Couldn’t you just up (or rather, lower) the “Motor min (regen”?
LHB Phat Matson Deck | 10S4P 360 Wh 18650 w/BMS | Ollin Vescs | Enertion Single 190kv 6372 & Mount | 83mm Flywheel Clones
yea, like I said: you might charge your cells outside specifications if you do that! the samsung 25Rs also have max 4A charge current per cell!
then again Im always suprised how much you can actually brake with these small negative battery regen current numbers. my FOC accelerating and braking test had 50A max and -16A min and in the end the wheel slipped and the farting sound gives away that there was really some force involved and not just a weight shift to the other wheel:
But you wouldn’t charge the cells outside of spec. Battery min (regen) is the field that determines how much charge goes back into the motor. Motor regen (min) is how much current can be in the motor for braking.
@guyguy congrats on the board. Our boards are probably very similar. I have not yet tested hard braking at all. As I mentioned in my impressions I have only been braking pretty gently and even using foot braking near the end. Now that you mention this, I will test the hard braking next time I’m out.
@longhairedboy I think for future sales you should maybe increase the price a bit, and have an “official” warranty. The extra cost will likely help you cover the crazy shipping fees for these big boards.
hmm, if you set battery min (regen) to 0, Im pretty sure you cant brake anymore. its the current the motor produces when you coast/brake. basically full brake means the motor phase wires are shortened via the battery and the current they produce goes right back into your cells as regenerative braking!
That’d be interesting to test out. Jason states here VESC FAQ | Regen Braking Configuration BLDC tool & Brake Force that they both affect braking potential, but I wonder if anyone’s tested braking with battery regen set to 0.
@longhairedboy if you haven’t priced a warranty into the full prices yet you may want to add that your product is sold “as is” otherwise an implied warranty will be applied to products that you sell. Even if you do have a written warranty, the implied warranties will apply unless you add language in your warranty saying that implied warranties are not applicable. It’s also common to attach shipping fees to warranties or something that states that the warranty holder will be on the hook for shipping/admin fees if it’s found that they’ve violated the warranty in some way. The flipside to offering strong warranties is that they’re very good marketing/sales tools. You also have a lot of options in how you set your warranties up - you don’t necessarily have to price it into your boards spreading it across all your buyers, instead you could always side-car the warranty, like, have it as a customization option on your site where an additional 200$ during will provide 1 year warranty. You can even have tiered warranties like Apple which has 90 day with-purchase warranty and then Apple-care for 1 year costs extra. Just some food for thought.
As an aside, good luck on your hearing in Texas, I hope it ends well.
@whitepony I guess we’ll find out when it gets here. I’m going to try a few different things and report my findings when i do. I think i have the max regen current set to something like -20. The default is -60 which is kind of ridiculous IIRC, but i don’t have it in front of me atm so i can’t be sure.
@Photorph i just bumped up my prices by $100 across the board. (haha… the board… see what i did there? sorry, dad jokes.) I’m trying to achieve the delicate balance of making money, covering my costs, covering say two or three returns for repairs, cover some goodies like extra belts and things, and still stay competitive price wise with commercial options despite not really competing with them on their business model. I expect prices will go up gradually as i make adjustments and as the market dictates, but for now i just want to get a few out there to tweak my production, make adjustments to processes, and gain some awareness. I can totally see going all the way up to about $2k for the fully loaded model though.
You guys are all wondering how i build these for what i’m charging. The answer is by paying my dues and not making much money at the moment while i get things sorted. I have a day job that allows me some buffer and allows me to keep paying bills while i figure this thing out. I won’t be quitting that job any time soon, probably not for a few years at least. In fact i’m actually trying to streamline my processes to allow me to do this nights and weekends without completely disappearing on my family. The xcarve is a big part of that, and so is having a third party make my fiberglass boxes. Cutting decks, routing decks for wire channels, and fiberglassing boxes are the biggest time sinks, but with a robot cutting my shit out i’ll be able to not only produce decks faster, i’ll be able to produce more variety in designs while still using the same deck press and mold.
The only thing i can’t do anything about at the moment is fucking china and their goddamned holidays. They owe me 4 remotes, two BMSs and two fast chargers. I’ve got three more builds i’m working on and i cant do shit with them because China. I need a US supplier of those steeze remotes, a US supplier of BMSs and a US supplier of 4amp ebike chargers. I’ll be set at that point. I’ll be able to reduce my stated build time and be able to build more boards in parallel. Currently if there are no delays on anything i can do about 5 at a time. I can double that with robots and third party fiberglass, and i could halve my build time if i could cut China out of the picture.
I just tried this - it still brakes, but very slowly. Setting motor min to 0 it doesn’t brake at all.
what was your motor min when you tested it?
I tried it at -60 and -50 on the motor and 0 on the battery. Didn’t notice much of a difference between the two.
I also tried both at motor and battery at zero - it just doesn’t brake.
So, my problem is that the vesc just cuts out a little too easily so I just upped (since it’s negative) everything by a little: -15 on bat min -50 on motor since, if I’m understanding what whitepony said, it sounds like the vesc cuts off when the regen hits a certain limit. I don’t mind if the brake is a little less strong, just don’t want it to shut off so easily.
Not sure if thats the right direction but hopefully I’ll have time tomorrow to test it out.
not sure what upped means! you need to make the battery regen min more negative, like 4x4V = -16V according to cell speccs -> change to -20V to have more headroom. the battery will be charged outside speccs, but only for short moments and its still a million times better compared to crashing into a car or something!
you can always leave the motor at the negated max current for min current, cause thats simply what the motor can take.
@guyguy so I don’t really have any big hills to test brakes on, but I tried them on flats.
I can easily say the breaking on the boosted is stronger. If using only the boards brakes I have to plan ahead of time. I’d say it’s not strong enough to throw you off when I slam on the brakes (which can be a good thing i guess?).
In terms of the brakes cutting out, I may have had that happen but I can’t remember clearly if they cut out while I was actually holding the joy stick back. I’ll again have to do more breaking tests. What situation were yours cutting out in so I can try that? Was it only down hills?
Here’s a little video I took of my friend just hard braking from about 10-15 mph (running pace) on flat surface. I asked him to brake as hard.
You can hear it rattle then it cuts out around the end of second 4 - you can also see him move forward a little on the board.
It’s not just in hard brake scenarios, it happens in long brake scenarios for example if I brake softly for over 3-4 seconds it cuts out - you probably have to be on a hill to mimic this.
@whitepony by upped I mean from -20 to -15. So, +5 on the battery min. I’m going to test it in a safe environment, if it’s really soft I’ll probably open it up again and retune. If I have to choose between softer brakes and the vesc shutting down mid-brake I’d rather have softer brakes. A lot of it is expectation and inexperience on my part too - when I was braking softly down a ramp into a tunnel it cut out and I just wasn’t expecting that to happen. I had to just jump off the board and the board took a hit.
@jinra this is what it looks like with motor min -50 and batt min 0: https://goo.gl/photos/XZwA7NwZRvGdU8Xz6
compared to out of the box settings which was motor min -60 and batt min -20: https://goo.gl/photos/jcEoxxgvpzPf5Nxr6
In both videos I’m just pushing the throttle back and forth. You can see in the first video it takes a lot longer to brake then reverse. You can also see it shutting down in both videos from pushing the throttle back and forth.
When I set the bat min to -15 (up from -20) I was able to push the remote back and forth 10+ times before it cut out. At -20 it would cut out after 2-3 swings.
weird, I wouldve thought otherway round: -15 = cutouts, -20 = mostly fine.
I was going off Jason’s post
The cut out is caused by too much power going back into the battery right?
yea, the min current is exceeded (larger negative number) and the vesc goes into error for a few seconds (red LED blinking), then comes back online!
but after your experience was contradicting my expectations, maybe I just shouldnt say anything anymore.
By “larger negative number” you mean -20 is a larger negative number than -15 right? Sorry this is a bit confusing. I’ll shoot some more video tonight before I close it up to test ride.
That rattle sounds like belt slipping? I didn’t have any rattle in mine for sure.
I think sending it back to him was the best option. He will take care of it.
What did you think of the board compared to the boosted performance wise? It’s top end is much faster im sure and your range must be way more. Not sure how your friend on the boosted kept up while you guys were riding together.
Brakes on boosted are solid though. And it has a lot of flex so the ride is more comfortable. LHB boards are pretty stiff so you feel everything. I ride mine on smooth pavement and that’s where it shines.