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  #1  
Old 09-08-2006
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Lightbulb Making Amps

Hey all,
Man with the plan here, again - looking to see how other Mariners are making volts.

Solar, wind, hydro, or combinations? The real question I have is in the details of the Amps per day (assuming 5-6 hrs of effective sun for solar).

My current outline of daily use shows about 170A/day. I am looking to go at least 4 days w/o recharge.

For example:
I think I need about six (6) Sunsei Solar Panels SE-24000 (24A Kit) by ICP Solar (http://www.batterycountry.com/ShopSi...chargers.html). At 60"x28" per panel - it is a large array, but I could theoretically collect around 200A/day. Are there any other panels out there that can do this job with less sqft?

Have no idea on how effective wind generators or hydro may be either. I'm open to all suggestions. Gas burining generators . . .? . . . trying to avoid them.

Thanks shipmates!
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Old 09-08-2006
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Making amps! / Storing Amps ?

A little light reading. Don't have any ties to these folks but the info seems resonabley complete, clear and good.
I have L-16's and a place to put them, however at 124lbs and 16+" tall, I would not wish them on anyone that did not require very high capacity. I have found 4V cells (24" tall) at several 'off the grid' places on the web. Any of those folks that specialized in 'OFF THE GRID' solar/wind etc are a wealth of info on things battery.

Excerpted from:
http://www.windsun.com/Batteries/Bat...attery%20Types

Lifespan of Batteries

The lifespan of a battery will vary considerably with how it is used, how it is maintained and charged, temperature, and other factors. In extreme cases, it can vary to extremes - we have seen L-16's killed in less than a year by severe overcharging, and we have a large set of surplus telephone batteries that sees only occasional (5-10 times per year) heavy service that are now over 25 years old. We have seen gelled cells destroyed in one day when overcharged with a large automotive charger. We have seen golf cart batteries destroyed without ever being used in less than a year because they were left sitting in a hot garage without being charged. Even the so-called "dry charged" (where you add acid when you need them) have a shelf life of at most 18 months, as they are not totally dry (actually, a few are, but hard to find, the vast majority are shipped with damp plates).

These are some general (minimum - maximum) typical expectations for batteries if used in deep cycle service:
Starting: 3-12 months
Marine: 1-6 years
Golf cart: 2-6 years
AGM deep cycle: 4-7 years
Gelled deep cycle: 2-5 years
Deep cycle (L-16 type etc): 4-8 years
Rolls-Surrette premium deep cycle: 7-15 years
Industrial deep cycle (Crown and Rolls 4KS series): 10-20+ years
Telephone (float): 1-20 years. These are usually special purpose "float service", but often appear on the surplus market as "deep cycle". They can vary considerably, depending on age, usage, care, and type.
NiFe (alkaline): 3-25 years
NiCad: 1-20 years


Battery Size Codes

Batteries come in all different sizes. Many have "group" sizes, which is based upon the physical size and terminal placement. It is NOT a measure of battery capacity. Typical BCI codes are group U1, 24, 27, and 31. Industrial batteries are usually designated by a part number such as "FS" for floor sweeper, or "GC" for golf cart. Many batteries follow no particular code, and are just manufacturers part numbers. Other standard size codes are 4D & 8D, large industrial batteries, commonly used in solar electric systems.

Some common battery size codes used are: (ratings are approximate)

U1..................34 to 40 Amp hours......12 volts
Group 24..........70-85 Amp hours.........12 volts
Group 27..........85-105 Amp hours.......12 volts
Group 31..........95-125 Amp hours.......12 volts
4-D................180-215 Amp hours.......12 volts
8-D................225-255 Amp hours.......12 volts
Golf cart & T-105.......180 to 220 Amp hours.........6 volts
L-16.........................340 to 415 Amp hours........6 volts


Cycles vs Life

A battery "cycle" is one complete discharge and recharge cycle. It is usually considered to be discharging from 100% to 20%, and then back to 100%. However, there are often ratings for other depth of discharge cycles, the most common ones are 10%, 20%, and 50%. You have to be careful when looking at ratings that list how many cycles a battery is rated for unless it also states how far down it is being discharged. For example, one of the widely advertised telephone type (float service) batteries have been advertised as having a 20-year life. If you look at the fine print, it has that rating only at 5% DOD - it is much less when used in an application where they are cycled deeper on a regular basis. Those same batteries are rated at less than 5 years if cycled to 50%. For example, most golf cart batteries are rated for about 550 cycles to 50% discharge - which equates to about 2 years.

How depth of discharge affects cycle life on batteriesBattery life is directly related to how deep the battery is cycled each time. If a battery is discharged to 50% every day, it will last about twice as long as if it is cycled to 80% DOD. If cycled only 10% DOD, it will last about 5 times as long as one cycled to 50%. Obviously, there are some practical limitations on this - you don't usually want to have a 5 ton pile of batteries sitting there just to reduce the DOD. The most practical number to use is 50% DOD on a regular basis. This does NOT mean you cannot go to 80% once in a while. It's just that when designing a system when you have some idea of the loads, you should figure on an average DOD of around 50% for the best storage vs cost factor. Also, there is an upper limit - a battery that is continually cycled 5% or less will usually not last as long as one cycled down 10%. This happens because at very shallow cycles, the Lead Dioxide tends to build up in clumps on the the positive plates rather in an even film.


The graph above shows how lifespan is affected by depth of discharge. The chart is for a Concorde Lifeline battery, but all lead-acid batteries will be similar in the shape of the curve, although the number of cycles will vary.

Amp-Hour Capacity

All deep cycle batteries are rated in amp-hours. An amp-hour is one amp for one hour, or 10 amps for 1/10 of an hour and so forth. It is amps x hours. If you have something that pulls 20 amps, and you use it for 20 minutes, then the amp-hours used would be 20 (amps) x .333 (hours), or 6.67 AH. The accepted AH rating time period for batteries used in solar electric and backup power systems (and for nearly all deep cycle batteries) is the "20 hour rate". This means that it is discharged down to 10.5 volts over a 20 hour period while the total actual amp-hours it supplies is measured. Sometimes ratings at the 6 hour rate and 100 hour rate are also given for comparison and for different applications. The 6-hour rate is often used for industrial batteries, as that is a typical daily duty cycle. Sometimes the 100 hour rate is given just to make the battery look better than it really is, but it is also useful for figuring battery capacity for long-term backup amp-hour requirements.
Why amp-hours are specified at a particular rate:

Because of something called the Peukert Effect. The Peukert value is directly related to the internal resistance of the battery. The higher the internal resistance, the higher the losses while charging and discharging, especially at higher currents. This means that the faster a battery is used (discharged), the LOWER the AH capacity. Conversely, if it is drained slower, the AH capacity is higher. This is important because some folks have chosen to rate their batteries at the 100 hour rate - which makes them look a lot better than they really are. Here are some typical battery capacities from the manufacturers data sheets:
Battery Type.............100 hour rate..........20 hour rate.......8
Trojan T-105................250 AH...................225 AH.........n/a
US Battery 2200..............n/a......................225 AH........181 AH
Concorde PVX-6220.......255 AH...................221 AH.........183 AH
Surrette S-460 (L-16)....429 AH...................344 AH.........282 AH
Trojan L-16..................400 AH...................360 AH...........n/a
Surrette CS-25-PS........974 AH...................779 AH..........639 AH


State of Charge

Here are no-load typical voltages vs state of charge

(figured at 10.5 volts = fully discharged, and 77 degrees F). Voltages are for a 12 volt battery system. For 24 volt systems multiply by 2, for 48 volt system, multiply by 4. VPC is the volts per individual cell - if you measure more than a .2 volt difference between each cell, you need to equalize, or your batteries are going bad, or they may be sulfated. These voltages are for batteries that have been at rest for 3 hours or more. Batteries that are being charged will be higher - the voltages while under charge will not tell you anything, you have to let the battery sit for a while. For longest life, batteries should stay in the green zone. Occasional dips into the yellow are not harmful, but continual discharges to those levels will shorten battery life considerably. It is important to realize that voltage measurements are only approximate. The best determination is to measure the specific gravity, but in many batteries this is difficult or impossible. Note the large voltage drop in the last 10%.
State of Charge........12 Volt battery............Volts per Cell
100%.............................12.7............. ............2.12
90%...............................12.5............ .............2.08
80%...............................12.42........... ............2.07
70%...............................12.32........... ............2.05
60%...............................12.20........... ............2.03
50%...............................12.06........... ............2.01
40%...............................11.9............ .............1.98
30%...............................11.75........... ............1.96
20%...............................11.58........... ............1.93
10%...............................11.31........... ............1.89
0...................................10.5.......... .............. 1.75

********* end of excerpt ********
http://www.windsun.com/Batteries/Bat...attery%20Types
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Old 09-08-2006
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If you're using 170AH per day, and you want to go four days without recharging,.

Some questions:

1) What kind of boat are we talking about? Size, beam, etc.

2) Where are you sailing/cruising?

3) Are you going to be anchored out, at marinas, or a mix?

4) What size alternator do you have on your engine?

5) Are you looking just at solar, or do you want a combination of solar, wind, and generator/alternator recharging sources?

Given your daily use, you'll probably need a bank at least 600Ah in size, which would give you basically two days worth of run-time without any recharging. That's about six T105 golf cart batteries, or three 8D batteries.

Also curious as to how you have such a high daily usage? What are you running?
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Old 09-08-2006
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Shack...ARE YOU BUILDING THE QUEEN MARY?
That 24A package is THREE panels each at 130 watts per panel and 5'ft by 2 ft. and you think you need 6 of those panels to make the amps you need. That is a panel that is 5 ft. long and 12 ft wide! (IF THE SUN IS SHINING AND IF YOU ARE ROTATING THEM AND KEEPING SHADOWS OFF OF THEM!)
I had TWO Kyocera panels at 80 watts each and they gave me about 40 amps on a good day. In combination with a wind generator (4 winds...excellent!) which combined averaged about 100amps a day.
With 170 AH/ day needs I would encourage you to think about a diesel generator.

Furthermore, at 170 AMPS/day and wanting to run for 4 days without recharge you'll need roughly 700 Amp hours which will require 1400 AH house battery bank or SIX 8D sized batteries. Where do you plan to put those?

It would be helpful to understand what type of boat you are considering and where you plan to cruise in order to help you with some of this stuff.
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Old 09-08-2006
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Kween Marie II??

Thanks for the replies

Here’s the boat info:
Sailing area – Caribbean and Eastern Seaboard.
Planning a 65’ steel hull multi-chine ketch or schooner with 100k disp.
Two living on board. Amp draw based on model by Constantine Von Wentzel’s, but plused up with a couple more appliances in the interest of conservative calculations.
(Small wash/dry, DSS TV, nuker, fridge, freezer, dehumid, standard boat equipment like lights, nav, windlass, autopilot etc.) See links below.

Yes- that is 3 panels in each CC24000 kit!!

Overview: Panels will fit on top of the wheel house. I would need to achieve 70% efficiency with 2 kits to get close to matching my theoretical 170A/day draw. With a 5 day charge I would need 1700Ah of storage to avoid going below 50%. (or 1360Ah for 4 day storage.).

Here’s my best Einstein impersonation for the Amp-math.

Assumptions:
Max cloudy day streak = 4 to 5 days.
Max Amp draw = 170Ah/day
Avg peak sun = 5 hrs

Solar Amps:
24A/kit x 2 kit = 48A
48A x 5hr/day = 240Ah/day
240Ah/day x 70% eff = 168Ah/day

Panel Array:
Each panel is 60’x28” or roughly 5’x2.5’
3 pnls/kit x 2 kits = 6 pnls (and a whole lot of $$$)
6 pnls arranged in 2x3 array = 10’x7.5’
Wheelhouse roof with overhang is about 11’x11’.

Drilling Down with some reality:
I can shave quite a bit down by including a generator, as you recommended earlier. A gallon of gas can probably go a long way in the right gen. I can also add wind or hydro to reduce the solar. However, I think I’d like to do a cost/Amp comparison there, too. I’m thinking a big batt bank not only gives me amperage for night time or rainy days, but also may extend batt life by allowing me to avoid deep discharge on fair weather days, too.

I’d like someone to shoot holes in this plan to help me shore it up.

http://www.vonwentzel.net/Battery/05.Model/index.html
http://www.bruceroberts.com/public/HTML/TRADER65.htm

“Leaning from one’s errors will make one a wise man, but it is the smart man who leans from the wise man’s errors.”
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Old 09-08-2006
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hi, i just the other day listed a classified on sailnet for 18 brand new solar panels. they are 55 watts each. if you are interested or want more information please send me a e-mail to: totallywiredracing@comcast.net. they are still in original boxes and never even been removed from them...mike
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"Planning a 65’ steel hull multi-chine ketch or schooner with 100k disp."

This puts you in a whole other class from, e.g., a 35-45' vessel. 170AH per day ain't that much for a vessel of this size.

The key to your onboard generation/charging systems (wind, solar, diesel generator, alternators bolted to engine, fuel cell, battery chargers, etc.) lies in your analysis of how you're going to use the boat.

If, for example, you planned to be aboard every day you could get by with a small diesel generator...5KW or more...a healthy battery charger (120A or more)....a big alternator (120A or more)...an a healthy house battery bank of 700AH or more.

If you plan to be off the boat for a few days, the calculus gets more complicated. One thing you need to do is to carefully examine that 170AH per day load estimate in terms of when you're aboard and when you're not aboard. For example, when you're gone you won't be using the instruments, most of the lights, the TV, toaster, hair dryer, etc., etc. What is the expected daily load in AH when you're off the boat?

Next, you need to think about battery space and capacity and cost and maintenance and how you're gonna charge a big bank. Knowing the amperage draw WHEN YOU'RE OFF THE BOAT will help you to calculate the battery capacity required with:

- no charging at all
- solar panels
- wind generator

To keep it simple, if you expect the load to be 150AH per day, then you'd need a house battery capacity of 150AH x days absent x 2. Example: if you expect to be gone for 4 days, you'd need a battery capacity of 150 x 4 x 2 = 1200AH.

Now, suppose you had solar panels capable of averaging 75 AH per day. Now, you'd need to draw only 150AH less 75AH or 75AH from the batteries each day, so for a 4-day absence you'd need a house battery capacity of 75 x 4 x 2 or 600AH. Say, three banks of two golf-cart batteries for 675AH capacity (which is what I have on my boat, with an average AH draw of 125AH per day when cruising).

A wind generator could cut this even further or, more practically, allow you to be away a bit longer.

Whatever you have in the way of solar panels and wind generators, however, it's very likely that you're going to need a diesel generator as well in order to keep those batteries well charged. Nothing kills a battery like chronic undercharging.

Hope this helps a bit.

Bill
S/V Born Free
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Old 09-09-2006
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Ditto what Bill said! You could mount two wind generators on there as well and that should take care of your "away from the boat" concerns" in combo with the solar panels.
As Bill says, the generator will be needed but not sufficient if you leave the boat at anchor for several days. If you go into marinas when you are going to be off the boat for a while, you can save the money for solar and wind power and simply use a diesel generator. My 8KW uses less than 1 Gallon an hour.
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Just ran across this thread on the SSCA board and thought you'd find it interesting as it pertains to the choices you're making. (See the tbeetle post on the page). Also not the additional amp load on passages due to autopilot use + other instruments. Have you figured this into your 170 amps/day?
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Old 09-09-2006
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Quote:
Originally Posted by camaraderie
Just ran across this thread on the SSCA board and thought you'd find it interesting as it pertains to the choices you're making. (See the tbeetle post on the page). Also not the additional amp load on passages due to autopilot use + other instruments. Have you figured this into your 170 amps/day?

Nice - I'll check it out. I have heard some Mariners speak of using smaller wind gens (less power) as the large ones get beat up in the higher winds. Nice how nature throws one curves?
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