T200 Current draw and choosing a suitable battery

[uchiha (Sasuke)]

I am building a boat with two T200 thrusters. I saw the chart on the product page. At 14v, one T200 thruster draws up to 20.71A at full speed. Two thrusters would then draw up to 41.42A. Does that mean, in order to run both thrusters for one hour, I would need at least a 41.2Ah battery? My 14v/16Ah battery would only last 20 minutes.

[EliotBR (Eliot)]

Hi @uchiha,

@uchiha

At 14v, one T200 thruster draws up to 20.71A at full speed. Two thrusters would then draw up to 41.42A. Does that mean, in order to run both thrusters for one hour, I would need at least a 41.2Ah battery? My 14v/16Ah battery would only last 20 minutes.

That’s correct, assuming you’re running both thrusters at full throttle continuously. Most ROV applications don’t have such extended periods of full throttle, which is why our BlueROV2 is expected to achieve roughly 2 hours of “normal” use (or ~4 hours of “light” use) despite having control electronics, a live video stream, 6 thrusters and only one 4S (14.8V) 15.6Ah battery.

If your application requires long, continuous periods of high thrust, then yes, that requires a significant amount of energy, and you’ll likely need quite a large battery for extended run-times.

[uchiha (Sasuke)]

Thanks for being so helpful, Elliot. I really appreciate it.

I noticed a couple things that I want to discuss with you.

The battery that I use comes with 12AWG wires. They are rated for 30A continuous draw. The power management board also comes with 12AWG wires rated for 30A continuous draw. Two T200 Thrusters, could potentially draw over 40 amps at 14V. Could it not be unsafe to use this battery and wires?

[EliotBR (Eliot)]

@uchiha

Thanks for being so helpful, Elliot. I really appreciate it.

No worries, glad I’m able to help

@uchiha

The battery … [and] power management board come with 12AWG wires rated for 30A continuous draw. Two T200 Thrusters, could potentially draw over 40 amps at 14V. Could it not be unsafe to use this battery and wires?

That depends a lot on how they’re being used. Hopefully this gives you some clarity, but feel free to ask follow-ups if you’ve still got questions afterwards

[uchiha (Sasuke)]

@EliotBR

this

Thanks. I have read it and after doing some more research, I am going to go give it a shot with 12 AWG wires, and take it from there. My only concern now is cooling the ESCs. Do you have any solution for cooling them?

[EliotBR (Eliot)]

@uchiha

My only concern now is cooling the ESCs. Do you have any solution for cooling them?

From the product page:

@BasicESC - Learn tab

Installation and Thermal Considerations

Like all ESCs, the Basic ESC can generate a significant amount of heat when operated. It’s important to consider this when mounting and operating the ESC to ensure that it is not damaged by overheating. Most of the heat is generated in the MOSFETs, which are underneath the blue aluminum heat spreader. Here are a few helpful tips:

1. If possible, make sure the heat spreader is exposed to free air or attached to a larger heat sink.
2. Do not use any adhesives that may insulate the heat generating components, such as silicone sealant.

This comment from another recent post may also be helpful:

@EliotBR

On the overheating front, it depends on the enclosure you’re using and the thrust you’re operating at. If you’re using a black plastic enclosure in strong sunlight while operating at full thrust then overheating is very probable. It’s possible to reduce the heating risks by shading the enclosure from sunlight, providing heat transfer/ventilation (e.g. a metal heat sink that touches the water, and/or a fan to circulate air and/or bring it in and out of the enclosure), and not running at full throttle for extended periods.

[KiwiPaul (Paul Arthur)]

Interesting post -
QGIS - is excellent - here’s my local rapids. Taihiki Rapids - ping 1d and QGIS

re boat - a catamaran made of PVC downpipe with 2xT200’s works well for me.
https://www.youtube.com/watch?v=XqXOKxnc47Q

With 20v batteries 3x4AH and simple esc’s no heating issues. Im having problems with a similar setup at 12v - which may be my wiring, but things are getting hot…

[ArduBuilder]

Hi there, we wanted to see if there would be any concerns with our desired battery setup for our RC bathy survey boat rover.

2x = T200 thrusters using 2x basic ESCs

1x = SOK 12v 100Ah SOK Lithium Iron Phosphate 12V 100Ah marine battery

various other electronics, but nothing beyond the amp draw of the battery while using the thruster at full (mostly using the thrusters around 15% - 25%)…

Setup like the one you detailed here, but using a large marine battery instead = Using an RC Transmitter to Control the T200 Thruster with Basic ESC

Our concerns was just the fact that we are using such a large battery and wanted to make sure we are not overlooking something.

Thanks again!

[EliotBR (Eliot)]

Hi @ArduBuilder,

Our T200 and Basic ESC can both operate at down to 7V, and the T200 maximum is 20V (Basic ESC is higher), so a 12V battery should be fine. A high capacity battery just means it stores more energy, so should be able to last for quite a while.

@ArduBuilder

various other electronics, but nothing beyond the amp draw of the battery while using the thruster at full (mostly using the thrusters around 15% - 25%)…

From a quick search of the battery you mentioned, it seems like the recommended maximum discharge current is 100A. Our T200s are specified to use 17A at full throttle when powered with a 12V supply, so even at full throttle your two thrusters should only be using about a third of the current-capacity of the battery.

Assuming your “other electronics” aren’t drawing more than 66A you should be fine (or even more if you’re not running your thrusters at full throttle). If anything, using below the maximum discharge current will likely help maintain the health of your battery