Motor help - first DIY build

Hey everyone, I’m making my first DIY build.

I’m going to be doing a lot of off-road, trails and there’s lots of hills so I’m gearing for torque looking for high quality and ideally sealed motors and something that wont overheat easy. I’m having a little trouble selecting motors but so far I have the following:

Apex Predator Complete

  • Haero Bro

  • Apex Air Trucks

  • MBS Rockstar 2 Hubs

  • 8" Tyres

  • F5 Footstraps

  • Moon Drives

  • Apex ESC Enclosure

  • Xenith ESC

  • Hoyt Puck

I think I will be buying a pre built battery from Apex with a BMS included. Will probably go for a Peli case 1200? Unless someone can suggest otherwise?

  • 21700 P42a (Size still to be decided buy I’m going big maybe 12s8p)

For the motors I am unsure as I’ve seen quite mixed stuff on other posts.
I live in the UK and have narrowed it down to the following but I need help on deciding.

Flipsky 2021 6384 4000W 140KV BATTLE-HARDENED MOTOR
Turnigy SK8 6374-149KV Sensored Brushless Motor
APS 63100 OUTRUNNER BRUSHLESS MOTOR 140KV 4500W

This is my first DIY so any suggestions at all are welcome. Have I missed anything? Thanks

what gear ratio on your geardrives? i see you want 140kv motors but higher kv is actually more efficient (not significally, but still)
personally i would actually buy either the 6384 battle hardened flipsky, or the 6374 battle hardened ones. The APS ones are not really different, + they are not battle hardened and so you MUST do that if you buy those. you also never actually use 4500w, so having that extra 500w headroom achieves nothing (in theory you have slightly better high end torque, meaning better torque response closer to max speed but eh, again very minimal)

also make sure your motor shaft is the same diameter as you geardrive pinion. either 10mm or 8mm.

I don’t have any personal experience with the hobby but i heard they lack a pit of power.
I personally own APS 63100, they are great, but def need to be battle hardened and since you are starting out DIY i wouldn’t venture into taking the motor apart when flipsky offers good, cheap, reliable battle-hardened motors

Peli is a good choice, i also think @Apex will sell an MTB top mount enclosure but they are busy af so i don’t know when that’ll drop.
other possibility is a 3d printed enclosure with bottom aluminium plate like i have.

12s8p p42a is a great middle ground. i have a 12s6p, i get around 35km with heavy mountain offroading (30wh/km) and about 20wh/ full speed on the road (~60km), it suits my needs perfectly
12s8p will take it just that step further without worrying about range.

I actually have a very similar setup to what you’ll have, 5.1 gearing with 8’’ wheels also.

the only other thing you may consider is changing the esc (like spintend), getting an 18s battery. this way you’ll have more speed and torque for the same gearing. it’s probably the best diy builds you could possibly build as of now with the current tech.
note you’ll have to change the remote as well if you do this, but consider this like top of the top build if you go this route.

It’s the one thing i regret with my build, even having 8’’ 5.1 gearing with 140kv, i would like even more torque, and higher speed because currently i can only do 41km/h, whicj imo isn’t fast enough. 50km/h would be better. especially with apex air trucks you will have so much stability. i can do 40km/h with my eyes closed, with the right setup going fast is easy.

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Ok cool, I think the highest that Moon Drives goes to is 4.89 ratio with a 8mm shaft so I reckon I will go for the flipsky to save me doing the battle gardening myself.
I don’t have a preference for lower kV motor I just thought that was better for a torque setup, however I don’t want to sacrifice too much too speed, something that can hit 28mph easy would be nice.

If I go higher to the 18s I guess the battery box is going to be pretty huge? Any ideal on rough dimensions?
Is the Xenith ESC not compatible with an 18s setup?
Is there an alternative to the Spintend? I live in the UK so ideally looking for something that I can get here.

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So I think I’m going to maybe go for a 12s12p stack in a pelicase 1300, that way it’s not going to extend over the board and I don’t have to worry about changing the ESC.

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No, many confirgurations are possible, it just makes it a bit harder for the battery builder haha.
you can calculate your battery size with either @ducktaperules amazing BatteryGenerater in Fusion

or there is an app called easy battery calculator

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nope, the only other 18s compatible is LAcroix and trampa, both you will pay a tremendous amount of money.
That’s why i suggested a spintend.

keep the money for other things, unless you plan on doing 100km+ a day i wouldn’t recommend, it also add A LOT of weight. if you use the Easy Battery Calc it shows you the weight of the pack

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Ok cool I’ll check it out thanks.

I’ll probably stick to a 12s configuration.
With gear I’m around 110kg easy and I would like to be able to hit 35 real world off road miles with lots of steep hills so I think it will still need to be quite big

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okay that’s a good reason for 12s12p haha. i’m 62kg so not that comparable :joy:
@ducktaperules is from the UK and weighs on the heftier side like you, and does some serious off roading. What’s your average wh/km Q?
@NogiYogi i think if you based his wh/km for you then you’d get a real decent estimate on your real world range :grin: :call_me_hand:

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It’s proving difficult. Honestly Peli 1200 is hard to beat as a robust waterproof option.

It doesent have to be any bigger as you can still use the same number of cells in a different layout.

That said I can’t really recommend an 18s battery for a first DIY sure to extra safety considerations.

21700?

Sounds like Your planned build is basically my board right now.

Apex Predator, moon drives, flipsky 6384 190kv, Xenith and case, Peli 1300.

I think me and Lee both usually get 50-60 wh/mile

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For reference, Here’s a good ride from last weekend

I weigh a lot more than you and was averaging 60wh/mile acrost some tough terrain though the forest. This ride used around 720Wh in total.

Last weekend I also did a similar ride on Mostley street. 15 Mile ride was averaged 780wh so was about 50wh/mile

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Yeah 21700, it seems like they will be almost the exact same.

Damn that 1300 case is looking pretty chunky. How heavy is your whole setup?