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Discussion Starter #61
I think the conversion to electric (for many) is less a "solution" and more an "intention" to move forward.

Here in coal-fuelled Alberta, owning an electric car is actually more carbon producing than a Honda Civic. Next door in hydro-powered BC it is way, way less. Doesn't stop concerned Albertans from buying electric cars, and IMHO it shouldn't—the more common it becomes the more likely it is that it will eventually make a significant difference.

So more power to the electric boaters!
Here in the US, WV gets 95% of it's power from fossil - 80% coal, 15% ng.

Even the best state, Oregon, only gets 45% of it's power from newables. Meanwhile Quebec and BC get 95% and 88% respectively.

We need to do better.
 

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Sean,

Thanks for the great info. I really appreciate it. No idea why I though the water would be a constant, but when I read it was dynamic I had a serious "duh" moment. OF COURSE it's dynamic. It's WATER. Too many years of car work, I guess. Anyway, thanks for snapping me out of that and pushing my knowledge just a little bit farther forward.

Looks like I should be making my most efficient point cruise, (say, 5kts) and leave about 25-35% more on top for emergencies. That sound about right?

Did you manage to sell your atomic 4? Seems like people either love or hate them.

Good on you for getting a scrapper and doing a total reno. That's a lot of work. I doff my hat to you, sir.
I still have the A4 -- I do plan on cleaning it up, tuning it up, and selling it at some point. It'll be another fun project at some point when I'm bored. And yes..the e29 has been a lot of work. I can really sympathize with your cleaning up after the removal of the ICE... I'll put together a refit story at some point, I have some real eye-opening pics to share.

Hopefully I get it into the water this year. I split my free time time between working on the '29 and sailing/drinking on the Mac 26s at the lake. Just bought a new 175% drifter for the Macgregor for Christmas too, can't wait to rig the solent stay for it and play with it in some light air...

Your plan sounds good to me. I really do encourage experimentation, though. Perturb and observe. Optomize for speed. Then optomize for grunt. Measure the efficiency of both setups at cruise speed in calm and heavy conditions. Hense my suggestion of getting a variable pitch prop, in spite of the additional cost, it allows you to implement, test, log, and optimize further. My whole point in getting involved in this thread is because I want you to be successful, and to make sure you don't buy $$ yourself into a corner you can't get out of. You should have the capability of selecting the best compromise of spead and thrust for your boat and your usage, something most people don't get the chance to do. You should be better equipped with the knowledge to make sense of your results, and selfishly I want to see your results :) :) :devil

Carry on, Cap'n.

:svoilier:
Sean
 

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Discussion Starter #63
I still have the A4 -- I do plan on cleaning it up, tuning it up, and selling it at some point. It'll be another fun project at some point when I'm bored. And yes..the e29 has been a lot of work. I can really sympathize with your cleaning up after the removal of the ICE... I'll put together a refit story at some point, I have some real eye-opening pics to share.

Hopefully I get it into the water this year. I split my free time time between working on the '29 and sailing/drinking on the Mac 26s at the lake. Just bought a new 175% drifter for the Macgregor for Christmas too, can't wait to rig the solent stay for it and play with it in some light air...

Your plan sounds good to me. I really do encourage experimentation, though. Perturb and observe. Optomize for speed. Then optomize for grunt. Measure the efficiency of both setups at cruise speed in calm and heavy conditions. Hense my suggestion of getting a variable pitch prop, in spite of the additional cost, it allows you to implement, test, log, and optimize further. My whole point in getting involved in this thread is because I want you to be successful, and to make sure you don't buy $$ yourself into a corner you can't get out of. You should have the capability of selecting the best compromise of spead and thrust for your boat and your usage, something most people don't get the chance to do. You should be better equipped with the knowledge to make sense of your results, and selfishly I want to see your results :) :) :devil

Carry on, Cap'n.

:svoilier:
Sean
I'l be doing quite a lot of experimentation, I think.

To wit, I've been thinking about how I want the place the batteries. After some consideration, I want to be able to remove them all, quickly, as one unit. While I don't expect that I'll need to do so very often, why design something in a cramped space when you can just insert and remove it as necessary? I just need a semi-clever way to connect the engine mains to the bus bar for the pack.

Speaking of wiring, I read a great article on battery drain vs wiring methods. Fascinating. I had no idea that in a 3 or more battery parallel arrangement the first battery in the line gets drained far more than the rest. Apparently the way around this is to give each battery an equally long connection to the bus bar and connect the mains and charger to that.

Hopefully, everything goes well with the battery install and I don't melt the boat. :) I'll have a chemical fire extinguisher on hand just in case, though.
 

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A perfect example of this is the lowly trolling motor, which may have 100lbs of thrust at zero speed, but at roughly 4-5 kts, is generating zero thrust. You can put 5 100lb thrust trolling motors on the same boat and it will not go any faster. It can't. The propeller blades are effectively at zero AoA to the water column they are moving in.
I can verify this, since I use a trolling motor as the auxiliary propulsion on my 22' Catalina.

The low-end power is great. It accelerates faster than a gasoline outboard, and I've driven into 20+ knot headwinds without problem.

But my maximum speed is about 3.5 knots. On the rare instances where I've had to motor any distance, WOW IT TAKES FOREVER!

Minnkota addresses the thrust / speed issue here:
How does horsepower compare to thrust?
How does thrust compare to speed?
 

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With your lifepo4 batts...
Any tool i use that goes down into where those batts reside is taped except for the extreme working ends.
I might sneeze or fumble...:)
Not really related to sailing, but kinda cool...

Last spring I got to meet Colonel Pamela Melroy, a space shuttle pilot and mission commander. She told a story about how a solar panel ripped when they were unfurling it on the space station. They had to send someone out on an unplanned spacewalk to repair the panel.

The solar panels are always charged and have no safety shut-off, since they aren’t designed to be serviced. They rigged up some tools from what was available on the space station, and this included taping everything. My favorite bit was that they armed the astronaut with a “poking stick” (that is the term she used) which was just a bit of aluminum wrapped in non-conductive tape. At one point a wave started rippling up the panel, headed towards him, and he was able to use the poking stick to hold himself away and avoid contact.

Oh, also the arm didn’t quite reach out to the damaged area. They have a foot restraint system that locks onto the feet of a spacesuit, and the other end connects to the arm. This extended the reach enough to get to the rip.



I love the idea that they have all this high tech, but sometimes they still have to rig tools out of available materials.

STS-120
 

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Sean,

Electricity is like the sea. If you give it a chance, it will kill you. I'm pretty careful with my wiring, having learned it from a friend of mine who's been a professional electrician for over 30 years. He's helped me reno three of my homes. I've also had to go through the OSHA safety training course a couple time for various contracts I've worked on. I don't consider myself an expert, but I am extraordinarily cautious around electricity and am a firm believer in "too much safety is just enough". I will be testing the hell out of the system I build long before it gets on my boat. If anything is going to melt down, I'd rather it do so on my concrete workshop floor rather than inside my boat.

I think I'm not explaining myself well. Thrust dictates speed. Once the water resistance matches the thrust from the prop, acceleration stops and the speed remains steady. Whether that thrust comes at 800 RPM or 1200 RPM is probably irrelevant. I guess I'll find out. I can't put Khaleesea on the hard until some space frees up, so I don't even know how big my prop is right now. Probably 16x10 or thereabouts. Hopefully I'll be up on the hard soon so I can take measurements.

Point taken about overdriving the motor temporarily. The DC cables on Kahleesea are already 2/0. From what I've read, at 48V that's over 200A, more than enough for cruising speed. Since DC and AC systems converge in the starboard aft compartment, that's where I'll put all electric connections. Looks like the charger and the inverter are going to have to be separate, since I can't find an inverter/charger unit that works with lithium batteries.

Are you putting your genset where your old diesel was? I can't imagine there are too many places in a 29' boat where you can put something like that. I'd also be interested to see your wiring diagram if you have one.

I find it interesting that you're going with the Chevy Volt model of hybrid propulsion. If I needed a longer cruising range, that would be the direction I would go too, but with as much solar as I could cram overhead.
One thing to be aware of, is that while Ohm's Law pertains to every element of electrical theory, standards and practices vary widely between residential, commercial, industrial, aviation, automotive, and marine electrical requirements and good practices.

ie, an excellent residential electrician, may not know marine electrical standards and practices at all.

I see this all the time, often due to marine survey reported deficiencies, where residential standards and practices were applied to boat wiring.

I'm not suggesting that everything was not done properly in your particular case, I'm just advising that the possibility exists in this or similar cases, where the work may not have been competed correctly.

I had a Canadian community college education and 30 years of experience as an electronic engineering technician (with a wide range of experience in residential, commercial, and industrial electrical systems, HVAC, and process instrumentation, before studying marine electrical and electronic standards and becoming Raymarine and ABYC certified. I was shocked (har har) at how much I didn't know that I needed to learn, to perform marine wiring correctly.

I do recommend, that anyone who performs DIY marine electrical work, to have it inspected by someone who is duly skilled and certified, just as you would for mods to your home, even though this is not a requirement on boats.

It may be free, or it may cost a nominal fee, to have a sparky (pet name for marine electrical technician) to inspect something, that your life could depend on.

For example, about 90% of bilge pump and VHF installations I inspect are deficient in some way, that could render them inoperative at some crucial time in the future, even if they are "working fine" right now.
 

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Discussion Starter #67
One thing to be aware of, is that while Ohm's Law pertains to every element of electrical theory, standards and practices vary widely between residential, commercial, industrial, aviation, automotive, and marine electrical requirements and good practices.

ie, an excellent residential electrician, may not know marine electrical standards and practices at all.

I see this all the time, often due to marine survey reported deficiencies, where residential standards and practices were applied to boat wiring.

I'm not suggesting that everything was not done properly in your particular case, I'm just advising that the possibility exists in this or similar cases, where the work may not have been competed correctly.

I had a Canadian community college education and 30 years of experience as an electronic engineering technician (with a wide range of experience in residential, commercial, and industrial electrical systems, HVAC, and process instrumentation, before studying marine electrical and electronic standards and becoming Raymarine and ABYC certified. I was shocked (har har) at how much I didn't know that I needed to learn, to perform marine wiring correctly.

I do recommend, that anyone who performs DIY marine electrical work, to have it inspected by someone who is duly skilled and certified, just as you would for mods to your home, even though this is not a requirement on boats.

It may be free, or it may cost a nominal fee, to have a sparky (pet name for marine electrical technician) to inspect something, that your life could depend on.

For example, about 90% of bilge pump and VHF installations I inspect are deficient in some way, that could render them inoperative at some crucial time in the future, even if they are "working fine" right now.
Funny you mention residential standards... I found that someone replaced the shore power connection at some point, and wired it with 12/2 romex. One of my little jobs I have to do is replace that with tinned stranded 10/2 wire, once I have the inverter/charger.

Speaking of inappropriate bilge operation, I'm running the bilge off of a group 31 battery connected to a trickle charger, connected to a NEMA L5-30 to 5-15R adapter. Yes, it's a kluge, but it should work until I get the new system in. It's not like Kahleesea is going anywhere at the moment anyway.

I'll have to add ABYC standards to my reading list before I start installing stuff. I don't have any experience with it, other than what I've seen as I've torn everything out of the boat. I am 100% certain that at least half the stuff I pulled wasn't to ABYC spec. I want to make sure everything that goes in is done right. Having the boat burst into flames while under power is not high on my to-do list, especially considering I'll be sitting just to the left of the battery pack while under power.

Anywho, thanks for the tips. They are always appreciated.
 

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I'l be doing quite a lot of experimentation, I think.

Speaking of wiring, I read a great article on battery drain vs wiring methods. Fascinating. I had no idea that in a 3 or more battery parallel arrangement the first battery in the line gets drained far more than the rest. Apparently the way around this is to give each battery an equally long connection to the bus bar and connect the mains and charger to that.
Wonder if this applies to the most positive battery in a 48 volt series string too. I replaced my 4 AGM's two years ago after eight years of excellent service powering my EP system. Actually only one of the batteries needed to be replaced but, I decided because of their years of service I did not want to mix the ages. So I bought 4 new ones for the system. Two of the new batteries arrived physical damaged on the pallet so they sent two new ones. Last year one of the batteries was not holding up as well as the other three. I'm suspecting it was damaged internally in the same shipment. In hindsight I should have rejected the whole shipment.) Though it was the most positive in the string too. I'll do some load testing in the spring just to make sure it's not my monitoring connections. Since my first battery bank held up eight years. The new battery packing it in after just two is certainly an anomaly.
 

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Discussion Starter #69
Wonder if this applies to the most positive battery in a 48 volt series string too. I replaced my 4 AGM's two years ago after eight years of excellent service powering my EP system. Actually only one of the batteries needed to be replaced but, I decided because of their years of service I did not want to mix the ages. So I bought 4 new ones for the system. Two of the new batteries arrived physical damaged on the pallet so they sent two new ones. Last year one of the batteries was not holding up as well as the other three. I'm suspecting it was damaged internally in the same shipment. In hindsight I should have rejected the whole shipment.) Though it was the most positive in the string too. I'll do some load testing in the spring just to make sure it's not my monitoring connections. Since my first battery bank held up eight years. The new battery packing it in after just two is certainly an anomaly.

Here's a great article that explains not only how, but why you wire parallel batteries a certain way.

SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank
 

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Funny you mention residential standards... I found that someone replaced the shore power connection at some point, and wired it with 12/2 romex. One of my little jobs I have to do is replace that with tinned stranded 10/2 wire, once I have the inverter/charger.

Speaking of inappropriate bilge operation, I'm running the bilge off of a group 31 battery connected to a trickle charger, connected to a NEMA L5-30 to 5-15R adapter. Yes, it's a kluge, but it should work until I get the new system in. It's not like Kahleesea is going anywhere at the moment anyway.

I'll have to add ABYC standards to my reading list before I start installing stuff. I don't have any experience with it, other than what I've seen as I've torn everything out of the boat. I am 100% certain that at least half the stuff I pulled wasn't to ABYC spec. I want to make sure everything that goes in is done right. Having the boat burst into flames while under power is not high on my to-do list, especially considering I'll be sitting just to the left of the battery pack while under power.

Anywho, thanks for the tips. They are always appreciated.
Ummm, a 30 A shore power connection cable should be 10/3 (normally).

Kluge shore power system is a big no no; boat could end up going to the bottom, or worse, electrocuting someone.

And as soon as you modify the shore power system it is supposed to be brought up to current ABYC standards, which is very specific, and will include a double pole 30 A breaker with ELCI and reverse polarity detection, and then branch breakers to suit each independent circuit.

If I were you, I would study (not just read) and ensure you fully understand ABYC E10 and E11 standards BEFORE you start the design stage.

Even at that, my usual recommendation is that reading some books or watching some videos, does not make one a qualified marine electrician.

Do yourself a really big favour, and no matter how much you think you understand the requirements, have a fully qualified "sparky" review your design drawings, material list, and final installation.

Even if it costs you a bit up front, I'll bet it actually saves you more in the long run, and will be inherently safer.
 

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Wonder if this applies to the most positive battery in a 48 volt series string too. I replaced my 4 AGM's two years ago after eight years of excellent service powering my EP system. Actually only one of the batteries needed to be replaced but, I decided because of their years of service I did not want to mix the ages. So I bought 4 new ones for the system. Two of the new batteries arrived physical damaged on the pallet so they sent two new ones. Last year one of the batteries was not holding up as well as the other three. I'm suspecting it was damaged internally in the same shipment. In hindsight I should have rejected the whole shipment.) Though it was the most positive in the string too. I'll do some load testing in the spring just to make sure it's not my monitoring connections. Since my first battery bank held up eight years. The new battery packing it in after just two is certainly an anomaly.
You guys are scaring me.

The current through all batteries in series is identical.

The only possible way to wire a series bank is with the positive lead on the most positive end and the negative lead on the most negative end.
 

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You guys are scaring me.

The current through all batteries in series is identical.

The only possible way to wire a series bank is with the positive lead on the most positive end and the negative lead on the most negative end.
Of course that's the way it is wired. My issue was with battery that was connected to the positive lead I'm able to monitor the voltage of each individual battery in the string at the helm. The one most positive in the string which is connected to the positive lead to the controller. It started dropping fast as I drew more current while the other three batteries showed pretty much the same voltage. The most positive battery quickly dropped to 12+ down to 11.8 and beyond. I had to start the generator and electro sail because of it instead of operating on battery alone. I think it might have some internal damage that shows up when higher amps are drawn from the battery bank.
 

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Ummm, a 30 A shore power connection cable should be 10/3 (normally).

Kluge shore power system is a big no no; boat could end up going to the bottom, or worse, electrocuting someone.

And as soon as you modify the shore power system it is supposed to be brought up to current ABYC standards, which is very specific, and will include a double pole 30 A breaker with ELCI and reverse polarity detection, and then branch breakers to suit each independent circuit.
And a GFCI on any branch circuit installed in a head, galley, machinery space, or on a weather deck. (In other words, pretty much all of them on a 29 foot boat) I'm putting an isolation transformer in my boat after the shore power ELCI (and another ELCI after the iso.. and then there's the inverter..) as well, since my gal really likes floating at our freshwater dock in spite of my strong recommendations against it. I can't protect her from the other boats, but I can at least put my points in the black box box... black box theory here John Vigor's Blog: The Black Box Theory

If I were you, I would study (not just read) and ensure you fully understand ABYC E10 and E11 standards BEFORE you start the design stage.

Even at that, my usual recommendation is that reading some books or watching some videos, does not make one a qualified marine electrician.

Do yourself a really big favour, and no matter how much you think you understand the requirements, have a fully qualified "sparky" review your design drawings, material list, and final installation.

Even if it costs you a bit up front, I'll bet it actually saves you more in the long run, and will be inherently safer.
I'll be honest, I think most sparky's are overpaid. However -- qualified marine sparkies -- i have a lot of respect for. They have to know their sh*t.
 

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Of course that's the way it is wired. My issue was with battery that was connected to the positive lead I'm able to monitor the voltage of each individual battery in the string at the helm. The one most positive in the string which is connected to the positive lead to the controller. It started dropping fast as I drew more current while the other three batteries showed pretty much the same voltage. The most positive battery quickly dropped to 12+ down to 11.8 and beyond. I had to start the generator and electro sail because of it instead of operating on battery alone. I think it might have some internal damage that shows up when higher amps are drawn from the battery bank.
I'm traveling on business so not a lot of time to post, but a quick note Mike -- The reason why parallel wired batteries can suffer charge/draw asymmetries is because each battery is connected to the loads by a different length of wire. Due to that, the voltage drop/resistance of the lengths of wire connecting them are different. The shortest-wired-battery is effectively on the least-resistance-path and gets the most charge (and discharge) current.

When wired in series, current through each battery is identical and has no other path, right up to and including when a weak/damaged battery becomes completely discharged and the other batteries in the string drive it into negative voltage (this is one way to set Lithium Ion chemestry batteries on fire (does not apply to LiFePO4, but you still perm damage LiFePO4 cells in this situation))

I think your particular circumstance was due to manufacturing defect or shipping damage to the bad battery.

Sean
 

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100.24.90.65

When wired in series, current through each battery is identical and has no other path, right up to and including when a weak/damaged battery becomes completely discharged and the other batteries in the string drive it into negative voltage (this is one way to set Lithium Ion chemestry batteries on fire (does not apply to LiFePO4, but you still perm damage LiFePO4 cells in this situation))

I think your particular circumstance was due to manufacturing defect or shipping damage to the bad battery.

Sean
Yeah I think so too. Which is why I'm glad I have meters on each battery in the string as well the overall voltage. It was a yikes moment when I noticed the battery all of a sudden reading 9.5 volts. Thanks for the info on current behavior in the string too. I'm still sticking with AGM's since they meet my needs electrically and financially. But if Lithium costs come down I'd switch but, I said the same thing ten years ago when I first installed the EP system. :)
 

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Discussion Starter #76
Update, 1/8/19.

Dekluged the boat (somewhat). Shorepower now goes through the old 30A breaker to a GFCI outlet, into which the charger is plugged. Charger clamps are on the big connectors, mains to the DC panel are on the others, secured with butterfly nuts. Not an ideal solution, but it will do for now, and the boat probably won't sink or catch on fire. Oh, and the 120V panel is completely disconnected, and will remain so until I figure out how I'm going to integrate it into the new setup.

I went to the local marine technical contractor today. I'm going to rent their most knowledgeable certified ABYC specialist to sit with me in my boat and go over potential issues. He's apparently done a couple of electric boat installs and a few lithium house battery upgrades. I'm looking forward to getting his advice while specifically looking at my boat. I think it will be money well spent. I can always call on them again if I hit a snag I can't overcome.
 

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Update, 1/8/19.

Dekluged the boat (somewhat). Shorepower now goes through the old 30A breaker to a GFCI outlet, into which the charger is plugged. Charger clamps are on the big connectors, mains to the DC panel are on the others, secured with butterfly nuts. Not an ideal solution, but it will do for now, and the boat probably won't sink or catch on fire. Oh, and the 120V panel is completely disconnected, and will remain so until I figure out how I'm going to integrate it into the new setup.

I went to the local marine technical contractor today. I'm going to rent their most knowledgeable certified ABYC specialist to sit with me in my boat and go over potential issues. He's apparently done a couple of electric boat installs and a few lithium house battery upgrades. I'm looking forward to getting his advice while specifically looking at my boat. I think it will be money well spent. I can always call on them again if I hit a snag I can't overcome.
Excellent move.

While I personally have no skin in the game, I find in many cases, DIYers over-estimate their capabilities.

The following is a bit of a public service announcement. It cost me time and effort and lost business opportunity to write and I likely stand to gain nothing other than the knowledge I may have helped someone.

Having a pro (someone properly educated, trained, and experienced) consult and/or inspect this type of work, generally saves money rather than costs.

It can also save your life. (This is not fear mongering; there is a natural cause and effect to everything we do or don't do.)

Here is some additional advice that I hope can help you and others:

1. An automotive type charger, even if the brand name sounds nautical, with spring clamps, is not ABYC compliant for use on a boat (but OK on land in a an adequately ventilated area).

This type of charger is not usually IP (ignition proof) rated, and can cause sparks, igniting the hydrogen gas (or other flammable combustible) present above the battery.

2. Wing nuts are not compliant on battery cables 6 gauge or less. It is very difficult to make these tight enough without tools, but because of their design, most people just finger tighten. This can lead to a loose, high impedance connection, that can cause sparks or extreme heat, especially when high current loads are present (hence the wire gauge limitation).

3. Ensure any service provider you hire is duly qualified IN THAT FIELD.

Few "mechanics" are truly "certified" by any recognized association or manufacturer.

Many "certified mechanics" (who are truly certified), could not wire a boat compliant to ABYC standards if their lives depended on it.

Not because they are not smart enough or capable, they are just not educated, trained, and sufficiently experienced in this field, as their continuing education is related to mechanical not electrical work.

Ask to see their "certification". If they really are, they should have a cert in their wallet, and will be happy to show it because they have heavily invested in it. If they don't, they will likely try to come up with some excuse.

My policy - no training cert, no boarding my boat.

4. Ensure any service provider you hire is insured FOR THAT TYPE OF WORK.

Ask to see their commercial liability cert.

They have paid handsomely for this piece of paper, and will gladly present it to separate themselves from boat bums who claim to be "professional".

If an insured contractor's actions burn down your boat, others around you, and the marina, the repairs will come out of their insurance, and their premiums will skyrocket, likely putting them out of business if they try to continue to carry insurance.

Hint - having insurance, is a good indication a service provider has not had a previous claim, and knowing the cost to livelihood if they ever do, provides extra incentive to do it right, every time.

My policy - no relevant manufacturers or association cert., no boarding my boat.

In closing, some people are surprised that they have to perform their own due diligence to ensure the people they hire to work on their boat are duly qualified.

Interestingly, some of those same people go to great lengths in time and expense to screen the people hired for positions in their company.

Go figure.

Unlike your house, you can't step off your boat, dial 911, and have emergency services there in 90 seconds.

Do everything you can to make sure the people working on your boat (including yourself) do not cause you to have to call a Mayday (and to ensure the radio works when you need it to.)

Hope this helps.
 

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Of course that's the way it is wired. My issue was with battery that was connected to the positive lead I'm able to monitor the voltage of each individual battery in the string at the helm. The one most positive in the string which is connected to the positive lead to the controller. It started dropping fast as I drew more current while the other three batteries showed pretty much the same voltage. The most positive battery quickly dropped to 12+ down to 11.8 and beyond. I had to start the generator and electro sail because of it instead of operating on battery alone. I think it might have some internal damage that shows up when higher amps are drawn from the battery bank.
I apologise if you found my response offensive. It was not intended to be so.

Based on your prior post, it sounded like you were questioning if the first battery in a series string could suffer the same "over-worked" condition as an improperly wired first battery in a parallel string.
My answer was in response to that.

Anyone understanding basic electrical principles should know that it does not.

Whether a temporary lapse or lack of understanding in general, it frightens me when I see posts offering electrical advice or recommendations.
 

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Here's a great article that explains not only how, but why you wire parallel batteries a certain way.

SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank
FYI, no doubt the wiring recommendations in this article are best practice.

It is relatively rare to see the common power post method (illustration # 3).

I don't recommend illustration # 4, as it needlessly places more terminals per post (risk of poor connection), and in practice is likely to result in a spaghetti breakfast of wiring.

Interestingly, some marine batteries are supplied with very short battery terminals, that in practice, will not support illustration # 4.

While the article touches on it, the consequences of wiring illustration # 1, are not as dire as indicated.

Illustration # 2 is definitely better practice, but if wired as indicated in illustration # 1, in time the internal resistance of each battery will increase, proportionally with it's proximity to the load connection, so that eventually the load per battery pretty much equalizes.

So in other words, the capacity of the nearest battery is relatively reduced, while the capacity of the furthest battery is relatively saved.

As a system, the resultant change in life expectancy will likely only be marginal if measurable at all.

This doesn't change that illustration # 2 is better practice and should be done this way if practicable.

When I encounter wiring per illustration # 1, I advise the owner that the wiring is suboptimal, but rarely will they pay to have it re-wired (if cables will not support illustration # 2 as is), unless planning a complete rewire for other reasons.

The worst I have had is a power boat I was called to because the electrical system was amuck. The series/parallel batteries were wired by the PO in a bowl of spaghetti fashion, which resulted in the new owner reconnecting batteries incorrectly in the spring, which had trashed the reverse connected battery before I arrived on scene.

After I diagnosed and corrected the specific wiring error (I had to draw myself a diagram to review the "as found" wiring and confirm the "as left" wiring), I quoted a reasonable fee (by local industry standards) to replace the batteries, correct the battery sequence and wiring routing, label it, and provide a proper wiring diagram for future reference and to help avoid recurrence.

Owner declined.

I had to leave knowing the boat, the owner, and his family were at risk of having a dead bank shortly after disconnecting charging sources, but there was absolutely nothing I could do about it.

(Addendum - I did offer the option of isolating the series pair that included the reverse polarity damaged battery, basically no charge, but that was declined also.)
 

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Captain Canuck,
While I'm still reading the last pages of posts, I am wondering why you don't have a diver take your prop off now while you're still waiting for space on the hard?
I'm a working diver, so with my Elec. Conv. I'll just pull my prop soon so I can get to working up the specs for that.
I probably won't be hauling this boat out until late Spring or early Summer this year.
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My boat is a Hunter 28.5.
The PO removed the diesel and purchased the Thunderstruck 10kW kit but never installed... I'm working on that now.
This boat will be primarily a bay sailer... Humboldt Bay California.
Motoring around here is primarily leaving and returning to one's slip... aside from grounding and trying to back off.. hahaha
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Great thread here. I'll keep watching and reading... not sure how much I can contribute though... so many of you are way more adept at the technical aspects of this than I am.
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Heck... I'm still mulling over my motor mount so I can get it installed and lined up properly!
 
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