Electrical system for boat

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fredrosse
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Re: Electrical system for boat

Post by fredrosse » Fri Aug 23, 2019 2:53 am

"Maybe it's time to head for Harbor Freight and buy a bore scope."

I bought the HF borescope, $69, not bad, it works OK, but only 240 pixels. My computer savvy daughter pointed out that one can get a 720 pixel borescope that is only 7mm in diameter, has a ring of LED lights around the camera, with user adjustment, and it plugs into a USB port, so you get the picture on a typical laptop computer, or even a phone. The cost, $12

I remember when borescopes came out years ago, cost thousands of USD
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DetroiTug
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Re: Electrical system for boat

Post by DetroiTug » Fri Aug 23, 2019 2:04 pm

It's important to know if corrosion is happening, but it is also important to know what effect it is having. An Ultrasound thickness tester which can be had for a little over a hundred dollars works well for this, they are very accurate to within .001" and will show if there is any thinning in areas of corrosion. A rusty area may or may not be an area of concern, but the ultrasound tester is the only way to know for sure. I checked my boiler all over in various spots and it measured .320 +/- .002". It will only measure the metal and it will do it accurately even if there is rust on the surface. Each material type has a specific frequency setting and if the material changes at some point in the cross section, it simply won't measure it and will only measure what it is set for.

A glycerin coupling agent is dabbed on a spot and then the probe is coupled to the surface and it reads the thickness right out in decimal digits.

-Ron
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Lopez Mike
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Re: Electrical system for boat

Post by Lopez Mike » Fri Aug 23, 2019 4:51 pm

I have a thickness tester. No problems anywhere I can reach on my boiler.

I'm more concerned with poor heat transfer. Probably I'll just wash it out with TSP and roll it around like a beer keg on the shop floor to make sure there isn't any serious buildup at the bottom of the water leg.
Last edited by Lopez Mike on Mon Aug 26, 2019 5:48 pm, edited 1 time in total.
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DetroiTug
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Re: Electrical system for boat

Post by DetroiTug » Mon Aug 26, 2019 1:12 pm

Quote: "To make boiler nipples removable, use neverseize."

I've had good service out of neverseize as well, what I swear by for sealing and non binding of threaded components is "Jomar Green Stuff" thread sealant. I've been using that for many years now and I have never had anything steam related that was too difficult to remove years later. I worked for a gas company about 30 years ago and that is all they would allow us to use. Apparently their engineers had tested various products and it was the best they could find.

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Lopez Mike
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Re: Electrical system for boat

Post by Lopez Mike » Mon Aug 26, 2019 10:17 pm

Ordered a can off of EBay. Thanks for the tip.
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Titan
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Re: Electrical system for boat

Post by Titan » Thu Jan 02, 2020 7:39 pm

My solution for electrical power:

www.youtube.com/watch?v=OC5pHkGR63E&feature=youtu.be

Not sure what rpm the engine is turning, but in normal applications it is designed to run at up to 2,750rpm. I am using a 300W 24V permanent magnet motor as a generator, so it does not need to spin too fast to generate 12V. I think the engine is rated at 1/3 hp.

In the video it is just charging my phone, so the ammeter is hardly off the mark, but it powers my front 55W spot lamp without breaking in to a sweat!

Still a work in progress though, I need to sort out a governor for it as it can only deal with steady loads at the moment, i.e. lighting and battery charging.
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barts
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Re: Electrical system for boat

Post by barts » Thu Jan 02, 2020 9:04 pm

Titan wrote:
Thu Jan 02, 2020 7:39 pm
Still a work in progress though, I need to sort out a governor for it as it can only deal with steady loads at the moment, i.e. lighting and battery charging.
I'd definitely use a battery to help regulate the output of your generator as the output voltage is likely to shoot up if the load decreases suddenly.

Given the complications of trying to drive a throttle with a servo or stepper, I would fit a controller designed for a small wind turbine. These dissipate excess current as heat (usually external resistors),and with a digital battery voltage gauge you can adjust the throttle to produce more current as needed if the battery voltage drops.

Simple, uses off-the-shelf parts and protect the battery & other electronics from over-voltage.

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Titan
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Re: Electrical system for boat

Post by Titan » Fri Jan 03, 2020 3:15 pm

In this case the voltage is near enough proportional to rpm. I suppose if a very heavy load was placed the internal resistance of the generator would result in a voltage drop - assuming the engine can still maintain the rpm of course. This would mean that a mechanical governor would be fine, just as used on many commercial generators, albeit full load voltage would be somewhat lower than no load.

I would have liked to have a traditional mechanical governor for the engine, but even if I could find something suitable it would have been expensive, or I would have had to make my own.

So on the grounds of cost and ease of manufacture I am in the process of building an electronic governor that reads the generator output and open/closes the throttle to maintain a steady voltage. As it is reading the generator output directly, I am hoping it should provide a more accurate voltage output.

I have a simple solution for driving the servo - a servo controller that uses a 0-5v signal for servo position, and a 10V zener used as a voltage follower. This means with the zener holding at 10V, a generator output ot 10-15V gives the required 0-5v signal to the servo controller.
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Lopez Mike
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Re: Electrical system for boat

Post by Lopez Mike » Fri Jan 03, 2020 3:41 pm

Consider a radio controlled vehicle servo.

They are relatively inexpensive, available in a wide range of sizes and torque ratings and easily interfaced with a small dedicated micro controller. This has already been done and is mostly a 'turnkey' solution. I've done so with a little controller called a Basic Stamp but there are others. The Stamp is just easier to program and there are programs already written and available.

You biggest problem then will be to contrive a suitable throttle valve. A non-trivial problem.

I try not to "Invent the Wheel" more often than I need to.
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Re: Electrical system for boat

Post by fredrosse » Fri Jan 03, 2020 7:27 pm

With the very low consumption associated with LED lights, it is very practical to just use ordinary battery power for running lights, as well as a LED searchlight. I had these on my boat, and the battery powered stuff can go for a full year with a couple of AA batteries. I now have kerosene running lights, but they cost a small fortune compared to LED running lights.

If using battery power for larger boat loads, such as a 12 volt Oil Burner, then the Lithium automobile boosters can be used. They are much lighter than lead-acid batteries, and easily charged overnight. A several hours running with a pressure atomized oil burner is within the capability of a typical group 27 marine lead-acid battery, which has about 40 pounds weight, and almost 1 kWH (kilowatt-hour) energy supply. Lithium batteries for bicycles come to mind, a 30 pound battery can supply 2.2 kWH, over double the lead-acid capacity, is about 9 inches x 10 inches x 14 inches, but will cost about $350US, plus $50US for a dedicated 120VAC charger. The Lithium battery will allow far more charging cycles than the lead-acid.

Very important, let us remember that electricity is a basically evil, unknown, mysterious thing. The engineers that use it many ways still don't know what electricity / magnetism is, they just use its interactive properties to do various things. Anyone who would consider electricity on a steamboat is dabbling with danger. Kerosene lamps work fine, and don't threaten your life like electricity can.
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