4S baseline run 1 / Capacity run 3:
I was supposed to be doing two runs today, one on a 2S2P setup and one on 4S. The 2S2P run lasted exactly 30 seconds. As I expected, the tiny Turnigy cells couldn’t supply enough current to get to about 5 MPH or to sustain that speed for more than 2 seconds. The truck covered a whopping 5m before the LVC cut in. The speed, distance and duration were so insignificant that the telemetry didn’t even record them, there isn’t any gif footage either as I forgot to hit the record button again.
I then swapped in the 4S, as anticipated some weeks ago, the run did not end well. It didn’t end as spectacularly as I expected but there’s still damage to repair. Conditions were pretty bad again, moist and slippery. The truck simply could not put down any of its power effectively to get up to any real speed with the current tyres. However, even in the slippery conditions, I could tell just how much extra power was available simply by the change in throttle sensitivity.
Rather surprisingly, through the course of the run, the motor temp stayed in a very safe range, the ESC got a little toasty, but nothing dangerous. What surprised me was that I got a little carried away with the throttle (this is what caused the run-ending damage) and didn’t drive as carefully as I planned. If anything, I drove slightly harder than usual and the motor stayed within a safe temperature range which really impresses me. The motor temperature curve also went back to looking almost completely normal, with only a couple of odd drops, but they didn’t cross the 0 mark.
As metioned a moment ago, the run didn’t end well (mainly due to my trigger happiness), I ended up stripping the idler gear quite badly around 20 mins into the run and that did some damage to the differential gear as well. It didn’t end as spectacularly as I’d predicted (exploding tyres or smoking motor or melting clutch), but it ended the run prematurely.
As well as getting baseline results for 4S running, the purpose of this run was to also test for capacity again, and again, the telemetry was claiming a lot more than the battery should have had in it (~4400mAH from a 3700mAH battery), and I hadn’t even hit the LVC, if the voltage reading is anything to go by, I was just past half way through the pack. I’m going to have to carry out some bench-tests at some point since the Turnigy experiment failed and I don’t own any other batteries not made by Overlander.
The stripped gears.
Technically the diff isn’t stripped, just damaged, but the idler clearly is. In the pic, the diff looks like it has lost all of its teeth, that is not the case. The diff housing is asymmetric and the teeth can’t be seen properly from the side seen in the pic. I took the pic from that side so that the differences in the tooth tips can be seen, otherwise the teeth would look fine.
Peak power for today was a pretty big 1760W (~2.36 BHP), peak current was 125.2A. As with yesterday, speed cannot be estimated from the RPM due to a lot of wheelspin on grass.
Power / Voltage / Current:
ESC temperature / Motor temperature:
Capacity / Voltage:
I’ve noticed that the gif footage has become bumpier over the last few runs, I suspect that is because I lightened the truck, but still kept the same suspnsion stiffness. I’ll probably soften it a bit in a run or two as well as lower it by a few mm.
This is probably the smoothest jump landing I’ve ever had.