electro magnet

[greenkarson]

I've been think about battery charge on deep dthives. Im hoping to dive 500 feet so a lot of battery life would be wasted on just the dive alone. So i'v been thinking about using a electro magnet to hold a small rock onto the bottom of the rov. With some sort of trap door. When the rov is near the botom of the lake i could shut off the magnet releasing the trap door and drop the stone. There is electro magnets on ebay for around twenty bucks. I figgered this would save alot of amp hours rather then using the propeller to drive the rov down 500 feet.

Any thoughts on this?

[thegadgetguy]

If you could set it up so the rock dropped when the magnet was on as opposed to off, you could probably save even more battery life, as the magnet would not be using current the entire trip to the bottom. Either way, it would be more efficient than a thruster being turned on the entire way down. Cool idea.

Hope you make it to 500!

[reHosea]

Hi. Just curious, have you taken an amperage load reading on your batteries while your ROV is descending, to determine just how much of the batteries are being used up? We have 6 small sealed lead acid batteries on board our ROV and I have assended/descended the ROV to 80-100 feet many times during an excursion with enough battery life still left over to run the three video cameras and continuously maneuver the ROV all over the bottom for many hours. Are your batteries top-side with you or on the ROV itself? Adding an anchor to the bottom of an ROV wouldn't be my preferred choice. But then, I never really thought of doing it that way. It's an interesting idea to say the least.

[bikerbones1968]

Hmmmm very interesting concept. Never considered anything like this and its the first I have read anywhere about doing. Cool stuff.