Flooded battery gassing...

[NYSail]

hello all
How much should one worry about a flooded battery gassing? Currently have 4d agm and want to go to 6volt. Big cost difference with flooded and agm and was just wondering if I am over worried. House battery bank is in engine compartment.

Thanks

Greg

 

[dlochner]

Greg, if you are concerned about the hydrogen gas, it is not a big issue if the battery box is ventilated. The gas forms slowly and dissipates quickly so it would be hard pressed to get to an explosive level. However, if the battery box is air tight, then it might become a low probability issue, but not one that would sink the boat. Take a look at this video: done by a chemistry professor who likes to blow things up.

On the other hand, there can be a small issue with hydrogen sulfide gas, but that is not going to explode, just corrode stuff. So don't locate the batteries under the fuel tank or other reactive metal. Ventilation is the key.

Sometime ago, @thinwater calculated the amount of hydrogen that is in a battery, turns out to be not all that much especially when the time it takes to break down the water molecules. If you have a good charger and follow the charging routine any risk should be well mitigated.

Now a poorly installed lithium battery bank is a different matter...

 

[markwesti]

I'm sure you have ventilation in the compartment , so I don't see a problem . Back in the old days when marine battery chargers were not what they are today , they could over charge to the point where you could smell the gas . That actually happened on my dads Grand Banks . We have always had FLA batts. on our boat with no problems with gassing . About 2yrs. ago I switched over to two Trojan T105 6V batts . with no problems . Our boat has no problem with engine room ventilation , but I'm in there all the time checking on things . Only one time have I seen a problem with a battery gassing to the point of doing damage , the battery was in a ridiculously small boxed in area with no ventilation and there was a lot of stuff in there and the battery was being charged with a car type charger .

 

[seadaddler]

I changed from 2-4D’s to 4-6 volt batteries and the 2- 4D’s were in my port cockpit with my Gen
and my boat was tilted to port so I put the 4-6 volt batteries under my main cabin salon back in 2010 and no problems with any gaming or any smell.
I did put them in heavy plastic battery boxes with covers and strapped them down and did this after another boater with my same boat.
Nick

 

[Bob J.]

If you're charging your batteries & it doesn't smell like someones catalytic converter passing you on the highway, you're not doing it right

 

[Gunni]

The problem is the acid spatter, not the gas, the engine bay is ventilated. Flooded batts will have to be boxed. Do you have room for them? Even then you will be cleaning corrosion. I had a FLA 4d in my engine bay and it made a mess. acid etching everywhere, rust on nearby metals. ...Gone.

 

[Charlie Jones s/v Tehani]

Well, I've had a flooded cell under the Vee berth on my 21 for many years, and in the deep bilge under the galley since 2004. Neveer had a problem with either one

 

[Maine Sail]

The problem is the acid spatter, not the gas, the engine bay is ventilated. Flooded batts will have to be boxed. Do you have room for them? Even then you will be cleaning corrosion. I had a FLA 4d in my engine bay and it made a mess. acid etching everywhere, rust on nearby metals. ...Gone.

No flooded battery should be "spattering", the design of the caps should prevent this. I see plenty of rusty engines with no batteries in the engine bay at all.... There are literally millions of flooded batteries on boats. AGM & GEL still represent a small part of the marine market.

 

[Bob S]

Is there room where the inverter is/was? When I bought my boat it had 3 4D's in the port lazerette. and a FLA in front of the engine. I replaced the 4D's with 6 6V and the start with an AGM. Like Gunni, I'm more worried about corrosion. The lazerette is quite huge so venting gas should be alright.

 

[NYSail]

I am going to do some measurements this weekend as I am going to disconnect and remove the inverter. It would be a great place for a battery bank..... just aft of engine

Greg

 

[Gunni]

The further you move weight out from the keel (left/right/fore/aft) on these Beneteaus the more problems you create with the boat coming off her lines and affecting the sailing characteristics. You can start counter-balancing with weight elsewhere but you end up making the boat heavy.

If you can fit 4 Lifeline 31XT in the space where you had those 2 4D you can pick up an additional 80Ah. The 31XT is about 3/4” taller.

 

[NYSail]

This area is just aft of engine on centerline of boat....... it would be a great place. In regards to counter balancing, my son is an elevator mechanic and has scored me about 400 lbs of weights...... also removing an Onan generator 375 lbs in my aft starboard cockpit locker. Boat will probably sit nicer....

Greg

 

[seadaddler]

My FP Gen is in my port locker in my cockpit and had 2-4D’s in with the Gen and the dealer added 400 lbs of lead on starboard side to balance out the hull.
I removed the 400lbs and did away with the 4-D’s and put 4-6 volt T-105’s on starboard salon
Table cushions and my wife with a super smelling never has problem and they don’t make any mess or corrosion in plastic battery boxes.
Nick

 

[NYSail]

My FP Gen is in my port locker in my cockpit and had 2-4D’s in with the Gen and the dealer added 400 lbs of lead on starboard side to balance out the hull.
I removed the 400lbs and did away with the 4-D’s and put 4-6 volt T-105’s on starboard salon
Table cushions and my wife with a super smelling never has problem and they don’t make any mess or corrosion in plastic battery boxes.
Nick

How far away is house bank from alt??

Greg