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Author Topic:   Battery Life
pvonk posted 06-07-2005 02:24 PM ET (US)   Profile for pvonk   Send Email to pvonk  
Here's another battery question:

For a (Montauk) boat battery that is "tended" during the winter (in northern climate), and a boat not used more than 100-hours per year, how long will a battery last? Is there a general limit? Or are there too many parameters involved?

Is is wise to just replace a battery after a certain number of years regardless of how well it seems, and if so, how often?

- Pierre

Backlash posted 06-07-2005 03:01 PM ET (US)     Profile for Backlash  Send Email to Backlash     

This Spring I just replaced both my Delco Voyager Deep-Cycle Maintenance-Free batteries. One was purchased in 1992 and the other in 1993! Like you, I average probably less than 100 hours a season on the boat. I have always stored the batteries in the basement during Winter lay-up and recharged every couple of months. Last season I noticed one of the batteries didn't seem to hold a charge as well as the other and thought it was time to replace them.

My experience with the Delco's is certainly not typical, but I would think that a quality battery, properly maintained, should last 4 or 5 years. I replaced my deep-cycles with combination starting/deep-cycle batteries.

The original starting battery that came on my boat lasted just over a year and the 2nd battery I added (also a starting battery) lasted less than a year. This was the result of an inept mechanic who left the master battery switch on for several weeks. After that, neither battery would reach a full charge. This is the problem with starting batteries; if they become fully discharged they may never again reach a full charge.


pvonk posted 06-07-2005 05:18 PM ET (US)     Profile for pvonk  Send Email to pvonk     
Thanks for the info, Steve. I know next to nothing about boat batteries. I gather "deep-cycle" batteries are for powering items that stay on for extended times, like an electrical kicker motor. These should not be used to start the main engine - right?

LHG posted 06-07-2005 08:19 PM ET (US)     Profile for LHG    
Except for a situation where you have a dedicated house battery and selector switch for charging it, I can't think of any reason to buy a deep cycle battery. There it makes sense. As for a simple starting battery, they are the bottom line in price, and you get what you pay for, and not much ability to handle the electronic loads of today, nor any draw-down and recharge cycle.

Always buy a COMBINATION starting-deep cycle, a battery which will give you plenty of reserve power for accessories, and yet accept a partial draw-down with out damage, and will always start your engine. They are heavier, but these batteries will last for years if taken care of. They will run house power at the same time for those of you that cruise, and still handle the morning engine starting and re-charging.

The Walmart Everstart brand sounds like a cheap-out, but their dual cycle marine batteries are excellent, and last and last, and you can get a replacement anywhere you travel should you have problem. They are about $65. Forget Sears DieHard. I've had REALLY BAD experience with their marine batts. For autos, they seem to be OK.

Backlash posted 06-08-2005 07:32 AM ET (US)     Profile for Backlash  Send Email to Backlash     

True, as LHG stated, deep-cycle batteries are not recommended for engine starting. However, I never had a problem starting my 200HP Yamaha with them over the past 13 years - until last season. Deep-cycles will drain faster than a starting battery when used for starting an engine.

BTW, I just paid $59.95/each for the Everstart Extreme maintenance-free combination starting/deep-cycle batteries at Wally World.


fina posted 06-08-2005 04:13 PM ET (US)     Profile for fina  Send Email to fina     
I have a dual battery system

should I be turning the switch to the "off" position after use?

pvonk posted 06-08-2005 05:32 PM ET (US)     Profile for pvonk  Send Email to pvonk     
As I recall, my Montauk's (original) battery (late 2004) has two different sized posts (for + and -) and the wires that attach to the posts have O-rings (or whatever you call the circular metal end that slips over the post) of different sizes. I'm not talking about the "big" posts, but the ones that are threaded. Do all marine batteries have this feature or is this an OEM battery feature?
JOHN W MAYO posted 06-09-2005 04:20 PM ET (US)     Profile for JOHN W MAYO  Send Email to JOHN W MAYO     
What I do, and what I understand, switch to 1 OR 2 and operate on a single battery, not both at the same time, except possible starting if your batteries are not to good and you are trying to get it started with weak batteries.

I alternate using each battery say 1/2 day with one and then switch to the other, and that keeps both charged good. Do Not switch to OFF with the engine running as that can damage the charging system. Swith to OFF only if the engine is not running, say after you put it back on the trailer.

Backlash posted 06-09-2005 09:33 PM ET (US)     Profile for Backlash  Send Email to Backlash     

I trailer my boat and when not in use the battery selector switch is off. I think it's a good idea in case you've accidently left something on you won't have a dead battery(s).


johnk posted 06-09-2005 11:53 PM ET (US)     Profile for johnk  Send Email to johnk     
On my 25' with dual batteries, I changed them every 3 years. Could they go another year (or 2)? perhaps, but the last thing I want to say when the sky is getting ugly, the wind is kicking up and I'm far from the dock is "I wish I had changed my batteries"

17 bodega posted 06-10-2005 09:38 PM ET (US)     Profile for 17 bodega  Send Email to 17 bodega     
In the interest of redundant systems, I changed my battery this year, partially because I couldn't crank my motor once. I cursed the situation and when I inspected it later, I realized the battery was fine but my wing nuts had loosened and made a poor connection. If you are a saltwater boater, many different things can wreak havoc on your battery charge. Check all connections regularly, including the battery terminals.

Cicada posted 06-11-2005 07:34 AM ET (US)     Profile for Cicada  Send Email to Cicada     
The two different sized threaded posts are not an oem only feature. Most, if not all, marine batteries have these. One of the suggestions I've received on this site was to discard the wing nuts and go to hex nuts that need to be tightened with a wrench. Helps to eliminate the loose connection.

Prior to this year I was running with a single start battery. The electronics would continuously draw down the battery and pretty much cooked it in a short period of time. I went to a dual system with one start and one dual purpose deep cycle. If I were to stay with a single battery system it would be the dual purpose.

Also cooked a battery over the winter leaving it on an inexpensive maintenance charger. Need to make sure you use a proper maintenance charger or check state and charge periodically as suggested.


pvonk posted 07-10-2006 11:44 AM ET (US)     Profile for pvonk  Send Email to pvonk     
Well, I'm reviving this thread since I started it. After just 23 months, my original Montauk 2005 combination battery was dead at the slip yesterday. I bought a new one from the marina shop, but didn't have time to research the topic (not too knowledgable of batteries). This one was a starting battery, the only kind they carry.

After re-reading this thread, I'm thinking I made a mistake.

The marina tested the old battery and it was dead. I'm trying to recharge it now (at home) to see if it can be recharged or whether it is truly dead. Here's a question - if the old battery does recharge, is it possible that the engine's recharging capability is not working, and how would I test that?

I am disapointed that the original got only about 23 months of life. I ran a trickle charge during last winter and this spring the battery started off just fine.

- Pierre

alfa posted 07-10-2006 12:16 PM ET (US)     Profile for alfa  Send Email to alfa     

very easy to test engine recharging capability : just with a voltmeter. I mounted one on my dash panel and monitor to be safe.


carl lazar posted 07-10-2006 12:47 PM ET (US)     Profile for carl lazar  Send Email to carl lazar     
A battery is the cheapest insurance that a boat can have. For $60 a year buy a new one, and if you have two alternate the years.
pvonk posted 07-10-2006 01:26 PM ET (US)     Profile for pvonk  Send Email to pvonk     
Alain, is the voltmeter the same as the "voltage gauge" that is already on the instrumental panel? Someone told me I need an ampmeter to measure charging. I'd rather not install yet another gauge, but how about some portable device to check charging? Doesn't a voltmeter just tell me the "strength" of the battery, not whether it's charging or not?

- Pierre

alfa posted 07-10-2006 02:38 PM ET (US)     Profile for alfa  Send Email to alfa     

Have a look : ?action=view¤t=Pearl_08_2005018.jpg&refPage=&imgAnch=imgAnch4
The voltmeter is under the Navman. Yes the voltmeter is same as voltage gauge. You don't need ammeter. A portable device is ok. They are cheap nowadays (I think 15 bucks). The charging system will not work at idle but above 1500~or 2000 rpm the voltage will hit 14 Volts if it works properly. But never run motor without battery, because the charging system will fail.

Tight lines


pvonk posted 07-10-2006 03:00 PM ET (US)     Profile for pvonk  Send Email to pvonk     
Thanks. I do have a voltage gauge on the console. Next time I'm out, I'll keep a close watch on the gauge readings.

- Pierre

jimh posted 07-10-2006 10:42 PM ET (US)     Profile for jimh  Send Email to jimh     
jimh posted 07-10-2006 10:55 PM ET (US)     Profile for jimh  Send Email to jimh     
With modern instrumentation you can easily test a battery for capacity in just a few seconds. Most stores that sell batteries have these instruments. They generally will offer to evaluate your battery at no charge, and most of the time their test results will convince you to buy a new battery. These devices use some fancy algorithms to test and evaluate the battery. You can always test the battery with a very heavy load, but this usually leaves the battery needing a re-charge to get back to where it was before the test.

As an anecdotal data point, I just replaced a Sears DIE HARD marine battery a couple of weeks ago. It was of 2001 vintage, thus about five seasons old. The battery had been stored indoors during the winter and maintained with periodic recharging. In the spring it was slowly re-charged to full capacity, and it initially showed no problem in cranking and starting the 225-HP V6 outboard. However, three weeks ago it rapidly lost charge and died after two short cranks while I was at a very busy launching ramp. There were 40 guys waiting to use the ramp, so it was out of the question to fiddle around with the battery. We hauled out and went shopping for a new one.

There is no sure formula for figuring the life of a battery, and a lot of it depends on the care and charging cycles the battery has been subjected to.

pvonk--A good quality marine cranking battery is never a bad investment for starting your outboard motor. The primary purpose of the battery is to get the engine to crank and start, so a cranking battery is the least expensive way to get those amperes of current. Most small Boston Whaler boats do not have extensive electrical drain when the engine is not running, and it is anticipated that the battery will be promptly re-charged once the engine is started.

pvonk posted 07-11-2006 09:11 AM ET (US)     Profile for pvonk  Send Email to pvonk     
Thanks, Jim, for your reassuring words. The only thing working when the boat is at the slip is the bilge pump, so I suspect that's very little load on the battery.

- Pierre

jimh posted 07-11-2006 09:24 AM ET (US)     Profile for jimh  Send Email to jimh     
If the bilge or sump pump is running continually, it will pull the charge down on the battery, and, if the pump runs enough, it will deeply discharge the battery. How much the pump runs while the boat sits in the water is hard to say, but it is probably a function of how much rain falls and how much water comes aboard via any scuppers or drains that back fill.

A cranking battery is not designed for deep discharge and recharging. It much prefers to be kept at near full-charge most of the time. Therefore a cranking battery is not the best choice for use in a situation where a bilge pump can run the battery down to a low state of charge.

You might consider wiring the bilge pump to a separate battery. This would keep the engine starting battery from becoming discharged. The importance of the engine starting battery is in proportion to the difficulty in pull-starting the engine. If you have an outboard motor than you can pull-start, the cranking battery can be thought of as a luxury. If you have a motor than you cannot pull-start, the cranking battery is a crucial component of the propulsion system and must be carefully maintained and charged.

andygere posted 07-14-2006 12:26 PM ET (US)     Profile for andygere  Send Email to andygere     
I am currently running a pair of combination deep cycle/starting batteries in my Outrage 22. One is dedicated to starting the main engine, and the other handles all house loads, as well as starting the 15-HP kicker motor. At the start of the season I began shopping for a new pair of batteries, since one of the pair would no longer take a full charge. These batteries are 4 years old, and replacement seemed reasonable. Also of note is that I replaced all of my primary wiring, and installed a new battery switch cluster with an integral voltage sensing relay. Since I was not able to find a pair of replacement dual purpose batteries that met my engine's starting requirements at any local retailers, I simply charged them both up and put them in, planning to get the boat running, and continue looking for replacements. Thanks to the robust charging system on my new E-TEC, they are both working fine, but I'm a bit conservative and still plan to replace them.

After reading this thread, I am reconsidering my plan to buy an identical pair of dual purpose batteries. Since the start battery only handles starting loads, I'm thinking about buying one start battery, and one dual purpose battery. Is anyone using a similar system, and is this the right way to go?

glen e posted 07-14-2006 07:16 PM ET (US)     Profile for glen e  Send Email to glen e     
Every three years I will replace all four of my AGM batteries no matter what the load or volt test say. I will then use them for emegency power for the next three years in the garage. I will then rotate the ones out of the boat and toss the ones in the garage.
kingfish posted 07-14-2006 07:29 PM ET (US)     Profile for kingfish  Send Email to kingfish     

I use one cranking battery and one "dual-purpose" AGM battery on Outré. Works for me.


alfa posted 07-15-2006 03:22 AM ET (US)     Profile for alfa  Send Email to alfa     

With your new e-tec, I believe there is a VSR on it. You just have to buy the second cable and the two batteries can be charged automatically by the motor...

andygere posted 07-15-2006 01:05 PM ET (US)     Profile for andygere  Send Email to andygere     
You are correct. The only reason I am not using that system, is that I installed a BEP Marine switch cluster with VSR and all new wires last year. The built-in VSR is a great feature, and one that Evinrude should really highlight in their marketing.
handn posted 07-16-2006 09:44 AM ET (US)     Profile for handn  Send Email to handn     
No one has previously mentioned that battery life is very dependent on how the boat engine charges the battery.
On my first boat, the 225 Optimax overcharged the batteries and I had to replace both batteries every year.
You can tell if the engine is overcharging because the batteries will use an excessive amount of water. The overcharged battery boils spilling water outside the battery and often soaking the terminals, leading to poor a poor connection.
If you have a digital voltmeter, the voltage readout will stay above 14 volts for all the time the engine is running.
It should read high for the time it takes to recharge the batteries and then go down to 12.8 volts or so when the batteries are recharged and the voltage regulator cuts down the charge.
I endorse using a load tester. A defective battery can have a 12v+ volt meter reading at rest but not have enough juice for normal use. The load tester will i.d. this defective battery. It should be used at the start of each season and everytime battery condition is suspect. The price of a load tester (about $60) is reasonable for offshore fishermen and others for whom battery failure is more than an inconvenience.
House batteries will fail prematurely if they are drawn down frequently to less than 50% of capacity.
Most outboard boats use wing nut battery terminals. These can be a problem if the engine vibrates excessively and loosens them. Not only will a poor connection not produce enough power to start the boat but it may also effect the function of the voltage regulator.
Even properly maintained batteries gradually loose efficiency over their useful life. I change even properly functioning batteries when the warranty period expires because where I boat, battery failure is a much bigger problem than a trip to Wally World. A load tester will identify a battery that is going down hill.
glen e posted 07-16-2006 07:33 PM ET (US)     Profile for glen e  Send Email to glen e     
Maintaining a good batt system

It's definitely a whole system that matters. Here's my recipe for a robust, rugged, dependable electrical storage system. Amazes me that people will pay 15 grand to see birds 12 miles away and then buy Wal-Mart batteries to save 60 bucks….. Spend $500 bucks and do it right. Steps to take:

• AGM batteries in a quantity that none are drained more than 25% in any situation.
• A 3 stage smart charger that is powered on and connected to the batts 24/7 - anytime the boat is not being used, the charger is maintaining float level
• A dash mounted battery monitor gauge that tells me when I should switch batts to fresh ones, again to not deplete any one battery too much. I use a Newmar DCE Energy Monitor.
• Battery switches in off position anytime the boat is in storage.
• Maintenance of all terminals every 60 days - all terminals loosened , cleaned and dielectric grease reapplied
• Run one batt at a time - switch to both in an emergency start - but also switch when rule #1 applies...(like on a drift...)
• nice touch - if you alternate engines when trolling - install a battery combiner which allows charging of both banks with just one engine

And here are the batteries I recommend. Group 27 if you can but the 24's are fine – Usually in a quantity of at least one more than the amount of engines you run.

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