EU/Belgian eBoard | 149kV | 12S LiPo -- Checklist & Buildlog

hey mcfly, thanks! It’s an idea, I’m not yet sure if it’s the correct method.
The idea is that when you want to charge the batteries you do as follow: you turn off the board by unplugging the loopkey as in the diagram, then you plu it into the battery u wish to charge. the balance leads of the same battery are right next to it so you can’t miss it. If battery1 is charged, unplug the loopkey and balance leads and plug it in battery2 etc. That way the charger XT90 cable can remain plugged into the same charger plug.

I didn realise that it would be a problem (about energising the VESC). A voltage is just a reference no? or is the VESC grounded through the motor?

Thanks for your answer. I will read up more on this. One issue I have is the having to open everything, connect/disconnect several cables to recharge. Would be nice to have a port connected to an enclosure and that be it for charging.

As for your question where to put the switch, read this article it explains it well why you’d want to interrupt the circuit in the live wire and not in the ground one.

http://www.acmehowto.com/electrical/switch-works.php

I just read through it. Good point, and must be taken into consideration. But I don’t think it’s completely correct. In a lightswitch u use AC which has a voltage relative to ground. In a battery the voltage is relative to the other battery terminal, so it doesn’t really apply here.

I do however not know if the VESC is grounded in another way then relative to the negative side of the battery. So I don’t think this applies to the VESC so please correct me if I’m wrong.

i too would like one plug: this is possible if you use parallell batteries and are willing to use a serial port (i’ve seen this pop up on the forum but can’t remember where).
For series batteries I don’t really see a choice without using a BMS, but those are bloody expensive for 12s.

@3sly Everything in the circuit is referenced from a common ground. So the ground for the VESC is the same as the ground for the Rx and the motors.

Having said that, the ground for the circuit is not connected to earth’s ground in this case. I read a few areas saying it doesn’t matter, and some where it does. I think best practice is to put the switch on the hot wire. At least one person from the industry says that here
https://www.quora.com/Does-it-matter-if-you-put-switch-fuse-in-a-DC-Circuit-on-positive-terminal-or-negative-terminal

@mcfly777 Jep, I’ll do it as well, like you said: good practice. I do wonder now though if it actually makes a difference.

UPDATE: I’ve received following componentes today: VESC, drivetrain, board, trucks, wheels and bearings.
I’m exceptionally impressed by the quality and thought that went into the esk8 products, the caliber trucks were modified and they even bothered to paint it again! I especially like the aluminium pulley, the fit on the orangatang wheels is impressive, they even have settings for screws, so the screws don’t tap into the aluminium.

Normally tomorrow I’d be meeting with @trbt555 for the batteries and enertion remote.
I’ve also seen that the motor will be shipped soon, so this build is going faster than expected.

These are the pictures as promised






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I have a quick question for everyone: Does the length of the cables from/between the batteries have an impact on something? Ofcourse theoretically the batteries will be at a different voltage if a resistance is between them and a current flows through it, but can’t that be neglected unless you have several orders of magnitude lengthier wire.

I’m asking because I might place the batteries in length along the roll axis of the board.

Dries

If it does … It shouldn’t be detectable … And shouldn’t affect anything

Just make sure that the cable length between batteries and the VESC is not too long. Else you might need to add capacitors in front of the VESC to avoid difficulties.

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How long it’s too long?

Depends on the cable type used. In general I think that everything up to 20-30cm is still ok with a good 12AWG cable for example.

re wire length, in this thread is some info re this, especially the external link posted by trbt555 is quite interesting.

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Thanks @shred and @elkick. I thought so that I read something about wire length. I’ll try and keep myself to the max30cm allowed. I suspect that ought to work.

nws, just found another link re VESC and wire length http://vedder.se/forums/viewtopic.php?t=46

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@shred, I’ll read up on that! Right now everything is going into high gear. Everything arrived.

I went to meet trbt555, to go buy the 3*4S 10000mAh batteries and the enertion steez remote from him. It was nice meeting him, a friendly and down-to-earth guy who gladly shared some advice regarding DIY esk8s with me.

While I was expressing my worries with him regarding my backorder on HK of the 149kV, the shipping gods must have heard me and not even 30 minutes later the motor, XT90s and cables arrived.

When I find the time I’ll read up on the cable length, but I don’t think it’ll be an issue. I’m thinking of placing them behind each other as in the picture, but then I’d have to probably use fiber glass for the enclosure as finding ABS to vacuum form the entire length is gonna be quite difficult. Other tips are welcome. (Yes I know the board is upside down :stuck_out_tongue: just for reference (board is 36"/96cm). I’ll also be using risers)
They’re very big, its gonna be a tough fit :stuck_out_tongue: but doesn’t matter, we’ll make it work.

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OK, update: I managed to config the VESC succefully, I have full control and managed not to blow up the DRV chips or screw up the firmware.

I do have a question though: I used a single 4S lipo for the setup and motor detection. But as I’m going to use 12s, I set the battery cutoff start at 42V (3.5V) and the battery cutoff end at 38.4 (3.2V). This gave me the thought that as soon as I write the config, I won’t be able to drive it with the 4S connected battery, as the voltage is lower then the end cutoff.

This isn’t the case though, I can still run the motor with the remote and with these settings. How can the VESC know that I only have 4s installed, or where did I go wrong.

Dries

Would be good if you can provide some screenshots from your settings.

Sure, but i don’t have access to it now. All the other settings are default though, I only changed to battery cutoff start to 42V, cutoff end to 38.4V. max voltage is default (57) and min voltage is default (8V). The battery and motor currents are also default. After that I only detected the motor and set the PPM enertion remote.

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Hi @3sly, it was nice meeting you, a pity I didn’t have more time to chat. Maybe we can ride together when your board is finished.

Personally I’d stay away from fiberglass and epoxy. It gets really messy really fast. And it isn’t all that cheap either.
I think thermo-forming an enclosure will give you better results.
Just search ebay.be for “ABS sheet” and you’ll find plenty of matrerial, mostly in the UK so without taxes to BE.

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Made that experience today - absolutely correct! It’s a mess and not drying anymore, made some boxes last year without problems, but now…

@3sly don’t worry, that corridor for cut off start/end is disregarded if your voltage is lower than that, since it only serves as limit for cut off. It will work with your 12s nevertheless. in the expected way. But don’t use FOC on your setup please, it’s safer on BLDC for now.