Venting Battery Compartment

[Scott T-Bird]

I have always found their customer service nonexistent. If you have a telephone number that someone answers for service please let me know.

That's a good question, but since our boats are over 20 years old, the previous owner made modifications, and I have a whole bunch of modifications that I am making personally, I don't ever think that customer service is really going to be of much help at this point. I just do my own thing.

You seem to be focusing a lot of attention on ventilation. Considering all the open spaces within the boat, I have never considered ventilation as a primary concern, except when it comes to venting the tanks. All the open air within the boat seems suitable to me. It's always worth making improvements where you have concerns. I tend to not worry very much about what the boat manufacturer did and simply focus on the modifications that I want to do and then go about figuring out how to make them work in the space provided.

 

[dlochner]

That's a good question, but since our boats are over 20 years old, the previous owner made modifications, and I have a whole bunch of modifications that I am making personally, I don't ever think that customer service is really going to be of much help at this point. I just do my own thing.

You seem to be focusing a lot of attention on ventilation. Considering all the open spaces within the boat, I have never considered ventilation as a primary concern, except when it comes to venting the tanks. All the open air within the boat seems suitable to me. It's always worth making improvements where you have concerns. I tend to not worry very much about what the boat manufacturer did and simply focus on the modifications that I want to do and then go about figuring out how to make them work in the space provided.

As Scott suggests, there are bigger things to worry about than an explosion from hydrogen.

 

[FastOlson]

I have always found their customer service nonexistent. If you have a telephone number that someone answers for service please let me know.

OooooKay! (apologies to the late Richard Moll.)

Next, have you joined and actively participated in your owners' internet group?

https://www.catalinayachts.com/catalina-associations/

 

[Tally Ho]

My good old O’Day 322 (1988) has the batteries (2 6-V GC batteries) under the salon settee. It does have a small round vent in the settee. I have never had a problem using or concern with outgassing and collecting hydrogen.

Yes - I am more concerned with potential propane leaks.

Greg

 

[JMR]

When I redesigned the battery system on my S2 9.2c I added a vent on the front of the box the batteries sit in, and added a standard computer fun to vent through a bulkhead into a vented engine compartment. The computer fan is several feet away from the engine and closer to the outside vent. Is that enough? No idea. I do have a modern Sterling multi-stage charger, so that should help too.

 

[Tom J]

I'd think you'd want an explosion proof fan in that application. I'd also think the multi stage charger would keep any off gassing to a minimum.

 

[dlochner]

When I redesigned the battery system on my S2 9.2c I added a vent on the front of the box the batteries sit in, and added a standard computer fun to vent through a bulkhead into a vented engine compartment. The computer fan is several feet away from the engine and closer to the outside vent. Is that enough? No idea. I do have a modern Sterling multi-stage charger, so that should help too.

That is more than enough and the fan probably isn't necessary.

The amount of hydrogen off gassing is related to the charging voltage. A programmable charger like the Sterling will keep the voltage low enough that a lot of off gassing won't occur and the off gassing that does occur will happen slowly allowing for plenty of time for the gas to dissipate. Old ferroresonant chargers, the big heavy ones, are the main culprits in causing rapid off gassing.

If you still have the old red and white battery boxes, it would be helpful to drill hole in the center of the top to facilitate the evacuation of any hydrogen that forms. Newer battery boxes have a vent in the top.

 

[JamesG161]

The amount of hydrogen off gassing is related to the charging voltage.

No !

It is related to the Amperage. No Amps, no Hydrogen Gas.

Jim...

PS: Look here for Reference

Sailboat Owner's Guide to Corrosion

 

[Davidasailor26]

No !

It is related to the Amperage. No Amps, no Hydrogen Gas.

Jim...

PS: Look here for Reference

Sailboat Owner's Guide to Corrosion

But if the voltage isn’t exceedingly high the battery’s own resistance will keep amperage within limits. You could have a 100 amp smart charger; as long as it stays within the absorb and float voltage specs of the battery the amperage won’t be excessive.

 

[JamesG161]

battery’s own resistance will keep amperage within limits

Not on a Dead Battery.

Jim....

 

[dlochner]

No !

It is related to the Amperage. No Amps, no Hydrogen Gas.

Jim...

PS: Look here for Reference

Sailboat Owner's Guide to Corrosion

Actually it's both. The chargers that aren't voltage controlled will try to push as many amps as possible into the battery as the internal resistance increases the voltage will rise to overcome the resistance. It is the power of the voltage that breaks the H-O bond.

A smart charger will limit the max voltage and allow the amperage to decrease as the internal resistance of the battery increases. This reduces the off gassing.

 

[JamesG161]

Actually it's both.

Nope!

Voltage is the Pushing power. [Volts = Pressure]

Amperage is the Flow. [Amps = Gallons per Minute]

A Dead Battery has no AMP flow.

Safety First...

Chemical Engineer Jim....

 

[dlochner]

Nope!

Voltage is the Pushing power. [Volts = Pressure]

Amperage is the Flow. [Amps = Gallons per Minute]

A Dead Battery has no AMP flow.

Safety First...

Chemical Engineer Jim....

Nobody said we're talking about a dead battery. The conversation was about charging a battery, creating H gas and the necessity of venting the battery compartment. The thread drifted a bit to what causes the gassing and how can it be controlled. To reduce H off gassing it a voltage controlled charger is necessary.

 

[Davidasailor26]

Nope!

Voltage is the Pushing power. [Volts = Pressure]

Amperage is the Flow. [Amps = Gallons per Minute]

A Dead Battery has no AMP flow.

Safety First...

Chemical Engineer Jim....

Interesting point about failure modes though. A dying battery that’s shorted internally could consume an excessive amount of current and heat up. I don’t know if the amount of current would be enough to cause enough electrolysis for significant H2 production though. Similarly with a deeply discharged battery - the current flow will initially be pretty high until the battery’s resistance increases.

In any case you don’t often (ever?) hear of boats blowing up from excess hydrogen gas. It sets off some propane or CO sensors but I think that’s more about cross-sensitivity of the sensors than actual danger levels. It’s very far down my list of concerns and demands little risk mitigation.

 

[pgandw]

Interesting point about failure modes though. A dying battery that’s shorted internally could consume an excessive amount of current and heat up. I don’t know if the amount of current would be enough to cause enough electrolysis for significant H2 production though. Similarly with a deeply discharged battery - the current flow will initially be pretty high until the battery’s resistance increases.

A lead-acid battery with a shorted cell hooked up to a fully charged battery in parallel WILL generate enough H2 for combustion, but not for explosion. Don't ask me how I know this. H2 makes the prettiest blue flame you can imagine. The parallel cables (#6 cables) running across the top of the battery melted their insulation, and turned cherry red due to the current, igniting the off-gassing H2. Putting the fire out just took cutting the parallel cables.

If you are going to parallel batteries, put a fuse in the parallel cables, as small as you can tolerate.