FrankenWheel {{Landwheel L3-X Mod}}

[pkasanda]

Hey Ryan:

Here are a few ideas for your Franken-board:

I’ve got a pretty good guess why you are having spontaneous braking. I believe it’s a sudden voltage crash.

Scenario 1)
You have your VESC wired to the battery via the BMS. The BMS detects low voltage because the voltage sags quickly under acceleration. Boom the VESC is disconnected and one or more of the three motor phases is suspended with a connection. That would be 100% brakes. Wait 10 seconds and you can power up again because the Lipo batteries have recovered several volts just from resting.

Scenario 2)
Similar to above except you have wired the VESC directly to the battery. Same voltage sag/crash issue. But instead of the BMS disconnecting the VESC from the battery, the VESC automatically applies EBRAKE when the voltage rapidly drops below threshold. This is a programmable feature. But even if you disable it, I think that a VESC could still malfunction with a Rapid voltage drop.

Your range seems about right for what looks like the equivalent of four LW batteries. So I’m thinking you don’t have a damaged cell in your Franken-battery. I suspect the VESC is not doing the same type of pacing as the LW ESC. So the VESC may allow much stronger continuous acceleration (and greater voltage sag) compared to a LW esc. You may or may not recall that this was a problem with the V4 LW. It would accelerate like a rocket and then cut out without warning. Jason fixed that in the L3-x with a very sophisticated pacing algorithm. It tracked voltage and throttled back automatically as the voltage dropped towards threshold. Essentially it kept the battery above threshold by accelerating less or slowing down. Without that characteristic you may have inadvertently engineered some of the V4 weaknesses into you Franken-board.

Potential Solutions:

1. Replace your VESC with your functioning Landwheel ESC. You would have to wire the ESC directly to the battery terminals for operation. Charging would have to be through the BMS. If you don’t wire it this way you will fry your landwheel ESC the first time the BMS pulls the plug due to low voltage (or high voltage from down hill regen).

A landwheel ESC properly wired to the battery could solve most or all of your problems if your landwheel cells are all in good condition. If there are one or two weak cells then you could still experience voltage crashes that are too rapid for the LW ESC to handle. The potential outcome would also be sudden braking or loss of brakes.

2. So, you are not going to want to hear this after all the work put into the Franken-battery but replacing those Lipo Cells with Lithium Ion cells might be the shortest distance between two points to make your Franken-board safe and reliable. TB Vescs are good reliable tech if the battery is sound. So most of your problems point directly at a battery that has difficulty sustaining the minimum voltage under load. It might come off the charger at 41.5 volts and it may read 39 or 40 volts after a ride. But under load it could be dipping way down low, then rebounding when the load is removed.

Germane has had really good results with two different lithium cell hacks.

Landwheel L3-X Reviews

Landwheel L3-X Reviews

Lithium Ion Cells are so much lighter and yield so much more range. The best evidence of that is my revel kit prototype which has the range of three to four LW batteries but weighs less than one LW battery.

Another option would be to go with a TB battery pack. Then you would have a proper paring of VESC and Power source. You could probably re-use your enclosure.

Another option would be to go for a Revel Kit if the cost of a TB battery pack is approaching the cost of a Revel Kit.

[pkasanda]

@ShutterShock

About the bushings. Yeah idk I put in bones cones roadside and that seemed to help a little but it still is just complete slop-ville, there is no precision or control in the turning, you turn/tilt your feet, and it just doesn’t turn like you expect it to. Very hard to explain and I don’t know if harder bushings will just make that worse.

You think double-trucks would work? Wouldn’t that make it much higher?

So hard 95a or 97 Durometer bushings will definitely solve the sloppy steering, That wil make your steering a little wider than soft bushings but I think your big problem is the sloppiness and the speed wobble. If you solve that then the added control might gve you everything you are looking for.

If your deck is worn out and has no lateral stiffness then this would also contribute to a wide turning radius and poor directonal control.

Double hung trucks would definitely give you a tighter turning radius but I’m told they also cause high speed instability. Another potential disadvantage of the double hung trucks is that the geometry would not match the rear drive assembly and that mismatch is not likely to pan out well at high speed. I have two sets of double hug trucks but I’ve been afraid to use them.

If you want a really tight turning radius and still want to keep your high speed stability then the best solution in my opinion is a long deck wiht a kick tail. The length gives you high speed stability and the kick tail gives you any turning radius you want if you have the skill to tick tack.

Thats what I did with my revel kit prototype. The results were amazing. Revel Kit + Loaded Tarib deck + 95A cone and Barrel bushings. I also moved the rear trucks forward 2 inches to create a longer kick.

I did a video on that combination.

Revel at the "brand" new competitor in the direct drive Esk8 race!

Hello All, Hi Mike and Flo: I’ve had the Revel Kit for a month. Jason shipped it to me. I’ve prepared a video review. I hope you find the review informative:

[ShutterShock]

Well here we are, finally getting around to a proper response lol - I have been busy this week. I have got a lot of things to point out and fill in some details.

@pkasanda

You have your VESC wired to the battery via the BMS. The BMS detects low voltage because the voltage sags quickly under acceleration. Boom the VESC is disconnected and one or more of the three motor phases is suspended with a connection

I do not currently have any sort of BMS in this build as of right now. I have an 8s BMS that I plan to install as a charge only, but it is not in place yet. I have the VESC’s wired directly into the battery -

@pkasanda

Same voltage sag/crash issue. But instead of the BMS disconnecting the VESC from the battery, the VESC automatically applies EBRAKE when the voltage rapidly drops below threshold

Normally I would offer this suggestion as well, but my case is not so. I experience random braking when coasting and sometimes when actively braking. Sometimes when I brake, it will randomly go full-brake. I have never experienced any cutouts when accelerating, given that I have 3 parallel groups and relatively conservative VESC settings I am inclined to believe that I am not overloading the batteries in any way. I have checked cell voltages each time I charge and everything is holding steady. When I built the battery I discarded all bad cells, the rest were all at proper storage charge.

I believe my range is appropriate as well, but like I mentioned before I have pretty conservative vesc settings and I don’t even believe I have matched the original Landwheel v4 acceleration. I get what you are saying, but again referring to my previous point, I don’t experience braking issues when I accelerate.

@pkasanda

A landwheel ESC properly wired to the battery

Again, sure, but I don’t believe it to be a battery issue. I want to explore more if I am having a remote issue, the only reason I haven’t is time constraints. I probably need to disassemble my mod to check solder connections. Definitely not interested in investing more into a li-ion battery for this build, as my main build doesn’t even have that pleasure yet haha

@pkasanda

hard 95a or 97 Durometer bushings will definitely solve the sloppy steering

I think it is more of a lack of steering rather than sloppy? I am not quite sure. I think I will try to mess around with the bushings a bit. I have never gotten speed wobbles though which is nice. I would like to have some more turning radius, and I think the deck is for sure partly to blame for that. I am going to be looking for a deck for it soon.

Thank you for your input and I look forward to continuing the work on this project!

[pkasanda]

Wow, that’s amazing. I mis-diagnosed ever item.

There are some Landwheel conversion VESC settings posted on this thread.

https://www.electric-skateboard.builders/t/useful-things-to-do-with-older-landwheel-components/53877

Did you look at those?

I suppose the cut-outs could be a loose connection or a bad solid state switch.

On the steering I guess now that I think about it, I do recall setting up one of my L3-x with bones medium cone bushings top and bottom. I guess I did find the L3-x steering a bit unresponsive.

The harder 95a bushings are what I put on the Revel Kit (as have many other Revel Kit riders)

[ShutterShock]

@pkasanda

I mis-diagnosed ever item

Lol totally fine, I didn’t give 100% of the details. I appreciate the help.

I did look at those builds, I got my VESC settings from there - thus why I think I need to look at my controller

And yeah I don’t really know what it is, maybe the truck width to wheel size ratio that causes the issues? I am gonna try some more bushings and see I guess

[ShutterShock]

Time for an update guys, here we go. Hope some people find it interesting because this took a ton of work! I am enjoying riding it so far and it has given me a lot more kick.

The upgrade: BMS + charge port, additional 3P of batteries, better mid enclosure, bluetooth module.

First thing is first - here’s some more information about the batteries I received. @KaramQ was kind enough to pass off 3 batteries from old landwheels & the first generation of the revel kit batteries that used the same cells as the l3-x. Upon receiving them during the summer, I didnt’ have much time to a whole lot with them except disassemble them into their pouch form.

This procedure was annoying as ever, but at least this time I knew what I was doing since I had done it before. Open the battery case, hack out the cables and lipo pouches, desolder the circuit board, rinse and repeat. Here’s some pictures of the disassembly:

These early version Revel U batteries had the same exact layout, BMS, and pouches as the old L-3X ones; this makes sense because the battery enclosures and interface were exactly the same as well. Given that I had 3 batteries and had already purchased the BMS, I was set on going with 8s. After opening them all up and removing the dead cells, I looked back in my inventory from the first time I had disassembled the original batteries, remembering that I had set aside the last few leftover good ones from before. To my dismay, I was only a couple short of being able to do 8s7p, or 10s6p, so I had to go with 8s6p, which isn’t bad considering I started with 8s3p from the original pack I had already made.

I don’t really recommend what I have done here as it is kind of dangerous, but here are the cuts I did to get the batteries out. These pouches are pretty well secured into their enclosures with silicon? adhesive on most of the sides. To get around this, you can cut the plastic out and bend the case to remove the cells. In addition to the silicon, the entire inside bottom of the enclosure is covered in double sided tape.

Step 1, cut out the latch area, pretty easy since the cells aren’t real close to it.

You can see that I have started to do the second and third cuts, branching out to the sides, along the vertical walls. These are very dangerous cuts because sometimes the batteries go right into the corner near the screw posts. I actually nicked a little bit of once of the cells when I was cutting and freaked out but fortunately it didn’t pierce all the way through.

After the branch cuts, you can slide down the sides, along the wall, to separate a lot of the silicon from the base and the cells. It is a pretty simple cut but you still need to be careful - this might be a good time to mention that I made all of these cuts with a dremel and the plastic cutoff wheel.

Here’s a top view of what it looks like with the front and the sides removed. After this step, you can peel the baseplate away and bend it down, sort of forcing the battery off of the double sided take and ripping away the remaining silicon.

Here’s a view of the second battery, with all of the cuts made at once. This is the one I nicked a bit I believe, since I was trying to make it go a bit faster.

Again I don’t super recommend doing this if you aren’t experienced with your dremel because sometimes the cutoff wheel catches in the plastic and goes deeper than you intend.

After separating the case from the cells, you can then remove the BMS carefully, slowly peeling away the adhesive so as to not cause weird pulls on the cells. Following that, the cells can be separated with the floss technique that I mentioned before.

For this part it is quite easy to cut your fingers on the floss, even though I was using screwdrivers to hold it, I found a few cuts on my fingers after separating all 30 cells.

Here’s all the good cells laid out and the extras, labeled with their voltages and eventually their polarities. You can see that they were mostly even, but with some variation within a reasonable amount. Their dead cells were seriously dead, like 1.5v or lower.

At this point I put the project on hold until I got to school and had some more time. (AKA until I found something to procrastinate on and do this instead.)

[ShutterShock]

Next steps! I’m at school and found a few Saturdays to procrastinate. Many thanks to my roommate Roger who let me take up the kitchen table for almost a month of school insanity while I tried to work on it between classes and in my freetime.

Anyways, the next steps after labeling all the cells was to do the painstaking process of manually balancing all of the cells and bringing them to a universal charge.

First, I worked on each P group, bringing them to even charges if they were not already at them. I used a 1s charger board that plugs into a USB cable (TP50xx or something I don’t remember, I bought them a long time ago). It’s pretty safe because it only charges at 500ma. This process took quite some time, requiring the charging of each individual 24 cells when necessary.

Once all the P groups were brought to the same charge, I paired them all up into their 3P groups and set them aside until I was able to solder them.

I didn’t really take many pictures as I was soldering the cells together because it’s pretty routine stuff. I will explain the way I did it breifly - stack the cells together using their adhesive to hold them, then fiber tape the non-terminal end. Check the length needed to span across all three cells and strip a piece of wire to that length, tin it with a good amount of flux and solder. After that, I cut off the piece while it was still hot.

I then fluxed all of the terminals that I was going to solder together, and laid the tinned wire across them. I had the 3P pack stuch in a vise with a towel so as to not puncture the batteries. This process was really annoying, holding the wire in place and adding solder to it while simultaneously trying to not heat up the pouches too much.

Here’s a picture with most of the parallel packs finished off.

For some reason wiring up balance leads has always been confusing to me, so I chose to do it as I went this time. I slowly soldered together the S groups by joining the P groups along the line with small bits of insulated silicon wire. I added the balance leads right onto there, and later realized after that I didn’r quite have them right, so I ended up switching out the leads within the connector because Ihad already taped it up.

I consider myself to have pretty good soldering skills and I am confident that all of my joints will hold up to the test of road vibrations. As I went along, I taped each balance lead section to the batteries, trying to make sure all the leads didn’t overlap.

In order to wire the BMS to the parallel packs, I made sure that all of the opposing batteries were at the same charge, and then paired balance leads from the ends of the pack, counting down into the center. At this point I made sure to check the charge one the big balance connector, and I found some discrepancies - this is why you always use a multimeter to check before you plug it in and fry your BMS.

After fixing the discrepancy in charge, I did a final check on the balance of all the cells and plugged it into the BMS. Nothing fried so I was happy. Next I had to wire in the rest of the important cables, charge port, pos and negative, the BMS, etc.

I will insert my schematic here later, it’s on my desktop at school.

I made sure everything was well taped up and started adding some foam bits before soldering to the BMS and Pos, Neg.

I skipped a lot of steps here between pictures, but here’s a picture of the BMS with all the leads soldered. Between the last pic and now, I designed a new enclosure with an extension in the center to hold the BMS and wires without crushing them, and support the sides of the cells. I put in the charge port and soldered it into the mix as well.

I quite like this connector for a charge port, but I need to design a small plug to stick in it while riding, because there is quite a lot of open space when the connector isn’t plugged in.

At this point I had to get more screws and then wait for the last piece of the enclosure to print.

Here’s a shot of the finished product - so many hours were put into this. Unfortunately, the troubles weren’t quite over. Somehow I had managed to break my GT2b when I was soldering it, so I picked up a Vx1, and I quite like it for this board.

[pkasanda]

Nice work Ryan. Help me out wiht the math please. Each cell is approximately 4 volts. You group them into bndles of three in parallell, Still 4 volts, then you put them eight in series. So that would be 32 volts fully charged and I think that’s a 25 volt battery. peak voltage of 30 volts, discharged to 25 volts.

Am I right?

So you can get a VESC to run on a 25 volt battery. But for a landwheel VESC, you would want a 36 volt battery that has a peak charge of about 42 volts but undercharged to 41 volts.

So that would require 10 in series instead of the 8 in series that you assembled.

Am I correct so far?

And the reason that you did 8 in series instead of 10 is that you only had enough cells to do two banks of 3s8p. Thats a total of 48 cells. And you would have done 2x3x10 if you had 60 cells? Correct?

Or you coudl have settled for a single bank of 4p10s but then 10 of your cells would have gone unused.

Am I correct on all the combinations?

So you only need 12 more cells to achieve two banks of 3s10p Correct?

[ShutterShock]

Everything you said sounds correct. I did 8S because I bought the BMS from SuPower before I got the 3 extra batteries, and because from the original 3 I didn’t have enough good cells to make a 10s3p.

So yes, I would need two more sets of 3p per bank to make 10s6p (so 12 cells). However, that would require a new BMS, rewiring of the balance wires, re-soldering of both the positive and negative at both ends, and somehow making more space on the board, which has basically run out.

In otherwords to expand to 4wd I need to use another 2 vescs or a maker x dual or something like that, since the landwheel esc is 10s.

[pkasanda]

And I have one more set of questions about the BMS wiring. What is the function of the balancing wires? do they charge each cell individually? Do they charge each bank of 3p individually? Probably not.

Do they draw excess voltage from the 3p banks that are charging faster so that the other 3P banks can reach thier peak voltage befor other cells overcharge?

And lastly what is the basic layout of the balancing wires? Is there a positive and negative balancing wire for each bank of cells? or is there a common negative across the series and one positive balancing wire for each of the 3s banks.

[pkasanda]

@ShutterShock

In otherwords to expand to 4wd I need to use another 2 vescs or a maker x dual or something like that, since the landwheel esc is 10s.

Another possibility would be to use two V2 Landwheel ESC’s. Those ran on 8s. You would just need to mechanically link two remotes.

[ShutterShock]

Like I mentioned in the article, I don’t have access to the screenshot that I took of the wiring diagram that I drew until I get back to school tomorrow.

Essentially I treated it as if each 1s6p cell is one cell on the BMS. The SuPower BMS’s have the exact number of wires and use the P-? (I think, I don’t remember if if it is p- or b-)

How the whole charging cycles will go I am not sure yet but on the first charge it seemed to all balance out just fine. I purposely put the BMS right in the center of one of my modular case scales so I can just unbolt that one to check balance leads.

I am hoping that this BMS will have enough UMph to take the leak current from out of a 6p group so they don’t overcharge. I have found the SuPower BMS’s to be extrememly reliable for 4.20v balancing. Every single time I have charged my main board (also lipos) it has balanced perfectly. I am hoping this is the case here as well.

*more clarification:

The whole pack has one common positive and negative, it just looks weird because the positive comes out of the center of the pack. I stacked the batteries into it in a unique way so I didn’t have to resolder the positive lead, and then I tied the negative all the way around back into the negative on my antispark switch.

[ShutterShock]

That is interesting, I didn’t know that they ever ran on 8s.

Since I am using the Vx1 that might be hard to tap into the landwheel ESC

[pkasanda]

Whats a vx1? Oh, a flipsky vx1 remote.

I was suggesting gluing two V2 landwheel remotes to a stick and joining the two joy sticks together.

However, the V1 ESC had a seperate reciever that coudl be replaced with any reciever. I saw them advertised on ebay with instructions for synching to a different remote.

The original Landwheels had 25 volt batteries that reached a peak charge of 30 volts. The batteries were too small and the voltage dropped like an anchor. So a kid could ride half way around the block or an adult could ride about 10 or 20 feet before the ESC grunted and powered down.

But when you substitute a 36 volt battery in to them, they are actually one hell of a peppy Skateboard ESC. I actually built a 4WD V2 Landwheel that ran on two V4 batteries. It was crazy fast but the brakes were flaky. 3 seconds of 60% brakes followed by 100% brakes.

I also built a travel V2 that ran on 18 volt Drill batteries wired in parallell for 36 volts with a peak voltage of around 38 volts. It was wicked fast and surprisingly had really good brakes.

[ShutterShock]

Haha that’s an interesting experience, I didn’t receive my first landwheel till the L-3x, so I never experienced a v2

[pkasanda]

https://youtu.be/RS5_tFmskoY

V2 Travel board experiment

[ShutterShock]

Lol that is dope, surprising that it just straight up works

[pkasanda]

More V2 Videos:
https://youtu.be/L8m2sFmebEE
https://youtu.be/LheMRbaKarM
https://youtu.be/KCJ5Sc8xyh4
https://youtu.be/B4wh1yvftY4

[pkasanda]

Yes, except for imperfect brakes, the V2 could have been a smash hit if it were not for the undersized battery.

[pkasanda]

The problem with the drill batteries is that the wires came loose from time to time and I think that’s not too good for the ESC. I think I might have damaged the ESC during one of the disconnections.