This past weekend we had our annual fun-run where a disastrous event happened. I have a Seaview with the standard SubDriver, SNORT, Vislero twin 1300 mah (7.4 volt) battery pack, etc. Since it had been a long time since I used my Seaview, I ran a system check the weekend before the fun-run. I charged up the battery, checked the SD electrical system, and performed a leak check with one problem; the flap on the top of the ballast tank was sticky so it wouldn’t open to flood the tank. I lubed it up and that helped a little but it still would stay shut occasionally. It would open up after a moment or two of holding the stick to the open position. I figured I could tinker some more with it at the fun-run and recharged the battery and transmitter one more time and packed them up.
At the fun-run, I had performed the usual checkout of the SubDriver before putting my Seaview in the water and everything worked fine. I put the boat in the water and ran it on the surface along the shore for a few minutes to get warmed up. I then commanded a dive and there was no response. The motors were still running and the rudders were still responding. I tried another dive command and held the valve open as I had at home. Well, the sub started to slow down and was not responding to any command. Then there was a very significant plume of smoke coming out of the limber holes in the front of the sub. Oohs and aahs from spectators made me think of the fourth of July. Another sub buddy pulled his sub along side of my Seaview and nudged it closer to the shore. As I walked over to take her out of the water she started to sink, the bow was fully submerged to the sail. Once I pulled her out of the water and removed the superstructure I found the battery had exploded and partially blown off the battery compartment end cap. There was a strong smell of smoke and battery acid and the battery compartment was discolored (white). I brought the wreck back to my table and took out the sub driver. I noticed the battery compartment was warm to the touch, but the aft (electronics) end of the SD appeared unscathed. The end cap wiring from the on/off switch to the battery was partially melted. I had to use needle nose pliers to tug out the battery by the Dean’s plug because the battery had swollen so that it was tight in the SD. The battery was hot so I placed it away from people and property where it could either ignite or cool down safely. I took the hull and SD and rinsed them off and put them away for later inspection at home. The battery cooled down and I packaged it up for the trip home. The rest of the day I got comments from others about using Li-Po batteries and their instability. Some recommended Li-Ion instead.
Once home I found that the wiring running from the battery compartment to the ESC was also melted. Everything else appeared to be in good shape. I replaced the burnt wiring and connected the electronics to another battery to evaluate the damage to the electrical components. Everything was still working except the ESC. It wouldn’t respond to forward or reverse commands, it would sputter a little and stop. I didn’t notice any more burning smells and it didn’t feel excessively hot. I cleaned up the SD with water, baking soda and a toothbrush, sealed it back up and immersed it in the bottom of my tub for an hour to see if it was still water tight. The SD passed that test, as there was no leaking.
At this point I’m not sure what other checks I should perform. I think that the cause was a short somewhere but I found no evidence of that. I think the damage is limited to the battery and the ESC and both should be replaced. The sticky valve and the battery explosion are two separate and unrelated problems but I have some questions I hope someone can answer.
1) What could be the cause and what can I do to correct the battery problem?
2) Is there anything I should use other than water, baking soda and harsh language to clean up any residual battery acid?
3) Could the battery acid compromise the SD so it will one day weaken and fail?
4) Is there anything else that I should check for or test?
5) Are Li-Ion more stable than Li-Po batteries?
6) Is there a fix for the sticky flapper valve on top of the ballast tank?
Thanks,
Lance
At the fun-run, I had performed the usual checkout of the SubDriver before putting my Seaview in the water and everything worked fine. I put the boat in the water and ran it on the surface along the shore for a few minutes to get warmed up. I then commanded a dive and there was no response. The motors were still running and the rudders were still responding. I tried another dive command and held the valve open as I had at home. Well, the sub started to slow down and was not responding to any command. Then there was a very significant plume of smoke coming out of the limber holes in the front of the sub. Oohs and aahs from spectators made me think of the fourth of July. Another sub buddy pulled his sub along side of my Seaview and nudged it closer to the shore. As I walked over to take her out of the water she started to sink, the bow was fully submerged to the sail. Once I pulled her out of the water and removed the superstructure I found the battery had exploded and partially blown off the battery compartment end cap. There was a strong smell of smoke and battery acid and the battery compartment was discolored (white). I brought the wreck back to my table and took out the sub driver. I noticed the battery compartment was warm to the touch, but the aft (electronics) end of the SD appeared unscathed. The end cap wiring from the on/off switch to the battery was partially melted. I had to use needle nose pliers to tug out the battery by the Dean’s plug because the battery had swollen so that it was tight in the SD. The battery was hot so I placed it away from people and property where it could either ignite or cool down safely. I took the hull and SD and rinsed them off and put them away for later inspection at home. The battery cooled down and I packaged it up for the trip home. The rest of the day I got comments from others about using Li-Po batteries and their instability. Some recommended Li-Ion instead.
Once home I found that the wiring running from the battery compartment to the ESC was also melted. Everything else appeared to be in good shape. I replaced the burnt wiring and connected the electronics to another battery to evaluate the damage to the electrical components. Everything was still working except the ESC. It wouldn’t respond to forward or reverse commands, it would sputter a little and stop. I didn’t notice any more burning smells and it didn’t feel excessively hot. I cleaned up the SD with water, baking soda and a toothbrush, sealed it back up and immersed it in the bottom of my tub for an hour to see if it was still water tight. The SD passed that test, as there was no leaking.
At this point I’m not sure what other checks I should perform. I think that the cause was a short somewhere but I found no evidence of that. I think the damage is limited to the battery and the ESC and both should be replaced. The sticky valve and the battery explosion are two separate and unrelated problems but I have some questions I hope someone can answer.
1) What could be the cause and what can I do to correct the battery problem?
2) Is there anything I should use other than water, baking soda and harsh language to clean up any residual battery acid?
3) Could the battery acid compromise the SD so it will one day weaken and fail?
4) Is there anything else that I should check for or test?
5) Are Li-Ion more stable than Li-Po batteries?
6) Is there a fix for the sticky flapper valve on top of the ballast tank?
Thanks,
Lance
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