I received a great query several days ago from one of our readers who has a very cool project in mind. He's asking some questions that should be shared.

Marshall Sanderling

Eddy writes:

Hello Ed,
I am about to pull the trigger with a mastervolt 2.5 kw on my 18' Sanderling catboat. I am also worried about runtime ie range. any updates? Looking to put 4 valence lithium Iron Magnesium phosphate 12v 138ah batteries. Any thoughts would be greatly appreciated. Thanks Eddy

The updates Eddy are referring to have to do with an article posted here last year talking about the Alerion Electric project that I got to follow through the build precess and report on. The basic story on that particular boat is that Vincent the owner ended up doubling his battery capacity over the original design (two Mastervolt Lithium ION units) to gain more motoring range for his boat.

So, let's take a quick look at a how we can figure this out. First of all, Eddy is on the right track with the selection of the Mastervolt 2.5 kW drive motor for his boat. Mastervolt recommends 2.0kW for sailing craft less than 6 meters in length. So, Eddy is more than OK on that front.

Now, to the question about the Valence batteries....... Nothing against Valence, but if it were me I'd be inclined to take a systems approach here because Mastervolt offers both LION and really good AGM batteries that can be matched nicely to both the motor drive and a suitable Mastervolt charger. We'd have to work the numbers here on component costs. 

Anyhow, to Eddy's question about the capacity of the batteriies, using Mastervolt's factor of 4.6 X kW motor capacity in kilowatt hours to achieve six to eight hours of run time it works out like this:  4.6X2.5=11.5 kWh.  So, with the Valence batteries he's contemplating each battery equals 12X 80% of 138 amp hours (80% is the approximate maximum discharge point for the LION batteries)...so 12X110=1320 per battery times 4 batteries=5.28 kWh. It looks to me like the run time Eddy can expect is going to be around 3 hours with the set-up he's contemplating now.

Keep in mind this is APPROXIMATE based on variables like the actual weight of the boat and the propeller he chooses.

So it all depend upon what Eddy's motoring needs are. Many sailors just want enough power to motor onto their mooring or in and out of their harbor.

Eddy, I hope I answered your questions here, and hey, take some pictures of your project and send them in if you do go this route. Good one to share!  Ed

I received a query yesterday from a reader asking about a really important issue related to marine electrical system component ratings for ignition protection. I say important because you don't want your boat to end up looking like the one shown here:

Doug's question goes like this:

Hi Ed,
I would like to know if any classes of products accepted as inherently ignition protected, not in need of testing / a label. Specifically I am wondering about:
- standard sealed inductive proximity sensors
- Brushless permanent magnet sealed motors (no air blowing on windings)
- sealed stepping motors
- Epoxy encapsulated electro-magnets/ electrical clutches
Basically electrical devices that generate NO sparks. Is there any mention of this in the standards
Thanks, Doug

Doug- This question is a tricky one that is a little bit subject to interpretation of the USCG CFR, under Title 33, Section 183.410, Ignition Protection.

Basically there are several statements made within the above referenced regulation that suggest that all of the devices/components you mention are indeed acceptable. I’ve scanned the applicable text right from the official manual:

My interpretation of this centers on the statement found next to # 2 above. I believe that the components you are referring to will meet that requirement Doug and are therefore properly separated.

I get folks asking me what I think about a product idea from time to time and recently I had a query that really got my attention. How about a waterproof electrical buss bar? This one has gone well beyond the idea stage and is actually available as a product right now. Check it out here:

So, what are you looking at? Its basically a bus bar with a 300 amp @ 48VDC rating that is completely potted and has two permanently installed and water tight Deutsch 12 pin plug connectors installed on it. The only exposed metal parts are the two 5/16" stainless steel studs you see. Those can be effectively sealed with a little squirt of Boeshield T-9 once the heavy gauge cables get attached. Why bother you ask? Well increasingly I'm seeing new boats coming through with rather large amounts of wiring exposed to bilge areas. The photo here is a good example:

Eventually, the bus bar you see above is going to end up with a nice green corrosion patina all over it. The electrical connections? Well they'll be quite suspect at that point. So, although there may be some limits to the use of the Deutsch equipped, fully potted bar in the top photo due to amperage handling capability, I can certainly see plenty of really good applications for this set-up in bilge areas and under center consoles, really anywhere on a boat that is exposed either directly or indirectly to the weather.

The weather sealed buss bars are currently available in several configurations, one with a total of 24 pins in the Deutsch plugs and rated for 300 amps as shown here and a smaller unit rated at 150 amps at 48VDC with 12 pins. The appropriate mating plug assemblies are also available from the supplier. The 24 pin models sell for about $60 and the 12 pin model sells for $40.

To find out more give Mike Miller a shout @ :  This e-mail address is being protected from spambots. You need JavaScript enabled to view it  

Over the weekend we received a query that should be shared with everyone. Here is John's question:

"Hi Ed, Alden Trull put me on to your web site, very helpful fellow.I am re-wiring two boats at present, my own 42ft cruising ketch and a Farr 37 racing boat. Both have split battery systems for motor start and ship and I have a nav station on the other side to the present batteries (VHF, HF, Radar, Chartplotter & GPS)and I am considering a dedicated coms battery near to the stations to reduce volts drop. Present installation has a VSR between the start and ships battery and I'm not too confident in it's its setting are out of my control. Considering diodes. What to you recommend? Will need solar and wind on mine eventually as she is on a swinging mooring in the Derwent River. I am in Hobart, Tasmania. I'm a Radio System Engineer (retired) so I understand the technology aspects. Regards John"

Today I see no reason to use diode type battery isolators when attempting to combine multiple battery banks. All of the vendors of DC equipment offer some sort of combining gear and the devices just keep on getting better. One good example fro Professional Mariner is shown here:

The ProIsoCharge 1-3 is a brand new offering from ProMariner and I don't have the exact specifications just yet but it looks to me like it offers the kind of functionality I typically look for in battery isolator/combiner devices, and could just be the ticket to take care of John's needs.

The unit above is rated to work with an alternator with up to a 120 amp rating, which covers most all engine OEM installations. Its rated for ignition protection which is super important on gasoline fueled boats (petrol where John's from).

I've got a call into ProMariner to get some additional specification info, but this unit appears to have pre-programmed outputs for both starting and house type batteries and it will handle one starter bank and two separate house banks. The box is totally waterproof to IP 66 standards too. The LED system monitor will indicate when each connected bank is in charge mode and provides warning indicators for both high and low voltage charging situations.

As for it's advantage over traditional diode type isolators, well unlike those units this device does not induce voltage drop into the charging system like the diode types do. That in itself is a major advantage. Alden Trull BTW, is a fellow who created a wire sizing software program I've been using for years called Wire Sizer, which is in complete compliance with ABYC wire sizing standards. Wire Sizer is avaliable for download at Alden's website:

http://www.midcoast.com/~aft/index2.html

One of our readers wrote in over the weekend:

Comment author: Marilyn K
Comment text: How many lives are lost each year due to faulty shore line power? How many boats and Marinas are lost? It would seem logical that if the National Electric code folks could prevent deaths by endorsing this product they would. What logical reason do they give for not endorsing it after this product has proven it is a safer choice? I'm assuming  you are referring to my earlier post touting the Smart Plug as a safer choice for boaters. That post is here: http://www.edsboattips.com/construction-a-technical/185-smart-plug-is-a-safer-choice for those of you who missed it.

Well Marilyn you ask a good question here. But to answer it completely is not as easy as it might seem. First of all is the matter of "endorsement" as you describe it. No standards writing body can actually endorse any product, not NEC not NFPA not ABYC not ISO, no one. The reason for this is simple, it represents a potential conflict of interest in any case.

What the ABYC has done over the years is to develop what we describe as a "performance-based" approach to Standards writing, which is a whole different than having Standards in place that describe how you will manufacture a product or what specific components must be included in the design of a given product.

This approach is really the only way we (the ABYC) see to develop Standards that remain relevant and that do not stifle technological innovation.

To answer your questions about deaths and fires, I do not know the total numbers on a national basis, but can tell you that the number of fires and deaths is high and growing every year. A related article that addresses one of the side-affects of faulty boats and shore power systems can be found in the article here, which a close friend and work colleague wrote for the Boat US Seaworthy magazine some time ago: http://www.boatus.com/seaworthy/kritz.asp 

The Smart Plug, if adopted with some additional modifications, could help to minimize some of the risks we now associate with existing shore power systems. That much I'm sure of. 

I can't answer your question about the why the NEC is being so difficult with the maker of the Smart Plug other than to say that from my understanding of the situation, the NEC has said that they would consider adding the plug configuration Smart Plug uses to their accepted list if the maker of the Smart Plug would give up their patent rights to the product......Again, I see that as stifling innovation. People have a right to make a buck for their work efforts it seems to me.

Anyhow, I am proceeding with some more writings about the Smart Plug in trade related insider publications in my effort to get this ball rolling in the right direction. If it takes the normal course these sort of issues take, I expect it to take five to seven years to get any change from the Standards writing people.