Are batteries the primary cause of fires on stored boats?

Doc

Liquid Addiction
Staff member
Since new we've always stored our other boat in a local fairgrounds and one of their requirements was removing the batteries from anything stored there. They state on their paperwork that batteries are the primary cause of potential fires and they wanted to eliminate that hazard. I always removed all batteries from seasonal equipment anyway, it's just easier to maintain them in the garage as needed anyway. There is also the peace of mind that my property is probably a lot safer in their facility because of their rule so it's a win / win situation IMO.

I've always left my batteries in the boats ...well for the past 15+ years. At first I would remov and charge it in my garage, but saw no advantage to doing it that way, so started leaving them on the boat.

Many years I did not have a charger hooked up to them, I would simply charge at the begining of the boating season. Most times this worked fine, but I did loose a battery or two in the process.

Now I have a new built in charger on my Baja, it has the smart diodes like the battery tender product so that it does not overcharge the battery but keeps the battery at it's peak charge.

My houseboat has an older charger and I did not even have it plugged in until this past Thursday. I plugged it into a timer so that the charger is on 5 hours a day. I did this in hopes of not overcharging but still keeping the batteries charged.

What do I need to watch out for to ensure I do not create a fire hazzard by leaving my batteries on my boat?
 

Bamby

New member
Doc,
The possibilities are almost endless when it comes to batteries and even chargers on boats. Many folks have fooled around with the wiring on their boats but many may unfortunately may have actually failed to adequately protect the wires. Their is an enormous amount of power stored in a battery just looking for a way to escape. Have you ever made the stupid mistake of carelessly letting a winch short out on a hot circuit, it will burn your hand almost instantly.

Now suppose a rat, mouse or other rodent were to start chewing on your wires. If the wire is hot and someone failed to protect it at the source with a fuse if it finds ground it will instantly start smoldering and become red hot back to the battery. If you're lucky the wiring just burns up, but should something easy flammable is against it (mouse nest, or rag for instance) the red hot wire can or will light it right up. There's a lot of well meaning people who work on their boats who may have unknowingly made their own firetrap. I hope yours ain't one of them but what about the boat parked next to yours in the yard?

I googled up batteries / shorts and boat fires and hopefully the results will come up on the link here: http://www.google.com/search?hl=en&...orts+and+boat+fires&btnG=Search&aq=f&aqi=&oq=
 

Doc

Liquid Addiction
Staff member
Good link Bamby. I found this info there:


ELECTRICAL FIRES
Boat insurance claims are a great way to understand what is going wrong on boats.
Whether it is your lovely new Bay Liner, Beneteau or a Sea Ray, Triton boat or Lund boat the same requirement for looking after your electrical systems apply.
Often after buying your used boat you need to survey and assess your systems. It makes good sense, it is good insurance.
Studying the causes of boat-insurance claims is a good way of preventing the causes occurring. This is something boat insurance companies do all the time. A report has recently been released based on a study by BoatUS and published in Seaworthy Magazine, which is the only damage avoidance magazine for boat owners and the marine and boat-insurance industry in the US. The causes of boat fires originating on board boats is summarized as follows and are based on fire related boat insurance claims:
55% AC and DC wiring and appliances
24% Engine and transmission overheating
8% Fuel leaks
7% Miscellaneous
5% Unknown
1% Stoves
55% AC and DC Wiring and Appliances

This result is a large number, and not unexpected and I will discuss the electrical breakdowns related to this value. Many who have purchased my books and attended the various lectures and seminars understand my own electrical safety based approach. I am for good boat-insurance by planning and installing your systems correctly.
30% DC Shorts and Wiring

The most common cause of boat-insurance related electrical fires is directly related to wiring and connection faults. The word "short" needs to be quantified as it is often misunderstood. Short circuits are relatively uncommon and in most cases it is because a positive and a negative cable have been inadvertently connected. This is called a "dead short circuit" and usually blows the fuse or trips the circuit breaker immediately. The other type of short has resistance involved between the positive and the negative or ground during a short circuit event. The best boat-insurance is to regularly check tighten all connections
Bilge Pump Wiring
Bilge pump connections, and associated float switches are commonly located in wet or damp locations. In many cases inadequate insulation and the binding or wrapping of the connections together leads to tracking and short circuits. This often results in excess current and heat causing fires. In cases of malfunctioning float switches the connections are also submerged in rising bilge water causing short circuits. This is also good boat-insurance because if the bilge pump doesn't work your boat is unseaworthy.
Wire Chafe
Where wires touch, or transit over or through conductive metallic materials they frequently move, and this movement chafes through insulation. A short circuit condition occurs when the metallic materials such as an engine, stainless tubing etc create a short circuit between the exposed conductors. Avoid a boat insurance claim by doing regular visual inspections.
Wire Connections
The most common cause of circuit failures are attributable to connections. They may simply fail open circuit and prevent power reaching equipment. In many cases as connections loosen, a higher resistance condition is created. This causes voltage drops and the generation of heat, often causing fires. It also may cause short circuiting to adjacent circuit connections.
12% DC Engine Regulators
This number initially caused some concern, however after consulting with the author of the report I am advised that these were due to regulators catching fire within outboard engines exceeding 100 hp. I have personally not heard of boats with diesel engine installations having regulator caused fires. However, I must tell you that fast charge regulators do create many fire and overheating hazards in the connected or peripheral systems. These are summarized as follows and readers should use caution and observe these when installing and commissioning regulators. The main causes that I have identified you will never see in any caution notices within the installation documentation. I have installed many hundreds of fast charge regulators over the years and this is a summary of situations that I have experienced and that do frequently occur:

Alternator Overheating.
In most cases an overheated alternator simply has a winding failure or a rectifier failure. The alternator then ceases to produce heat as it is no longer generating power. This is often caused by an alternator charging into a relatively large and discharged battery bank for a long time period.
Connection Overheating
In many alternators, the output cable connection is often under-rated for maximum output current. In many cases the original alternator is replaced by a higher output alternator without up-rating the cable or connections. You can check your own by simply placing finger on the main output terminal. You may find it is hot, possibly even too hot to touch, if it is you need to look at up-rating.
Cable Overheating
In many alternators, the output cable is often under-rated for maximum output current. When this is coupled with an engine negative return path to the battery with voltage drops across the various mechanical connection points, problems occur. The maximum current values passing through the under-rated cables cause overheating and the insulation catches fire.
Battery Overheating
Batteries in poor condition and in a relatively discharged condition often get hot under high current charging conditions. Often the greater risk is the generation of hydrogen gas.
Pulley and Belt Overheating
The increased load on single pulley alternators often causes overheating. It is not a cause of fire however the heat travels along the alternator shaft, overheats the bearings and the grease melts out, and the bearing fails. Also the belt may stretch with greater slip and eventually fail.



4% AC Appliance Heaters

These fires are not really electrical and are caused by fan or radiator element type heaters located close to timber or other combustible materials. The heat causes the materials to smolder and catch fire.


4% Shore Power

Shore power fires are almost exclusively found in the shore power plug and socket, as these are exposed to rain and spray. Condensation and salt crystals form a path between the terminals and tracking occurs. This resistive path creates heat and the tracking path starts to carbonize as it burns. Eventually it gets to a point where the current values create sufficient heat as the short circuit level rises, and a fire is caused.

2% Battery Chargers

Battery charger fires are caused by overheating. This in turn is caused by under rated chargers charging relatively large battery banks. The over temperature Klixon type temperature safety switches on rectifier bridges or transformers fail and the transformer windings subsequently overheat. The insulation reaches a point where combustion occurs and a fire occurs. In some cases the DC output cables also overheat causing a fire situation

1% AC Power Surges

I have been unable to define precise causes. A surge within a marina is capable of causing damage and a fire to any connected appliances. Surges may be caused by lightning surges or even network switching surges.
In summary most boat-insurance claims can be avoided by good systems design, and good systems maintenance. Check your systems before season start, during the season and after seasons end.



from: http://www.fishingandboats.com/boat-insurance.html


 

Bamby

New member
OVER CURRENT PROTECTION:
Each ungrounded current carrying conductor must be protected by a fuse or by a manually reset trip-free circuit breaker.
This means that the hot wire, that is the positive wire in DC systems, must be protected. The negative wire does not have to be protected. However, you can use circuit breakers that break the connection in BOTH positive and negative at the same time for even better protection. There is often confusion here. The circuit breaker or fuse is not there to protect the motor or appliance. CIRCUIT PROTECTION IS THERE TO PROTECT THE WIRE. Too much current in the wiring causes it to get hot, melt the insulation and start a fire.
If there are still any positive ground systems out there in the world, everything is then reversed from what I am saying here.
What in the world is a manually reset, trip-free circuit breaker? Obviously it is a circuit breaker, but what does the rest mean. Well, it means it can't automatically reset itself. You have to manually reset it. Trip free means you can't hold it in the on position while there is still a fault. If the circuit is going to trip the breaker, it must trip whether you are holding it place or not.
Look for the UL MARINE listing on the package.
DO NOT USE circuit breakers intended for house wiring! They are not designed for marine use and are not ignition protected.
DO protect all circuits.
The only exception is the starter motor circuit.
Location of Overcurrent Protection
The fuse or circuit breaker must be within seven inches (17.8 cm) of the source of power.
Exceptions:
Exception 1. If it is physically impractical to put the fuse or circuit breaker within seven inches of the source of the power it can be up to 40 inches (101.6 cm) away, if the wire is contained for it's entire length between the source of power and the circuit breaker, in a sheath or an enclosure.
This has been interpreted many ways. The obvious is a conduit. But who uses conduit on a boat? Maybe on really big boats. Putting a sheath such as wire loom or heat shrink wire covering over the wire works. Some even say that wrapping it in electrical tape is ok. I think that this is really a shoddy way to do it and not very professional. There are many different wire sheaths available, some that are fire resistant. Also if the wire is in an enclosure such as a panel box or electrical box then it is ok. The whole idea here is to protect the wire in such a way that if it overheats it doesn't set the boat on fire.


Since this is an important topic and needs serious consideration from anyone who's ether renovating, working on, or adding additional features to their boat that draw on electrical resources I'm going to open another thread that goes extensively into the topic.
 

Bt Doctur

Super Moderator
Staff member
My buddy had a small fire over the winter with the boat covered. All it did was singe the harness and some padding ,but it was caused by his battery operated flashlight.
I didnt believe it either till I saw it myself. I leave NO KIND OF BATTERY in a boat anymore.
 
Top