I guess this is technically my 2nd build. My first ‘build’ was throwing together a DIY Meepo with a few minor mods like doubling the battery and using Waterbourne Surf Adaptors. I’m upgrading the ESC from a 30amp Hobbywing ESC out of a Meepo Mini 2 ER with a Maker X Go-FOC DV4 ESC and a cheap DIYE enclosure to house everything for a larger battery upgrade down the track.
Where it started:
It definitely seems like overkill using these bullet connectors over the MR30 plugs already on the Meepo hub motors but the 14AWG wire on the Maker X ESC seemed too large to fit MR30 plugs. I won’t be going over 30 amps per motor on this but what the hell.
It was a bloody bitch of a job ripping grip tape off and scraping off the old foam pads! My fingers have all lost a layer of skin on my sensitive hands haha. I then filled old holes and the charging cable channel on old Meepo AWD GT deck. Still needs tidying up but getting there…
And my first attempt at a loop key was much harder than expected. My soldering of larger wires/plugs sucks! I think I need a hotter iron (I’m using my old man’s iron which is at least 30 years old haha).
I know this is a very basic “build” compared to the stuff I’ve seen on here but it’s all a bit of practice for my next project. Especially getting my head around this VESC stuff!!!
I tried DIY foam underlay on the deck. It came up pretty nice although I think next time I’ll put the enclosure bolts under the foam and glue them in. And I won’t foam the deck where the trucks attach either as bolts sink in to foam.
I gripped over the foam no problems and the grip tape appears to have adhered well. Time will tell…
I stapled some straps in to the deck to hold the weight of the batteries as the enclosure is pretty cheap plastic. Seems to have worked well.
I’m sure I’ll need to open her up and play with VESC tool settings after a test ride. I’m still getting my head around optimal settings. I’m going with sensored FOC to start with in the hope it runs ok.
I was pleasantly surprised the VX1 controller/receiver worked straight away without running any detection for it. It’s in a UART port.
Get yourself a bluetooth module dude. Save you opening up the case if you need to change settings.
I have to say, that deck looks so much better without the grab handles.
Make sure your truck bolts are torqued down nice and tight if you are gonna keep the foam there… could lead to fatigue in the bolts over time if they aren’t fully compressing the foam.
Yeah I am nervous about the foam! And yes to the Bluetooth module for sure, I should have bought one and still will.
I was going to go BLDC like you suggested but when I ran the wizard it all seemed to work in FOC so I’ll see how it goes being careful like you mentioned.
As for the handles I agree with you on looks although they are actually very handy, not only for carrying, but also for grabbing on hard turns.
I thought I’d nailed this build as the first ride started great. I had greater acceleration and braking capability compared to the 30amp Hobbywing ESC. Top speed seemed a tad lower though at around 48km/h compared to 51km/h.
Then shit hit the fan!!! Strange noises, surges, loss of brakes then brakes kick in. It was un-rideable but nursed it home 4km or so.
Opened her up and realized I’d fucked up. I didn’t secure the esc properly to the deck and saw the inside of the enclosure had melted where exposed bullet connectors had been pushed in by the loose ESC. Two bullet connectors had burn marks (somehow heat shrink had shifted!??). I think I’ve killed the motor but I guess it could be the bullet connectors (definitely not ESC as switched sides with motors to check). The motor in question does weird shit like work sparadically but with strange noises and shudders particularly under brakes.
So I guess I need to first try changing bullet connectors (need to order some) or replace the bloody motor .
I should have taken some but closed her back up feeling defeated for time being haha.
Below is a pic of the worst looking bullet connector though. The female end on the VESC was burnt too but when I plugged the good motor into it there were no issues which makes me think I’ve killed the other motor.
Update: Good news for me is it was only burnt bullet connectors and not a stuffed motor. After changing the three bullet connections the motor was fine. I also secured the ESC better and ran the motor phase wires to the side of the esc in case it does come free again.
Second test ride was interrupted by some light rain. I did 10km and everything working well.
I’m running 35 amps on motor and -35 brakes (so I think that means 17.5amps per motor as it’s a dual VESC). I’m considering bumping the motor amps up to 40. I don’t think the Meepo hubs can handle more than 20 each so that will be max ( the VESC Tool wizard sets them at 31amps).
Current battery setting is 80amps and -40 brakes.
My top speed has taken a hit maxing out at 47km/h compared to 51km/h on LingYi ESC. Not sure why??? I might ask in the noob thread.
Default max duty cycle is set to 95% on vescs, that might be it. Not sure how safe it is to increase it though, I believe there’s a reason why it’s there.
Ah fuck!!! Same shit happened again but on the other motor this time. I don’t know WTF is going on. First I thought it was because the esc came loose. This time that is not the case but the phase wires have melted at the bullet connectors same as before, just the other motor this time.
My settings I feel are well within the capabilities of VESC and wires/connectors I’m using:
Motor amps 35 (17.5 each motor)
Motor brakes -35
Battery 80amps
Battery braking -40
(Battery is 10s4p of Sony VTC6 cells).
As the pics hopefully show, you can see the heat shrink that seems melted or somehow shifted on connectors. Definitely some melted spots though. And on the enclosure where phase wires touch.
Edit: Thanks to B264 for the help! It appears I just suck at soldering and had a cold joint. Will do a pull test on the remaining connectors and hopefully good to go with new connectors again. Time for a new soldering iron although a good craftsman never blames his tools. So yes, I’m not a good craftsman haha
I did think the Meepo motors had small gauge phase wires. I read somewhere on the forum that they can handle 20amps max and I’m running them at 17.5amps each. I guess if it happens a third time after checking all my solder joints again then I’ll adjust down.
Cheers
I’ve had this board running well lately. Stupid me didn’t know how to set my motor amps correctly on both sides of dual vesc in the VESC tool app so only one motor was running at 40 amp and the other at 30 lol. Probably why I was only burning one side of motor phase wires!! (And my poor soldering too I’m sure). Thanks to @Athrx for talking me through the VESC Tool app settings to access the other side of the Maker X DV4 over CAN.
Both sides are running at 37 motor amps and all is well. I changed out the bullets for MT30 connectors to tidy up and to be sure I had no more bad solder joints.
The only other hiccup was my VX1 reciecer shitting itself. Luckily there was a local guy selling his spare Hoyt St Puck so I’m back up and running for work tomorrow!
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It looked so clean and proper before
. Ah well. It’s a learning curve for me. Planning a 4wd build later this year so good to iron out kinks on cheaper builds first.
