Hi, long time lurker, first time poster. I have been into esk8 for years but after months of reading and research during the pandemic, I want to take the leap and do a full build myself.
My Main Board right now (building to replace this)
Right now I have a Trampa mountainboard, with 12s8p 30Q pack, Trampa 190kv motors, and Trampa 7:1 metal gears, Trampa bigboi deck (17ply), 9" tyres all round.
Overall its a great board. But as with everything, its not perfect.
Torque is spot on and just about throws my fat arse up steep hills.
Range is terrible. I am using 50 to 60+ Wh per mile, and getting maybe 12 to 15 miles range off-road. * Speed is spot on, tops out around 32Mph.
Motors overheat on hot summer days.
Turning/Carving is spot on, with Trampa barrels outside at the back, and on the inner position at the front.
The Trampa remote is priceless. I love the info screen and general feel/response of the remote.
The new build
Main goals = double the range (30miles), keep or increase the torque, keep or increase the top speed (32Mph), no more overheating!
Now this is where I have questions and could use some advice!
For the battery, its between a 12s12p P42a pack to increase range, or an 18s8p pack (to also increase power/torque?). But then I get lost on what motors and gears would be most efficient for the job
For the rest of the stuff, its probably going to be Apex Air trucks, Trampa bigboi deck (18ply), 9" tyres, peli1300 case, separate vesc case.
yeh, I could just change the battery. But that only solves the range issue.
Since I increased the gear ratio to get the torque I need, the motors overheat on hot days too So really, I would guess I should change those too at a minimum.
But budget really isn’t an issue here. So building out a whole new second board is the way I am leaning.
Imo bigger motors with the same KV, and a bigger battery is all you need.That’s some crazy consumption though, I wonder if changing to higher pressure tires or something could help with that.
Why same KV?
Slightly more efficient. He doesn’t need more torque, needs more efficiency. Bigger size should help against the heat.
But what if he goes high voltage?
Boo hoo, as I said – he has enough torque and lower kv would be less efficient. Just enjoy the increased speed Or increase the gear ratio even more, if that’s even possible
If you’re keeping the same board, then sticking to a 12s battery to use the same ESC would be best. On the other hand, a 48Ah pack is going to take a long time to charge, so first lookup available chargers and BMSes that can handle that charge current, and then decide if going high voltage would be beneficial to reduce that charging time
Its a combination of being a fat bastard, low(ish) tyre pressure, and charging very steep hills, that end up with those extreme consumption levels on most rides
My bud has the EXACT same setup as me. And gets closer to 40Wh/Mi just by being a few stone lighter. So it takes far less energy to push his arse up the same big hills haha.
This will be an entire fresh build. So everything can be changed. With that in mind… what is more efficient? Bigger motor with same KV with the same gear ratio, or lower KV and lower gear ratio? and are there any advantages to going higher voltage/18s?
With esk8 limits in mind, in general a higher gear ratio will always be more efficient. So will a higher kv motor, but you can’t go too high, or else your ESC will have a hard time having it produce torque.
The order I go about thinking about these things is:
Pick my drivetrain to have the highest gear ratio possible
Check how big of motors I can fit / how big I even need on a build. Although kv has a small effect on efficiency, how much torque a motor will be producing is the main factor in how much it heats up or not. Not current, torque!
— If I can only fit small motors that are going to overheat before my ESC does, then I don’t care about going low kv to help my ESC by pushing less current, I’m just going to go with a kv that gives me my desired top speed, and possibly even higher, because high kv is slightly more efficient for the motor.
— If I can fit big beefy motors that are either never going to overheat for my use case, or so powerful that my ESC can’t even drive them to their limits, then I no longer care about motor efficiency that much, and instead focus on giving the ESC an easier time by choosing a kv value that gives me my required top speed (if there is one), but not much more. If I really don’t care about speed, then I’ll go with the lowest KV I can get my hands on.
High voltage! What to do in a scenario where your ESC is the bottleneck, and you can’t drive your motor to both A) suit your torque needs B) suit your top speed needs? That’s where high voltage ESCs come in! Thanks to the higher voltage, at the same current (which produces heat in the electrical components) we can have a higher total power output! It also has some niche benefits like being able to use a lower current rated charge port for faster charging, less current going through thin nickel strips, compromising for a small penis, and for boards where you have a very low kv motor with a fixed gear ratio (for example, direct drive in an EUC), and you really need to increase your top speed.
Some examples of each scenario within my upcoming builds this summer:
travel board that can only fit 6355 motors, so I went with 190kv for efficiency + so that even at low battery I can hit my desired speed
mountain board where I don’t care about top speed – I went with the highest possible ratio and 140kv Flipsky motors for max torque
16s build, where 16s just allowed me to fit the maximum number of cells in my enclosure + use a small chargeport + want to pull more power than 12s ESCs would allow, if I can manage
Aside from that, your post suggests going higher voltage might be good for me actually. With the same voltage I have now, I can only really sacrifice speed for torque. Not maintain (or increase) speed and increase torque to accelerate faster, and get up steeper hills.
I also can’t really gear any higher. Infact, as I am looking at Apex Air trucks I will probably need to gear down just to find compatible gears. Probably changing from 1:7 to 1:6.
So… I am thinking perhaps. 18s, 1:6 gears, and the chonkiest 140Kv motors I can find, would be a reasonable way to go?
If your ESC is also close to overheating from the power you’re using, then yes, high voltage is the way to go! It’s pricier though, but I guess that means nothing to someone planning a 12s12p otherwise Could help with charging time for a pack that large too
Oh, I guess I forgot to mention that going 4WD is also a common solution to needing more power. Depending on your setup, it might be pricier / heavier though. On the other hand – it means more traction. So decide for yourself. It definitely uses more power though, so if I were you (range important), I probably wouldn’t do that.
afaik the esc is nowhere near overheating tbh. But afaik the only ways to increase acceleration are to increase gear ratio, decrease motor kv, increase volts, or lose weight haha. And I think my only real option there is to increase the volts.
Looks 18s, 1:6 gears, and the chonkiest 140Kv motors I can find would likely increase the top speed more than I need though.
Price isn’t really the issue for this build. But with so much weight already (on me and the board), thats my main turnoff with 4wd.
Nope! Increasing volts doesn’t affect torque, it affects speed! If you need more acceleration, just turn the current up in your ESC settings (Assuming your motors are big enough to handle it. In your case the motors are the limit, so they can’t really. On your new build you could though!)
Yeh, my current motors definitely cannot handle more amps, and overheat already. Those poor guys.
I see what you are saying about more volts not increasing torque. But because it increases speed, it opens avenues like lower kv to turn that extra speed into extra torque instead. At least thats what my monkey brain is saying.