Batteries and charging system

[rkappel]

I'm the new owner of a 2000 26x there is 1 Battery in it and Ive several Questions. If we want to be out for a week at a time what do you sujest we do to the system to allow us to stay out with out recharging. Do you have a sujestion on specific components with out spending all of my money. Can I charge the battery with the outboard motor. its a 50 hp mercury bigfoot??

[kmclemore]

That's really hard to say - it all depends on how much energy you use! If you're like many of us and you've got a computer going or have a TV or stereo on board and other conveniences, then no, you probably can't go a week. However if you're only talking marker lights at night and the occasional interior light, then yeah, you'll make it for a week.

The Merc 50 has a 10 amp alternator, and it puts out around 8.5 actual amps, so it's not the best battery charger but will certainly help.

As for me, I went solar and have a small 1000w genset on board for when things get cloudy or if my solar can't keep up.

[Matt19020]

I also believe your best bet would be a generator. Especially if you are going to be staying out that long. Honda & Yamaha both have nice items from what I have read. They are more money but I think in the long run it will be worth it. You can get some cheaper ones at a Pep Boys or similar type of store for under $300, but I am unsure on the reliabillity or the noise factor.
A generator is on my wish list this year. I think I will go with the Honda 2000 only because I have a portable Air Conditioner I hope to be able to power with it.

[jeffz]

There was a fairly in depth discussion on this last fall. Search for "cruising and batteries"

Bet you will find as much agreement as which engine is best! LOL


it is titled "batteries & extended cruising" authored by poker rick

Seemed many thought our choice of 2 6v golf cart bats plus a 12v starting bat were overkill but who cares. I like my music and want to be able to start the motor any time.

Our dealer recommended this setup. They said about one night is all their single battery is good for based on sailing most of the time and running the stereo.

jeffz

[Night Sailor]

Hi welcome to the energy conundrum....
Be aware that the battery that came with the boat may not have been charged properly, so may be more than half way gone. You can't tell with a voltmeter how well the battery will hold a charge. Since you only have one battery, and that is the most convenient way to start that big motor, I suggest not trying to go a week on it, even with minimal usage, unless you intend to motor quite a bit every day.

There are many posts in the archives about various systems of multiple batteries. First, decide what kind of battery you will want in the future, since one should not mix different kinds, ages, or sizes of batteries on one charging system. Then I suggest going ahead and increase your system to two brand new batteries of the same age, size and type. By all means be sure you get a pure deep cycle battery, not a hybrid or starting battery. It will serve you best for short periods of charging and long periods of current draw. One primarily for starting the motor , one for everything else. Study the methods of switching used, and choose one that you like which allows you to use batteries individually or in an emergency, to use both together in parallel to start the motor.

Happy reading, then happy cruising.

[Catigale]

Kevin - were you basing that 10 Amp rating on the Merc 50 on the 2000 model year? By 2002 they were shipping 18 amp (200 Watt) alternators on Merc BF 50s I believe.

You next step for batteries should be a backup jump start battery which You can count on to start your engine. You should also practice to see if you can pull start your motor to see if that is an option.

With a single battery and a starter backup, you can cruise with lights only for a week if you watch your light consumption. Stereos and DVDs will change that of course.

I like the dedicated separate jumper battery that I know cant be left on accidentally and drained so that I know Im always a few minutes from engine on.

[DaveB]

I recently bought a Mac X 1997 for $7500 in good condition, without trailer and same single battery without a battery switch. I figuare I can get all new things I want includeing a aluiminum Tandem trailer and still be under market value (trailer $2650, will be here tomorrow) .
I am going to put almost same setup as I have on my Potter 19. Twin AGM batteries (Potter has Gell, yr 2001) with battery selector switch, these batteries will be parrel and be used for house and engine starting. I will also have a very small battery not connected to anything for motor backup.
I will install AC power outlet connected to a 10 amp battery charger so when I come home all I do is plugin.
I have been crusing the Potter up to 6 days (that was at BEER and went down to 11 volts)and the 5 hp outboard has no charger, I have autopilot, TV, vhf,Depth and sterio going. The anchor light is a WM LED Garrity, runs on three c batteries and set in low will do 98 hrs, this is close to the coastguard requirement, med is for sure.
Use LED lighting below decks to except for reading. (I have twin pack 6 leds thru Lowes for $15 that you can clip anywhere and two settings, 2 AAA batteries).
The Mac has a Honda 50 hp and doesn't say in owners manuel what the charge rate is but I assume 10 amps or greater so this will increase the batteries power.
I also will install another elect. panel and install a digital volt meter.
I will also bring My $125, 1200 watt 2 cycle generator that will fit in gas storage and put aft when in use for AC (I live SW FL.)
Dave

[Moe]

The first thing to check is whether your existing battery is a starting battery, or a dual-purpose or deep-cycle battery. A starting battery is NOT designed to be deeply discharged and will have a short life used in that manner. A dual-purpose is a deep-cycle battery slightly modified for starting use as well. However, with small 50-60 HP outboards, a deep-cycle battery is way more than enough for starting.

In 2000, the Mercury Bigfoots may have had only 10 amp charging, but later models have twice that. This is the most available for charging and its output will only be what the battery draws from it. A single Group 24 deep-cycle battery (roughly 75 amp-hours capacity) can draw as much as 15 amps or more (if it's available) when discharged down to 50%, but will only draw about 7-8 amps when 80% charged, and even less than half that when 90% charged.

It's really not worth running the outboard (or an on-board generator powering a 120VAC charger) for charging when the battery isn't below about 80% (which in the case of a Group 24 means within 15 amp-hours of full), because it takes between two to four times as much charge time per amp-hour above that charge level.

Let's say you run a 10 watt USCG-approved anchor light (0.73A) for 10 hours/night or 7.3 amp-hours. Plus you run the two cabin lights (1.44A each) for 2 hours/night or 6 amp-hours. No other electrical use. The first night gets you down from fully charged (assuming a new battery with full capacity), to 61.7 amp-hours (83%) left and it's not worth recharging the day after the first night. However, on the third day, after the second night, you'll be down to 48.4 amp-hours left (about 65%), so it's worth running the outboard. Charging at about 6 amps at whatever the minimum rpm is (2,000-3,000 rpm usually), you'll need to run about 2-1/2 hours, since you have to put back at least 10% more than what you used, in order to get back to 80-83% charge. As long as you do that every day, you should be able to continue for 7 days or beyond until you run out of gas.

And each day, you should have sufficient battery capacity left to start the outboard. If you're going to make a 5+ hour outboard run one day, you may be able to skip charging the day before and still have about 50% capacity left, which _should_ be able to start the outboard for the 5-hour run. However, using one single battery or battery bank for both starting and "house" use, you should definitely have a jump-start pack.

If you want to power other electrical loads, you have two choices, either add more battery capacity and/or reduce the power required for anchor and cabin lighting (with LED alternatives for example). If you're a sailor who cringes at the thought of having to run an outboard for 2-1/2 hours every day, the latter should be attractive anyway.

If you add a second battery for two in parallel, and use additional power for other electrical loads, you may have to run the outboard longer. I say "may" because with only one battery, you're probably not using all the capacity of even a 10 amp alternator and certainly not that of a 20 amp alternator. Even if you use twice as much electricity with a second battery on a 10 amp alternator, you won't have to charge quite twice as long.

If yours is like ours, it's easy to add a second Group 24 battery to a 26X, but it's best to use two identical deep-cycle batteries of the same age. Our original Group 24 battery was held by a metal strap bolted through the inboard face of the aft galley seat. It sat directly on one of the molded in tubes that join the front and rear water ballast tanks. Our boat actually came with the second battery, but it was just sitting on the hull. I removed the batteries, placed them together on a 1/4" piece of plywood and cut a piece large enough for the two. I placed some shelf liner on the ballast tube to help protect it, and a couple of cheap, small boat fenders outboard of the tube to support the plywood and keep the second battery off the hull, protecting it. I did have to adjust the air in them to get the plywood level. I then reinstalled the first battery, with nylon straps that would go around and hold the second battery to the first. Then the second battery is tightly strapped to the first. Our boat came with a Perko Off-1-Both-2 switch, installed in the aft face of the aft galley seat facing the aft berth, but you could just parallel the two batteries (+ to +, - to -) with short battery cables if the batteries have screw terminals.

That's a start. I hope it helps.

[Catigale]

Just reiterating one part of Moes comprehensive post above.

DONT BUY a starting battery even though a well meaning person might say you need one. A 50 HP outboard is a pipsqueak motor in the marine motor world and a dedicated 'starter battery' is not required.

[c130king]

Stephen, Moe, or anyone else that may know,

Apologies if this question is too "rookie-ish"...

I don't have a battery meter but I do have a multi-meter and I occassionally check my voltage on my single battery...not sure what type it is...probably the standard battery from the factory.

Voltage has always been 12 or a little higher.

Is there anyway to check amp-hours remaining? Or do you just have to know amp-hours to begin with and mentally subtract your useage for the day as Moe described?

Do the battery monitoring systems mentioned in earlier posts on this thread tell you more than voltage?

Thanks,
Jim

[Moe]

On our C-18, I carry a cheap digital multimeter (I've checked against a good one) with a lighter plug on the end of the leads. I use it against this resting voltage chart from The Twelve Volt Side of Line. I also have no alternator in the outboard to put a surface charge on the battery, which can make a hugely different, misleading voltage reading. So I don't have to make sure I've waited 6-8 hours for it to bleed off. I also recognize that reading voltage without temperature compensation is pretty inaccurate, so I seldom use this method, mainly for Barb's peace of mind (she's afraid the anchor light will go out overnight).

If you want a much closer to accurate method of monitoring battery capacity, there's no substitute for a battery monitor like the Xantrex Link 10 or 20 or XBM, Trimetic 2020, etc. They give you amp-hours or percent capacity used or remaining, and instantaneous voltage or current.

[Catigale]

Apologies if this question is too "rookie-ish"...

Philposophy of this Board is that no question really fits this description here!

[Captain Jim]

Cat,

Would two deep cycle batteries be best or would a marine and deep cycle battery be best?

DONT BUY a starting battery even though a well meaning person might say you need one. A 50 HP outboard is a pipsqueak motor in the marine motor world and a dedicated 'starter battery' is not required.

Great information here!

Thanks,
Jim

[opie]

Link Here

Some thoughts: 1.You need a good digital multimeter to test the battery voltage since the expected readings are all close to 12 volts but mean significantly different things as you go up and down a few tenths of a volt.
2. The above link should be read thoroughly and note the voltages given in item # 6 on the link.
3. Specific gravity is very important. True Value hardware has a hydrometer for $6.99 that has built-in thermometer for temperature corrections. My experience was that I had bad cells that would not show up on a voltage test with my Fluke digital volt meter.
4. "Surface Charge" can fool you into thinking your battery is fine when it is not. Read the link above and put a heavy load on the battery for a minute or two before the voltage meter reading.
5. Remember to add distilled water to cells if your battery has openable cells. When I bought my X it took a quart to top off the cells.