4WD builder room

General Discussion
1

How do you route the battery terminal for 4WD? I know for top mounted trampa and MBS all you need to do is parallel battery terminal leads. Have anyone else besides from @mackann done a 4WD on a street deck?

I’m thinking to building a HAYA 4WD with TB DD with my modules. With a lack of a center channel I can’t imagine doing a terminal lead split. Also long battery wire produce high inductance and can potentially blow VESC. Something 270uF per ft is required. I’m thinking of opening the series connection at the middle of the pack for the other side of the ESC. Afaik, both sides should read 6s from ground through other ESC and 6s from other ESC back to positive. Is there anything wrong with this design?. Pic TMR.

What i concern most is voltage drop across ESC and uneven load distribution between front and back.

3 Likes
2

I have just done a top mount quad, but why not to split your battery in two packs? on for the front, one for the back. no issues anymore.

3

Yeah but but that will require 2 separate BMS and 2 charge port? How does that eork?

4

if you go 10s that´s definitly also no issue. there are super small micro bms. even with 12s a d140 is not really big and can just be placed on the top of the pack

5

Space is not an issue with a 12s4p 4wd on HAYA with my modules. But I do plan on using D140. Just trying to think of a clever way to do this but the more I type the more i realized it might not work.

Cus essentially. If the load distribution is off. When the heavier loaded side need more current, it will need to pull that much through the other ESC.

6

just place the packs in a cyrcle than. so the main terminal is in the middle of the deck. same length of wires to both sides. should be easy peasy

7

No channel to wire from middle to the sides. If I use my modules, which I am currently pretty stubborn on.

8

so you have place for a d140 bms, but not for the wires? :thinking: how tight your modules sitting in the deck? do you have a picture?

9

Don’t have a HAYA yet, but here:

Module is 76mm wide exactly and 74mm long and 22mm tall.i wanted to do it this way because the balance wire will look so nice.

10

flat copper braid, routed on fishpaper, maybe? there should be enough space to route them under your packs to each side.

11

Not enough height clearance. not a bad idea tho. Can’t make the modules shorter unless I redesign the whole think to not use standoffs with I could.

Sorry if it sounds like I’m not buying any of your ideas. They are good but doesn’t immediately clicks in my mind.

12

ok, so if you want it not other… the haya is definitly strong enough to dremel out small chanels of 3mm to place the flat copper in it. you can even cover it than with fishpaper or silicon or silicon than fishpaper. that should be bullet prove!

1 Like
13

A bit an off topic question. why you want to build a 4WD and than just go with 4P? I mean i understand that there is not more space in the deck, but even if you use VTC5A with 35A it´s max 35A per vesc. With VTC6 or Q30 it would be only 20A and 4WD will also reduce your range at min 20-40%.I don’t see a real advantage with it for a street board.

1 Like
14

That I didn’t consider. The 4p modules just looks so nice in the HAYA. and leaves lots of room for 4WD.

Hehehe don’t mind me fantasizing a clean AF build. :kissing_heart:

15

what you don’t consider?

16

The 20% range reduction and the current draw. Do I need that much draw tho.

Theoretically, you will only draw more than 2WD during acceleration which last for < 10seconds and doing some extreme hill climb. And a little bit less efficient from the rolling resistance.

17

if no than quad doesn´t make a sense :sweat_smile: besides the fact that you through some extra money and parts on the taple, add more stuff that can fail etc… Don´t get it wrong, I totally can understand if you just want to make a quad because you want one :stuck_out_tongue_winking_eye: My main reason was also, just because I can… but non the less, there is always the questioning if it makes sense for somebody or not.

18

Might build it once for the frame and glory and revert back to 2WD for practical reasons. :stuck_out_tongue_winking_eye:

Unless someone pays top dollar for it.

Otherwise I can build a external pack to charge while riding or modify the lid to easily open and close like my hyperbeast and do swappable.

Can someone agree to disagree that splitting battery in the middle would work.

1 Like
19

I would split only with higher P groups. In the first post I forgot that you can use max 4P. 2P would prop. sag really hard.

20

Yup, also do you concern about slight difference in voltage between 2 packs. For example, one hits soft cutoff before the other. I guess you can put a huge resistor to parallel the two pack so it slowly even out.