I’d think you’d want to put electrically conductive grease on the battery connection not anti electric.
Actually, I do mean dielectric grease. Silicone grease is conductive. Dielectric grease is an insulator. The land wheel battery terminals are spaced pretty close together. You would not want to use silicone grease on the LW battery contacts because it could conduct current across terminals if the film is continuous between contacts. Obviously that would produce a short circuit. Dielectric grease does not interfere with the electrical connection once the two metal contacts are mated. However, as the contacts approach each other and the air gap narrows, dielectric grease will act as an insulator to prevent arcing.
I used dielectric grease very successfully to prevent arcing on the LW V2 batteries. Without it the battery contacts were heavily damaged after the first short ride. The vibration caused air gaps and the arcing was significant.
Silicone grease would be good for a permanent contact that is screwed down tight and is not disconnected while the current is live. Dielectric grease is more appropriate for switch contacts to prevent arcing. If you put silicone grease on switch contacts, it won’t stop arcing because it is conductive. Furthermore, when subject to arcing, silicone grease produces bi-products that actually damage switch contacts.
“Silicone grease should not be applied to (or next to) any switch contact that might experience arcing, as silicone can convert to silicon-carbide under arcing conditions, and accumulation of the silicon-carbide can cause the contacts to prematurely fail. (British Telecom had this problem in the 1970s when silicone Symel® sleeving was used in telephone exchanges. Vapor from the sleeving migrated to relay contacts and the resultant silicon-carbide caused intermittent connection.)”
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maybe you can prevent arcing with anti electric grease and maybe this battery is unique in that you can’t add an antispark and the contacts will deteriorate with connection but that’s not normal and for battery connections using only compression to make connections I’ve only ever seen conductive grease. A compression connection for a battery is rare to begin with. I wonder how much resistance it has with either conductive or dielectric grease.
you say the contacts were getting damaged from just one ride? If it’s arcing then it’s losing contact and that might also be stopped with the conductive grease I think. If they were damaged from arcing wouldn’t you board be losing power often…every time the connection was broken? as it is now with the dielectric grease you would still have breaking connections just not the burn marks as it arcs. You’d be having more time with a broken connection with dielectric vs conductive.
conductive you definitely don’t want to connect terminals where it shouldn’t be and you have to take care about that but it generally stays put.
Hi Hummie:
Good question. You asked what the resistance was with the dielectric grease on the battery contacts. I put an OHM meter to it. The answer is 0.2 OHMS. If I measure the resistance of an inch of 10 gauge copper wire, the same meter also reads 0.2 OHMS. So the dielectric grease adds no resistance when there is contact. It only insulates in the context of an air gap.
I recognize that it is counter-intuitive to put insulating grease on battery contacts. However, it does work. And as per the wikipedia article you should never put conductive silicone grease on contacts that may arc.
Prior to winter, my son drove the one landwheel V2 that continued to function. He rode about 10 kilometers before the snow fell. He rode it with a healthy layer of dielectric grease on the contacts. That unit had no arcing and no signs of intermittent connection. Before I started adding dielectric grease to the contacts, the arching damage was pretty aggressive. I’m just sharing this information with V3 Riders because I’m confident based on experience that dielectric grease will extend the life of the contacts.
Also, I’m confident that the dielectric grease played no role in the failures of my landwheels. Three broke before I started adding the grease. Two broke after. Rider weight seemed to be the one consistent variable in the failures. The unit that continued to function was never ridden by me. It was only riden by my son. I disassembled three of the broken units and determined that the sensor wires were damage in the left motor of each unit.
What was damaged with the sensor wires? That is a bit I think for the sensor wires to get damaged?
do you think the battery to esc connection could be made with no circuitry to limit the inflow and just dielectric grease would be good?
Hi Pantologist:
If you look at some of the earlier posts, you will notice that the Landwheel representative posted that the V3 immediate shut down error was due to a short circuit in the “Hall Line”. Search for those two words and you will find his post above.
When he says “Hall Line” he is referring to the five wires that connect to the Hall Sensors in the motor. Hall sensors tell the motor controller what position the stator is is in so that the motor controller in the ESC can send the correct polarity of current to the correct coils. There are three coils on the interior of a brushless motor. The current through those coils needs to pull the stators towards the magnet that ahead of it’s rotation. Several magnets are mounted on the inside of the cylindrical motor housing. Torque doubles when the ESC is smart enough to push away from one magnet and pull towards another. The ESC needs Hall sensors to do this. Some brushless motors can function sensorless but torque is compromised, especially at start-up. I believe that sensorless operation only provides for pulling forward (no dual action).
The land wheel rep indicated that in the motors that they examined that had failed, the wires running to the hall sensor were damaged. He attributed it to faulty workmanship.
I replied that I was suspicious that the hall sensor wires may have been damaged by an excessive current flowing through the small hall sensor wires when the motor was subject to heavy load (such as accellerating a heavy rider). That’s exactly the moment that each of my landwheels blew the left motor.
I was unsuccessful in disassembling the malfunctioning motors. The screws appear to have lockite on them. However, I was able to identify which motors were functioning and which were defective by swapping motors around. Also, With a continuity tester and OHM meter, I was able to verify that the three stator coils on the damaged motors were intact and normal compared to working motors.
By process of elimination, the sensor wires are at fault. This was corroborated by my observation that one of the Land Wheel circuit boards had a manfunctioning sensor circuitry on the side that was connected to the broken motor. I estimate a short circuit of the sensor wires in the motors damaged the sensor circuitry.
One more observation that I’ll mention is that most brushless motors have six sensor wires. I believe that’s one pair of wires for each of three hall sensors. Oddly, the LandWheel V2 motors only have 5 wires. I suspect that the absence of the sixth wire might be a factor if indeed an overload current is flowing through the sensor wires. I’m wondering if one of the hall sensor circuits has only one sensor wire and if the circuit is completed via one of the wires that run to the stator coils. That’s just speculation since I can’t get the motors apart.
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I should say that I am guessing that the V3’s have five sensor wires. I’m assuming that they are the same as the V2’s. I have never seen V3. They may be different. Maybe now they have 6.
V3 is heavier indeed, we upgraded the battery and the AL struction ect.
It’s great pleasure to discuss with you guys here, thanks for your supports, we will keep working hard on this project. If you have any suggestion, please leave message here, we will read it.
Hi Paul，Thanks for your professional feedback, our control panel have malfunction indicator light, we tested the drive, it’s Hall line problem, but we will adopt your suggestion, test it with more heavier loaded. If you have any more suggestion, please let us know. Thank you. Landwheel
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Thanks “Landwheel”.
I suggest the following testing program.
Test 6 different Landwheel V3.
With 220 lb rider (or rider carrying enough weight to add up to 220):
I Endurance tests: 1) Try up hill 1 kilometer 10% grade. (Repeat x 10 per LW) 2) Try continuous ride, top speed from full battery until empty battery. (Repeat 2x per LW)
II Acceleration Load Tests: 1) Try full acceleration from a stop to full speed without kick starting (repeat x 10)
III Rough Road tests:
1) Try the endurance and acceleration tests (I & II) on rough pavement.
If you can’t find rough pavement then spread 1/4 inch grains of gravel or salt on the concrete floor of the warehouse. Use glue to hold the grains to the testing surface.
IV Road Crack Test:
- Drive over sidewalk with expansion gaps
example (http://ww.stonegraphix.com/Gallery/sidewalk_A.JPG)
or - drive over 3/4 inch plywood to simulate cracks in the road. Use two pieces of plywood with a 1 inch gap between them. Glue or screw the plywood to the warehouse floor so they do not slide.
Road Crack Simulation Diagram:
--------------------------------------___ Warehouse Floor…Plywood…Gap…Plywood…Warehouse Floor
Try to ride over both sheets of plywood at full speed with 220 pounds of rider weight.
Repeat 10 times per landwheel
V 250 pound load. Repeat tests I, II, III, IV with 250 pounds of rider weight.
If all 6 landwheel V3 can survive 8 these tests then the units shipped to customers should be pretty reliable.
If the landwheels fail during any test, then the test should help identify the vulnerability.
Thanks pk
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I like that extensive test mentioned by PK. It’s a bit extreme, but LW needs to realize their customers all ride differently and have different needs and it’s only a matter of time before we kill faulty designs, engineering and manufacturing. Because of LW previous issues, I personally would not ride it as rough as I do with my other boards that have proven to be dependable by abusive riders aka Casey or easily fixable in my garage with knowledge from people in this forum.
I guess many of us are lucky to have Uber that can give us a ride if we get stranded. BUT I’m not sure what the liabilities are if the board bursts into flames in their car
so both of my V3’s were shipped out to their technician Mike in the US (California) , which he took out to china with him last weekend. Eileen says that will be finalizing testing a few things and then will ship out two new ones mid this week (i think tomorrow), expedited shipping.
i appreciate all of the help and i do have hopes for Landwheel to get these bugs worked out and make a great product.
I expected would happen, my v3 doesn’t work anymore I don’t know what it could be, I drove for about two minutes with a charged battery and after changing slightly rougher the asphalt drive type is disconnected by sending one long beep until I turned off Now if remote controller signal not power back up or better battery indicator drive reports download but you are charged My v3 worked then for about 5/6 cycles battery the first day was more powerful, I realized that the couple declined after two days Although slight had a power failure now my v3 how do I repair?
Does anyone in the USA want to sell me their broken V1, V2, or V3 Landwheels (cheap). I’d like to do a few science experiments to teach my 13 year old son some electronics and mechanical skills.
I’m holding off for a few more months before I ask Eileen to ship me my 6 replacement V3’s. No point taking delivery of them with so much snow on the ground.
If you are interested in getting the broken skateboards out of your basement, let me know. Here is a temporary Email Address (that I can delete in a few weeks when the spam starts rolling in):
For shipping, I can provide a New York Post office box. I live in Canada but can drive across the border. I can pay via Paypal.
Thanks, send me an email and we can discuss price and shipping cost.
@pkasanda you have/had 6 broken drives and that wasn’t enough for you to experiment on? what on earth are you trying to do over there?
At this point, I’m wondering if you should wait for V4 or have @Landwheel fly you to China and teach their people along with your son while you are at it.
He Mike:
I have some experiments in mind that will need a few more broken Landwheels. I’d like to try to synchronize two drives to one remote for a 4WD single remote board. I may fry a few boards in the process. If I’m successful, I’ll post a how to video in case others want to try it with the more reliable V3’s that we are hoping for in the future.
I’d like to try it a few different ways. First I’d like to try it with the stock Landwheel circuit boards. Second, I’d like to try it with four aftermarket VESC’s.
Hence, I’d like a few more broken Landwheels.
pk
Wow! Are you trying to make a 4WD electric skateboard with two LANDWHEEL drives? Very interesting.
Yes, I’d like to perfect it with some disposable Landwheels so that when the final reliable units come out, I can post a well tested method.
Have any broken drives?
pk