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Old 15-11-2010, 19:23   #31
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Originally Posted by capt_douglas View Post
... top off the batteries with either distilled water or RO water directly from the RO.
Does anyone else use RO water from the Watermaker to top off their batteries?

I have been doing this for a few months, using the "double processed" water that is output during the fresh water flush phase of my Spectra watermaker. When you flush it with product water, the water has been through the membrane twice - hence "double processed" and only 100 PPM or less. The standard water output is around 250 PPM.

Having said that, I am now finding I have to replace my Trojan T105s! Not sure if that was just end-of-life or my new filling practice!!

Also, on another point, I am considering just switching to AGM, though worried these won't last as long as the good old Trojans. At least you have a chance to equalise the Trojans and get another year or two from them? How long do people expect to keep their FLAs?

Rebel - check out the Trojan Maintenance Manual - Trojan Battery Company which reminds us not to top up BEFORE charging, unless the plates are not covered.
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Old 16-11-2010, 11:27   #32
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[QUOTE=Highlander40;559548]For those without generators. DO NOT buy AGM batterys.

Would not a proper solar/wind charging system be able to fully charge the battery bank? From what i have been reading plenty of folks here without generators are getting good mileage out of their AGM's when properly cared for. This may mean running the engine for some charging when conditions warrant I suspect, but assuming one designs an adequate solar system I cant see why the batteries wont get charged while Im at the beach...

I just removed a generator from my boat because I dont have any use for the thing. Its heavy, Im sick of buying diesel, and it annoys everyone else in the anchorage...
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Old 16-11-2010, 12:32   #33
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A proper solar/wind system will not charge beans on a cloudy day with no wind, which happen, and that's when you get the partial charges going on (and if you're living aboard, you'll be hunkered down inside watching movies with the lights on). You have to full recharge AGMs every time; no partial charging.
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Old 16-11-2010, 12:40   #34
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Thanks RH but thats why I said "This may mean running the engine for some charging when conditions warrant I suspect," I have a friend who lives on the hook in BVI and charges his AGMs with solar and winf. Been doing it for a few years now. He finds that most often on the overcast days it is windy too and so he ends up getting a charge from his wind genny. But there are still days when he has to run the engine to get back the amp hours.

My point was mainly that I just cant accept the comment that one should only use AGM batteries if they intend to charge off a generator. I trust the group her to elighten me to the error of my thinking.
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Old 16-11-2010, 12:54   #35
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thanks for reminding me why I love my AGMs.............
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Old 16-11-2010, 13:05   #36
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OK, this is all about sizing of the bank and charger.
AGM's need a charger that can put out a minimum of 25% of the bank AH.
Example, my bank is 400 AH and the charger can put out 110A running off shore power or the generator.
At idle or even 1000 rpm, the mains don't even come close to this.

This is why generators were invented. A small engine running at 25% to 75% load is very efficient.
Running the mains uses more fuel, wears out the engines, makes more noise and smoke. In the long run a generator can save money. This assumes that the boat gets lots of use.

My little genny has one cylinder and runs clean and quiet, burning less than 1 ltr/hr.

The boat can also be designed to be livable without a generator.
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Old 16-11-2010, 13:11   #37
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A small engine running at 25% to 75% load is very efficient.
Not totally correct...most normally aspirated small (<250 hp) engines are most efficient in the 70 to 80% range. Not that this adds or detracts from your basic premise.

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Old 16-11-2010, 13:17   #38
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"The boat can also be designed to be livable without a generator"


Please elaborate on this comment as this was my intention.
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Old 16-11-2010, 19:39   #39
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Cook with gas, cool with ice, light with wicks or small LED lights.
Forget AC and TV.
Very small house bank with FLA batterys.
Charge with wind, solar and alternator.

I know a couple who would spend 2 weeks on the hook at a time with no charging at all.

Different strokes, not my choice but it works.
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Old 16-11-2010, 19:46   #40
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Charlie, the range is a practical matter. If I could put on a 25A load all the time I would. You just run out of stuff to run. Unless its hot outside , or cold.

That range is what the generator mfg recomends.

When the charger only draws 8A I turn on the water heater for 10A more.

This is why my wife calls me the power nazi.
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Old 17-11-2010, 08:14   #41
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So my alternatives are:

"Cook with gas, cool with ice, light with wicks or small LED lights.
Forget AC and TV.
Very small house bank with FLA batterys.
Charge with wind, solar and alternator."

Or Buy a generator?

Maybe I need to add the following caveat: Im not interested in TV or AC I can stay home for that nonsense. Although the TV I have only draws 3 amps when running.

Im still having trouble understanding this need for the generator, in my application. If I inted to have a 540 watt solar array ((4) 135 watt panels) and a wind generator. I should be able to produce on most days 150amp hours of power, yes? With my refer and all the other crap I use 70-80 amp hours per day. Would I not be able to fully charge my AGM bank? Now I did say most days, not all. There will be days when I cant make solar or wind power and these are the days I will have to find a way to fully charge my AGMs. My battery bank FWIW is 800 amp hours so I can typically go almost 5 days at 80 amps per day before Im at 50%.

Im sorry if I am not getting this but Im still not seeing why I need the genset. Thank you for your patience with me on this.
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Old 17-11-2010, 08:24   #42
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A properly installed generator does not wake the 8 year old or the 47 year old wife.

.
Usually the folks on the boat running the generator are not the ones that complain. It's the neighbouring boats that complain.
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Old 17-11-2010, 10:12   #43
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You may choose AGM's because they are sealed without any concern for the economics.
Are you happy replacing them every 3 years?
Slow charge rate and incomplete charging will shorten the life of an AGM more so than a standard FLA battery.

It's just the nature of the beast.
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Old 17-11-2010, 10:27   #44
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Not to start the LIFEPO4 thing again, but I bought the 200ah LIFEPO4 pack that Dimitri was attempting to sell here on CF. As a price that was in line with buying the cells and the BMS separately, not $2100 as he was originally asking.

This will be replacing the 4 t-105 that came on Alchemy. It should solve all of the issues you are discussing here about watering, AGM charging, etc. I'll let you all know how it works out when I find out myself!

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Old 18-11-2010, 08:52   #45
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So Highlander40 it sounds then if I am reading you correctly then, I would be best off using flooded batteries NOT AGMs or gels for the following set up:

Charging Equipment : (4) 135 watt solar panels, wind genny, engine alternator 120amp.

Battery Bank: 800ah, (8) 6volt batteries 200ah each, in series and parallel.

Daily AH load: 70-80 ah
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