Association Forum - battery charging

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

battery charging

New Topic

Topic Locked

Printer Friendly

Author

Topic

Page: of 2

knightwind
Navigator

Member Avatar

Canada
114 Posts

Initially Posted - 04/23/2008 : 13:10:17

I recently purchased a 1973 Catalina 25 and am now looking for a parking spot. My question is...do I need a shore power hookup to charge the on board battery? Does the boat have a built-in charger? Will an outboard motor charge the battery? I can't get a hold of the previous owner to ask these questions. He said it doesn't have two but it has "one big battery".
Any help will be greatly appreciated.

Edited by - on

newell
Navigator

Members Avatar

USA
113 Posts

Response Posted - 04/23/2008 : 13:27:10

The answers to your questions are multiple!
1. You do not need shore power if you do not store for an extended period of time
2. You do not need shore power for extended storage if you have a solar panel.
3. Your bot may have a buit in charger....you will haev to look for it as they did not come standard equipment.
4. An outboard motor MAY charge the battery but that will have to be determined empirically.

Edited by - on

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 04/23/2008 : 13:28:47

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by knightwind
 I recently purchased a 1973 Catalina 25...<hr height="1" noshade id="quote"></blockquote id="quote">

Are you sure you purchased a 1973 C25? They didn't start making them until 1976.

Edited by - on

knightwind
Navigator

Members Avatar

Canada
114 Posts

Response Posted - 04/23/2008 : 13:32:35

Its a 1979.

Edited by - on

stampeder
Master Marine Consultant

Members Avatar

1608 Posts

Response Posted - 04/23/2008 : 13:50:49

Welcome to the group Peter.
Where are you looking for a parking spot?

My C25 is on a mooring ball, we found we don't use our house batteries that much. We usually leave them at home on a trickle charger then take them to the boat when needed. ie- cruising for a week or long weekend.
Our OB will charge our batteries. You should either buy a meter that can be permanently installed to monitor your batteries' status, or get your self an inexpensive all-round electrical meter that you can leave aboard. I paid $14 for one at Cdn Tire.
Your electrical system is one you will want to tweak to your own preferences. As I often tell new buyers of these boats - wait until you've sailed it before you make too many decisions.
Best way to get advice and info on the forum is to post pictures along with your questions, and to add details to your profile so any potential responses can be addressed to your specific boat.

Edited by - on

knightwind
Navigator

Members Avatar

Canada
114 Posts

Response Posted - 04/23/2008 : 13:58:21

Thanks.

So you only typically charge a sailboat battery at the start of the season? and won't need to re-charge unless you're running interior lights all night etc?
Wouldn't a standard meter generally show you the 12V on your battery but not really tell you if your battery has enough power in it to start a motor?
I'm looking for a slip in the Port Rowan /Port Dover area.

Edited by - on

stampeder
Master Marine Consultant

Members Avatar

1608 Posts

Response Posted - 04/23/2008 : 15:00:47

A battery should be kept fully charged at all times. My point is, find the strategy that works best for you. A good place to start is 'The 12-Volt Bible for Boats' or similar book, that will answer all your questions and give you a lot of good, simple ways to manage your electrical system.
My suggestion is to attempt to use what you have first, because you may find that what you already have will work just fine.
For my own usage, I've found that two batteries is more than I need and we often don't even take our batteries when we go sailing. Especially if we're racing or if we are lake sailing for a day.
Because we're on a mooring ball, we can't plug-in to a charger and have to take the batteries home to do so. We have a small solar charger but it only maintains a charge and is not big enough to replace the charge on a depleted battery.

Also, there are certain tools that I think are a must for a boat, one is a multi-meter, that can be used to check continuity in wiring, and the health of your batteries etc.

Edited by - on

Frank Hopper
Past Commodore

Members Avatar

Pitcairn Island
6776 Posts

Response Posted - 04/23/2008 : 16:39:10

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by knightwind
 Thanks.

So you only typically charge a sailboat battery at the start of the season? and won't need to re-charge unless you're running interior lights all night etc?
Wouldn't a standard meter generally show you the 12V on your battery but not really tell you if your battery has enough power in it to start a motor?
I'm looking for a slip in the Port Rowan /Port Dover area.
<hr height="1" noshade id="quote"></blockquote id="quote">

Sailboats have a hard time charging their batteries from the outboard because most of us run our engines ten minutes at a time twice a sail. I don not factor my ob into my charging strategy.
If you get a slip or dry sail spot with power, get an onboard charger, keep it plugged in and check the water in the cells every year.
If you get a slip, dry sailing spot without power, or a mooring, get a solar panel.
If you are a fisherman who accidently ended up with a sailboat, take your batteries home after every sail and charge them at home and bring them back when you return to the boat.

Keep your batteries up

Welcome to the group.

Edited by - on

Dave5041
Former Mainsheet Editor

Members Avatar

USA
3758 Posts

Response Posted - 04/23/2008 : 16:57:39

12 volts is a nominal value, a standard meter will give you some indication of falling voltage and charge but a cheap battery monitor has a narrow range around 10 -14V and can be found for less than $15 dollars. If you don't use a lot of amps, the motor will charge at 5 - 6 amps and that may be enough. I have a hardwired 6 amp charger for shore power and it meets my needs, My wife has motion issues, so we don't anchor out as often as I would like and can plug in nearly every night. Little details like that are why Stampeder suggests sailing as is for a while - I could have bought a bigger and much more expensive charger and solar panel for no reason.

I sort of had two batteries for my previous boat - one on the boat and one charging on a backup sump pump at home and I switched them out every month.

12 Volt Bible for Boats is a good book to have from the beginning and so is This old Boat, they are both on my shelf. In the mean time, check boatus.com or West Marine for helpful tips, guides and articles. Welcome aboard.

Edited by - Dave5041 on 04/23/2008 17:00:17

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 04/23/2008 : 22:52:34

I found the the outboard kept my battery up for the whole season (including using the electric starter). We had to motor for half a mile from our slip before getting sails up, and again coming back in. We didn't do a lot of overnighting, and when we did, it often involved a fair amount of motoring.

Stampeder: If your outboard has an alternator, you really shouldn't run it with no battery hooked up--eventually it'll burn out the alternator.

Edited by - on

OLarryR
Master Marine Consultant

Members Avatar

USA
3477 Posts

Response Posted - 04/24/2008 : 05:52:26

A 12 volt battery in good condition reads more than 12 volts. My battery generally is in the 13+ volt range. Once a battery drops below 12 volts, then something is up, it is becoming weaker and is not fully charged.

I think many get away without having to charge with shore power or a solar panel thru the season because they use the battery for very limited uses and most have a motor that when used charges their battery. The thing is that some will use the motor sparingly - Just to get in and out of the marina. If you use your sailboat every week and keep the motor on (one that charges the battery) for perhaps an hour a week, then probably will have no issues through the season. But if you use the motor hardly at all (ie. 15 minutes/week) and on occasion also use your navigation lights for a few hours each week, then you might need to charge your battery every so often to maintain a full charge.

A battery will lose a little less than .5Amps/day in the summer moths and about .25Amps/day in the winter months just sitting around. So, on a weekly basis without being charged at all, it may be losing around 3Amps/week. Add 3 hours of navigation light use (with the standard bulbs)each week and that is (2 bulbs X .87 AMPs/each X 3 hours) about 5AMPs. So, there is potential to consume anywhere from 3 to 8 Amps a week and that is not using a depthfinder, etc added into the mix. Depending on the vintage and brand of your outboard, the max it will recharge is somewhere between 3-12Amps/hour , probably not that high if the battery is anywhere close to fully charged. So, a lot depends on just how long you run the outboard.

Having said all that, there are those that do not have an outboard that charges and they get away without shore power. They run the battery down and charge it up during the season. Probably get less service life out of the battery that way...but that's what some do.

A modest investment into a 5 Amp solar panel would not require a solar controller and would at least handle the day t day trickling down of the battery. It would at max put out about .3Amps/hour but probably closer to .15Amps if not always perpendicular to a full sun. At say 5 hours of sunlight/day and say for 5 sunny days/week, it would help charge the battery about 3.75Amps/week. That would help immensely and with some use of the outboard (charging as well), then you would be okay for a season. Less use of the outboard and coupled with more use of navigation lights and a depthfinder, then you may need to supplement the minimal charging.

Edited by - OLarryR on 04/24/2008 05:55:43

stampeder
Master Marine Consultant

Members Avatar

1608 Posts

Response Posted - 04/24/2008 : 10:35:47

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Stampeder: If your outboard has an alternator, you really shouldn't run it with no battery hooked up--eventually it'll burn out the alternator<hr height="1" noshade id="quote"></blockquote id="quote">

Thank you. I did not know that.
Maybe I better re-read my copy of the 12 volt bible.

Edited by - on

tinob
Master Marine Consultant

Members Avatar

USA
1883 Posts

Response Posted - 04/24/2008 : 11:42:13

Hi Peter, welcome aboard,

I'll keep this short. I start the New York season with two fully charged batteries, and moor at a dock with shore power. I sail daily , weather permitting, and run a Tohatsu 9.8 hp motor with alternator ten minutes to get the sailing area. I seldom need to charge at the dock, but do so when some of the electronics start to give questionable readings, especially the depth sounder( I sail in skinny water). If I were to be into overnighting I would do things differently, I don't so I'l let others cover that territory.

Val on the hard DAGNABIT, # 3936, pATCHOGUE, n.y.

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 04/24/2008 : 16:40:59

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by stampeder
 [quote]Maybe I better re-read my copy of the 12 volt bible.<hr height="1" noshade id="quote"></blockquote id="quote">...and your outboard owner's manual.

(Who knows--maybe I'm wrong about yours.)

Edited by - on

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 04/25/2008 : 08:29:59

If most, if not all, outboards come standard with an alternator, do you think everyone is putting a battery in their dinghy's or small runabouts? Do you think outboard repair shops hook up a battery when tank testing outboards?

Edited by - dlucier on 04/25/2008 08:30:34

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 04/25/2008 : 08:43:11

Don--just passing along what I've been told by a mechanic... If you use your outboard on a dinghy with no battery, you probably don't care. It's why 1-2-All-Off switches are designed to maintain contact in any changes between 1, 2, and All.

Edited by - Dave Bristle on 04/25/2008 08:44:52

OLarryR
Master Marine Consultant

Members Avatar

USA
3477 Posts

Response Posted - 04/25/2008 : 11:35:54

I understand that a dinghy, etc that has no battery has no need or care if the alternator does go kaput on an outboard. But this whole issue that running an outboard with charging capacity must be hooked up to a battery or it ruins the alternator, I wonder just how long running it that way does create the deficiency. Don, brings up a good point that when an outboard is tank tested, it is probably rare that anyone or a shop hooks up a battery...to protect the outboard's alternator. I just do not have the electrical smarts to know just how long or under what conditions you can get away without a battery hooked up but I have read/heard same thing that you should always have a battery hooked up/not keep the battery switch in the off position. Anyone know the real scoop on this ?

Edited by - OLarryR on 04/25/2008 11:37:08

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 04/25/2008 : 12:46:54

One would think that when buying an outboard with an alternator, if a potentially damaging thing might occur from not hooking the alternator output to a battery, the manufacturer would have warning stickers/labels plastered all over the place. I hope outboard engineers might have some clue that their outboards might be used in differing applications, such as dinghys or small runabouts, where a battery might not be used.

Edited by - dlucier on 04/25/2008 12:47:29

Dave5041
Former Mainsheet Editor

Members Avatar

USA
3758 Posts

Response Posted - 04/25/2008 : 18:22:51

Many engine electric systems include a sensor and substitute a dummy load to limit field voltage, but I don't know about outboards - read the manual. Generally, only electric start outboards 6 HP and up have an alternator as standard equipment; it can be an option on some manufacturers manual start motors down to 4.5 HP.

Edited by - Dave5041 on 04/25/2008 18:24:06

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 04/25/2008 : 19:07:48

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Dave5041
 Generally, only electric start outboards 6 HP and up have an alternator as standard equipment; it can be an option on some manufacturers manual start motors down to 4.5 HP.
<hr height="1" noshade id="quote"></blockquote id="quote">

I believe alternators are standard equipment on all Hondas, regardless of starter option, 8hp and up.

Edited by - on

Voyager
Master Marine Consultant

Members Avatar

USA
5418 Posts

Response Posted - 04/26/2008 : 23:44:38

Two comments on this thread (just in case you wanted to know): (a) what happens if your alternator is not hooked up and (b) how to tell whether your battery is charged up by reading the voltage.

(A) If your outboard has an alternator, but you never use it - that is, if the cables aren't even connected to the outboard, the alternator will not generate. Simply because the alternator's rotor is connected to an open circuit, so current can never flow and no current can be generated.

Now, the problems occur when you connect the alternator to a battery or circuit THEN you disconnect the circuit. This is bad, because the inductors and magnetic fields in the alternator are still pushing current - due to induction - they cannot stop delivering current instantaneously.

This current causes the terminal voltage go way up, so it arcs over causing a short - blowing out the rectifier diodes.

Moral of the story - its not the open circuit that causes the damage - its the OPENING of the circuit that does it.

(B) Battery Voltage and Charge
According to Don Casey, a standard deep cycle lead acid battery will be fully charged when the battery voltage is 12.8 volts. You need a well calibrated digital voltmeter to read this. Many inexpensive Digital Multi-Meters (DMMs) are remarkably accurate.

As the battery discharges over time (not measured under load*) the voltage will droop from 12.8 V.

At 12.6 volts, the charge is about 75% of full. You can continue to use the battery at this point.

At 12.4, you're at 50%. It's still ok to use the battery at this point.

At 12.2V, you're at 25%. Now you're in trouble, you have to recharge and soon.

A deep cycle battery should not be allowed to fall below 40% of full charge, and worse, remain discharged below that level for any length of time.

If so, a destructive sulphate coating will build up on the internal lead plates and will quickly limit battery life. This condition slows down the rate of charging and discharging of the battery and eventually, makes it unusable.

Moral of this story, don't let your battery voltage discharge below 40% or much below 12.4V.

* Note: measuring the battery's voltage under a heavy load will result in a very low terminal voltage. During starting, it is not unusual to measure 9.5V or less at the battery terminals. The numbers listed above are "resting" voltage, with minimal or no current draw

Edited by - on

OLarryR
Master Marine Consultant

Members Avatar

USA
3477 Posts

Response Posted - 04/27/2008 : 06:49:49

Bruce,

Thanks so much for the explanation regarding the "opening" of the circuit. Your explanation sounds plausible. Where did you come by it ? Your electrical background ? Don Casey's Book or some other source ?

Edited by - on

Voyager
Master Marine Consultant

Members Avatar

USA
5418 Posts

Response Posted - 04/27/2008 : 12:11:56

Wa-a-a-ay back in engineering school I took this course involving Maxwell's equations and electromagnetic theory. My wife says that was the most stressful course she's ever lived through.

A collapsing magnetic field is pretty irresistable. You can illustrate this yourself if you have an old 12 or 24 volt doorbell transformer in your junk box.

On the 120 volt side, twist the insulated wires together so that the conductors are about 1/4" apart without the metal touching.

On the low voltage side, connect up two wires to the screws. Connect a D battery momentarily between the wires.

When you disconnect the battery, you'll see a little spark on the D battery side. This is from the collapsing magnetic field (it does not want to stop).

But on the 120V side, you will see a bright spark between the wires. Again, the collapsing field, but stepped up by the transformer.

Ah - my mis-spent youth!

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 04/27/2008 : 12:27:32

See, I warned you I might be wrong!

I went to Purdue, but not to their EE school.

Edited by - on

stampeder
Master Marine Consultant

Members Avatar

1608 Posts

Response Posted - 04/27/2008 : 13:06:20

<blockquote id="quote">quote:<hr height="1" noshade id="quote">(A) If your outboard has an alternator, but you never use it - that is, if the cables aren't even connected to the outboard, the alternator will not generate. Simply because the alternator's rotor is connected to an open circuit, so current can never flow and no current can be generated.

Now, the problems occur when you connect the alternator to a battery or circuit THEN you disconnect the circuit. This is bad, because the inductors and magnetic fields in the alternator are still pushing current - due to induction - they cannot stop delivering current instantaneously.

This current causes the terminal voltage go way up, so it arcs over causing a short - blowing out the rectifier diodes.

Moral of the story - its not the open circuit that causes the damage - its the OPENING of the circuit that does it.
<hr height="1" noshade id="quote"></blockquote id="quote">
On a manual start OB, does the act of plugging in the alternator plug to the OB constitute opening the circuit? I have a 1-2-all battery switch (3 way Perko) - my understanding of battery circuitry is that this switch should be off when I do not have any batteries hooked up. (recall that this hi-jack started when I mentioned that I often sail without batteries) Do I unplug at the OB, or is keeping my battery switch in the off position keep this a closed circuit?

Edited by - on

knightwind
Navigator

Members Avatar

Canada
114 Posts

Response Posted - 04/27/2008 : 13:22:08

Good info. Thanks.
I'd suppose you could calculate the right shunt resistor to work with a small inexpensive analog (needle-gauge) voltmeter to display a range of 12 to 13 volts and that would work quite well.

Edited by - on

Page: of 2

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.