Where to locate the battery?

[Beardylong]

I've a 5m Zodiac RIB with a 60hp Mercury Mariner outboard and after my first season on the water I know what improvements I want to make over the winter. The battery is currently located in the bottom of the console, but I'd prefer to relocate it to free up the space for kit that I need to access on the go. I have a bench seat with storage space inside it or it could go in the open on the rear deck behind the bench seat next to the fuel tank.

Are there waterproof battery boxes available and is this a wise option?

Would welcome your advice.

Many thanks

[A1an]

could you glass in a shelf inside the bench seat to keep the battery up off the floor?

[Beardylong]

Yes, I was thinking of putting in a slatted wooden floor in anyway to lift stuff up from the deck. I was planning on raising the bench seat by 1/2 or so with wooden bearers 'allowing' any water to slosh under the seat rather than attempting to seal it. The slatted floor will allow any water that gets in from above to drain out. What do you reckon?

[jwalker]

Put the shelf as high as possible in the console to keep the battery above flood level, you already have the battery cables there, and you can then store other things below the shelf.

[jeffstevens763@g]

Originally Posted by jwalker

Put the shelf as high as possible in the console to keep the battery above flood level, you already have the battery cables there, and you can then store other things below the shelf.

+1 above flood level.

[Nos4r2]

+2 for above flood level. Make sure there's some airflow around it as well.

Waterproof battery boxes don't shouldn't exist as they'd be subject to hydrogen buildup. Even 'sealed for life' batteries have a pressure release.

[GuyC]

I agree with the vast majority of what has been said above but with one word of caution. If you are building a shelf higher up in your console it will need to have a reasonable amount of structural integrity. A couple of batteries at 15kg each will put quite a load on the shelf and console when the boat is bouncing around.

If you take the approach that whatever you build should be able to take your weight without either falling off or deflecting too much, then I think you'll be OK.

There are some sweeping assumptions made in the statement above but it is in the right ball park.

My batteries are in the console at deck level but the are contained within a tray with 75mm high edges. Whilst I haven't worked it out I suspect that this puts them above the waterline if it is only the tubes providing the buoyancy.

I have considered getting a small, motorbike style battery and mounting it high up in the console so I can provide emergency electrical power in the event of significant flooding.

Happy New Year

[kerny]

My battery is at deck level in a plastic battery box fixed to the deck in the forward console, I've had plenty water come into to boat due to forgetting to pull the elephant's trunk while moored up overnight and also from the occasional stuffing...never been a problem so I'm quite happy leaving it as it is.

[jambo]

Originally Posted by kerny

My battery is at deck level in a plastic battery box fixed to the deck in the forward console, I've had plenty water come into to boat due to forgetting to pull the elephant's trunk while moored up overnight and also from the occasional stuffing...never been a problem so I'm quite happy leaving it as it is.

Yep me too[emoji106]

[beamishken]

If you fit a box over the top of the battery which comes down the sides of the battery say 3/4 of the way, as long as it's secured and can't float off then there will always be air over the terminals and the gasses can drain out the bottom
The battery can then be totally submerged but won't short out because of the air trapped in the top of the box
Much easier than trying to make a totally air tight box and vent the battery
Won't help if you capsize but in most circumstances that would be game over and the battery is least of your concerns

[Maximus]

Originally Posted by kerny

My battery is at deck level in a plastic battery box fixed to the deck in the forward console, I've had plenty water come into to boat due to forgetting to pull the elephant's trunk while moored up overnight and also from the occasional stuffing...never been a problem so I'm quite happy leaving it as it is.

I would add...The smaller the Craft the more important Battery (and all weight distribution) placement is,you want the Battery forward and Central in a 5m RIB.
Giving thought to balancing all loads (including Crew) will make for better handleing and Hole Shot ..and with less weight at the Back,it will be more stable,and get on the plane easier...every little helps!

[sameh]

Originally Posted by beamishken

If you fit a box over the top of the battery which comes down the sides of the battery say 3/4 of the way, as long as it's secured and can't float off then there will always be air over the terminals and the gasses can drain out the bottom
The battery can then be totally submerged but won't short out because of the air trapped in the top of the box
Much easier than trying to make a totally air tight box and vent the battery
Won't help if you capsize but in most circumstances that would be game over and the battery is least of your concerns

It looks interesting idea but not clear to me how exactly.
If flooding water comes from below won't it fill air between box and battery?
How exactly will box be mounted?
Theoritically air can be trapped but wont battery weight forces overcome flotation power of trapped air? Eventually water will be getting inside?

[beamishken]

As long as the cover is watertight at the top like an upturned bucket and it is secured to prevent it floating off there will always be water trapped in the top of the void. The cover would need to extend well down the sides of the battery to prevent water getting in as the boat rolls
In most cases it would keep the battery terminals out of the water in an occasional flooding of the boat

[jwalker]

Originally Posted by beamishken

..... there will always be air trapped in the top of the void.....

Fixed it for ya....

[beamishken]

Yes well spotted 🖒

[northstar 4.80]

the bench i guess on your zodiac has a smaller internal space, in this case keep your battery as far as possible from fuel tank. ventilation is a important issue, there has to be a 1/3 of free space in the fuel tank compartment.

[office888]

Originally Posted by beamishken

If you fit a box over the top of the battery which comes down the sides of the battery say 3/4 of the way, as long as it's secured and can't float off then there will always be air over the terminals and the gasses can drain out the bottom
The battery can then be totally submerged but won't short out because of the air trapped in the top of the box

US battery boxes are vented in the top.

Hydrogen is lighter than air, so it will float to the top...

[beamishken]

Originally Posted by office888

US

Hydrogen is lighter than air, so it will float to the top...

I wasn't aware of that I guess you'd need either a sealed battery or one with a vent pipe so it could vent outside the bottom of the case
Most popular UK battery boxes have a shallow lid and deep bottom section which are splash proof but if they become immersed they will fill with water and will leave the battery sat in a tray full of water over the top of the terminals
If they were made the other way round ie shallow bottom tray with a deep cover even submerged they could only fill to the top of the lower tray
It's a simple idea but none of the manufacturers seem to make them like that

[Poly]

Originally Posted by beamishken

It's a simple idea but none of the manufacturers seem to make them like that

Because they would then be full of explosive gas?

I wonder in really rough conditions, when flooding is most likely, how well you can keep a big enough air pocket to keep the terminals dry?

[Pikey Dave]

The best place for a battery is in the console as far forward as possible. Imo naturally.