Human Instrumentality Project | 6s3p | Single Racerstar 140KV 5065 | Custom Deck | Battery box holder | FVT 120A ESC

Hi girls & guys,

after endless hours of reading through others building threads and hours of building my deck and wiring everthing i´ve finaly rode my board for the first time ! I could´nt be happier and want to share some of my experiences. This is a low budget board so if you question some of my descisions, most of them were to keep costs down.

You´ll find my shopping list at the end.

4 layer of pinewood for the deck

plywood leftovers for the box

again leftovers for the cover

2 layers of Livos

Neon Genesis Evangelion griptape

Here is where the magic happend and i can totaly understand that a lot of ppl wont like this but it was the only way to make a battery pack without soldering it and untill now everything works "good" wiring the BMS was horrible since there were 3 different explenations on their website. C- for charge/discharge was the way to go

1st day of riding at the former Airfielder, IT WAS AWESOME !

6,5 Km ( 4 miles) with top speeds of 20 km/h (12,4 mph), which i´am totaly happy with.

Even if i shit my pants because of the wet track had to go for my first ride and it was a lot of fun, the programable ESC is good imo, smooth acceleration/breaks and a lot of options via program card. The Performance is sufficient for me. It drives pretty stable and had no performance los at all.

Still the Voltage sag is relevant in my case, at full speed i lose like 25% - 30% battery which will probably be a problem if i go under 30% charge. I hope an upgrade to 6s4p will help.

If you have any questions or suggestions just go for it.

Big thanks to the community for helping me out especially @rojitor , @krloz , @wafflejock and @bartroosen12 . Your help is really appreciated and i would´nt have been able do it without your help, THANKS !

Part list Motor :

Motor Gear:

ESC : (with USB Program card)

Battery : 18x Samsung 18650 30Q 3000mah 15A

BMS : 6S 60A BMS

Battery holder:

Motor Mount :



Luv it :heart_eyes:! All of it. Specially the evangelion art. That’s one of my absolute all time fav. Have fun pal :slight_smile:


good work. The pulley kit is HTD5M? I heard that racerstar pulley is 5GT, so how does it work with your belt? can you post some pics?


I actually did’nt knew about that, but it works good from what i see but i have no comparison so take this opinion with caution. Here are some pics, let me know if you need more.


looks great :+1:

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Luv it. Enjoy

How are those battery holders holding to the power draw of an esk8?

Yeah, i thought that the battery holders would cause more problems but until now they work pretty good.

The charging issue thems also to being solved. It was just like @rojitor said

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If you wanted to improve the performance you could try this one?

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Yeah sadly i had already ordered as someone told me about a higher kv with a 6s setup but i’ll think about it again thx m8. This motor has a really great price.

Do you know how voltage sag will accure with a motor with more kv ? Same or worse ?

Sorry I am not sure on this. I think I may get one of these to try and make a board for the kids though.

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Hi guys,

as i already mentioned before voltage sag is kinda a bigger deal on my setup and i want to overcome the problem at least a little. But at first i would like to understand the problem. And have several questions on this topic.

  1. What does voltage sag cause ?

2 .How do i overcome/avoid it ?

3 . Does it damage my cells if the V of my system sags under 3.3V (per cell) under usage but stays at 3.8V in idle ?

My battery usally sags betwen 25% - 40% at full throttle so i can only use until 55% charge at idle

So my plan is now to upgrade my battery to 6s5p. I would really appreciate any help.

You won’t like, but I think most of the sag is because of the battery holder, the contact resistance is high and a lot of power may be lost there

Did you manage to fell if the contacts are hot? If not do some hard accelerations and braking and immediately open the enclosure, remove one cell and see how warm it fells

The 30Q is a very good cell, you have most sag than most because your ESC doesn’t limit the current like a VESC, so you may be drawing more than 100A for a short period

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Yeah i read about that but was hoping to not be a big of a deal but it thems like it is indeed a big deal.

After every ride a had a close look to the temperature of Esc, Battery and motor and the motor was the only thing that got like handwarm, maybe 40-50° celsius.

I´ll test the contacts and see what i got.

This is something i don´t understand why does my Esc draw up to 100A even my motor only draws 36A max ? from what i understand 100A discharge would´nt be that good for my batteries :frowning:

36A is what’s the manufacturer decided to rate the motor, but nothing prevents it from drawing more when a high load is placed, which is the case when starting from slow speed

Yes, this high current is bad for the batteries, that’s why most people here will say that going cheap in the long run will be more expensive, you saved a little bit of money found with an FVT esc, but maybe because you can’t limit the current you will kill the batteries way faster than expected

But for now, you could measure you’re entire pack internal resistance, this way we can see where the problem is

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Wow, thats bad news and yeah some ppl. stated that some parts of my build were not that good but i never understood why. Now i see whats the problem and i’m very thankfull for that advise m8.

So my next step will be finding out how to messure the internal resistance and then hopefully get a not so pricy vesc and spotwelder.

Just get a few ceramic resistors, a 5 ohm one will pul about 4A from the battery at 22v

Knowing the rest voltage, the voltage under the resistor load and the precise resistor resistance, measured with a multimeter we can easily measure the internal resistance, is not the most precise method, but will give some idea if something is really odd, for example if the battery holders have a tô high contact resistance

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So if i have to buy some resisstors anyway which would cost about 5$ at least shouldnt i buy an internal ressistant messure tester if they can do what i think they can? i saw some on amazon for like 10 bucks, also isint my multimeter capable to do this for me it has ?

Sorry for the question im havent worked with electric that much yet.

You may also be drawing more power than needed due to the 140kv motor on 6s. Especially if you are riding at max speed quite often. A higher kv motor on 6s could possibly give you less current draw at speed(but more current draw during acceleration)

how is that motor mount holding up?

On another note: the board looks great dude. I love the enclosure.

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Yeah @Pedrodemio mentioned that already and i will defenitly get a vesc very soonish but at first i want to get rid of this battery holders first by getting a spot welder, its pricy but this wont be my last build thats for sure.

And also i would really like to meassure its internal resistance before i build a new pack so i can compare it and see how good these holders does their job, it could be helpfull for others who also dont have a spot welder.

The motor mount does a pretty good job compared to its cost, had to Tweak it a little but now everything fits tight.

And thx m8 i put a lot of effort into this deck and enclosure, still not happy with it but thats another story :rofl:

So how has your board been. I’m looking at the racerstars as motors for my first build

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