Archived: the OG noob question thread! 😀

How-Tos & Esk8 mechanics Esk8 Mechanics
#14933

i do it another way.

  1. I go into reply thread
  2. open a new reply
  3. go back onto picture thread
  4. select the image a ‘‘quote’’ it
  5. type what you want to type
  6. post it ( you will get promted to chose the thread where you want it to post, always chose the top one)
#14934

Can you drive 2 vescs via canbus from the android vesc tool? What’s the correct setup for this?
I’m waiting for the last few bits, including the remote, and in the app i can only control 1 side at a time

#14935

Off because if one motor glitches, I want to be able to ride home instead of the board thinking a wheel is slipping constantly

1 Like
#14936

Has anybody tried a split-truck length setup? Say for example a 275 hanger in the rear and a 240-260 up front. The idea is to improve carveability but would this affect stability in any negative way?

#14937

What are the practical benefits and drawbacks to using lipos vs li-ions, and vice versa? Ex. voltage sag, more charge cycles, durability, safety, etc.

For background, I’ve been considering LiPo for a build because it seems cheaper (2100Ah for ~$400), more plug-and-play, and I already have compatible chargers and voltage alarms, but I have no idea if they last as long or are more sensitive to vibrations or whatnot. Li-Ion seems safer, but is much more expensive because I can’t build my own packs.

#14938

define lipo

1 Like
#14939

Definitely helps off road and in gravel slips, doesn’t help if you’re trying to drift haha. I was wondering why my drifts were all so weak one day…

1 Like
#14940

Hello everyone,

I have been reading a lot before posting this, but the amount of info is overwhelming.

I’m building a 12s3p molicel p42a battery pack using NESE modules. I want to connect each modules using ring connector and 12awg cable. Looking around i can only find ring connectors rated for 80A. Each cell is rated 45A continuous discharge, even my plan is to only pull 30/35 A for better battery life, 30x3 = 90 A. Would this connectors stand it? should I aim for the 135 max A just in case? is 12awg cable good enough?

I’m thinking about this bms for charging only.

I will order it for 12s, 20A.

My deck is a zenith rocket v1, and im kind of tight for the components, that is the reason for that bms.

What do you think about It?

And my last question, a 15 A fuse between the bms and charging port is to high?

Thank you for your time!

#14941

Li-Ion:
Pros:

  • Much higher energy density and specific energy. A worst-case 1-liter cube of Samsung INR18650-30Q cells (square packing, none of that fancy hexagon rubbish) has 512Wh in it. A solid 1L cube of Turnigy Nanotech 65C Lipos has about 266Wh for comparison.
  • Generally considered to be safer, E.G. les likely to become fireballs when abused.
  • Datasheets are available with real numbers.
  • Have their own metal shell for puncture resistance and the like
  • Can have much longer cycle life

Cons

  • Lower power density - Takes more cells to get the same number of watts.
  • Can be more expensive in terms of $/KWh.

LiPo: See above, but the inverse.

3 Likes
#14942

Depends on the type of wire. Multistrand, solid core, etc. Typically, you’re going to be using multistrand though. Also depends on length.

12AWG cable is rated for 40A-60A and at shorter lengths, can be higher for brief periods of time. You should be fine with 12AWG. Most XT60s are terminated with 12AWG. Most XT90s are terminated with 10AWG. Should give you an idea of which cable you need.

What motors are you running pulling 90A continuous? :thinking: That’s pretty intense AT board territory

Fusing rule of thumb is twice the charging current

#14943

Isn’t this contradictory? Power and energy use same units no?

#14944

Power uses watts, horse power, or joules per second

Energy uses joules (calories too to nitpick)

I.e.

Power = Energy/time

4 Likes
#14945

Got it, I see where I got confused. He’s essentially saying good energy density, poor power output (relatively speaking)

4 Likes
#14946

Bingo

3 Likes
#14947

thank you my friend,
90a peak, no contunuous. my fault
any opinion about the bms choice?

#14948

Thanks! I always thought LiPos had higher energy density, especially since it’s solid vs the airgaps you get from having cylindrical cells in a rectangle. Li-Ion does seem to make more sense for esk8s. They do seem pretty heavy though compared to a comparable LiPo build - in my calculations, a 12S2P 2100Wh LiPo would be 6.6kg, while a 12S12P 40T 21700 that’s also 2100Wh build would be nearly 11kg. I think I’m leaning towards LiPos right now, mostly due to cost and lack of any way to build packs.

Edit: 40T cells, I’m bad at reading

Edit2: And math too

#14949

Honestly, I think just about any BMS will be fine. DS140 is a popular bms choice.

#14950

How do you plan on building the pack with lipos?

#14951

Kid at my college seems to believe that there are less problems with cheap antispark switch compared to a loopkey…

He also says there is no spark protection in a XT90s loopkey…

Also claims himself to be an engineer…

1 Like
#14953

Wrong. Loopkey is akin to just bridging the wire manually whereas AS has more compents that can fail

Wrong. There is a small resistor to limit inrush current to prevent sparking.

Wrong. Engineering doesn’t necessarily mean you’re electrically competent :wink:

2 Likes