Battery gases

[mick]

I have a Sadler 26 on which both batteries are kept in a moulded box under the quarter berth. They have short "breather" tubes (about 12 inches) venting nowhere in particular. In the light of comments about dangerous gases from charging batteries, is this safe? All replies gratefully received.

 

[JamesS]

Given the fact that the boat designer put them there then the answer is probably yes.
As I recall the gas given off is hydrogen and will therefore dissipate into the atmostphere quite easily.

Never inspect the battery with a naked light!!!!

A healthy battery should gas very very gently whilst charging.

If the battery is bubbling like mad then its in an unhealthy state and probably needs replacing.

Hope this helps.

 

[Strathglass]

Battery gasses are lighter than air, unlike propane and butane. They are still inflamable. The two pipes should be vented through a skin fitting with a flame barrier gauze. Somewhere reasonably high is best perhaps on the cockpit sides.

 

[brianhumber]

If vented into a large volume such as the main cabin no problem as certain concentration is required before the gases can explode and I doubbt your small battery bank/charger can produce gases that will get anywhere near that level. Ask yourself how many yachts blow up due to battery gases - none. You are in far greater danger from poorly maintained/leaking butane/propane systems.

 

[Guest]

One thing you have to be very careful about is not to cause a spark near the battery while it is being charged. I have seen a car battery explode because someone disconnected the battery charger while it was switched on, causing an electrical spark which ignited the hydrogen. Not a pleasant thing to happen in a boat!!!

 

[ccscott49]

Batteries produce both hydrogen and oxygen, I agree the amounts of gas given off, if mixed with the normal atmosphere in a cabin are unlikely to meet the lowest explosion limit (LEL) so I wouldnt worry too much, it is of course safer to have them vent to outside the boat and if this is possible easily go ahead and do it. I dont agree with the comment, a boat designer put it there so it should be OK! Have you seen some of the disasters waiting to happen that designers have put on paper! or built into boats, it makes one shudder!

 

[yachtbits]

Battery compartment should ideally be vented to atmosphere. But batteries shouldn't generate large volumes of gas if;

1. batteries are in good condition
2. charging voltage is correct.

point 2. should be checked if you are experiencing excess gassing. 13.8v is the idea charging voltage, if it's over this then gassing will be increased and you may have a charging system fault.

www.yachtbits.co.uk
sales@yachtbits.co.uk
marine electrical/electronics specialists

 

[jollyjacktar]

You have to be quick

Hydrogen released into the atmosphere will accelerate so fast that it will escape Earth's gravity, so let it vent freely, do not bottle it up.

 

[Guest]

Most boats have the battery box under the 'divan', that does not make it correct. Some boats are designed with the battery's in the same locker as the gas.... even worse, again this does not make it right.
But as said by others the amount of gas should be small. But we all, I am sure, have had a whif of the sulphur and the ozone'y when opening the battery box. THAT IS NOT TO prompt some smart alek comment !

Another gave the letters LEL ... this stands for Lower Explosive Limit ....... with Hydrocarbons and Hydrogen you can have a bang at less than 1% by volume. Now the average yacht cabin far exceeds the amount required to be gassed of to reach anywhere near 1% of its volume. BUT if you fix a gas tight / close fitting lid to the battery box .... you could pass into the LEL very easily in that small box.

So what do you do ? Make sure that the box vents ........ at the top edge, for the hydrogen is lighter than air and will collect under the lid.

Better still is fashion a place in one of the cockpit lockers separate from the gas bottle.

Last of all ....... Just make sure that the box under the bunk / divan doesn't collect the gas ..... I admit that my box is under the main cabin divan .... like a lot of older boats and I have no plans to move it .... I lift the lid often, I do not seal it down, and I do not do anything intentionally to create a spark situation in / near the box.

 

[Sammy]

I think the battery compartment on the 26 is vented into the engine compartment which will remove any amount of hydrogen gas that your batteries could produce while the engine is running by taking it into the air intake. No gas is produced when the batteries are not being charged so this is fine. Be careful if you are charging the batteries with a charger as this can lead to a build up. Having said that it is almost impossible to trap Hydrogen gas its molecules are too small so the ewxternal vent to the engine should be more than adequate.

Have you tried the Sadler Forum it is generally quite useful to Sadlere owners its at www.mikelucasyachting.co.uk some useful stuff on there at times,
Good sailing.
. Chris.

 

[mick]

Many thanks for all the helpful replies.

 

[VMALLOWS]

Re: post by 'yachtbits'

Sorry, can't agree with your 13.8v 'ideal charge voltage'. I agree it's the ideal long term 'float voltage'. You must either do a lot of motoring or have a shore connection. I get bored with having to motor back when there's a good wind just to charge the batteries.
I would suggest 14.2 - 14.4v for a sailing boat. (measured at the battery terminals).
Won't tell you what I push in sometimes.......but I do watch the amps and remember how much I took out the night before.