can anyone share the total power requirement of making a 7 thruster ROV?

# Power budget calculation

An overly simplified estimate would be 500 to 1500W max power and 100 to 300W/hour average usage.

An 8thruster BlueROV2 will fly pretty fast at 35 to 70 amps on a stock battery. The stock 18AH battery usually last me 2hours of hard operation, 4hours of light operations without current, and never less than 45min. 18Amp hour battery at an average of 14.4V and and figuring you pull 90% of the power before shutting down and you have about 230Whrs total power. So that is one hour operation at 230W or 2hrs at 115W power usage. I have seen gives as long as 6hours on one battery, meaning that the average power was not even 40W.

The other aspect is average power will increase with the cross sectional area of the ROV in each axis of movement. There are a lot of subtleties here but if you double the area of all sides, for example by going from a hypothetical 14"L x 14"W x 10"H to 20"L x 20"W x 14"H the required power for the same speed would be a little more than double. There are many assumptions here, but it will get you started. Total mass of the ROV, as well as desired lifting capacity, top speed, and power for accessories will all be factors as well. If you want a 30W multibeam sonar and an extra 50W of lights, then add another 80W to your power budget.