Vanguard: Would this split battery design work?

Inspired by @whitepony’s Vanguard build, I’m thinking about rebuilding my board with a split battery design on a 42" Flex 1 Loaded Vanguard with dual diagonal motors. The battery will be split into two parts but wired together to create a 10S4P pack. I’ll be looking to get a small BMS just for charging and then something like @torqueboards softswitch.

I’ve drawn up a basic circuit diagram but I’m hoping someone would be able to confirm if this design would actually work. The thing I’m unsure about is having a VESC at two different points in the battery circuit. Would this be an issue for any particular reason?

I’m going to be looking at running grooves on the top side of the deck for wires to run down under the grip tape, similar to how @longhairedboy does with his boards.

I’ve also thought about having both VESC’s at one end which would probably save some space as it’d allow me to have them both connected to a single capacitor bank. The only issue with this is that I’d end up with a total of 5 wires running the length of the deck (3 phase wires and 2 battery wires) but I’d be concerned that this would probably be getting a bit much in regards to reducing the strength of the deck.

Looking forward to hearing people’s thoughts :slight_smile:

Typically, you’d wire both VESCs on one side and and just extend (one) motor with 10-15"+ motor wires to the opposite motor. Much easier that way and you want less “length” from the VESC to the Battery.

Otherwise, you’d have to also wire in the Canbus connector, power wires for the VESC.

That’s essentially what I have now. This idea is really just to eliminate the need for any extra wires running down the deck for the other motor. I don’t use canbus so that won’t be an issue.

1 Like

Hey OP, nice to see someone else building a vanguard :smiley: I myself am ordering all the bits and pieces at the moment.

What enclosures are you going to use?

The idea will work. Another approach will be to split the enclosure one for the battery and the other for the VESC.

Like in this

And run flat wire like this one under the grip tape.

I have thought about this a little bit, how does it handle the flexing though? One concern I have with a longer enclosure on one side is that it’ll make it hard to make fairly watertight

my 10S4P split vanguard build thread is here - the layout is very similar to yours and available on the first post:

the split vesc diagonal setup is something I dont really like - long wires everywhere (long wires = unecessary inductance = bad) and for me it simply doesnt look very pleasing to the eye compared to a dual rear 6355 setup. but thats just me … and for flat norther germany, a single 15mm drive is best anyway. lighter and definitely more efficient. :smiley_cat:

Yea I’ve looked through that thread several times, really awesome stuff :slight_smile:

Maybe it’s not quite so obvious from my diagram but there wouldn’t be any more longer wires than your build, the front motor would connect to the other end of the battery so that the only wires running between the two enclosures is two battery wires to connect the battery packs in the same way as yours. Ive never seen someone do a build where each vesc is connected to the opposite end of a battery but I can’t see any reason why it wouldn’t work?

maybe my brain is damaged after a day of coding, but i dont see how you can get away with 2 instead of 4 wires? :confused:

@michaelcpg, you want to connect vescs at both ends of the battery? This will not work.

You could split the battery into two 10s2p packs, each driving one motor.
Then you only need thinner wires for can bus or ppm signal. And possibly some wires to make sure the vescs are at the same voltage.
This setup will need two power switches.

It handles the flex pretty good. You can always split the long enclosure into 2 small ones place side-by-side along the long axis for more flexibility.

For waterproofing I use thin double side tape on the perimeter of the enclosure and clear pvc sheet to cover everything. At the wires exit holes apply silicone. that seals all the electronics inside and allows for visual inspection.

The clear pvc sheet you can get at any flower shop. They use is to wrap the flower bouquet. You can get it for free if you ask nicely :wink:

i´d prefer the upper one. 4 wires


And don’t forget the extra long servo plug for the signal. Why do want dual diagonal vs dual rear?

Also with dual rear you have more space in the front because you can move batteries closer to the trucks.

Looking at my diagram a bit more, a think the main issue with this design is that it’d be putting the VESCs in series instead of in parallel.

Not sure how I feel about the idea of two separate packs due to the added complexity/extra components required. Something to consider though.

@TarzanHBK Would it be preferable to run longer wires between the battery and one of the VESCs or between a VESC and a motor? I thought you can have issues running long wires between a battery and VESC.

@Titoxd10001 Tbh I wouldn’t mind dual rear. The main issue being though is that I already have dual Ollin motors which don’t fit on the Enertion trucks/motor mounts that I have.

@whitepony Do you expect that if I ran wire along the top of the deck similar to how you did with your build, increasing the widths of the groves to add room for another 2 or 3 wires would reduce the strength of the deck too much on a Flex 1?

Why not use flat wire and dont route your board?? Grip tape would hold it in place.

This could end up being something I’ll do tbh. Just trying to work out all options at this stage :slight_smile:

Fair enough… Where did you get your batteries from?? I looked high and low for some here and the cheapest i could find were $8.5 each for samsung 25r

I initially bought a 3p space cell from Enertion then ended up buying another 10 cells from here:

Not cheap at $10 a cell but getting them overnight as opposed to having to wait multiple weeks to get them shipped from overseas was enough of an incentive for me to buy locally :stuck_out_tongue:

Yeah fair enough, these guys would drop the price to $8.5 if i brought 30 and put one of his stickers on my board haha. Im getting a battery from torque boards but highly contemplated to make my own but i didnt want to purchase a spot welder and wasnt comfortable to solder $255 worth of batteries together haha

Yea I wasn’t too sure about it initially either but I’m glad I did build my own in the end, learnt a lot and now I can fairly easily rebuild my battery/add more cells as needed. I use fuse wire on all my cells for an extra level of safety which also makes it much easier to solder directly to the cells seeing as the fuse wire is really thin.