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Old 28-07-2014, 17:31   #16
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

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Originally Posted by Ex-Calif View Post
This post is key - You are sort of starting at the wrong end of the equation.

Any consumption needs to be figured out first. Then you need a charging plan to producing that consumption plus a charging efficiency loss, say 10%.

A fridge is gonna consume 60-70amps a day + everything else means you are looking at maybe 150 amps a day.

First you gotta figure out how to produce that number of amps.

The battery then is simply how long you can go before charging consider the max you want to use is about 50% of battery capacity - a 600 amp bank will let you go ~2 days without charging.

Finally deeper cycles reduce battery life - 30% cycles are easier on the battery than 50% cycles all things being equal.

AGM batteries really need to get to 100% frequently and the last 10% is hard to get into the battery.

Wet cells are more tolerant but they also have certain maintenance needs.

It isn't really, "Get the biggest battery for cheapest" equation here.
Ok Im beginning to understand,
It looks like I should research getting golf cart batteries then?
I dont know off hand but I know I want a whole bunch of them, but realistically, how many batteries would you recommend I make a series of?

Are there any other deep cycle batteries that I should look up rather than buying 6 or so tiny golf cart batteries?
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Old 28-07-2014, 17:34   #17
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

To get an idea of how many amp hours you need in a battery bank you need to have an idea of your daily consumption in amp hours, then you need a battery bank that has about three times that many amp hours.
You shouldn't discharge below 50% as doing so reduces a batteries life, but it's very difficult to charge beyond 85%, leaving you with about 35% capacity to use.
These are just a few things you need to know before you spend your money, I'm sure someone has a link to explain from beginning to end all you need to know about batteries, but I don't, I'm learning myself.
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Old 28-07-2014, 17:44   #18
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

Quote:
Originally Posted by masterolive View Post
Ok Im beginning to understand,
It looks like I should research getting golf cart batteries then?
I dont know off hand but I know I want a whole bunch of them, but realistically, how many batteries would you recommend I make a series of?

Are there any other deep cycle batteries that I should look up rather than buying 6 or so tiny golf cart batteries?
Again you are sort of at the wrong end of the equation. I guessed at your consumption of 150 amps. 200w of solar will net you maybe 80 amps a day in good sun. You are still short 70 amps of charging per day.

When one decides to have full time refrigeration the "power" game gets a whole lot more complicated.

You could go with a 300 a/h bank and a Honda generator for example.

You could get 400w of solar and run the engine a bit every few days.

At some point you have to generate the power regardless of the battery you store it in.

The most common setups are wet cell with 2 plus days of reserve. So if you consume 150 amps a day you need a 600 amp bank. Minimum (baring the generator idea). As others have posted that can be divided among batteries of the same type (Wet, Gel or AGM)

Wet cells are most common because they are more tolerant of charging errors and abuse. AGM is the second most common install and require more care with the charging cycle.

For Wet cells, golf cart batteries are common because the supply is plentiful and they are purpose designed for slow repeated discharging. The other "go-to" battery in wet cells is Trojan (I encourage you to look at their website)

For AGM I encourage you to look at Lifeline's website - pay particular attention to the links at the bottom.

Lifeline Batteries - Marine & RV Deep Cycle Batteries
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Old 28-07-2014, 17:45   #19
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

DISCLAIMER.

You guys are helping me so much and I really really appreciate all of this info.
Each post I learn more, and have new questions, but Im starting to respond out of order.
I am learning as I go, and when I discover new batteries, I read the specs assuming that the high numbers is what Im supposed to look for.

SO, Just so I dont sound like a thickheaded numbskull: Im starting to understand, DEEP CYCLE, GOOD! CCA, BAD! AMP PER HOUR, MANY ENERGYS!

Im sitting in McDonnellds right now unable to look at fuses and devices that we are using to figure out our consumption in amp per hour, but I wish I could because I need to figure this all out ASAP.

So Im asking the stupid question: how the hell do I add up my consumption by amp per hour?
Do I go directly to my switch board and add up the fuse amps and assume they will run constantly?
Once I figure out HOW to properly add up my consumption, I totally understand how to match up how many "Golf Cart" batteries I may need.

Ive never been good at math, but a simple explanation what I physically have to look at on my boat in order to add these number up will help.

Or suggesting a number of golf cart batteries would also help as a numbered guide for starters.
Thank you again guys, you have literally saved me money, and taught me a good deal about batteries.
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Old 28-07-2014, 17:52   #20
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

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Originally Posted by Ex-Calif View Post
Again you are sort of at the wrong end of the equation. I guessed at your consumption of 150 amps. 200w of solar will net you maybe 80 amps a day in good sun. You are still short 70 amps of charging per day.

When one decides to have full time refrigeration the "power" game gets a whole lot more complicated.

You could go with a 300 a/h bank and a Honda generator for example.

You could get 400w of solar and run the engine a bit every few days.

At some point you have to generate the power regardless of the battery you store it in.

The most common setups are wet cell with 2 plus days of reserve. So if you consume 150 amps a day you need a 600 amp bank. Minimum (baring the generator idea). As others have posted that can be divided among batteries of the same type (Wet, Gel or AGM)

Wet cells are most common because they are more tolerant of charging errors and abuse. AGM is the second most common install and require more care with the charging cycle.

For Wet cells, golf cart batteries are common because the supply is plentiful and they are purpose designed for slow repeated discharging. The other "go-to" battery in wet cells is Trojan (I encourage you to look at their website)

For AGM I encourage you to look at Lifeline's website - pay particular attention to the links at the bottom.

Lifeline Batteries - Marine & RV Deep Cycle Batteries
Following my post above, I WILL be able to run my engines alternator, assuming that would work as an alternative method for a "generator"
I have a 50gallon tank to A4 engine.

I didn't mention it because Im trying to overestimate pure solar+batteries for now, so I can get a good set up, and be in a better situation to power them up with the alternator as a last resort. (If possible)
I allredy have two deep cycle starting batteries dedicated to the motor.
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Old 28-07-2014, 18:25   #21
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Help with batteries: TWO lead 4Ds or ONE gel 8D.

One way to determine electrical consumption is with a device made to do just that, but they are about $300, I think.
Another way is to buy a clamp on load meter and actually measure electrical consumption of "everything" one at a time, then honestly you have to guess at how many hours a day each device is used and add that all up.
Or and this will get me in trouble but I think by measuring starting voltage of your current battery bank, than 24 hours later after normal use, measuring it's voltage after letting the batteries rest for a few hours, re measuring it's voltage you can get a decent educated guess on consumption as long as you know your banks true capacity to start with. If you go by what the batteries say on them your actual capacity will be less, so you'll overestimate consumption, which means you'll end up buying a bigger bank than you will need, which I think you should do anyway.

But first you will need to address your recharging plan, if you don't frequently recharge your batteries to full or almost full, you'll shorten their life.

Are you going to live on the hook full time, or will shore power be available? That will make a big difference on how your going to recharge.

It may be prudent to cover your recharging ability first, after determining how much power your going to have to put back in each day, before buying a new bank. If you abuse new batteries by not recharging them well, they won't last nearly as long.

This whole electrical consumption "budget", battery bank size, type and how to charge thing is complicated and expensive.

I'm a weekend sailor until I can afford to go full time, so I have shore power during the week while I am gone, so I think for me I first need a good smart charger, I want one that is an inverter too, then a good battery bank, but maybe wait on Solar and a high capacity alternator and external regulator until we go full time.
As I understand it, there are essentially four sources to charge a battery bank.
1. Shore power
2. Engine alternator, most people go to an expensive high power one that is externally regulated as if you don't you'll be running your engine for long times to charge batteries
3. Solar
4.Generator, little Honda's are real popular
Or usually all or most of the above, Generator may be the first to get cut,
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Old 28-07-2014, 18:31   #22
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

But, I think if you plan on living off the grid so to speak and not having shore power available, depending on where you live and if you have a place to mount enough of it, Solar seems to be preferable
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Old 28-07-2014, 19:01   #23
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

As A64 says the best thing to do is to measure your loads. Then complete an energy worksheet - sample attached. It's not mine but I think it is a good one and leveraged it from the internet.

A clamp meter is useful to have.

However - to get started you can guesstimate like everyone else does. Then I'd post it and get a "sanity" check from folks who are out there.

If you are going "off grid" you really need something to measure your eventual battery bank.

I have been searching myself for the best solution but really have come up with this.

Smartgauge - Smartgauge is pretty much the latest technology and is self correcting in measuring the state of charge of your battery. Unfortunately it doesn't count amps.

I am also installing a BMV602 monitor which will count amps. It is about $170 more but I haven't found a stand alone amp counter although many members post they have one, no one has coughed up a model number - LOL.

I know this is getting far afield from - "Which battery do I buy?" but if you are seriously going "off-grid" your energy management will become one of your most important skills.
Attached Files
File Type: pdf Energy Budget Sample.pdf (20.1 KB, 33 views)
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Old 28-07-2014, 19:08   #24
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

OK, let's start over.

1. Forget all the nonsense you think you know about 8D batteries. Hogwash. *d and 4D batteries are NOT deep cycle batteries.

2. You need to do an ENERGY BUDGET, just like your household budget.

3. You will NEVER be able to run a fridge with only a 100W solar panel wihout other methods of charging.

For you to followup:

1. Buy a book about boat electrical systems. Calder's books are very good.

2. Wouldn't hurt to read this: Electrical Systems 101 Electrical Systems 101 Might save you some time.

Good luck.
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Old 28-07-2014, 21:33   #25
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

electrical storage is electrical storage. a hernia or sprained back is another problem , usually one which will sideline many dreamers.
8D batteries weigh in at 160 pounds. ok
i use 4 costco equivalent of t105 trojans, easier to carry and pullout of the infernal place they always have batteries hide in boats.
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Old 28-07-2014, 21:37   #26
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

What zeehag says. 4 golf cart batteries. 6 if you've got the room. Also bigger solar panel. By the way, 8d and 4d are not deep cycle batteries.

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Old 28-07-2014, 21:38   #27
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

Well, im back on the boat on my phone so i can atleast respond.
All of this is very hepful, Will archive this page for reference when i visit some places to look at batteries and while i check my boat.

Hopfully this wont become a drag but ill be reffering to this post for more questions as i come closer to figuring this all aout and making a purchase.
Thanks again, ill also check out those 101 links and the charge monitors.
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Old 28-07-2014, 22:02   #28
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

You have to look at your electrical system as a SYSTEM before you can start dealing with individual parts and pieces. What is your consumption going to be? How much can you expect your solar cell to provide to make up that consumption? How much can your alternator provide? What equipment do you need to protect your batteries? etc, etc. These are some of the questions you need to answer before you run out and buy batteries.

Here is a link to an excellent site that will help you to answer some of those questions.
Compass Marine How To Articles Photo Gallery by Compass Marine How To at pbase.com
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Old 28-07-2014, 22:14   #29
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

Masterolive,

Good luck, be patient

I had two 4D batteries. I could lift one by myself out of the locker, the other one took two people and a handy billy. Battery quality varies greatly. I killed both batteries because of the way they were wired together (typical 1980's factory wiring). I replaced them with 4 golf cart batteries. Redid the wiring (not entire boat wiring, just the wiring between sources and panels) to make the system easy to manage.

Now, I have a system that is easy to manage, easy to equalize, easy to add charge inputs (made my own bus bars so all cables had their own studs).

Below are two threads I started to get this done.

Battery Replacement/Rewire

House Bank - 2 separate or 1 parallel - SailboatOwners.com

There are many opinions and there are some very, very helpful people.

Do some research before you jump in and start buying stuff. Read, Read, Read and ask questions. Figure it out, then sleep on it and take your time. Your mind does a lot while you are asleep.

attached is a spreadsheet that might help you with the energy audit.
Get the Calder book, Boatowner's Mechanical and Electrical Manual
ISBN 0071784063

Stu, thank you again for all your help a few months back.









weight
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File Type: xls EnergyAugit.xls (30.0 KB, 29 views)
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Old 29-07-2014, 06:26   #30
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Re: Help with batteries: TWO lead 4Ds or ONE gel 8D.

Quote:
Originally Posted by masterolive View Post
Thank you for your reply, How well would golf cart batterys hold up when we are trying to create a large energy house with solar panels and a inverter?
(Im assuming they are small?)
Quote:
Originally Posted by masterolive View Post
Thankyou for this post.
YES I alredy have two deep cycle batterys dedicated to the engine ONLY.
Quote:
Originally Posted by masterolive View Post
Ok Im beginning to understand,
It looks like I should research getting golf cart batteries then?
I dont know off hand but I know I want a whole bunch of them, but realistically, how many batteries would you recommend I make a series of?

Are there any other deep cycle batteries that I should look up rather than buying 6 or so tiny golf cart batteries?
Quote:
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I allredy have two deep cycle starting batteries dedicated to the motor.

You don't need (and sometimes don't want) deep cycle batteries to start your engine.

Golf cart batteries are not "tiny." Imagine lifting approx. 70-lbs each. A single pair of golf cart batteries gives you almost the same amp-hours (Ah) as a single 8D. Say approx. 220 vs. 245. You can probably lift each golf cart battery by yourself. You may or may not be able to lift an 8D by yourself. Imagine shifting 70 lbs or so (at a time) into the appropriate location on your boat. Now imagine lifting the 120 lbs into that location. Your call.

You need as many pairs of golf cart batteries as will fit in the available space. More Ah is almost always better for house functions. (You may need to next examine your current or proposed charging capability.) Space will be a hard limitation; you have as much space as you have, period, end of report. Your consumption will therefore be subject to that limitation, too.

(You can calculate your projected consumption as others have suggested -- always a good exercise -- but it's often slightly easier to just put in as much battery as you can stand, and consume within that limitation. Augmenting with solar or wind or whatever can be useful, of course, but your (electrical) storage space is what it is.)

You might be able to massage that "available space" a bit by replacing your two deep cycle engine batteries with a single engine starting battery. (CCAs are important with starting batteries, but as I understand it, your engine is relatively tiny, so it probably doesn't take much. Your engine manual will say minimum CCAs, and your starter motor will likely have a plate on it with minimum CCAs stated.)

-Chris
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