Lithium Iron Phosphate batteries in the wet

[feet wet]

I and many other have and continue to use SLA batteries in our subs. In most cases the batteries are located in the free flooding section of the hull, rather than in the WTC. Now, with Lithium Iron Phosphate batteries becoming more readily available, although I still gag at the price, I wonder if they too can be used in the "wet" to power our subs. The cases appear to be similar, with vent holes, but do they have valves as well?
My reason for using them instead of SLA's is two fold. One, the weight is about half. Second, they store vastly more energy and my beast uses quite a lot of energy in it's drive motor.
So if anyone knows the answer to this, please enlighten me, not too quickly though, I need to save pennies to purchase a couple of these beauties.
Thanks
Jonathan

[coryhenry]

I use LiOn in the wet that have been waterproofed and have had no issues. Change out the plug to a waterproof connector, place inside think shrink tubing with silicon in the ends.

[bob_eissler]

I would advise against putting a battery in the wet. LiPo and Nickel metal batteries are composed of multiple cells tied together with straps and connections that corrode very quickly. It is hard enough to keep water out of a wtc, I don't have any confidence in keeping it out of a battery pack you cannot inspect. If you cannot put the battery in your wtc, make a wtc for your battery.

[feet wet]

Gents,
Thanks for the replies. Let me clarify: the LiPo batteries I am referring to are direct replacements for 12V 7 and 12 amp SLA's. The case are the same dimensions and the spade connectors are sealed as on a SLA. The case has a very small vent, as does the SLA. The SLA vent includes a on way valve allowing hydrogen to vent off is discharged or charged too fast. When I have use SLA's in the wet, I seal the terminal connections with silicon rubber or grease to prevent corrosion ( especially in chlorinated waters). The SLA's last for years this way, without issues.

[feet wet]

Well, when in doubt, go to the horse. The answer to my question, as was previously pointed out, is NO, these batteries require a WTC because they are not glue sealed and contain a circuit board as well as the battery cells that will not tolerate flooding. So, SLA's will continue to be my power.

[Guest]

Why the Li-family ??

Why not relying on good old NiMH batteries ? Our subs do normally require a considerable ballast just to achieve neutral buoyancy.

In my eyes there is no need to go for lightweight batteries. If you need more juice: Go for more parallel NiMHs !

OK, in RC flying we are confronted with the opposite problem: Be as light as you can, but here...


Cheers

Volker

[salmon]

I like NiMH batteries and I agree we need the weight anyways. There are some circumstances that the power packed in a LiPo is needed, but in the wet is not where I put my batteries.