Rick writes in with a really good question about his batteries and Prosine 2.0 Inverter charger. I'm going to share this one because I'll bet many of you have similar questions/concerns.

Prosine 2.0 Inverter charger is shown in the center-upper unit with yellow trim.

 Ed--"I have a Xantrex prosine 2000 watt inverter/charger. I have been using the inverter but am just getting to hooking up the charger. I recently purchased new agm batteries, 2 grp 31 for eng start and bowthruster and 2 8D for house batteries and inverting. Each 8D is rated at 225 amp hr. My current charger is only capable of an initial 40 amp charge, ramping down as it goes. running an 8K generator requires many hours to fully recharge the 8D's. With the Xantex charger I believe is capable of throwing out 100 amps to the batteries. The batteries are west marine (DEKA). Can the AGM's handle that rate of charge? I have been told they will but dont want to over charge them if this is not correct. I may or may not connect the grp 31's to this charger, mainly I need the faster charge for the house batteries as to not run the generator for such long periods."  Rick

First, let me answer Rink's question about the ability of his new AGM type batteries to accept a high rate of charge. Yes they can! One thing we have learned over the last ten or so years is that AGM batteries, of all the battery chemistries we typically find in marine applications have the highest "acceptance rate". We have learned over time that these batteries can take a really fast charge compared to their traditional flooded or gel cell cousins without any cause for concern.

Its important for everyone to understand that by connecting any battery to a high output charger is really not an issue. The battery is self limiting for the most part when it comes to current. In other words, a given battery is only going to accept X charge rate based on such factors as it's own internal resistance and chemical make-up. An AGM type battery has an acceptance rate somewhere on the order of 35-40% of it's amp-hour capacity rating. This compare to as little as 25% for a traditional wet cell tech battery. What this all means is that you can have a 200 amp rated charger connected to a small battery but it just doesn't matter, the battery is only going to accept the charge at it's personal acceptance rate, and indeed it will vary from one battery to another.

So, no wories on that count. Your Prosine will do just fine with this selection of batteries. Follow the detailed instructions that came with the Prosine because it has a very sophisticated multi-phase re-charge capability that is completely programmable to meet the specific requirements of your batteries.

I spent a bit of time over the past weekend looking over some of the many photos I take whenever I serve as a Boat Of The Year judge for Cruising World Magazine. Sometimes I wonder why I take the hundreds of photos I always manage to shoot during our boat inspections. Primarily the photos I take are to either illustrate really good and innovative things I see being done with on board systems installations; or, sometimes the photos are to illustrate things that absolutely drive me crazy when I consider either the engineering or workmanship side of things.

 Anyhow, the photo below is one from the "It Makes Me Crazy" collection. What you are seeing is a collection of hoses and a wiring loom routed behind some cabinetry. I can't remember who's boat this was taken on, but the careful attention to detail this builder exhibited I'm certain did not get them into the winner's circle among the boats we tested and inspected that particular year. Check it out:

If you look carefully you'll notice the red and black hoses as they travel downward through the molded in opening in the lower center of the picture. If you look carefully you will see a bunch of brownish "fuzz" along the top edge of the cutout. What you are looking at are razor sharp fiberglass strands that are resinated and quite stiff, rubbing directly against the hoses. This view not only looks a bit messy, it is a spot where chafe on the hoses will occur over not too much time. Its a workmanship issue. Really sloppy workmanship. I don't know what runs through those hoses, and don't really care either. All I do know is that the hoses will fail long before their normal life expectency is reached because of chafe against this really sharp fiberglass edge.

So boat builders, please, take the extra 60 seconds you might need to trim and fair this edge so you don't send me to the crazy house! Much appreciated.

Basic Lightning Protection System as per ABYC TE-4

One of our readers wrote in last week with a question about lightning for his sailboat. What really caught my attention was that he is also converting the propulsion system from diesel to electric. Since he is (wisely) electrically isolating the electric motor from the propeller shaft and propeller, he's lost one of the potential links to ground through the bottom of the boat that a lightning protection system needs. Joe's letter follows:

Hi Ed,

I am installing an electric motor into my 1977 Orion S&S 35 sailboat. Consequently, upon removal of my diesel, there is no grounding system. The shaft of the new motor is isolated so I can't use it as ground. I have a lead keel and was considering hooking a grounding bus to a keel bolt. I was also going to do the same with the chainplates for lightning protection. The wiring diagram calls for 4/0 AWG cable. Here are my questions:
Does my ground cable need to be 4/0 AWG as well? What size Bus might I need?
What size cables are best for lightning protection?
If I am struck, doesn't that fry everything that might be tied to the same ground? Is there a way to isolate lightning from boat ground?

All of this is new to me, so please pardon the numerous questions.

Thanks,
Joe

So, let's sort through this for Joe, because this is a question I get fairly often. First of all let's consider the primary conductor shown in the diagram above. It lists 4 AWG wire as the requirement. Its important to remember here that on a boat with an aluminum spar, the mast will serve as the primary down conductor. On boats with carbon fiber spars, the ABYC does not consider the spar a suitable conductor. Obviously, a wooden mast is not good either, an actual cable needs to be routed up the spar. I'm not sure whether Joe's Orion uses a wood or aluminum spar. I'm going to assume it is aluminum. Also important to know here is whether the mast is deck or keel stepped. If it is keel stepped, all that's needed is to run a 4 AWG cable from the mast base to one of the keel bolts.

As for the chainplates, we consider those as secondary conductors within the system. Use 6 AWG wire to connect to either a bus bar or directly to a keel bolt.

If the system is not going to be connected directly to a keel bolt, a minimum 1 square foot ground plate, preferably made of solid copper stock should be mounted on the outside of the hull.

Joe's question about other items like electronic equipment that may be attached to the same ground system being vulnerable is certainly a valid concern. The short answer here is that yes, any electronic equipment connected to the system might be subject to damage after a strike. Its important to understand that the sole purpose of any LPS (lightning protection system) is to protect people from harm and hopefully prevent the boat from sinking. There are absolutely no guarantees related to equipment protection. The safest, sure bet is to disconnect the equipment from the system during a lightning event.

As for the size of the bus to use, this is always an interesting guess. The actual strength of a lighning strike is a huge variable. But, based on the historical 4 AWG, 6 AWG values for wire that TE-4 recommends, a bus bar that could be used to link secondary 6 AWG conductors might be a Blue Sea # 2104 or 2107. These are about the most heavy duty units available without getting into custom made equipment.

Joe, I hope these answer your basic questions about LPS. Hey, we'd love to see some pictures of your electric conversion project too! How about sharing? 

SAE Type B Thermal Circuit Breaker

Today's post came in as a question from one of our readers. Its a really good question, so let me share:

Ed-

I have a 30 amp Cooper Bussmam Series 25X Mid-Range circuit Breaker #25530 SAE Type B that I need to replace. The only thing I have found online or in a store similar is the 40 amp #25540. I don't know if this was an OEM part or not. It fits in a custom housing or I would use a different brand. The 40 amp is the same shape. Can I use a 40 amp in place of the 30 amp?

Rob

This is a fairly common question and its a good one because it does not have a simple yes or no answer. It may be OK to use the 40 amp breaker as long as the wire its installed in has sufficient "ampacity".

The other issue with this case is the AIC (ampere interuppting capacity) rating of the breaker. Also in some cases, depending upon whether the boat uses gasoline for fuel and where the breaker is located, whatever breaker gets used must be rated for ignition protection.  

So, let's look at the issues one at a time. First of all, the Bussman breaker Rob is referring to is rated for ignition protection, so that means it can be used anywhere on the boat without fear of it causing an explosion, always a good thing.

Since these particular breakers are usually used as main breakers in DC systems, there might be a problem with the AIC rating, which for this device is only 2500 amps. ABYC requires breakers to meet certain AIC ratings based on the size of the battery bank, or more precisely the CCA rating (cumulative) of the batteries they are connected to. the problem here is that the minimum requirement is for a 1500 amp AIC rating for a master breaker, and that is for a battery or battery bank that only has a cumulative Cold Cranking Amp rating of 650 or less. That folks is a pretty small battery. Typically a standard group 24 size, and no more. As soon as you add a second battery or move up to say a group 27 size, you are going to be past that 650 Amp CCA rating. That means, according to ABYC, that you are going to need to up your AIC rating for that first main circuit breaker to a minimum rating of 3000 amps AIC. So, Rob, not sure what you have for a battery or batteries, but this install may not be compliant for that reason.

Next, we have the matter of the nominal amp rating for the breaker. 30 amps vs. 40 amps. Ro'bs basic question is, hey Ed, any harm done by just bumping the original 30 amper up to 40 amps?

It depends on the wire in the circuit. ABYC rates the sizing of fuses and circuit breakers based on the amperage handling capabilities of the wire it is installed in. That is determined by a few factors, but the basic considerations are the wire's insulation temperature rating, and AWG size as well as whether it is routed through an engine room space or outside an engine room space. Fatter wire with a higher temperature rating for the insulation can theoretically handle more amperage, so it "ampacity" is higher.

ABYC says that the overcurrent protection rating for conductors (wire) can be no greater than 150% of the ampacity of the conductor that it serves..

So, Rob to answer your question, with all of this taken into consideration looking over the tables in ABYC tells me that if the wire that breaker is installed in is 10 AWG or bigger, and it is in fact 105C rated cable, there will be no harm done by switching that 30 amp breaker for a 40 amp breaker. 

BUT, keep in mind readers, you must take into consideration all of the things mentioned here to be sure. If you are unsure, go through this drill backwards and use the Blue Sea Circuit Wizard hot button calculator in Ed's Tool Box to figure it all out.

Marine shore power equipment maker Hubble Marine Electrical Products made an announcement today that will offer help for boaters heading to Europe or for those based in Europe. The announcement reflects one of my basic observations about all of us and our "appetite for amps". Hubble is expanding their offerings to include 63 amp 230V 50 cycle service shore power plugs and receptacles. Gotta help feed that appetite! The new units are shown here:

The new units feature a unique configuration that is not interchangeable with domestic/US systems, Hubbell's 63 amp offering employs standard NEMA designs.  It is intended for use with 50 cycle systems only, similar to Hubbell's non-interchangeable 16 amp and 32 amp international shore power systems.

Resembling traditional shore power style and appearance, the 63 amp, 3-wire inlet, along with its sealing threads, is available in #316 stainless steel.  Mating plug and female connector utilize rugged nickel-plated brass housings for added durability.  The weather-proof boot for the female connector utilizes a #316 stainless steel sealing ring to minimize cross-threading when mated with the inlet's stainless steel threads.

All 63 amp devices feature Hubbell's high heat-resistant thermoset interior and box-lug terminations as used in its high-quality 50 amp US offering.  Hubbell's 63 amp inlet and connector retail for under $150 a piece.

Need more info? Contact Hubbell Marine Electrical Products, 40 Waterview Dr.Shelton, CT  06484. 475-882-4838; Fax: 203-783-9195.  or go to their website at: www.hubble-wiring.com