Final ROV upgrades for July 1 Algalita Expedition

I picked up the ROV from Algalita last week after they had a few weeks with it.   They only had time to put it in the water for about 30 minutes on a cruise to the Channel Islands.   It didn’t get a proper test because the buoyancy wasn’t properly adjusted.   Anyway when I picked it up, another charger had failed and it looked like several batteries were discharged below 3 v which will damage the batteries.    Not sure why this happened but I suspect that the UltraFire batteries have defective overdischarge circuits.

Battery/Charger replacement

After I got the batteries home, I tried to resuscitate the batteries to no avail.   Finally wound up with only one good battery out of six and one good charger out of three.   This convinced me to return both batteries (UltraFire 6000mah) and chargers  (TrustFire TR-06) to Amazon and try some other brands.     So ordered 12 TrustFire batteries and 3 Nitecore IntelliCharger i4  four slot chargers  .   This will give the capability to have two sets of batteries ready for a dive.

Motor Salt Water Hardening

We are doing some experimental testing with epoxy filled motors and plastic bushings.   The current motors have two 3mm shaft metal bearings with outside diameters of 7mm and 8mm.   The micrometer measurements on a set of bearings from one motor are as follows:

8 mm (.31961 in) … measured  .31485 in

7 mm.(.275591 in) .. measured .2753  in

Shaft 3 mm (.11810)  measured .10176 in  or 2.585 mm.    So the shaft is about 14% smaller than the so called 3mm spec.

Mr. Paulson , our team machinist mentor,  fabricated several plastic bushings to try out.   These will be added to some epoxy hardened motor cores and painted outrunners for testing in salt water.   Here is a picture of the new bearings.

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Tether Buoyancy

We have in hand 1 in and 1.75 inch bobbing spherical floats to attach to the tether line to try to get it neutrally buoyant.   The biggest issue is how to deal with storing the tether with the floats on.   It would be nice to do this. Otherwise they would have to be removed after each dive.

 

Chris