FOCBOX UNITY $299 | R-SPEC DRIVE KIT $588

OllinBoardCo's High Output VESC


#1

In our testing we have found the VESC mosfets to run a little hot when riding at roughly 30mph. This induced a few thermal shut downs when we exceeded the default high temp setting. You can raise the default limits within the BLDC tool to keep the VESC from shutting down but I think we have found a better approach to this situation.

We have mounted the VESC to an aluminum base which doubles as a heat sink for the bottom three mosfets and added individual heat sinks to each of the top mounted fets.

This unit is now standard in our integrated decks and has alleviated any overheating during extended high output sessions. It will soon be available in our online shop too, feel free to contact me if you would like to get in ahead of its launch and order this model now.


#2

Hey chaka, looks great!

I experienced a shutdown on my current dual VESC setup after some “spirited” riding.

two questions:

  1. Has anyone determined what the safe maximum operating temperature is for the VESC? It looks like it is set standard at 100. Could I safetly bump that up a bit?

  2. I placed an order from Ollin about a week ago for a single motor build I am working on. Could I add this on?


#3

Hi Jeff,

You could bump the temp up a bit but it is less than optimal. Would decrease efficiency and increase resistance.

If you would like this model I will send you an invoice for the difference, a whopping $10!!! This unit will list for $120 with cables, capacitors and heatshrink.


#4

Pretty cool that little passive heatsinks make a difference. I’ve got some heatsinks around here somewhere and will put them on mine when it comes in.

Good work!


Are 50mm OR 63mm Motors Better on V4.12 VESC?
#5

They run hot at 30mph, but will they be hot at 20 mph? Do they need ventilation at 20mph?


#6

No, the VESC handles that type of use very well as designed. At 30 mph we use almost three times as much wattage as when we travel at 20mph.


Are 50mm OR 63mm Motors Better on V4.12 VESC?
#7

So the heat problem you are having is to do with the higher amps you are pulling, right?

Because I think that the speed you travel is not directly proportional to heat - Watts is though. I mean technically (without atmosphere) you could travel at 80-100mph and not generate much heat if there is no load on the motors.

So I think me must look deeper, I assume what creates too much heat is the sustained load on the motors, they keep pulling more & more amps until the load reduces, this can happen at any speed if the gearing is not setup correctly. So maybe the heat problem you are having is a gearing ratio problem? Are you still running 2:1 reduction? What size wheels?

What RPM are your motors at when riding at 30mph? Might you just need some higher KV motors & more reduction?

Or perhaps if the gearing is already optimized you are now simply experiencing a speed point which most of the load is now due to wind resistance.

This chart shows how much more power is required to battle wind resistance on an ebike - 0ver 25mph you start wasting lots of power.

Here is a similar chart, it shows the relationship between actual speed & required power.

I can ride at 25-28mph and there is no heat, at least not enough to cause system shutdowns. So i assume once you past that 30mph zone the effect of wind resistance really starts to hurt perfromance.

To help mitigate your heat problems I recommend optimizing your drive train & then maybe installing a wind shield.

Also maybe a bonnet scoop with vesc inside.


#8

Lol that would look hilarious on the front of a deck.


#9

Aerodynamic drag is proportional to the square of velocity.
Double your speed and you’ll quadruple the drag.
Power needed to maintain velocity is proportional to said drag.
Current drawn is proportional to power needed.
Heat generated is proportional to current drawn.
Hence heat generated is proportional to square of velocity.
20mph squared is 400, 30 mph squared is 900 so theoretically you’ll generate 2.25 times more heat at 30mph than you would at 20mph.

Just sayin heat sinks make sense if you wanna go faster.


#10

also, and i’m strictly being pragmatic here…

Adding heat sinks to the VESC just makes sense. So what if it runs fine without them under MOST conditions. Under MOST conditions, MOST things won’t fail. What sets a quality product apart from MOST products is its ability to NOT fail even under conditions that rarely ever happen.

Doing 30mph isn’t a “regular occurrence” even on this forum. 95% of the time we’re during 25 or under i would think because most of us aren’t geared up to do those kinds of speeds all the time.

Al of that being said, I think heat sinks should be a regular feature of the VESC. Its not like having them on there is going to make your box any bigger or make anything else any more inconvenient. All its going to do is raise the price $10 and allow the unit to perform much closer to its maximum performance level much more comfortably. After all, if it can take 30mph with a yawn, it will probably last damned near forever doing the regular cruising and carving most of us are doing on these most of the time.


#11

Not sure if I should post this here or in a new thread but it is along the same topic.

I was riding my dual VESC 4.10 setup from Enertion earlier today. After climbing a decent sized hill at ~25 mph, I felt the VESCs limit the power. I assume I had pushed them too hard and they went into shutdown mode so they don’t damage themselves.

However, now that the board has 100% cooled off, the motors don’t spin up anymore. I can connect the VESCs to the BLCD tool without issue, all the normal lights come on and the VESCs receive a signal when I pull the trigger (lights activate on VESCs).

The motors were barely hot at the time so I am almost 100% sure this is a VESC issue. Is there anything I can do to troubleshoot/fix this? Once I do get it running I will probably mount heat sinks to my VESCs to prevent the issue from happening again.

Thanks everyone!


#12

Are you using thermal double sided tape for the top heat sinks? Or are you using a thermal adhesive?


#13

Thermal adhesive. This is just the proof of concept, now that we have measurable results we are switching to a single threaded heatsink so it will also be mechanically fastened.


#14

Very cool man. I will have to get a few of these eventually.


#15

Can’t wait to see the mechanically fastened option.


#16

Hey, so I am building a eboard and am planning to use a 150kv outrunner at 10-12S. Will there be a noticeable difference using a high output vesc versus a regular esc?


#17

The only modifications I have done to this VESC is add heat sinks. If you plan on pushing the envelope with the VESC I would suggest heat sinking but under normal use the VESC will operate fine without.


#18

What are the new dimensions of this VESC ? (also height)


#19

Hey Skirk!

The dimensions are 40mm x 65mm x 23mm


#20

Thanks ! But, could you give me the dimensions of the unmodified VESC ? I have read that it is 1 inch, but I would like something more accurate.