Yeah chain is great! It doesnt break unlike belts and gears wont get worn out (also looks better imo). Drilling holes in my 36 tooth sprocket was such a pain tho. I only own chinese drill bits and I dont even have a drill press. I have a decent drill tho but still it was lots of work cause the sprocket is made of hardened steel (yikes!). I had to use multiple sized masonry bit to slowly enlarge the holes. Certainly was a learning experience! I would make my board 10s cause if would be safer for the vesc but I want speed! This is the reason I went with the tacon 245kv. It has a high kv but also if a large motor like enertion’s r-spec motors so the tacon 245kv will still have a good amount of torque. I believe that Jason has his motors made by they same people who made the tacon motors and they have a similar design. Btw they are not coming back in stock. Sorry but even Jason said so. I must have gotten one of the last ones from hobbypartz.
He’s the theoretical calculations of my board (41 mph!!! 32 mph with 80% efficiency):
UPDATE: Im not going 12s anymore! Im going 9s but 8s would be safer for the vesc
I think Ill just go with the lipo setup for now cause I already purchased 2 of the lipos. I may as well just buy the rest. I think I build my 12s2p battery later and really regret not plan to make a li-ion battery in the first place cause li-ion is safer, longer last, and I would put a bms on it. The 12s2p li-ion battery would have only cost me 200 buxs to make including the bms and a charger where as the lipos cost me 86 buxs and I have to deal with an annoying balance charger which cost me 40 buxs. I conclusion… go with li-ion instead of lipo.
I did see your recent post about trying to get mega speed with 245kv and 12s.
I didn’t realize that you had already read Chaka’s post.
I just ordered a couple Vesc’s and I’m a little worried over the fragile DRV chips myself.
About the speed thing, I’m currently running dual 6355 230kv motors(some have said they’re only 200kv. I will be testing them soon as my motor analyzer comes) on 12s lipo with 16/36 gears and I’m only getting 28mph tops. 185-190lbs
I use to run 145kv hub motors and got 33-35mph tops
Had to switch to slower belt drive setup for hill climbing.
Anyway, when my Vesc’s come, I’m gonna drop down to 10s
Didnt know their was a newer vesc. I recall seeing vender’s new vid on his youtube though where he was using a 500 kv motor I think. I didnt look it much tho. Does the newer vesc go over the 60k erpm limit so now you wont get drv chip errors? Also I was told by @Jinra that you can hit the 60k erpm limit and not damage the vesc. I asked Jinra in another thread (link to thread below) if going above 60k erpm was alright and he said it wouldnt harm the vesc cause it only causes errors. He said that 100k was the hard limit. So I assumed I could not harm my vesc with a 12s 245 kv setup.
A Tacon will pop a drv chip at 12s the first time you spool it up on the bench, I speak from experience. Even at 10s it will be dicey, it will work but it wont be long before it throws a fault at high ERPM and toasts your drv. My recommendation for the max voltage to use with the Tacon is 8s
Don’t beat yourself up too much about buying lipos and a balance charger. It is invaluable to have some perspective on the differences between the two types of cells and a balance charger is a great tool to have on the bench as a builder.
Thank you very much for the info! You are the real OG on this forum. Anyways I will totally take your advice to go down to 8s but I will be going to 9s cause I already purchased 2 3s lipos. I just will not go full throttle when the cells are a 4.2 volts cause Ill get 64827 erpm (37.82457). I think it would be safe to go full throttle is the cells were at 3.7 cause the erpm wouldnt exceed 60k.
Yeah you can take it to 9s but treat it like a high performance machine. Meaning, don’t spool the motors up to max rpm on the bench or with the board riderless on the ground. You will want to only max it out under load. When not under load the motor will receive around 4.1v per cell because of the low voltage sag under such a light load from purely the drag of the drivetrain alone. This is assuming you have a full charge with the board fresh off the charger.
You will be breaching 60k ERPM by a relatively low amount so it isn’t as bad as 10s but it does have some small risks. Also, if it is geared to climb hills with a low top speed you will need to be careful not to coast beyond that speed because it can then easily surpass 60k ERPM during regen.
I consider a system like this to be pushing the envelope and would be great for a high speed racing board if it where fitted as a dual diagonal. Really fast with standard gear ratios but temperamental. Luckily V6 looks like it will solve some of these restrictions and allow for more experimentation.
Edit: One of the reasons I am stressing the full throttle risk so much is because the way the VESC works in “current” mode. Even at a 1/4 throttle the motor will spool up to max rpm if unloaded.
Thanks for all the info and risks. I didnt even consider the fact that the motor would exceed 60k when unloaded and the fact that go past my top speed down a hill I will be also be exceeding the 60k erpm. My top speed on 9s should 30 mph which is still very fast. I will be sure to get the new vesc when its available so I possibly go the full 12s.
If I happen to damage my drv chip could I just buy a knew one? I do have access to surface mount soldering tools and some experience using it to replace parts in phones. Is this a good place to buy the chip? http://www.mouser.com/search/refine.aspx?Ntk=P_MarCom&Ntt=113734323
It is maybe the the best place to buy replacement parts for the VESC. Everyone here on this forum would be recommending this shop in the first place for sure !
Started working on this thing again for the past 2 days. Ordered the remaining parts a week and a half ago. I should finish for sure within the next two weeks. I’m leaving tomorrow on vacation though. Was aiming to finish the board so I could take it but my 3d printed chaka cell holders have yet to come I started the project almost a year ago and I here to FINISH!
UPDATE: Im not going 12s anymore! Im going 9s but 8s would be safer for the vesc
- unless you have a newer version which works, but i don’t think 4.12 fixed and v6.0 isn’t out yet.
I started the project almost a year ago and I here to FINISH!
