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ContinuousWave: Small Boat Electrical
The Ultimate Battery
|Author||Topic: The Ultimate Battery|
posted 03-13-2010 11:12 AM ET (US)
The Ultimate Battery
What is the ultimate battery for a small boat? The criteria are, in order of importance:
--ability to start the outboard motor
The primary function of the battery is to provide starting current for the outboard motor. In most cases, once the outboard motor has been started there will be a surplus of electrical energy available to power all electrical loads on the boat, and the surplus will be used to immediately re-charge the battery. Starting the outboard motor is critical. The battery must provide enough current to run the starter motor. The battery must provide enough voltage to run the starter motor at a sufficient speed to allow starting. And on some motors, the battery must maintain a minimum voltage during cranking to permit the motor's electronics to operate properly. As a result we now see requirements for outboard motor starting batteries that are significantly more demanding than previously needed. It is common for the cranking amperes to be rated for a minimum of 1,000-amperes. During cranking the voltage sag must be kept as small as possible for two reasons: some engines will not attempt to start until the rotational speed hits a minimum RPM; some engines will not start if the battery voltage sags too low and their electronic controls malfunction due to low voltage.
High reliability is important in a marine battery. Boats are often operated in remote areas and without access to other vessels or shore support. The failure of a battery can result in failure to obtain engine starting, thus stranding the boat. Most engine starting battery systems use two batteries for redundancy to improve reliability.
Boats are often operated at infrequent and irregular intervals. The ability to hold charge for long periods of non-use is very desirable.
Is the ODYSSEY Marine Battery the ultimate boat battery?
Consider the specification for an ODYSSEY model 34M-PC1500:
This battery size should be compatible with most current GROUP 24 size battery applications. The 34M is smaller than a GROUP 24 except in length, where the 34M is 0.6-inch longer.
posted 03-13-2010 12:08 PM ET (US)
There is a well-known relationship between Sears and EnerSys, the maker of ODYSSEY batteries. In a press release (presumed to be dated 2007) the following was announced:
--begin press release excerpt--
EnerSys Signs Multi-Year Contract to Provide Sears Holdings With Long-Life DieHard(R) Platinum Batteries
READING, Pa. and HOFFMAN ESTATES, Ill., Feb. 27 /PRNewswire/
Beginning in March, 2007, Sears Auto Centers will be the exclusive distribution channel for DieHard Platinum batteries. "By working with EnerSys on the new DieHard Platinum battery, we continue the legacy of innovation that was established with the original DieHard battery 40 years ago," said Rick Sawyer, vice president/general merchandise manager of Sears Auto Centers. "We're confident this new battery will live up to the DieHard brand name and that users will be pleased with its performance. These premium-grade batteries are designed for a longer life than traditional batteries, offer increased levels of safe operation, can withstand extreme heat and cold, and are durable for consumer automotive/marine applications. The DieHard Platinum battery will offer proven vibration resistance to the consumer market.
The new DieHard Platinum batteries have up to 28% more Cold Cranking Amps (CCA) than comparatively sized spiral Absorbed Glass Mat (AGM) batteries providing much more starting power to automobiles and boats, along with unmatched reserved capacity. These thin-plate pure-lead batteries will carry DieHard batteries' best-ever, free replacement warranty. See your local Sears store for written warranty details.
"We're thrilled to provide this high-end, durable DieHard Platinum version to consumers," said John Craig, chairman, president and chief executive officer of EnerSys. "This partnership represents a great opportunity for more users to benefit from our pure-lead technology products."
The DieHard Platinum batteries are manufactured in EnerSys' U.S. manufacturing facility in Warrensburg, Mo, where the first DieHard Platinum came off the production line today. They have a valve-regulated design that allows them to be installed in any orientation ,except inverted, without spilling and the U.S. Department of Transportation has classified them as non- spillable for safe shipping.
--end press release excerpt--
One can presume that a Sear brand Diehard marine battery with AGM construction is likely an ODYSSEY marine battery. Following this correlation, it should be noted that there appears to be a substantial price reduction available if the battery is purchased from Sears. At this writing, Sears are selling a PM-2 Platinum Marine Battery from DieHard with specifications comparable to the ODYSSEY 34M-1500. The current price of the PM-2 is $189.
posted 03-13-2010 07:07 PM ET (US)
For my use an AGM battery is as close to perfect as I've been able to find.
The quandary is which AGM battery is the most reliable while meeting the electrical requirements for the boat and engine combination.
If I had to replace my AGMs I would use the Sears DieHard Platinum battery. At less than $200 each they provide a lot of peace of mind.
Mercury Verado engines reportedly require AGM batteries for proper operation. What battery is installed with Verado engines on new Boston Whaler boats?
posted 03-14-2010 08:58 AM ET (US)
Butch--What battery is used by Boston Whaler on boats rigged with a Verado engine? That is a good question. I don't know the answer. Perhaps someone can jump in and tell us.
posted 03-14-2010 09:17 AM ET (US)
Interesting subject. What electronics do you leave ON when anchored overnight? I think any decent battery should be able to support the VHF radio, anchor light, and GPS (for the anchor alarm) for a 12-14 hour engine off period and then still start the engine the next day.
posted 03-14-2010 10:25 AM ET (US)
To meet your requirement a decent battery would have to be part of a dual battery with isolator setup on my boat. One battery would be devoted to engine starting and one to all other loads. Furthermore, I would want the anchor light to be an LED to reduce current draw. It would be useful for the GPS to have a "sleep" mode or at least be turned to the lowest brightness setting. If the GPS is an MFD supporting a sounder it would be useful to be able to turn off the sounder function while the GPS function remains active.
What is the function of the VHF radio while sleeping aboard an anchored boat?
posted 03-14-2010 11:11 AM ET (US)
The Merc dealer service bulletin #2008-04 does not tell you what name brand batteries a dealer is to install. It just specifies the requirement of AGM type and 800 minimum marine cranking amps (MCA) with a minimum reserve capacity of 135 RC25 rating.
posted 03-14-2010 05:58 PM ET (US)
I just buy the largest K-Mart Marine Battery (Eveready Marine) guaranteed fully for 18 months, replacement free, replace it every year. 1st cost about $80.00 next new battery either free or pro rated. Starts my engine every time 875 cranking, 675 cold crank. Never have had a problem...
posted 03-14-2010 09:09 PM ET (US)
My ultimate Trolling battery would be a deep cycle group 27 that weighs ½ of what a normal battery weighs.
I keep my boat at dry rack storage and there is no way to charge it there. I must haul the battery to the boat ,use it, haul out, haul it up a hill, take it home, charge it, put it away and repeat the process again. I would pay twice as much for 1/2 the weight. Currently using a Wal-Mart I get three years then trash it buy a new one works out to about to 20 bucks a year
posted 03-15-2010 12:07 PM ET (US)
Dick: Can you set up a trickel charge using a solar pannel?
posted 03-15-2010 09:31 PM ET (US)
It is in dry storage in a building where the sun does not shine.I don't think it would work
posted 03-16-2010 11:49 PM ET (US)
Sometimes, particularly when gunkholing with other boaters, VHF is the only communications channel between everyone and you want to be able to reach your travelling companions at any time.
I even went so far as to install a RayMic remote in my cuddy to complement my Raymarine Ray 55 VHF so I wouldn't have to get out of my sleeping bag to answer a call.
Your radio's manual will tell you what the amperage draw is while monitoring. It's should be quite minimal (if it isn't, you need a different radio).
I have two Group-27/105aH deep cycle batteries on my boat. I rarely worry about current draw from any device on my boat, even overnight.
posted 03-17-2010 06:22 AM ET (US)
Why leave the VHF on overnight while anchored: weather alarms. I got into the manuals and the idle load is about 1 amp for the radio and GPS. The sonar in the HDS-5 can be turned off independently of the rest of the unit. I plan on converting the OEM anchor light on my Outrage V20 to LED this season. I'm due for a new battery this season and the Sears Diehard Platinum looks like what I'll get.
posted 03-17-2010 08:42 AM ET (US)
"Why leave the VHF on overnight while anchored: weather alarms. "
Rather than leaving the VHF on drawing 1A-Hr, why not just buy a cheap portable radio with Weather Alert? There are all kinds of radios from a portable VHF radio to family GPRS radios to stand alone radios with Weather Alert functionality. If you are at an anchorage with traveling companions, there is little reason that a portable VHF radio wouldn't work to hear incoming calls and most likely to respond thereto.
For anchor lights, consider switching to a low current draw LED.
For GPS anchor drag alarm, I use the separate battery powered portable because the multi-function display I have on my boat uses much power.
As you can see, you can worry about the power source or you can work around that by using alternative devices some of which add diversification, backup and redunancy benefits.
posted 03-21-2010 12:43 PM ET (US)
I just picked up two of the Platinum PM-2's. Sears had 10% today so each was $170.99.
posted 03-21-2010 03:10 PM ET (US)
If your battery can't handle a white-all around incandescent anchor light, the VHF Radio and the GPS being on all night and reliably start your motor in the morning; you need one of two things:
1.) a new battery
Seriously - a strong battery will handle these nominal loads for as much as 12 hours. Just remember to turn these devices off in the morning and fire the engine(s) for a short period to bring the charge back to full.
posted 03-21-2010 06:39 PM ET (US)
I don't disagree with your assessment.
Some engines require a certain battery voltage to start regardless of cranking speed provided. I believe FICHTs and perhaps E-Tecs require a fairly fully charged battery to fire the injectors. Or, perhaps not as I'm told that some smaller E-Tecs can be rope started without a battery. Verados may also require some minimum voltage. If it's not the injectors it may be the ECU.
I like the idea of a fully charged AGM battery being available to start my FICHT after a day of fishing with the GPS, sounder, and VHF operating continuously. Dual AGM batteries meet my requirement. Admittedly, probably overkill.
posted 03-26-2010 08:25 PM ET (US)
"Why leave the VHF on overnight while anchored: self-protection. "
On our first trip to Green Turtle Cay in the Bahamas with the Whaler Group in 1993, in our Montauk, we were putt-ing back from a party at one of the local islands, and were being followed by a 27 Whaler.
Jeff (the guy in the other boat), radioed me and said, "Hey Ace, do you see that anchored sailboat?"
"Where?" I responded.
Within seconds, about twenty mast-head lights came on, and I realized I was in the middle of a sailboat anchor field.
That could be one reason to leave the VHF on . . .
posted 03-27-2010 10:17 AM ET (US)
No question of having the VHF on while underway. I believe the question was why have it on while sleeping at anchor.
Perhaps your story was to point out the sailboats had VHFs on and were thus able to turn the masthead lights on when they learned you may have been approaching them. Or perhaps it was the sound of your engine amongst them? Are not boats at anchor during darkness required to display a light? Darned rag boaters!
posted 03-27-2010 02:59 PM ET (US)
Maybe I was to subtle in making my point. Yes, the sailboats WERE at anchor, it was at night, and I was running slightly above idle speed, since White Sound looks different at night than it did in the day.
Yes, the point was that these sailboters (MB&S used to spell it that way) were monitoring their VHF and heard imminent danger. Their reaction was to illuminate themselves so that I could see them.
And given the laid-back attitude from the permanents at Green Turtle Cay, the Rules of the Road are merely a suggestion when it comes to certain duties.
posted 03-28-2010 12:03 PM ET (US)
Interesting narratives, but we are far afield of our topic: the ultimate boat battery.
Curiously, this topic is reviewed in the April 2010 edition of POWER & MOTOR YACHT magazine on page 24 by author Bill Pike. His conclusion for his next battery purchase: conventional flooded cell lead-acid batteries, whose cost is much less than batteries of other technologies.
posted 03-28-2010 04:13 PM ET (US)
I chose an AGM battery as opposed to a conventional battery because I did not want to worry about checking the water level of a conventional battery.
I boat in some pretty choppy conditions. With the AGM battery I don't have to worry about checking water level after boucing around for a few hours.
I have not taken the battery box covers off my AGM batteries for a couple of years. The boat is stored for the winter with the batteries in the boat and the battery switch off. I have not had a battery problem.
Maybe I could get away with a flooded cell battery? My last set of conventional batteries that were only a couple of years old always needed water. My engine charging system always charged the batteries dead on at 14.2 volts.
I honestly just got tired of removing all the gear I store in the console to check the water level. The AGM cost me double but it was worth it to me to not have to worry about maintaining the water level of a battery.
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