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GPS Automated Raft

2x T200 with ESC with additional heatsink
5s20p 18650 Sony VTC6 21v/60Ah
10x10 inflatable raft
BMS for Charge. Discharge Bypass and through fuse instead.
Arduino Mega
2x Linear Single Turn Pots for Manual Control (Ended up not using slider pots for waterproofing reasons)
BN-880 GPS/Digital Compass
Battery Monitor
LCD Screen
120mm cooling fan
Anti-Spark Power Switch
10v step down converter for Arduino and Cooling Fan

Speed 2MPH

Will post video in future.

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Hi @cody00, welcome to the forum! :slight_smile:

Looks like a fun project. The two raft adventurers look particularly pleased with themselves… :stuck_out_tongue:

That’s a lot of batteries… Looks self-assembled, were they stripped from an old EV battery or something, or just bought as cells and wired up?

Are these used to set a desired latitude/longitude, or for direct manual control of the thrusters?

Also, given there’s a “Destination” button on the top, presumably there’s some support for specifying GPS locations to travel to. Do they need to be pre-programmed into the Arduino program that’s running, or can various destinations be set up using the pots and the other buttons? :slight_smile:

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Thanks for the welcome @EliotBR.

I bought the cells new which were a majority of the cost but I wanted something with high capacity to prevent extreme voltage sag and not have to worry about running out of juice. It takes a long time to charge at 4amps though.

The two buttons are Mode and Destination.

Mode= Manual or Auto

Manual: controlled using the two linear pot dials. Eat pot controls one motor.

Auto: Automatically does direct line to one of 3 hard-coded destinations OR hover mode.
If in hover mode or arriving at destination it will keep itself in a 10 yard diameter. Constantly adjusting itself if it floats outside of the circle.
Automatic mode will actually take the highest valued potentiometer and use it for its base speed

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No problem - a welcoming community means people are more inclined to stick around, and contribute with cool projects and/or helping others :slight_smile:

Fair enough. Did you do the pack construction/assembly yourself? :slight_smile:

Curious about the low current - is that a power limitation of your charger? From my (limited) understanding Li Ion batteries last longest if charging is kept at or below 1C, but with a 60Ah battery your 4A is only at 6.7% of that. Or is 4A the average over the full charging time, including the constant-voltage portion after the initial higher current region?

Interesting stuff!

Perhaps a future expansion could be adding a new mode for setting a custom destination, where you can use the two pots as rate controllers for changing the lat/lon from the current location. Would mean someone could message you somewhere to meet them and you could float your way over :slight_smile:

Fair enough. Did you do the pack construction/assembly yourself?

Yes. Sony VTC6 cells. Nickelstrips and spot welder.

Curious about the low current - is that a power limitation of your charger? From my (limited) understanding Li Ion batteries last longest if charging is kept at or below 1C, but with a 60Ah battery your 4A is only at 6.7% of that. Or is 4A the average over the full charging time, including the constant-voltage portion after the initial higher current region

It’s limited to 4Amp because the variable power supply i built is limited to 4Amp. I suppose to i could build one that handles higher amperage.

Interesting stuff!

Perhaps a future expansion could be adding a new mode for setting a custom destination, where you can use the two pots as rate controllers for changing the lat/lon from the current location. Would mean someone could message you somewhere to meet them and you could float your way over :slight_smile:

There is only about 3 places that i would ever go in this bay. Because of speed and currently having the line of site capbility ill probably leave this functionality. I wouldn’t mind doing some type of remote control function whether through RF or through my cellphone. I would like to be able to send it from location A to location B with a load of kayaks unmanned. I could do that now but requires setting destination while on the raft.

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Nice explanation, and loving the pirate flag :joy:

I’m amused by the quickly-retracted foot at 22 seconds in, perhaps you can mark them with a youtube timestamp chapter… :stuck_out_tongue: