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Siting batteries - cruiser stern


Kathymel

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Good evening, 

 

I’ve started refurbishing my engine hole and part of this will involve moving my batteries from one side to the other so I can scrape and paint the side they’re currently on.

 

Their temporary (potentially permanent) home is going to be on the same side as the exhaust. Is there any legislation or are there any safety guides concerning how close batteries can be to an exhaust? 

 

The tray you can see in the photo is the footprint of all four batteries. They won’t all fit together astern of the exhaust unless I move the fuel line (which goes to the Eberspacher and moving it is on the list, but I hadn’t planned to do it just yet). I plan to split the batteries into two separate trays either side of the exhaust, but I need to know about any safety guidelines before I can do that. 

 

My BSS exam is next month, so no cutting corners for me. 

4B183125-973D-4C41-BCB0-C213C7C06EFC.jpeg

F5CB66C0-DE85-4411-A7C9-2C4687257CE6.jpeg

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28 minutes ago, Kathymel said:

Because he’s not due for a month and I thought someone on here might know. 

 

No-one here knows what your BSS bod's opinion is gonna be.

 

Stuff like this boils down to opinion. Unless Alan De E can come up with a defined min distance from a batt to an exhaust!

 

 

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I’m not asking people to guess what my BSS inspector’s opinion is going to be - until I get a reply to my email, it’s not even a given who that will be - I’m asking if anyone on here has an opinion. 

 

It’s fine if you don’t have one but, if you don’t mind, I’ll wait to see if other people have anything to say on the matter. 

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1 hour ago, Kathymel said:

Is there any legislation or are there any safety guides concerning how close batteries can be to an exhaust? 

If they’re ‘very’ close then the BSS inspector could argue that they’ll be in danger of melting. Besides that, excessive heat is damaging to any battery. 
 

So no, there’s no specific rule, just common sense and your inspector’s opinion of such. I agree with asking the inspector’s advice in advance. Email him the same photo as you posted here and ask him for his opinion. 

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6 minutes ago, Kathymel said:

It’s fine if you don’t have one but, if you don’t mind, I’ll wait to see if other people have anything to say on the matter.

 

I do have an opinion actually, but my opinion is not what gets your boat passed or failed, so it is on no value. 

 

 

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4 minutes ago, Kathymel said:

I’m not asking people to guess what my BSS inspector’s opinion is going to be

Unfortunately whilst there are published requirements to achieve the BSS the implementation and interpretation of those 'guide lines' is very inconsistent, and each examiner will have different ideas on what the rules require and how he applies them.

 

Decide on your examiner and then ask him.

If you ask one examiner and do as he suggests then actually employ another examiner, it is a fair-bet that what you have done will not be accepted.

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7 minutes ago, Alan de Enfield said:

Unfortunately whilst there are published requirements to achieve the BSS the implementation and interpretation of those 'guide lines' is very inconsistent, and each examiner will have different ideas on what the rules require and how he applies them.

 

Decide on your examiner and then ask him.

If you ask one examiner and do as he suggests then actually employ another examiner, it is a fair-bet that what you have done will not be accepted.

Thanks Alan,

 

When I get a response, I’ll ask them. It’s interesting that there is no hard and fast rule though. I might have to do some temperature tests. 

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11 minutes ago, Alan de Enfield said:

Unfortunately whilst there are published requirements to achieve the BSS the implementation and interpretation of those 'guide lines' is very inconsistent, and each examiner will have different ideas on what the rules require and how he applies them.

 

Decide on your examiner and then ask him.

If you ask one examiner and do as he suggests then actually employ another examiner, it is a fair-bet that what you have done will not be accepted.

Yup. 3.1.1 states “Advice for owners – batteries should be located away from heat sources.”  
 

How an individual inspector interprets that will differ from one inspector to another. 

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I wouldn't have the batteries in the engine compartment at all, a horrid place especially on the swim tops, very awkward. I'd put them indoors, under the back step or something and away from all that engine and sun heat, this makes them easy to check and service and leaves more room around the engine to work on it. Mine are under my bed which is a cross bed which folds up in half and there are my batteries all lovely to get at.

Edited by bizzard
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1 minute ago, bizzard said:

I wouldn't have the batteries in the engine compartment at all, a horrid place especially on the swim tops, very awkward. I'd put them indoors, under the back step or something and away from all that engine and sun heat, this makes them easy to check and service and leaves more room around the engine to work on it. Mine are under my bed which is a cross bed which folds up in half and there are my batteries all lovely to get at.

Thanks Bizzard. That’s not a bad idea at all. It never occurred to me to bring them indoors. One of the reasons I’m changing the layout is the unnecessary length of cables in the current set-up. Putting them under the step would make a huge difference to that. 

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6 minutes ago, Kathymel said:

Thanks Bizzard. That’s not a bad idea at all. It never occurred to me to bring them indoors. One of the reasons I’m changing the layout is the unnecessary length of cables in the current set-up. Putting them under the step would make a huge difference to that. 

Surely under the back steps can't be very much further away from the engine than where they are at the moment. Many older cars and trucks have  batteries a long way from the engine.. Old Jaguars, Rover's, Mini's ect in the boot. Not to mention aeroplanes.

Edited by bizzard
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Well ok, maybe not a huge difference to where I was thinking of putting them, but the way the wiring is now, putting them inside would get rid of about 3 meters. Some of that wiring is way too thin and needs replacing, so every little helps. 

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46 minutes ago, WotEver said:

If they’re ‘very’ close then the BSS inspector could argue that they’ll be in danger of melting. Besides that, excessive heat is damaging to any battery. 
 

So no, there’s no specific rule, just common sense and your inspector’s opinion of such. I agree with asking the inspector’s advice in advance. Email him the same photo as you posted here and ask him for his opinion. 

I go along with that, I wouldn't want my batteries to close to the exhaust so they got hot, it will do nothing good for your batteries.

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27 minutes ago, Kathymel said:

Thanks Bizzard. That’s not a bad idea at all. It never occurred to me to bring them indoors. One of the reasons I’m changing the layout is the unnecessary length of cables in the current set-up. Putting them under the step would make a huge difference to that. 

Just remember that if you bring them 'in-doors' that you will have to put in ventilation that leads directly out of the cabin and thru the hull.

If you are putting them under the steps, under the bed, or in a  cupboard then that is not a ventilated space.

 

If you are using 'sealed' batteries then be prepared to provide documentation from the battery manufacturer that they are happy with you keeping the batteries 'inside the boat'

 

BSS Requirements :

 

All unsealed or open‐vented batteries must
be stored within a ventilated space.
Dedicated battery spaces or boxes for
unsealed or open‐vented batteries must
be ventilated at the top or the highest
point of the sides of the space or box
and any ductwork used must run
horizontally or upwards.
The ventilation pathway from all battery
storage locations must lead to the
outside of the hull or superstructure.

 

NOTE ‐ if batteries of a ‘sealed’ type are stored in a non‐ventilated space verify that storage in
unventilated spaces meets with the battery manufacturer’s recommendations by reference to presented
documentation from the manufacturer.

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26 minutes ago, Alan de Enfield said:

Just remember that if you bring them 'in-doors' that you will have to put in ventilation that leads directly out of the cabin and thru the hull.

If you are putting them under the steps, under the bed, or in a  cupboard then that is not a ventilated space.

 

If you are using 'sealed' batteries then be prepared to provide documentation from the battery manufacturer that they are happy with you keeping the batteries 'inside the boat'

 

BSS Requirements :

 

All unsealed or open‐vented batteries must
be stored within a ventilated space.
Dedicated battery spaces or boxes for
unsealed or open‐vented batteries must
be ventilated at the top or the highest
point of the sides of the space or box
and any ductwork used must run
horizontally or upwards.
The ventilation pathway from all battery
storage locations must lead to the
outside of the hull or superstructure.

 

NOTE ‐ if batteries of a ‘sealed’ type are stored in a non‐ventilated space verify that storage in
unventilated spaces meets with the battery manufacturer’s recommendations by reference to presented
documentation from the manufacturer.

 

But the BSS also says:

NOTE - Ventilation pathways into accommodation spaces having fixed high-level ventilation or into canopied areas are also acceptable.

 

So you don't necessarily need a dedicated battery vent duct system direct to the exterior. Provided your under step or under bed battery location is vented at its highest point into the accommodation space and you have fixed high level ventilation (which is otherwise only an advisory matter) then you will be BSS compliant.

 

Edited by David Mack
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For batteries in a box in the cabin the bss requires -

 “Dedicated battery spaces or boxes for unsealed or open‐vented batteries must be ventilated at the top or the highest point of the sides of the space or box and any ductwork used must run horizontally or upwards.”
 

So your battery box in the cabin needs ventilation holes at the top, now you can duct from the hole to the outside of the craft or use the requirement in the guidance note “ventilation pathways into accommodation spaces having fixed high‐level ventilation or into canopied areas are acceptable.”  In which case a mushroom vent in the roof within the same accommodation space should be acceptable.

 

Hydrogen gas is what needs removing from the boat, and being much lighter than air naturally rise and flows along the roof to a mushroom so long as there are no barriers creating high level pockets.

 

added - I need to learn to type faster........

Edited by Chewbacka
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The whole idea of re-siting the batteries from their current position seems rather unnecessary to me if the main objective was simply to repaint the uxter plate/counter. Why not just reposition them temporally until the job is done? I did see your post about trying to reduce cable lengths but wasn't sure if moving to the exhaust side achieved this.

Edited by blackrose
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7 hours ago, David Mack said:

 

But the BSS also says:

NOTE - Ventilation pathways into accommodation spaces having fixed high-level ventilation or into canopied areas are also acceptable.

 

So you don't necessarily need a dedicated battery vent duct system direct to the exterior. Provided your under step or under bed battery location is vented at its highest point into the accommodation space and you have fixed high level ventilation (which is otherwise only an advisory matter) then you will be BSS compliant.

 

Indeed - but - as you correctly state you will need to drill big enough vent holes in the bed base / steps (obviously no mattress on top of the vent holes)  to comply with the requirements.

 

Advice for owners – in the event that no ventilation provision is identified for unsealed or open‐vented
batteries this may be calculated using the following formula. Ventilation (mm2) = number of cells x capacity
in Ah x 1.935. Supplementary guidance is given at Appendix G.

 

Appendix G states that you will need 3x 25mm diameter holes for each 100Ah battery 

 

7 hours ago, David Mack said:

Provided your under step or under bed battery location is vented at its highest point into the accommodation space and you have fixed high level ventilation (which is otherwise only an advisory matter) then you will be BSS compliant.

It is 'strange' that the battery 'box' vents sizes are specifically dictated and are a mandatory requirement of the BSS (Pass / Fail), but having high level ventilation of a sufficient size in the 'accommodation area' is only 'advisory'  

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24 minutes ago, Alan de Enfield said:

Indeed - but - as you correctly state you will need to drill big enough vent holes in the bed base / steps (obviously no mattress on top of the vent holes)  to comply with the requirements.

 

Advice for owners – in the event that no ventilation provision is identified for unsealed or open‐vented
batteries this may be calculated using the following formula. Ventilation (mm2) = number of cells x capacity
in Ah x 1.935. Supplementary guidance is given at Appendix G.

 

Appendix G states that you will need 3x 25mm diameter holes for each 100Ah battery 

 

It is 'strange' that the battery 'box' vents sizes are specifically dictated and are a mandatory requirement of the BSS (Pass / Fail), but having high level ventilation of a sufficient size in the 'accommodation area' is only 'advisory'  

But not advisory for that accommodation space if that is the high level vent for the battery box, though the calculation for total craft high level ventilation remains advisory.

 

added - though Interestingly the minimum size of the high level vent is not specified.  Just another example of the poor proof reading of the BSS before issue.

Edited by Chewbacka
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7 minutes ago, Chewbacka said:

added - though Interestingly the minimum size of the high level vent is not specified.  Just another example of the poor proof reading of the BSS before issue.

That was my point.

 

I'm not sure that it is poor proof reading that is at fault, just a lack of 'joined up thinking'.

 

When new requirements are added there appears to be no looking to see how they interface, support or contradict other requirements.

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