battery box, what is the point ?

[simonfraser]

the hydrogen moves upwards, so not going to collect in the box
if the battery explodes is the box going to be of any use ?

yes it will catch the spills if topped up carelessly
and less likely to drop a spanner accross the terminals

but providing the bats are in a locker, why do they need idividual boxes ?

 

[Gary Fox]

the hydrogen moves upwards, so not going to collect in the box
if the battery explodes is the box going to be of any use ?

yes it will catch the spills if topped up carelessly
and less likely to drop a spanner accross the terminals

but providing the bats are in a locker, why do they need idividual boxes ?

Good question! I have never felt the need.

 

[dankilb]

My plan for a box for our batteries in their new location under an aft cabin bunk - once so belt’n’braces it included repurposing a defunct water tank vent to the topsides - is now looking likely to be a battery ‘shelf’ instead.

I read up on various threads and had a plan in mind for a fully-sealed, gas venting, acid collecting, epoxied ply assemblage. It wouldn’t be that difficult to make…

But with LiFePO around the corner and no plans to accommodate sleeping infants above charging batteries in the near future, I can’t really see a longer-term return on the effort involved in the building the aforementioned ‘box’.

Even some brand new production boats seem to sling them any old where under floors/bunks etc. anyway.

 

[Bristolfashion]

But if I didn't have one, where would the bats live? ?

 

[PaulRainbow]

the hydrogen moves upwards, so not going to collect in the box
if the battery explodes is the box going to be of any use ?

yes it will catch the spills if topped up carelessly
and less likely to drop a spanner accross the terminals

but providing the bats are in a locker, why do they need idividual boxes ?

They don't. They just need to be secure and located so that nothing can fall onto the terminals and cause a short.

 

[Daydream believer]

My battery "enclosure " also houses a bus bar, the backs of the 3 on off switches, the shunts, some fuses to the domestics, wiring for the shore chargers, VSR for the start battery ( in another compartment due to space) wiring for volt meter etc
I spare circuit set of wires & fuses ready to connect direct to VHF & GPS to battery, thus byepassing everything in the event of a serious failure in domestic wiring. This is so I can jump the entire circuits in about 10 minutes if I get a wiring overload or some problem I cannot solve at sea quickly. I can get GPS & VHF working.
Bracing to prevent movement in a roll of the boat & vibration. Containment of spillage
So I am more than happy to have that lot isolated from everything else, to prevent shorts etc if anything did fall across the terminals or junctions & to keep it all neat in one space

 

[LittleSister]

My battery "enclosure " also houses a bus bar, the backs of the 3 on off switches, the shunts, some fuses to the domestics, wiring for the shore chargers, VSR for the start battery ( in another compartment due to space) wiring for volt meter etc
I spare circuit set of wires & fuses ready to connect direct to VHF & GPS to battery, thus byepassing everything in the event of a serious failure in domestic wiring. This is so I can jump the entire circuits in about 10 minutes if I get a wiring overload or some problem I cannot solve at sea quickly. I can get GPS & VHF working.
Bracing to prevent movement in a roll of the boat & vibration. Containment of spillage
So I am more than happy to have that lot isolated from everything else, to prevent shorts etc if anything did fall across the terminals or junctions & to keep it all neat in one space

But isn't all those wires, bus-bars and the backs of switches within the enclosure, themselves more likely to lead to an accidental short than surrounding the battery with fresh air?

 

[Gary Fox]

But isn't all those wires, bus-bars and the backs of switches within the enclosure, themselves more likely to lead to an accidental short than surrounding the battery with fresh air?

Thet won't just short themselves without human intervention, I approve of DD's belt and braces approach.

 

[Rappey]

Was out offroading. We stopped for a coffee break. Friends car wouldn't turn over ?
Checked the battery for loose connection. That was not the problem, the sides had literally fallen off the battery, exposing all the lead plates and all that lovely acid everywhere.
I have battery boxes on my boat.

 

[Daydream believer]

But isn't all those wires, bus-bars and the backs of switches within the enclosure, themselves more likely to lead to an accidental short than surrounding the battery with fresh air?

Not really because it is all fixed down securely. What is "fresh air"? A locker in which things can be dropped over the connections & batteries. If the batteries are in a locker, on their own, then is that not a battery box? ----Just an over sized one, in which someone might accidentally throw something that should not be in there?
Is it not better to put all the fuses etc, in some single contained area with the power source, where they can be laid out neatly on display & one can tell where each one is connected at a glance

 

[MADRIGAL]

yes it will catch the spills if topped up carelessly
and less likely to drop a spanner accross the terminals

Exactly that, especially the bit about the spanner! I just built one with that in mind, with a solid, hinged top and large openings in the sides for ventilation and battery leads.

 

[John the kiwi]

I have a battery box with a strong lid.
I know that i will always find the battery where i left it -even if the boat was completely inverted.
I know that nothing can accidentally fall on terminals.
I know that spillage will be contained.
My fuses and switches are all outside the battery box itself. If you combine Daydream Believers set up with Rappey's scenario, with the boat in a seaway is there not a probability that the acid will adversely affect all of the other components inside the battery box or enclosure?

 

[yerffoeg]

My start battery exploded a couple of years ago. It is handy to have the batteries in separate boxes because it isolates the mess!

 

[simonfraser]

My start battery exploded a couple of years ago. It is handy to have the batteries in separate boxes because it isolates the mess!

was that in one of this kind of a plastic bat box and the box survided ?

 

[Daydream believer]

If you combine Daydream Believers set up with Rappey's scenario, with the boat in a seaway is there not a probability that the acid will adversely affect all of the other components inside the battery box or enclosure?

I have AGMs & the wiring is all at the upper levels of the box not the bottom anyway
My Red Flash start battery can be mounted on its side if I wished.

 

[Gary Fox]

My start battery exploded a couple of years ago. It is handy to have the batteries in separate boxes because it isolates the mess!

Battery boxes have probably helped explosions to occur, by reducing the airflow which wafts away hydrogen and oxygen, and also cools the battery. Batteries rarely explode and when they do, there is always a reason. Out of sight, out of mind.
After reading this thread, I am shifting further to the 'battery box bad' standpoint.
Strong restraint, free ventilation, and well clipped wires are most important.

 

[jamie N]

Batteries require ventilation, as Gary Fox states, which is air flow across them: fresh air in, and (potentially) explosive gases out.
WIth commercial submarines, the sub comes to deck, the battery pods are opened and the fans are immediately run as charging is commenced. This is a little bit extreme compared to the standard yottie scenario, but is the basis of having safe battery enclosures.
On a boat, ALARP is quite useful here because it's simple to get right where the spark and ignition potential is great.

 

[Moodysailor]

Another reason for a box of some kind is to protect the batteries from damage. The casing is quite easily cracked if something is dropped on them, you can ask me how I know if you like...

So, a battery box/enclosure does serve a few useful purposes, however it is not exclusively needed.

 

[Wing Mark]

Batteries can vent acid when overcharged.
On a motorbike, you'd have that taken away by a tube.
On a boat, not a bad idea to contain it.
Also if the terminals are greased, it's good to keep everything away from them and to keep things clean.
I've looked at a few boats lately with unprotect batteries, dirty connections etc etc.
I've also seen a few unprotected 12V bus bars, isolator switches etc etc.

 

[dankilb]

I know that spillage will be contained.

My start battery exploded a couple of years ago. It is handy to have the batteries in separate boxes because it isolates the mess!

Batteries can vent acid when overcharged.
…
On a boat, not a bad idea to contain it.

Not to criticise the above - all are valid observations of the potential issues. The problem is that the solution starts to look very much like a fully-enclosed box, with an acid-resistant floor/‘tray’ (grp/epoxy), and all the venting challenges that go with it.

It is ‘reasonably practical’ to fabricate such a thing. But is it worth it? What are the probabilities of needing to contain the acid for a length of time? And what are the new risks created (e.g. trapping gasses if vents fail to function)?

As I said above, a separate enclosure is one thing - an acid-containing box, quite another.