Please Help! ROV 2.4 shutting down as you take off in water


#1

I'm at my wits end and would love any troubleshooting suggestions anyone may have. My college professor bought v2.4 quite a while back and it was just sitting around in the box. I volunteered to put it together and get it going. I put everything together meticulously and everything works like a champ on dry land (i.e. countertop). I loaded the "2.4 stable release" and the arduino code loaded fine from the cockpit as well. All lights, motors, controls work and test out just fine.

The problem is when I put it in the water and try to run around. The tube is watertight with no leaking as well as dry battery tubes. As soon as I throttle the motors up in the water, within a few seconds the cape and beagleboard completely shut down. I have to pull the batteries and reboot only to do the exact same thing next time I drop it in the water. I've done several test and regardless of whether I throttle the vertical, port or starboard motor it does the same thing in the water. Again, everything works fine out of the water.

Anyone have any ideas for me? I'm stressing :)

Has anyone seen the motors being throttled in the water shorting the whole board out somehow?

Thanks in advance! Buddy


#2

I have a little more info after continuously rebooting and testing. The ROV is only instantaneously shutting down when I'm driving the motors at a 3 or above for speed (i.e. pressing 3, 4, or 5 in the cockpit prior to moving around).


#3

Follow this tread for your possible answer:

http://openrov.com/forum/topics/cockpit-crash-1


#4

David,

I can't thank you enough. I followed your link and some more links through that one to get everything figured out. Here's what I found out in my case with my v2.4 model:

1. I tested the insulation issue testing instructions and my motors did not fall into the problem category: http://openrov.com/profiles/blog/show?id=6365107%3ABlogPost%3A82907

2. It turned out that I indeed cannot push my motors above 3 or the whole system will just crash. However, earlier today I couldn't push past a 2 without crashing. It turned out, I never calibrated my ESC's and my vertical thruster was pushing a speed above in the reverse direction crashing sooner than it should have.

Thanks again!


#5

Buddy,

Glad to hear you're getting the issue figured out! I also wanted to give you a link to some new batteries we've been trying around the lab that seem to be working great:

http://www.batteryspace.com/lifepo426650cell32v3300mah19.8arate10whunapproved.aspx

These LiFePO4 batteries can source a lot more current then the LiMnNi ones, so they'll allow you to use a higher throttle setting (we use all the way up to 5) without killing the system. They're a tad bit shorter, so you'll also need to put some coins or something in the tubes to make up for the length, but other then that they should be drop-in replacements. You can even use the same Trustfire chargers we recommended for the other batteries- only remember to move the little switch on the side of the chargers to "3.0v" instead of "4.2" when charging the LiFePO4 chemistry!

We look forward to seeing how this all works out- keep us up to date with your progress!

Eric


#6

Thanks!