Build Diary - Plastic Fantastic - FW

[Maxamuslead]

looks like a beauty, your going to take to Manchester ?

[Al_]

looks like a beauty, your going to take to Manchester ?

Yep, I'll be there with both of them.

[Al_]

Quick update following a fantastic weekend at Manchester. Other than one very annoying and recurring problem, I’m pretty happy with how Plastic performed at the event.


Melee 1 – I started with my colson wheels that give me about 5mm of ground clearance. These are fantastically grippy, but I got hung up a few times on the seams between the arena floor panels and had to sit there until someone hit me off them so I could get going again. Now a good portion of this was down to my poor driving and could defiantly be minimised but I decided I would swap wheels after the fight to be safe. When I wasn’t stuck on the seams I was able to get stuck in and mix it up a bit. Lots of speed and pushing power from the bot which I was pleased to see.....and then it just stopped. Power lights still on but no movement from it. Resetting the transmitted did nothing either.


Back in the pits with Plastic on it’s cradle, I put the link in and it worked fine, wheels turning but under no actual load. Nothing felt too hot in there and although its a good 10 minutes from the robot stopping to getting it to back to the pits and taking the top off, I would have thought if something were overheating it would be obvious. Damage suffered to the top from Shrekt, but nothing else other than the usual bumps and scratches.

IMG_20180421_145131208.jpg


Melee 2 – Bigger wheels fitted which give 10-12mm ground clearance. They were homemade HDPE wheels with bike tires screwed on the outsides. Not as grippy as the colsons, but no more issues crossing or stopping on the arena seams. Also the grip did seem to improve as the newness was scrubbed off the tires. I don’t remember much about this fight, but the same problem happened again with the robot just stopping after a couple of minutes.


Back to the pits again, same diagnosis again. At this point I was wondering about voltage sag from the Lipo not being at its best in some way, and maybe this was causing the ESCs to cut out due to low voltage. However having no way of reading the voltage during the fight I’m only guessing. The battery voltage still showed fine after the fight (under no load of course) and each fight was only taking about 1000mAh out of what should be a 4250mAh battery. The charger was happy to charge it each time too. Neither of these rule out voltage sag from a loaded battery though.


I decided at this point I would switch to Pressure Point’s battery for the next fight, its smaller (but still ample) capacity and the same voltage at 5s. I took a nice hit from Binky in the fight, a gouge out of the side and some bending of the top panel above it. The top panel was sorted with the heat gun and some brute force but I think it’s a bit of a design flaw. The vertical spinners will always want to rip the edges of the top panel up and bend it out of shape like in this case. I think in a future re-design I'll extend the sides to where the top panel currently is and the top panel will sit recessed inside them instead of on top of them to minimise the chances of this happening more. The fact that the sides of the robot have taken all the hits while the front wedge is essentially unscathed speaks volumes about my driving!

IMG_20180421_173052840_BURST000_COVER_TOP.jpg


Melee 3 – AKA the 5 spinners of doom. Some serious damage flying around in this one, somehow I manage to miss the worst of it. However the same issue happened again which was getting frustrating.


Since there was only one more fight left for the weekend, I decided I would remove the sponge that the ESCs have around them just in case they were getting too hot, though there were not much more than warm each time I had checked them.


Melee 4 – Not a lot to say other than the same thing happening after the same amount of time, capping off a promising but ultimately frustrating start for the bot.


Now I am considering the possibility I have knackered both my batteries. I didn’t storage charge either of them over the winter and they were left in my shed. Maybe it got too cold in there and the 2 things combined has somehow damaged the cells. I have ordered a new battery to test this out. I have also already swapped the Rx and checked all wiring as a precaution but this made no difference. If this doesn’t work, then unless both ESCs are somehow failing/stopping at the same point I don’t see what else it can be.


Anyway, that’s enough rabble, sort this problem out, a couple of other minor tweaks and off to Portsmouth in a few weeks time.

[Maxamuslead]

but didnt Pressure Points battery work fine in The feather fun time match ? ( has anyone got a video as that was really fun)

[Al_]

but didnt Pressure Points battery work fine in The feather fun time match ? ( has anyone got a video as that was really fun)

It did but the bot didn't run for very long before I stopped due to the wheel problem and also the current draw in Pressure Point is generally lower then on Plastic. Therefore if it was going to do the same thing it didn't really get the chance. I'll be looking to test this battery too if putting the new one in Plastic fixes the problem.