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Old 06-09-2014, 07:35 PM   #81
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I dont understand the aversion to 120v ac power. Or a properly sized and used ac generator. Given the right sized house batt bank and right sized charger/inverter system it is every bit as efficient as a more expensive dc setup. All power generated by rotating magnets is a.c. Why convert it to d.c. (which is not free by the way) when it is more efficient to use an inverter to convert it to d.c. Another plus is that 120v wiring is MUCH smaller than 12 or 24 volt d.c. wiring. My trawler has a 2 hp Ideal windlass on the bow. Its 120v motor can run continuosly with no fear of overheating and has 10 gauge wire to it. It can be ran off of either inverter or the generator. It is more reliable than a dc powered windlass and WAY more powerfull. My water heater is 120v or main engine heated. My fridges/freezers are 120 volt dirt units. Washer/dryer are 120v. Lighting is all 12v. I can charge the house bank at 300 amps, make hot water and do laundry while loading the 15 kw gen reasonably well (read efficiently). In the summer the air conditioning load down here makes efficiency a moot point. We just run the gen and try to stay cool. I can run the 5000 btu air unit in the master with the inverters, so we dont have to run the gen all night. That seriously increases the charge time. If I boated up north the dc approach might make sense, but not down here. And, I dont really want to "camp" in a boat, just not my thing. My wife and I did spend 2 weeks camping in a tent and cooking over a camp fire on Kodiak Island a few years ago. It was great fun, but she didnt get eaten by a bear so I dont want to do it again.
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Old 06-09-2014, 07:42 PM   #82
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It was great fun, but she didnt get eaten by a bear so I dont want to do it again.
To be clear, if the goal was to get her eaten by a bear, and that was accomplished, um why would you want to repeat? Or are you hypothesizing a subsequent wife who needed a similar fate?
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Old 06-09-2014, 09:09 PM   #83
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Just joking, bears are afraid of her, even Kodiac Brown bears I like camping, just not in my boat. Full air conditioning, microwave, etc. but still kinda power concerned. I dont like to run the gen unless neccessary, and then I like it loaded properly if possible.
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Old 06-10-2014, 06:01 AM   #84
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>I can charge the house bank at 300 amps.<

WOW , most batts are charged for long life at C/10 , so with a 300A charge you are charging a 3000AH bank that weighs about 3000lbs?

Way back when there were more universal motors (AC or DC) it was not uncommon to string 10 12V batts together and simply go all house for bulbs and electric toys.

A 60 cps vibrator would change the DC into AC with little loss, tho they had points so were amps sensitive.

Where air cond is required 24/7 noisemaker is the norm , but 1 gal an hour for fuel is $100 per day in money burn.

We live in FL ,( Winters only) and find if we can reduce the boat temperature to about water temperature , with a fan on , nothing else is required.

The coolest air is in the bilge on hot days , with a bit of work the bilge need not stink of diesel or engine.
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Old 06-10-2014, 07:15 AM   #85
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Putting 300 A into a battery bank is no big deal these days.

An advantage of AGM batteries is their charge acceptance rate. There are other advantages as well. Typically C/3 is the limit, but Odyssey batteries can take a higher charge rate.

I have a 1284 AH Odyssey house bank, made up of 6 x PC 1800-FT and total weight is 790#. I have seen my alternators feed in up to 360 A when the bank has been discharged a bit. The batteries could take higher inrush current if I had it available.
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Old 06-12-2014, 04:23 PM   #86
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Came across this long, interesting article on DC Charging System Design: Duckworks - DC Charging System Design. It's DIY cruiser oriented, ABYC--what's that, small type with paragraphs repeated, but good food for thought imo. I made a cleaned up copy in Word, PM me if you want a copy. Hope you find it enjoyable.
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Old 06-12-2014, 04:32 PM   #87
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Have you priced a hydraulic windlass?
No, I don't even own the boat yet, it's all speculation. Maybe instead I'll go with a 24v windlass, or a 110v windlass, or keep the 12v windlass, who the hell knows. Just want to get on the bloody thing and start living on it, seatrial & survey aren't until early July.
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Old 06-12-2014, 04:35 PM   #88
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Putting 300 A into a battery bank is no big deal these days.

An advantage of AGM batteries is their charge acceptance rate. There are other advantages as well. Typically C/3 is the limit, but Odyssey batteries can take a higher charge rate.

I have a 1284 AH Odyssey house bank, made up of 6 x PC 1800-FT and total weight is 790#. I have seen my alternators feed in up to 360 A when the bank has been discharged a bit. The batteries could take higher inrush current if I had it available.
+1 . The article I posted goes into this pretty well.
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Old 06-14-2014, 02:20 PM   #89
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I have always felt Lifeline AGM's were by far the best. They can also be equalized if done carefully if they start to go into replacement mode.
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Old 06-15-2014, 12:11 PM   #90
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when I spec'ed my boat, I gave much thought to a 24v system. But since ease of maintenence/parts availability in remote foreign ports is critical to this boat's mission, I opted for a 12v system (thruster is 24). Carrying lots of extra spares is an alternative (the list is really extensive, if you get down to it), but I concluded that cost and on-going effort wasn't justified by really rather marginal benefits of a 24v system.
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Old 04-26-2015, 10:51 AM   #91
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I read all these posts just to get to the last one by MYTraveler. That's the question I want to post; my bow thruster and windlass ( already purchased) are 24v DC and I want the rest of the boat to be 12v. All my past boats were 12v and I understand it and am comfortable with it. I planned to have a pair of AGM batts in the very deep v-berths to power these two devices and charge the AGM batteries with a dedicated 24 v charger that receives its 110v ac from the generator. My questions: Shore power, two 30A hookups or one 50A? AC power, 110v only or combination of 220v and 110v? How do I do a combination of both voltages? Other batteries onboard are starting battery for generator, assuming genny's alternator will charge it, single diesel main engine, possibly a single 4D starting battery with an engine driven 100 Amp alternator to charge it, (already installed) and three 8D batteries for house bank; how do I charge those? I know some people install another alternator to charge house bank but I'm thinking at 170 horse power on this completey new Lugger might be a bit much on it...not sure.
Could sure use some insight.
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Old 04-26-2015, 10:55 AM   #92
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Switch to 24V or 12/24V Hybrid Electrical System

Single 50A with a 230v panel and in addition to that 115v panel.
You use one of the legs of the 230v or a transformer (my boat has one).
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Old 04-26-2015, 11:02 AM   #93
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Single 50A with a 230v panel and in addition to that 115v panel.
You use one of the legs of the 230v or a transformer (my boat has one).
This is how our DeFever is set up too. We also have an adaptor for the cord that allows 50A 220V to come in on one leg from a 30A 110V dock post.
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Old 04-26-2015, 11:18 AM   #94
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Yep, it works both ways if I just want to leave a battery charger on I can just hook it up to the 30A plug and I got 230v. If you have a lot of HVAC's I would consider a second 50A inlet for those. We have found that very hand when we have all the AC's running and also have a large house load.
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Old 04-26-2015, 11:39 AM   #95
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Wil said: "solar panels (on the pilothouse roof of a KK42 for instance) and wind generator would extend the time intervals where the very quiet little DC generator would be needed."

It's a very interesting "thought problem" but I don't know why you'd bother. You mention the KK42, and I know of a local KK42 that has 500 watts of solar panels that operates for 6 months of cruising in the PNW, and that averages 0.5 hours of genny runtime/day. There are bigger fish to fry for the new boat owner (speaking from experience :-)) than to worry about converting the entire boat over to 24 volt IMO. The only thing that we have that is 24 volt is the bow thruster and it has it's own charging system and AGM setup.


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Old 04-26-2015, 11:56 AM   #96
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Great responses, thank you. But what about charging the 3 battery house bank? Will the 100 Amp alternator, after it replenishes the starting battery of its start up drain, can I use it to slowly recharge the house bank while underway?
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Old 04-26-2015, 12:16 PM   #97
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It might help to think about electrical power as being easily converted. DC to / from AC, 12vdc to 24vdc, etc. and watts = volts * amps.

So the question is, how many watts are you using - on average - and how do you replace them (shore power, alternator, generator, solar, etc).

And the answer - in general - is reduce usage first. LED bulbs, low power entertainment systems, alternate cooking and heating fuels, more efficient refrigeration, et cetera.

And to reduce usage you have to be able to measure and record that usage. And that's where every boat and operator is different. Do you use AC? Water maker? Satellite TV? Electric hot water heater (our Insta-hot in the galley is a high priority item!), ice maker, and the list is truly infinite in variety.
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