ride this board but if then not much turns and never on concrete except in skate park. It is mostly dirt.

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Also looking forward to this, building a light board with a minuscule pack is in my future plans

If there is too much sag, you can just put a really aggressive cut off value, something like starting at 2.6 V and ending at 2.4 V, since you will abuse them anyway I don’t think it will make that much of a difference, just make sure to charge them after you ride, if it’s resting bellow 3 V, any minor discharge from a BMS or even self discharge can bring them to the 2 V dangerous territory in a matter of days

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Good idea with the low cut off settings if voltage sag is a problem :+1:
The only disadvantage would be that i would always run the battery completely empty because i don’t pay too much attention to the voltage while driving. I always ride until the vescs cut off.

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What actually happens when you hit the cut off end voltage setting in the vesc? The vescs switch off totally and you can’t even brake anymore?
Never tried that out, always stopped riding short after the cut off start kicked in and throttled down the power.

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When hitting the soft cut-off the power is reduced and you can ride quite slow only. The brakes behave normal.

When hitting the hard cut-off the board is dead, no more brakes and the remote disconnects.
On this build the soft and hard cut-off settings are almost equal (5Ah lipo only) so it’s always straight the hard cut-off and I have to be quick to open the heel straps to save myself :joy:

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you got a metr? If so, set notifications for certain voltage levels.

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No because it would add weight :laughing:

On the VX1 are 4 led’s 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 don’t 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 :smiley:

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