Charging New Trident Battery using charger from openRov


I just received my new Trident on 20 Dec 2018. My question is about charging the new Trident. I read the manual but a bit confused. I need to know charging sequence.

  1. Connect the charger to trident.
  2. Power on until trident fully charged ie 4 green LED lighted up on Trident.
  3. Power off the charger and take out charger connector from Trident? OR
    Take off charger connector from Trident and power off the charger?

As you can see I am bit confused about step 3. I am a bit cautious because I don’t the battery slowly drained if I wrongly disconnect the charger. Thanks and cheers.


It’s a bit hidden in the manual, but it says to disconnect the charging cable from the Trident before unplugging the charger from the wall.

I’m not sure if it will continue to drain the battery if you also disconnect the charger from the Trident but I imagine if you leave the charger connected to the Trident AND unplugged from the wall there may be some back current to the charger that draws from the Trident battery. I have a few other electronics that if you unplug from the wall but leave the charger still connected an LED on the charger will remain lit, draining the battery. Maybe someone with more technical knowledge will chime in.


Yes, thats what I recall about charging.

Plug the charger into the power supply (and turn the supply on if it is switched) before connecting it to the tether connector on Trident. When Trident is charged, disconnect the tether connector then turn the supply off before unplugging the charger.


As others have mentioned, you should disconnect the charger from the Trident itself before you unplug the charger from the wall.

There’s no harm to the Trident itself if you unplug from the wall first. But note that Trident is powered on whenever the charger is attached to it- the reason for this is to allow one to download the data from a dive while the Trident is charging for the next dive. So if you’ve unplugged from the wall but the Trident is still attached to the charger, the battery will slowly run down.


Does the Trident make it’s own wifi separate from the topside module? I suppose the topside unit could just be a range extender. I thought it had to be attached to the topside in order to create the wifi to download, but all the better if I can download while it is charging.


Yes, the Trident has its own WiFi module on the inside of the ROV. This can be used to communicate with payloads that are in contact with the Trident shell when Trident is in the water, and it can be used to pull video data off of the Trident when it’s above the water.



Awesome…more gold!

Since the lighs were all off during charging I never thought to look for a signal from Trident. I can’t wait to get home to check this out.

Trident off grid charging system

Good to know! Thanks!


Hi @pforperry:

The tail lights should be on while you’re charging. If you have a very early Trident (a beta unit or an early kickstarter unit) that might not be the case- we realized the need for having the Trident on during charging after we had shipped out a number of beta units. The fix was easy- we just epoxied a small magnet inside the charger connector, similar to the magnet that is on the tethers. The presence of this magnet is what turns on Trident.

If you do have a very early unit, I’d contact customer support to see about getting an updated charger. Reference this post so that they know what you’re referring to.


Thank you Walt_Holm…this is like Christmas all over again. I was aware of the magnet in the tether connector and just assumed he charger connector didn’t have one to make sure Trident wasn’t powered up during charging. It seems so obvious now.


Is it possible to pull images from the Trident whilst it is on charge?


Yep, see Walt’s post before the last one, about 5 posts up.


Yes, thanks. Do I need to do anything to turn on the charging wifi?
Whilst charging I cannot currently see a wifi network.

Thank you


The Trident RPi WiFi connects to your LAN WiFi. It will be setup in the Cockpit app the first time you navigate to Maintenance -> Check for updates -> Connect to WiFi. It will ask for your LAN SSID and password. Thereafter, it will connect when you connect the charger.

You can use FileZilla to transfer the 1080p videos to your PC. Fill in the Quickconnect fields with :
Host: sftp://Trident-IP UN: rov PW: OpenROV Port: 22 and click Quickconnect
Browse to - /data/openrov/video/sessions/<session#>
and look for the *.mp4 files.

Just make sure you use the Cockpit app Past Dives to delete the video files, if you want them deleted.


Thanks, for the clarification, I haven’t tried it yet.


Trying to connect with FileZIlla whilst the Trident is charging, using the settings described above.
FileZIlla gives the following error:

|Error: |ssh_init: nodename nor servname provided, or not known|
|Error: |Could not connect to server|


I double checked and I had to enter Port=22, NOT blank.
I Googled your error and it mentioned using sftp:// vs ftp://. I had to use sftp://.
Can you login with PuTTY or similar using the above UN PW? UN PW case is significant.