Electrical system

[william24424]

Electrical system & reasons?
As a coastal cruiser/racer, occasional weekender I've used the following system. Not judging, not sure if I'm doing right thing, would like to know/learn what you folks are using for power?
1) Two lead acid batteries for starting, dual purpose, a switch (1-2-both) for LED interior lights, Nav lights, VHF radio, bilge pump, and GPS.
*Reasons= they work, & costed less.
2) Jackery 500 Lithium power station.
*Reasons= other stuff, fridge/freezer cooler, charging handheld VHF, iphones/devices, back-up jump if needed, charges with portable solar panel.

So far no problems, or course I believe there is always a better way. Thanks for your input.

 

[dlochner]

If it is working, there's not much need to change it.

The most important part of the electrical system is a good battery monitoring system to tell you what the batteries state of charge is and it state of health. Voltage readings sort of work, but they are not very accurate. Knowing the SOC will allow you to make good decisions on charging and use. The Balmar SG200 with the smart shunt and Bluetooth dongle works well.

After that, there are lots of changes that can be made depending on your actual energy consumption and your budget. The MarineHowTo.com site has a wealth of great information on batteries, monitors, and charging.

 

[Don S/V ILLusion]

It's important to the life of your batteries to charge/recharge them properly if you want to them to be dependable.

 

[Scott T-Bird]

Curious if your FLA batteries are in parallel on one battery bank or one battery for each bank. What is your capacity?

 

[william24424]

Parallel FLA 12V 800 amps each battery... I think, I'll check this weekend, doing some winter jobs under the canvas. I put a trickle charge on batteries while working on boat a few times a month. I'm going through the electrical system & checking wires, cleaning runs, and learning about electrical systems/maintenance ect. I removed old speakers, along with wires going no where, it's amazing how much stuff the boat has accumulated over the years.

 

[jssailem]

it's amazing how much stuff the boat has accumulated over the years.

Oh yes.
Folk buy boats, then think I'll join a race to test my skills.
They see all the boats sailing away from them. They immediately start too try and buy new gear, sails, bottom paints so that they will be as fast as the other boats.

It fails to work.

So then they start looking at training, classes, seek help from a coach.

Only to have the coach show up on the boat and tell the owner "My God man... Get rid of all this junk on the boat. Call me when you have her lean and mean".

As you remove comfort stuff, you'll see the boat rise up out of the water.

 

[Scott T-Bird]

I was asking about capacity in amp-hours (ah) which is the typical capacity specification for deep cycle batteries. Describing it as 800 amps makes it sound like dual purpose starting and moderate deep cycle batteries (usually marketed as a "Marine" battery). I'm guessing they may be Grp 27 size? The 800 amp is cranking amps, I suppose. I'd guess that each might be 75 ah in deep cycle capacity? You might have 150 ah capacity, which translates to just 75 ah in useful capacity. (That's just my guess - specifications seem to be pretty vague on these batteries) I suppose they are fine for the moderate needs of a casual (weekend) cruiser. That type of battery is typically marketed towards power boaters (I think). Don't cringe. It sounds like they are perfectly suitable for now. Besides that, if you are maintaining a racing sailboat, your goal could be to limit the size and weight of batteries to a minimum - perhaps shop for LiFePO4 batts?

Since you are wondering (wanting to know/learn) what many of us are doing ... on cruising sailboats, we typically lean on true deep cycle batteries depending upon our capacity needs. I went with 200 ah capacity for house bank on my 27' pocket cruiser. Now I have about 400 ah capacity on my boat. I have 2 deep cycle (4D size) 12v AGM batts (200 ah each). I also have a single 100 ah AGM (Grp 27 size) dedicated for start and windlass. It serves as my auxiliary battery. With our small engines, we typically don't need a powerful cranking start battery. Many folks simply start with their house bank and others use a small starting battery that may by described as an 800 CCA FLA.

This discussion can easily be launched into an epic thread if you are asking more specific questions!

One thing I will comment on at the outset ... don't rely on a cheap automotive trickle charger if you care about the health of your batts. They will be chronically undercharged to an early death if that is your mode of charging. It may not matter if the batts are the cheapest available.

 

[Scott T-Bird]

Another question ... do you use a trickle charger only in the winter when you don't plug into shore power? Do you have an on-board marine charger hard-wired to your AC system?

In the winter, I plug my shore power cord into a 15 amp outlet (with an adapter) and use my on-board charging system to keep batts topped off when I'm visiting the boat - I find that the charger and an occasional hand tool doesn't require a lot of amps so I think it is safe.

 

[dlochner]

Parallel FLA 12V 800 amps each battery..

This is unlikely. The batteries would be quite huge or a large number of them. Do not confuse cold cranking or reserve amps with actual amphour capacity. An amphour is a measure of usage or capacity and is equal to 1 amp used in 1 hour. CCA refers to how fast energy can be delivered, which is essential to starting engines because of the huge rush of energy that is required to start the starter motor.

Some basics you'll need to understand are amp hours and wattage. They are related. Watts are equal to volts times amps. So a 1 amp load is 12 watts at 12v or 120 watts at 120 volts. Likewise something that consumes 120 watts at 120v draws 10 amps at 12v. Once you get the hang of the math it is all pretty simple. Read and study Ohm's Law.

 

[william24424]

Thank you. Reading & studying.