Oasis Firefly battery boxes

[Ken Pole]

Apologies up front if this has been deal with already but extensive searches of the forum have not yielded anything consfructive.

I have two Oasis Firefly Group 31 batteries, installed last season as my house bank. From what I have read elsewhere, because they are a "dry" AGM, no battery boxes are required/suggested. However, my personal inclination is to build a single box sized to permit the manufacturer's recommendation that Fireflies should be separated by one inch due to heating while charging.

Any thoughts? Thanks in advance.

[Pete7]

Are these batteries in the engine space? They don't necessarily need a box, a frame to hold them secure will do., if you keep them cool.

Pete

[BillKny]

I think you need to decide what you want the box to DO. If it is to contain an acid spill, or to secure the batteries in place?

If you are worried about acid spill, consider the design box shown in Calder's book Boatowner's Mechanical and Electrical Manual. It is vented and fan cooled. If you just want to secure them in place, the less box and the more vent the better. Or as Pete7 suggests, a suitable frame is the best in this case.

[sailorboy1]

Originally Posted by Ken Pole

Apologies up front if this has been deal with already but extensive searches of the forum have not yielded anything consfructive.

I have two Oasis Firefly Group 31 batteries, installed last season as my house bank. From what I have read elsewhere, because they are a "dry" AGM, no battery boxes are required/suggested. However, my personal inclination is to build a single box sized to permit the manufacturer's recommendation that Fireflies should be separated by one inch due to heating while charging.

Any thoughts? Thanks in advance.

I say if you are concerned go ahead and build the boxes.

[Ken Pole]

Thanks all. I think the frame concept is a good one from a security and cooling perspective. My batteries are not in the engine compartment.

[MerMike]

The Fireflys require constraint but not containment.

I went with 2 1100lb poly cam straps, and 6 316 ss footmens loops, through-bolted with thick 316 ss washers for backing. There's a 1/2" gap between them. If this setup lets go I've likely got bigger problems already.

I would think that putting them in a box is not going to improve cooling.

[Captain Puget]

Firefly batteries do not need boxes, as you already stated. Strapping them in with good airflow is the recommended method. If you want a box for esthetics it’s your choice, of course, but not needed. Just be aware you are impeding the airflow and the esthetic choice could actually hurt the batteries.

[Offshore1960]

I made this bracket to go in the starboard cockpit locker of my B40. The boxes are mockups of Firefly G31's. The batteries will be held in place with a turnbuckle and nylon strap.
One thing that is very important to do is to provide shorting protection over the positive terminals.


IMG_3678.HEIC

[Jetx]

FWIW, my 8 Firefly G31's sit on a plywood platform, with 1x2 lumber screwed down around the perimeter, and in-between the individual batteries to restrain them and to provide air space for ventilation. They're then strapped down using ratchet straps and footman loops as MerMike has done.

[walbee]

Agree with all comments so far. One other aspect to consider is visual inspection. Being able to clearly see all sides of each battery for bulging, heat discoloration and cracks.

[Scubaseas]

ABYC E10 10.7.10 Battery boxes, whose cover forms a pocket over the battery, shall be vented at the uppermost portion of the cover.
NOTE to 10.7.9 and 10.7.10: These requirements also apply to installations of all batteries whether they employ removable vent caps, non-removable caps, are “sealed” or “maintenance free” batteries, or have pressure regulated valve vent systems with immobilized electrolyte (gel and AGM batteries).

Technically you actually DO need a "battery box" with Firefly batteries (or any AGM/Gel immobilized electrolyte type battery). Essentially you need to restrain movement in any direction to the tune of 90lbs of force and to vent the top of the "box". Good ventilation will keep the batteries cooler and some kind of venting is required even though they are sealed batteries.

[MerMike]

Originally Posted by Scubaseas

ABYC E10 10.7.10 Battery boxes, whose cover forms a pocket over the battery, shall be vented at the uppermost portion of the cover.
NOTE to 10.7.9 and 10.7.10: These requirements also apply to installations of all batteries whether they employ removable vent caps, non-removable caps, are “sealed” or “maintenance free” batteries, or have pressure regulated valve vent systems with immobilized electrolyte (gel and AGM batteries).

The note regarding 10.7.9 and 10.7.10 is about ventilation, not battery boxes. Containment is not a specific requirement for immobilized electrolyte batteries. Constraint/immobilization and ventilation are required for all battery types.

[Scubaseas]

As are the following required for all battery types.

10.7.7 To prevent accidental contact of the ungrounded battery connection to ground, each battery shall be protected so that metallic objects cannot come into contact with the ungrounded battery terminal and uninsulated cell straps. This may be accomplished by means such as:
10.7.7.1 covering the ungrounded battery terminal with a boot or non-conductive shield, or
10.7.7.2 installing the battery in a covered battery box, or
10.7.7.3 installing the battery in a compartment specially designed only for the battery(s).

Then consider the dielectric shielding requirements if applicable. True there should be consideration of immobilized electrolyte containment but there is nothing in E10 that exempts carbon foam, AGMS or Gel cells from any of the other requirements except spillage. By the time you are done with it the batteries are effectively in a vented box of some kind. Might be called a battery compartment might be called a battery room. Or a battery box. A lot of surveyors treat AGMs just like flooded except for the heel angle consideration. So I'm wrong, I take it back. The AGMs do not need a battery box but by the time you meet all the requirements they might as well be in one.

You are right and I stand corrected.

To the OP/ Ken Pole. Putting the batteries in a box is fine as long as it's vented and the batteries can't move around more than an inch. Vent and power fan the box or battery container if you want. The hold down Pete & has seems beautiful but I personally would not use what looks like aluminum. You can get fiberglass reinforced plastic battery hold downs like this made by Moeller. Very substantial and even my dive shop guys haven't broken them yet. Held down by 4 of #12 screws or 4 of 1/4" bolts. I used to have webbing straps but find they can loosen. Been very happy with the performance of the above hold downs on power skiffs that get beaten up all day long.

PM me if you want more of ABYC E10 standards.

[Scubaseas]

Originally Posted by MerMike

The note regarding 10.7.9 and 10.7.10 is about ventilation, not battery boxes. Containment is not a specific requirement for immobilized electrolyte batteries. Constraint/immobilization and ventilation are required for all battery types.

Nor is containment specifically an exemption for AGM/Gel batteries. I've seen a lot of surveyors look at it both was.

[MerMike]

A surveyor can say whatever he or she wants, but has to back it up. With the covers in place, I can show that it meets the requirements. They won't be able to reference a section from the standards that says it has to be a box.

I gave this a lot of study beforehand because a box was not an option and I wanted it to meet the standards.

You're right though. A surveyor who has not studied E-10 in detail might write it up. Not much I can do about that except educate.

Originally Posted by Scubaseas

Nor is containment specifically an exemption for AGM/Gel batteries. I've seen a lot of surveyors look at it both was.