did i dream it

[gravediggermax-vabeachva]

well now cavedweller

in like 19 years, i have had 4 excals - 3 of those 4 all suffered from crack battery plug or pod - once

mine occured when i left the rubber gasket out of the equation.................something happens - i did not image and just crack that plug for the picture and i have had the battery pod do the exact same thing once

u also have to watch out for water seeping by the rubber wire gasket from the other end...............maybe i imaged this also

 

[Cavedweller]

Yeah if you unscrew the cap off the battery and leave the plug in you will see that it has a 1/6 of an inch between each side of the rubber gasket - you can't push it tight enough to make any kind of a
seal - I think what you have there is corrosion or eletrolysis - but it not from that not sealing because
it was never meant to seal if it were it would be a capsured oring type seal - Cavedweller

 

[Cavedweller]

Here is a picture of the plug and the top of the battery housing and you can see this is as tight as the
the gasket will go - as you can see there is no seal happening there - the gasket is intended to help
reduce electrolysis only, not to seal, hope this helps clarify - Cavedweller

 

[rdi]

Max's pictures I refer to are posted under topic Excal Batteries cracking? (june 8 2008)


I'm sorry but I have to put my 2 cents in....The gasket has to seal water tight or you'll get electrolysis/corrosion between the battery terminals.which will look like Max's picture ( battgasket 2.jpg ).....

You can prove this by hooking up volt meter in series with Minelab charger and a cup of salt water. Put one lead of the meter to one post of the charger,the other lead from the meter to the cup of salt water.Now a wire from the other post of the charger into the salt water....Your meter will read 0 volts.Plug in the Minelab charger and your meter will read around 20 volts....If you didn't have your battery post insulated from the saltwater it would discharge through the sea water...Throw a new 9 volt battery in saltwater for a few hours
then measure the voltage, you will see it is dead...

Minelab designed the gasket so it would seal tight without much pressure applied to it ....By making the sealing area small....You can see the little doughnut around each post... in Max's pic. ( battgasket 1 jpg )...With this design, you only have to snug it up lightly to make a waterproof connection...If the seal was the same thickness it would require more pressure than the plastic threads could stand..... rdi

 

[gravediggermax-vabeachva]

exactly

i got the business

100%

 

[Cavedweller]

These detectors are rated down to 200 ft. and I would'nt trust that gasket to keep all the water out of those connections completely and like I said before you could flood the battery housing and those connections and the detector will still work but the eletronics that is a different story
- I have seen cave lights and scooters run with they're battery housing
flooded completely and dc voltage is not affected by the presence of water and if you rinse your
detector with fresh water you will never have a problem with corrosion on those connections- Cavedweller

 

[rdi]

Cavedweller........I know you have many hours diving the caves. I only have a few cave dives under my belt, but I do know that most caves in Florida have some of the purest water I've ever seen. You can take a cup of pure water and it will not conduct electricity. However if you add a tablespoon of salt to it,it will conduct electricity,the salt will lower the electrical resistance so that it becomes a good conductor. I will not disagree with your assessment of your dive lamps filling full of fresh water and still working because I have dove with a flooded lamp in fresh water also,however the next time we see each other I will show you a waterproof walkie talkie that has its battery charging contacts almost eaten away from electrolysis. I have to keep it in a plastic bag to prevent this from happening,however in the river it is not necessary.

As far as the seals go,if you'll notice on commercial underwater housings they use a small diameter o ring
or x type gasket to seal up their housings. It has been proven that small gaskets of an 1/8 in or less are more effective and durable than a wide flat gasket. On almost all my underwater camera housings that I've made. I have used a 1/8 diameter o ring type gasket. which means there is probably and I'm guessing no more that 2/32 of an inch contact between the plastic and the o ring. All the housings that I've built have been pressure checked to 6 atmospheres or approximately 200 ft and held up over time very well to dive depths of 150 to 160 ft.

I tend to agree with you that the cracks are probably from over tightening the nut.

Please do not get upset with our discussion. If nothing else we can agree to disagree,however I believe if you do a little research on the effects of salt water on electricity you will understand that I am correct . You are 100% correct on your statements that fresh water has little to no effect on electrical components.

Hope to see you at the get together at Coquina on June 28th and be sure to say hello to your wife....rdi

 

[Cavedweller]

RDI -I also am not trying to make anybody upset with anything I say this is all just good information for
everybody to learn from and you know I really enjoy talking with you and it is hard to get everything
you want to say in just a few lines - my point was salt water is the real enemy here and I'am
meticulous with everything I do, If you leave salt water on any metal one time that starts the process
of corrosion -I'am not going to trust the gasket to keep that from happening so before any crystalization
takes place I'am going to be soaking my detector and It's going to last a long time and as for water
purity it is measured by the megohms resistance to eletrical flow - the purier the water the less
electricity will flow though it but it has to be higher than 20 megohm quality for no electrical flow and
this can only be done in a lab - you won't find that kind of water common in nature and some of the
caves I dove were in brackish and salt and routinely dove to 100 & 200 ft and have done miles of video
I do agree with you on many of these issues but let's face it - were human - and I'am looking forward to seeing you at the get together and also say hello to your wife too ! - Cavedweller