Eve cells 280 304 are not really suitable for offshore sailing boats

[Fuss]

They are not waterproof, I’ve got these and they are sort of well protected but I had lots of sea water and spray down below in a storm and I’m not convinced they would like any sort of real flooding.

Better would be waterproof ones, maybe even drop ins, i did not have space and the Eve 280s were a perfect fit down to the millimetre.

[Cpt Mark]

I disagree. Your problem isn't that they are not waterproof it's that your battery boxes are not waterproof. Are they in a box? With a top? Strapped down somehow?

[wholybee]

Of course they are not waterproof. You would be just as ill advised to let salt water splash on a lead acid battery. Batteries need to be mounted in a dry location. All of them, regardless of chemistry.

LFP cells are meant to be part of an assembly. That assembly would include keeping them dry.

[Fuss]

Originally Posted by Cpt Mark

I disagree. Your problem isn't that they are not waterproof it's that your battery boxes are not waterproof. Are they in a box? With a top? Strapped down somehow?

Absolutely on all counts…but the box is not as waterproof as the new waterproof drop ins…it’s still much more waterproof than the old la. However the old la ones would survive a few major dunkings… not so sure with these…. If they had plastic boxes and not alu , this would be better.

[Cpt Mark]

It's a battery. Period. You short the pos/neg terminals by dropping a wrench on them, connecting them together for fun or flooding them or enough water so they make contact the result will be the same.

The difference between creating a battery from cells vs buying a premade "drop in" battery is this.
1. On a premade battery, sealed you only have 2 short points. Pos/neg. On diy batteries you have 8 short points. 2 per cell. Pluse any junction terminals.
2. On AGM/LA batteries you have a battery. On LFP you have a BMS which is very sensitive. Another short problem.

The solution is to locate the batteries in a dry area where they cannot get wet unless you're sinking.

Because LFP don not off gas you can put them anywhere as long as you follow the cabling rules.

[Fuss]

Yep…but as we all know, the first high water event and it’s a big problem… you might get away with it with la and sealed lifepo4 drop ins but not with self built….look around, you know that most high water events always gets the batteries

[Fuss]

Put the batteries up high … really, put the batteries up high, that’s not what sailors do.

[rslifkin]

If you're worried about it, you could always build a battery box with a latched and gasketed top to make it water tight. To provide ventilation, run a duct or 2 to somewhere higher in the boat. Then you can have your custom built batteries down low but keep them dry (unless you breach the hull directly into the battery box, but that's a very small risk).

[Cpt Mark]

LFP batteries are light. Mine are up around 6 feet from the bottom of my cat's cabin sole. You won't ever make anything foolproof. All you can do is the best you can. After that, is this an acceptable risk for you?

[Pete7]

There is a US company which sells kits to DIY build a lithium battery. You could check to see if they have a suitable empty battery box. Sorry just can't remember the company name.

Pete

[fxykty]

Originally Posted by Fuss

Yep…but as we all know, the first high water event and it’s a big problem… you might get away with it with la and sealed lifepo4 drop ins but not with self built….look around, you know that most high water events always gets the batteries

What about the electrical distribution system the battery(ies) is(are) connected to? Do you bother to waterproof your fuse, shunt, switch, bus bar, etc?

Simply mount your battery close to your distribution system and you’re done. And besides, if the top terminals of your sealed battery get wet or flooded then you’ve got a short anyway - what’s different with a 4S (or whatever topology) battery that has a bunch of inter-cell connections in addition to the two main terminals?

But if you must put your battery in the bilge or whatever then building a waterproof enclosure is a bit of a pain but not that big a deal. As pointed out earlier, the biggest hassle is ventilation (for heat control; not talking about off-gassing), but that’s an issue common to any battery chemistry and type.

[Fuss]

Also these eve cells are sort of unprotected aluminium, so some salt water exposure (splashing) is going to start a corrosion process more so than with other solutions…. For sure the lifepo4 are better protected than the old la as they are in a box with a lid…but it’s not totally waterproof…only splash proof. A totally waterproof solution with Ventilation and cooling would not be easy.

[SailingHarmonie]

The idea that any battery of any design or chemistry should be expected to tolerate salt water splash or flooding is insane. From corrosion to short circuits there are many reasons that all of your electrical system needs to not be in contact with salt water—ever.

The problem here is your boat, not the construction of your batteries. If you can not keep water out of your boat you have much bigger problems than batteries.

[Fuss]

Originally Posted by SailingHarmonie

The idea that any battery of any design or chemistry should be expected to tolerate salt water splash or flooding is insane. From corrosion to short circuits there are many reasons that all of your electrical system needs to not be in contact with salt water—ever.

The problem here is your boat, not the construction of your batteries. If you can not keep water out of your boat you have much bigger problems than batteries.

Thankyou sailingharmonie, so what your saying is that most boats don’t get water inside them in storms, especially when offshore. This is news to me because in my experience 95% of boats would. Of course there are the very few exceptions, sailing boats, storms, water inside, that’s how it works. I’ve had waves that still had not really become spray by the time they reached the spray dodger and then flowed off the back of the Bimini.

Even if we just take the drip water from your wet weather gear, it adds up with a few up and downs through the companion way!!

You’ve never heard, we had a really rough passage and got beaten up, we are still drying the boat out…..

[boatpoker]

Originally Posted by Fuss

Thankyou sailingharmonie, so what your saying is that most boats don’t get water inside them in storms, especially when offshore. This is news to me because in my experience 95% of boats would. Of course there are the very few exceptions, sailing boats, storms, water inside, that’s how it works. I’ve had waves that still had not really become spray by the time they reached the spray dodger and then flowed off the back of the Bimini.

Even if we just take the drip water from your wet weather gear, it adds up with a few up and downs through the companion way!!

You’ve never heard, we had a really rough passage and got beaten up, we are still drying the boat out…..

Is your alternator waterproof , starter motor, windlass motor, refrigeration compressor, bow thruster motor, macerator pump, potable water pump ?