CAT 2000 '98 Battery Comparison via ESC Data Logging

[Typpo]

While driving a Schumacher CAT 2000 ’98 with more modern equipment (Tekin Redline gen1 8.5 turn motor and RX8 gen2 ESC), there was a noticeable difference in speed when using a LiPo versus a NiMH battery. Though the battery dimensions were similar, the capacity, chemistry and weight were all different (2S 5000mAh LiPo at 295g (10.4oz) and 6 cell 3000mA NiMH at 345g (12.2oz)). Also, both batteries were a few years old with an unknown number of charge and discharge cycles. To better understand the battery performance during use, Tekin’s data logging was used to record the battery voltage, motor RPM and throttle input during each run. Afterward, a .csv file was exported via Tekin’s Hotwire software and MATLAB was used to import, plot and time align the data.

The following image shows the performance of the batteries when used with the 8.5 turn motor in the 4wd buggy. The results were obtained by driving the buggy up a hill, turning around and then driving down the hill. Each run started at approximately the same location. Between runs, the turn around location varied. The first 12 seconds of the plot correspond to ascending the hill, the middle section is the turn around time, and the last 11 seconds correspond to descending the hill. The blue plots represent the LiPo battery and the orange plots represent the NiMH battery.

On the throttle plot, 97.8 corresponds to full throttle. With each throttle input, the impact of the motor load is visible on the battery voltage and corresponding motor RPM plots. Comparing the drops in battery voltage and motor RPM for the LiPo and the NiMH plots confirmed the difference in apparent speed.

Please note: These plots are intended to demonstrate the advantages of combining an ESC with data logging capability and software for plotting (e.g. Excel, MATLAB, Python). The performance shown below is unique to the batteries tested in this comparison and is not intended to represent the performance of these batteries in general.

Equipment notes:
Buggy: Schumacher CAT 2000 ’98 including Schumacher Menace rear driveshafts (https://www.rc10talk.com/viewtopic.php?f=28&t=28751&p=447564#p447564) and Fibre-Lyte custom battery ring.
Electronics: Tekin RX8 gen2 ESC (factory reconditioned), Tekin Redline gen1 8.5t motor (used)
Batteries: Thunder Power TP5300-2SPR65 (295g / 10.4oz) LiPo and Duratrax DTXC2054 (345g / 12.2oz) NiMH