Battery terminals - Waterproof?

[paul von braun]

Dear all,

Does anyone mount their batteries outside their WTC? I would like to place my lead acid (gel cell) outside, but this means I need to water proof the connections/terminals - I can't really fathom how I should do this. Thus, I ask the forum!!


Thanks in advance,





Paul Brown.

[JWLaRue]

Paul,

Mounting gel cells outside of

Paul,

Mounting gel cells outside of the WTC in the 'wet space' is a very common practice.

There seems to be a somewhat even split as to whether folks do or do not waterproof their connections. Those that do mostly use some RTV....just paint it on.

-Jeff

[paul von braun]

Jeff,

Thanks again, old son!!! Did

Jeff,

Thanks again, old son!!! Did you see the pics of my type VII?
And what is RTV? (I was going to look up a sill y answer to this in one of my medical books, but didn't want to offend you).



Thanks,



Paul.

[liftmys10]

We can put batteries in

We can put batteries in the water?? what kind are these?? Who sells them?

[paul von braun]

I am using a 12

I am using a 12 volt 4.8 ah gel cell. I have heard that you can use these wet, not sure about nicads or nimh batteries, but I don't see why not. I think I am right in saying Jeff Larue uses his nicads as a keel weight.


Paul.

[m. munger]

Gel Cells or lead-acid batteries

Gel Cells or lead-acid batteries are fine 'in the wet.' Some folks use RTV (Room Temp. Vulcanizing) rubber (ie 'Marine Goop') to seal the terminals. In my experience all you need to do it lube the positive terminal with a little vaseline if you want to stave off corrosion.

Nicads & NiMhs can handle the water just fine too, just remove any wrapping. Without removing the wrapping you might have a challenge with trimming... and you'll eventually get plenty of corrosion inside the wrapping... shake the water off when you're done running and you should have no trouble.

Matt

[chips]

Be sure to cover the

Be sure to cover the gel cell vent hole (s) with a strip of electrical tape. The holes are there to vent off gas when you charge the batteries. I check and make sure the tape is sealed down good before I install the battery in my sub. I use the RTV from Radio Shack on my battery terminal connections - readily available inmost US cities.

[JWLaRue]

Hi Paul,

Sure did see your

Hi Paul,

Sure did see your photos.....very, very nice work!

Gel cells do not require that their vent holes be covered. These batteries already have a self-sealing vent to allow the hydrogen to escape!

There are a number of companies selling gel cell batteries under a variety of different names. PowerSonic and Yusa are the two principle ones that come readily to mind. Whichever brand you eventually get, I suspect that they are actually all manufactured by the same company. PowerSonic has an excellent web site that lists all the varieties of their gel cells and has technical data sheets for each. Their web site can be found here]PowerSonic[/url]. There is a chain of stores in my area called "Battery Warehouse" that I can walk in and get what I need. There may be something similar where you are located. Alarm companies also use these same batteries.

In both my Type VII and Seehund, I am using NiMH batteries that are indeed in the keel. This essentially means that all the weight in the boat is down where it does the most good. These batteries are not in the 'wet' space. I built what amounts to mini-WTCs for the batteries using acrylic tubing. End caps were machined on a lathe.

Matt's advice is right on....if they are used wet, removing the plastic wrappers will help to slow down the creation of rust.

-hope this helps!

Jeff

[wingtip]

JWLaRue

thanks for posting that link

JWLaRue

thanks for posting that link to the battery place!.. they have a much better selection of odd sizes than the places i have been finding online...

im planning on using 2 12vdc batterys, and some fellow enthusiasts of my project are designing a circuit so i can hook both batterys to it, it senses when the battery reaches a preset voltage/load, it compares and decides when to switch over to the backup battery uninterrupted and turn on a light to indicate the sub is on backup power.

anyways, if i couldnt squeeze in two batterys (shouldnt be a problem now with the link u posted) i'd just go with one large capacity one.

[eckloss]

Jeff

I'm curious as to exactly

Jeff

I'm curious as to exactly what batteries you are using in the keel, and what charger you might suggest. How do you have them configured? I'm assuming two tubes, one on either side, low in the sub? A pic would be great =)

[JWLaRue]

For my Type VII, I

For my Type VII, I am using 10 of the 4/3AA-sized NiMH batteries made by Sanyo. These are the 'tabbed' versions, laid end-to-end and the tabs soldered together. The resultant 12 volt battery fits into a one inch diameter acrylic tube that is approximately 34 inches long.

I run both positive and negative wires out of the same (front) end cap.

For my Seehund, I use the same type of batteries, but in this case they are arranged in two parallel sticks of two. An acrylic tube with custom endcaps is also used for this pack too.

I'll need to take a few photos since I do not have any on hand.

-Jeff

p.s. I purchased the batteries from Batteries America.

[eckloss]

Thanks for the info.

Do you

Thanks for the info.

Do you find you get a long enough battery life this way, as opposed to a sealed lead acid?

[JWLaRue]

I haven't found it to

I haven't found it to be a question of NiMH vs. sealed lead acid.

In this particular case, the NiMH batteries that I am using are 4000MAh (4 amp-hour) batteries. This battery allows me to run long enough that I start to think about lunch! (I haven't run them down enough to really note a max run time....but it's at least as good as the gel cells)

The largest gel cell that I'm using (in a 1/72nd scale Skipjack) is a 3 amp-hour battery. In this boat, I get about 2+ hours of run time....depending on throttle speed of course.

I suspect that if I had batteries of the same amp-hour rating that I should see the NiMH provide a higher level of voltage over a longer run time, but then drop off all at once. The gel cells tend to have a more gradual voltage drop.

Total battery run-time was not really the reason that I decided to go with the NiMH batteries. I wanted to get that dead weight out of the bow (and sitting, on average, about mid height in the hull) and place all of it in the keel where it's no longer adversely affecting the operating characteristics of the boat.

-Jeff

-Jeff

[eckloss]

one last question...

you said they

one last question...

you said they are soldered together at the tabs...so you are able to charge them all at once as a unit, then? what type of charger do you find to be effective?

thanks again for all the good info

e.

[JWLaRue]

Yup, all soldered together. I

Yup, all soldered together. I charge it as a 'single' 12 volt battery.

I use one of those microcomputer-based chargers from FMA that I really like.....

-Jeff