I gathered more data for voltage vs amperage at full throttle and modeled it in excel. I found the relationship to be a power curve. I recorded the voltage in two ways (Open Circuit Voltage and Load Voltage). I performed measurements with 2 and 4 Bonkas (12S1P and 12S2P). Here’s a chart of the data after which I will explain what it all means and how I collected it:
First we need to understand that a battery is NOT an ideal voltage source. The voltage at the terminals will drop when a load is applied. This drop in voltage occurs because of the resistance within the battery itself. Here is a link if you want to learn more: https://learn.sparkfun.com/tutorials/measuring-internal-resistance-of-batteries/internal-resistance
Those who own an OpenPPG will be very familiar with the fact that increasing the throttle will drop the voltage (and the battery percentage). But did you know that doubling the number of batteries in parallel will cut the resistance in half resulting in a smaller voltage drop? This actually increases the voltage to the ESCs and motors and gives you more power (watts). This increase in watts comes from an increase in both volts and amps. The ESC is rated for 80 amps so we should be careful not to run higher than that.
Those who are flying with 8 batteries need to be careful at full throttle because that resistance will be cut in half yet again and supply even higher volts resulting in even higher amps. I’m already drawing over 80 amps with 4 batteries while with 2 batteries it barely reaches 80 amps. Remember though, that flying with fewer batteries puts more load on the batteries which can be dangerous. So more batteries is better as long as you are careful at the top end with the throttle as to not draw too many amps.
Back to my data. “Open circuit voltage” is the voltage of the battery before applying a load. I recorded the voltage, then applied full throttle and recorded the amps. You can see a clear difference in amps when using 2 vs 4 Bonkas because of the way the voltage drops more under load when fewer batteries are used (Fewer batteries=more resistance=more drop in voltage=less amps).
“Load voltage” is the voltage during throttle up. To collect this I recorded a video of my amp meter and voltage meter (throttle controller). Then I stepped through the video and recorded the values.
According to this data model, if you actually delivered 50 volts to the ESC you would draw 110 amps! However, because of the resistance of the batteries you would never get there but high quality packs with low resistance and/or multiple packs in parallel could put you well over 80 amps which is already possible with 4 Bonkas.