Do AGM batteries need to be in boxes?

[crayiii]

I currently have two AGM 8d batteries in the engines compartment. Both are in covered battery boxes. We need to add capacity but are in the Caribbean and can't find any battery boxes except group 31.

If I add batteries, it will mean I can't have them in battery boxes. Is this okay?

[Stu Jackson]

it will mean I can't have them in battery boxes. Is this okay?


Nope. They still have acid in them and if the case cracks?

[Pizzazz]

Let’s be realistic though. One of the main advantages of AGMs is that you can mount them in any orientation. I wouldn’t worry about it but will put it on the to do list.

[GILow]

Originally Posted by Pizzazz

Let’s be realistic though. One of the main advantages of AGMs is that you can mount them in any orientation. I wouldn’t worry about it but will put it on the to do list.

Not something I would put on the to-do list. Too easy to forget (batteries are usually out of sight and out of mind) and the consequences of a spill are too big to disregard.

[Wotname]

Originally Posted by Stu Jackson

it will mean I can't have them in battery boxes. Is this okay?


Nope. They still have acid in them and if the case cracks?

It is a good question and one I do not know the answer of however here are two battery people who suggest that AGM batteries do not leak acid if the case is cracked.

Deep Cycle AGM Batteries

https://batteryguy.com/kb/knowledge-...a-sla-battery/

Edit: AFAIK an AGM battery has no free liquid that is available to leak out.

[a64pilot]

In my opinion they don’t need to be in boxes.
For whatever that’s worth.
Lifeline says that if they are laid on their side it’s possible that a few drop of liquid could be expelled from the vents and you could them in a tray.
Doesn’t sound like they think they need to be in boxes either.

Mine are not in boxes

[Reefmagnet]

I've got a dud AGM with a leak around the negative stud. A green salt like crust forms around the leak and nearby stuff starts to get attacked by acid fumes, leaving that white powdery stuff like often seen on car battery terminals. As far as I can tell though, very little liquid oozes out.

[john61ct]

IMO at least a tray if not enclosed

But they can (rarely) fully explode.

Skills and gear can ensure a level of care that prevents surprises, proactive replacement long before EoL.

[jamhass]

Some sort of hold-down or other means of keeping them in place is never a bad idea!

[David M]

Something that nasty I would keep enclosed.

[Tillsbury]

Yes, as long as they’re very securely bolted down in a tray I don’t think AGMs need a full box.

[billknny]

Originally Posted by jamhass

Some sort of hold-down or other means of keeping them in place is never a bad idea!

That's kind of like saying breathing on a regular basis is "never a bad idea."

The consequences of a battery that has come adrift in a seaway would be a disaster. Between the electrical energy that could be released in arcing, acid spillage, and just the mass of a battery flying around, it's scary to think about.

The ABYC does not explicitly require a "box" around the battery, they only require that the surfaces on which is sits not be damaged by battery acid.

ABYC Standard E-10.6. Storage Batteries - Installation
a. Batteries shall be secured against shifting.
b. Each installed battery shall not move more than one (1) inch in any direction when a pulling force of ninety (90) pounds or twice the battery weight, whichever is less, is applied through the center of gravity of the battery as follows:

(1) Vertically for a duration of one (1) minute
(2) Horizontally and parallel to the boat’s center line for a duration of one (1) minute fore and one (1) minute aft.
(3) Horizontally and perpendicular to the boat’s center line for a duration of one (1) minute to starboard and one (1)
minute to port.

c. To prevent accidental contact of the ungrounded battery terminal to ground, each battery shall be protected so that metallic objects cannot come into contact with the ungrounded battery terminal. This may be accomplished by means such as:

(1) Covering the ungrounded battery terminal with a boot or nonconductive shield,
(2) Installing the battery in a covered battery box, or
(3) Installing the battery in a compartment specially designed only for the battery(ies).

d. Each metallic fuel line and fuel system component within twelve (12) inches and above the horizontal plane of the battery top surface as installed shall be shielded with dielectric material to protect against accidental short-circuiting.

NOTES:
1. Terminal insulation or battery covers do not comply with this requirement since during installation or removal of a battery, these protective devices are usually removed in order to connect the cables.
2. Any nonconductive material maybe used for shielding as long as it is durable enough to withstand accidental contact by a tool or the battery terminals during servicing, installation or removal.

e. Each battery shall not be installed directly above or below a fuel tank, fuel filter, or fitting in a fuel line.

NOTE: This does not prohibit a battery from being installed directly above or below an uninterrupted fuel line; however, if this fuel line is within the twelve (12) inch envelope of the top surface of the battery it shall be shielded dielectrically as required in ABYC E-10.6.d.

f. A vent system or other means shall be provided to permit the discharge from the boat of hydrogen gas released by the battery. Battery boxes whose cover forms a pocket over the battery shall be vented.

NOTE: These provisions also apply to installations of sealed batteries.

g. If the mounting surface or components of the boat in the immediate vicinity of the battery location are of a material attacked by electrolyte, a mounting means shall be provided that is made of a material that is not damaged by electrolyte.
h. Fasteners for the attachment of battery boxes or trays shall be isolated from areas intended to collect spilled electrolyte.

[MarkI]

For another Viewpoint, Beneteau ships new sailboats with batteries tied down securely and securely sitting in a plywood indent to prevent sliding but no plastic or box. I am not saying this is best practice, but thousands of boats are without boxes. I just got a new boat and have no plan to change this. They are smaller group 31, auto sized batteries, 5 or 6 of them.

[tarian]

I have had an lead acid sealed battery leak out everywhere due to faulty charge and cooked it , the box kept the fluid in one place rather than all over the engine room.
Risk and consequences,
Do batteries leak YES
Can I sail for 20 years and never see one leak YES
but this is the catch 22 ?

[john61ct]

question was AGM specifically

emits much lower volume of actual liquid

some SLA are sealed but "Flooded Wet", more liquid can be released if they explode or are physically damaged

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And yes **of course** ALL battery types need to be securely held in place, against shocks or even a full turtling