Venting the battery storage area

[raptor]

I am the new owner of a 2005 43DS and one of the required "fixes" from the survey was to vent the battery storage under the aft bed. I am not sure why this wasn't already done since it would be an obvious safety requirement (even a sealed battery needs some ventilation - but the previous owner put in regular lead-acid batteries - so even more of a need).


If anyone has thoughts I would appreciate hearing - pics are even better. 


Thanks!

Aaron 

[Charlie-Bravo]

I feel that my battery compartments are not sealed, and can 'breath' to the engine bay.
Did the surveyor suggest a venting route? .... I have not come across a boat battery vent on boats I have seen, nor has it been mentioned on surveys I had carried out, ..... so either my surveyors were not as thorough, or yours couldn't find many faults to write about , but had to find something to justify the fee.

I haven't really thought about it too much, but reading your thread has prompted some thoughts, my battery boxes are acid proof as in a battery leak, but open from the top, hydrogen I think is given off in venting lead acid batteries .... lighter than air, so , you would need a sealed battery box and a tube out the top to control the passage of gas. The amount of gas is pretty small unless you are boiling the batteries, I would question the surveyor, after all, you are paying for this information, I don't see it as a great threat, through hulls worry me more.

CB

[zaphod]

My battery compartment is neither water tight nor sealed. There are openings into the engine bay as well as into adjacent compartments.

I think Jeanneau designed the boats to be equipped with AGM batteries, which do not vent any significant amount during normal charge cycles, and they do not leak so do not require watertight enclosures.

The previous owner of my boat replaced the original AGMs with cheap flooded lead acid batteries, and the engine battery did leak acid, and the damage to the plywood battery box is still apparent. Flooded lead acid batteries do off-gas as part of their normal charging cycle, which is why they need to be topped up with water as part of their regular maintenance.

I understand that FLA batteries are much cheaper than AGM, and that is why people buy them, but "downgrading" batteries has other consequences such as the need for wather tight battery boxes and better ventilation.

Rather than worrying about adding battery box ventilation, you may want to consider changing back to AGM batteries. They may be more expensive but they are safer and easier to maintain than FLA.

[puravida35]

I’ve purchased 2 new Jeanneau boats (2005, 2016), neither came with AGM batteries, both came from factory with FLA batteries. There is perhaps an option to order a boat with AGM batteries, but in my experience, the stock equipment is FLA. On my 2016, the batteries were vented FLA but labeled as “low maintenance”, which meant you could not add water. Those have been replaced with AGM’s.

[zaphod]

Mar 31, 2021 23:05:59 GMT puravida35 said:

I’ve purchased 2 new Jeanneau boats (2005, 2016), neither came with AGM batteries, both came from factory with FLA batteries. There is perhaps an option to order a boat with AGM batteries, but in my experience, the stock equipment is FLA. On my 2016, the batteries were vented FLA but labeled as “low maintenance”, which meant you could not add water. Those have been replaced with AGM’s.

Interesting, my broker told me AGM was standard on my boat.

[bereboot]

On my fathers boat (nautor swan), the sealed battery box had a vent pipe attached to the bottom of the mast.

[Tafika II]

Our 2008 SO42DS has not installed venting. The standard batteries that were specified on the boat were wet cells. We had the wet cell batteries deleted from the order and replaced with AGMs, that lasted about 7 years. We had a Catalina 320 with wet cell batteries and we added venting. With AGM's I don't see vents as necessary.
Is your survey for insurance or just the surveyor's recommendations? If insurance, they may demand you add vents, but is only a recommendation, that's your call!

[raptor]

Thanks to everyone for the feedback. The last owner had put in FLA's - and though I am not sure what was there earlier, I expect they were AGMs. I decided to upgrade to 2xAGMs for the house, and hope there is not too much hydrogen venting from the "sealed" FLA that's the starter battery.  I believe that vents less than a traditional FLA and doesn't require checking the water levels. 

But I have also decided that when I upgrade the power with Solar, I am going to look seriously at Lithium Iron Phosphate LiFePO4 batteries. The big advantage being you can draw them all the way down, so the AH ratings are really double of an equivalent FLA or AGM (which can only be drawn down 50%). If I am missing something here, please let me know. 

[zaphod]

Apr 12, 2021 12:12:20 GMT raptor said:

Thanks to everyone for the feedback. The last owner had put in FLA's - and though I am not sure what was there earlier, I expect they were AGMs. I decided to upgrade to 2xAGMs for the house, and hope there is not too much hydrogen venting from the "sealed" FLA that's the starter battery.  I believe that vents less than a traditional FLA and doesn't require checking the water levels. 

But I have also decided that when I upgrade the power with Solar, I am going to look seriously at Lithium Iron Phosphate LiFePO4 batteries. The big advantage being you can draw them all the way down, so the AH ratings are really double of an equivalent FLA or AGM (which can only be drawn down 50%). If I am missing something here, please let me know. 

You can also consider Firefly Carbon Foam AGMs. They are still a lead-acid chemistry, but you can draw them down below 30% and they can be kept at partial charge without doing any permanent damage. They don't sulfate like regular AGMs do. They are more expensive than conventional AGMs, but not as expensive as Lithium, and won't require a full system upgrade.

[andreshs1]

Hi there

I am also starting to look at LiFePo4 batteries, the cost is not that big if you look directly at manufacturers in Alibaba.com

I was looking at these until the aircon decided to break just as the summer is near...... :

EVE 3.2V 280AH Grade A Lifepo4 Battery Cells Fully Matched 

560AH will work out around 900USD, then you need 200~300USD for BMS, new battery charger and DC to DC modulator for the alternator

But the improvement on space, weight and longevity is exponential

Cheers