We are using Two T200 thrusters with basic ESC’S for up-down motion with 30 meter tethered power supply (battery on ground), we have tested two of the thrusters with 14.8 volt, 4 cell lipo battery and we observed at full thrust it drawn 16 amp current and the voltage drop cross tether was 1 volt.
For longer and reliable expedition we are thinking of going for higher voltage battery aprox 18 Volt but we found that the ESC’s voltage range is 2-4s lipo battery(14.8 v) and 18 volt battery we can get only with 5 cell lipo battery.
Can we use the 5 cell 18 volt battery for the same ESC’s ?
We have used the Basic ESCs successfully at voltages up to 24V, but there’s a good chance they will have reduced lifetime at high voltages, especially above 20V. A fully charged 4s lipo is 16.8V, so you’re pretty close to 18V already.
Also note that the thrusters will be capable of reaching higher current at higher voltages so you might want to limit the throttle somewhat to avoid very high current through the ESCs.
I’ll let you use your judgment as to whether you want to try it.
Yes, you can connect two batteries in parallel and their capacities will add together. You should only do that with two batteries of the same capacity.