posted 01-26-2007 01:14 PM ET (US)            

I usually put a charger on them overnight before and after a day of fishing, but have never run out of power and never had one fail.

posted 01-26-2007 10:47 PM ET (US)            

--buy a quality battery
--take good care of it.

Having a small fleet of cars and boats I have bought about 7 batteries in the past year. Just about every battery I replaced lasted at least as long as its warranty period. If you are in the battery business you will not be in business very long if you give out a warranty that lasts longer than your battery.

If Walmart house brand batteries only last six months, and you are getting a new one under warranty at no charge, that is called a perpetual battery, isn't it?

Something is not right in this situation. Either the battery is very poor quality and it only lasts six months and at the same time Walmart is stupid and gives you a much longer warranty and perpetual free replacements, or the way the batteries are being used is not giving them proper care.

In most things like a battery--not a particularly stylish sort of thing where people will pay extra for a name brand or a style--you get what you pay for, more or less.

posted 01-27-2007 01:36 AM ET (US)            

I think minitauk85's high use with the trolling motor will shorten a batteries life. If you use a cheap, unregulated battery charger to charge after a day fishing, that will shorten battery life. If you don't charge a battery to a full charge each time, that will shorten battery life. If the battery is used everyday, I'm not surprised they only last 6 months. To make a trolling battery last long, only discharge it to a max of 50% before charging. If that is the problem, get two batteries to run the trolling motor and alternate them.

This is how I typically handle battery problems. Once a battery fails to start a motor, I remove it and bring it back to my shop to charge it back to full charge. I charge at a low rate(2-5 amps) and usually it takes 2-3 days of charging. I use a good quality, wheel mounted, regulated charger. After full charge, I connect the load tester to see if it is worth re-installing the battery. If it tests good, I charge for a few hours more to replace the lost watts that the load tester used. If it fails the load test and it is still in warranty, it goes back to Walmart. If the load test is just barely below limits of passing, I will install it in one of my tractors with an older battery.

Buying 7 batteries in a years time would be a chunk of money to save if buying at Walmart.

There is actually 3 different ways to test the battery.
One would be a voltmeter to check voltage. This requires a some what reliable voltmeter or multimeter. I think the full charge voltage is 12.7 to 12.9 volts. If the voltage is only 10 volts or so, that is an easy indication of a bad cell in the battery. That checks voltage but it really doesn't mean that the battery can handle a heavy load. It may handle electronics(Radio, GPS or VHF radio) but may fail to start an outboard or run a trolling motor for very long.

The second method is with the load tester. The load tester can be used even if it still installed in the boat or vehicle. It is as simple as connecting the clamps to the positive and negative posts. A spring loaded toggle switch is actuated for 5 seconds and a reading is displayed on the meter. It places a dummy load of close to 100 amps on the battery. You do this while watching the meter on the load tester. It is calibrated in voltage and if voltage readings scare you, it has a scale which reads BAD, WEAK or OK. 5 seconds is long enough time to be engaging the starter motor on an outboard or vehicle. If you boat motor takes longer or if it takes multiple tries to start the motor, that can be simulated with the tester also. Just actuate the switch on the tester to mimic what your starting procedure is on your boat. I like this test. It comes as close to what your battery actually needs to do, to produce the CURRENT(not voltage) to turn the starter.

The third way is by measuring the specific gravity of the electrolyte. This is the most accurate way to test a battery, but most people don't want the extra work involved to accomplish accurate results.
You need a temperature compensating hydrometer to do this. They are available at some auto parts stores for $20-40.
It looks like a glass turkey baster and it is used during charging to see the rise in specific gravity of the electrolyte. You need to remove the caps on the battery to use this device. If your battery has sealed caps, you can not use this method. A discharged battery is around 1.120 and fully charged is 1.265. You test all of the cells(holes) by sucking some electrolyte(it is sulfuric acid and distilled water so be careful and wear eye protection and if it gets on your clothes, it will eat a hole in it) into the glass tube, read the value on the floating bulb and note the results. All 6 cells(on a 12 volt battery) must be tested. Squirt the electrolyte back in the cell and go on to the next until all are tested. The cells should not vary. If they do, battery capacity will suffer. The wider the gap, the less reliable the battery.

Wet cell lead acid batteries are pretty simple devices. Do a Google search to really get to understand them. They are needed to operate our boats safely. Not much difference between a flashlight battery and a lead acid except weight, size and electrolyte type.

When I was a Coastie shipboard electrician, I was in charge of the battery locker. It contained banks and banks of batteries to operate emergency systems including the main gyro for navigation. Later when I transferred to Coast Guard aviation, I ran the lead acid shop which supplied batteries to all fixed wing and helicopters and the ground support equipment at the Air Station. I also spent the last two years of service teaching electrical theory.

posted 01-27-2007 10:48 AM ET (US)            

I am currently "managing" two rather large UPS devices. Each has 40 batteries connected in series, providing about 530-volts. The batteries are all valve-regulated lead-acid (VRLA) 12-volt cells, or "jars" as the UPS company guys like to call them.

We have a supervisory system which monitors the individual jars in the battery string. Each jar is monitored for terminal voltage and checked hourly. Each jar is also checked for internal resistance every six hours. The technique for checking the internal resistance is proprietary with the manufacturer of the monitoring device, but it does not involve significant discharge of the cells.

The jars are arranged in trays of four batteries, and one monitoring device handles all four batteries in a tray. Due to the high voltage accumulated across the entire string (530-volts) and also due to interconnection to the power mains (240/480 Volt AC), the monitoring devices are strung together with a nonconductive fiber-optic network in order to avoid creating any DC connection between them which could create ground loops or other stray potentials in the system.

The fiber-optic loop terminates into another device which converts the data for transmission via copper (UTP) ethernet networking to a dedicated monitoring computer. The monitoring computer collects and stores the data.

The terminal voltage and internal resistance measurements of all 80 jars are recorded into a database. The supervisory software plots the historical data on various charts. The software also monitors for out of tolerance readings. When one is detected the software emails a notice to me regarding the reading, and it identifies the particular battery which triggered the alarm.

The UPS device itself (not the monitoring system) periodically (about once a month) puts the battery string under a load of about 40-Amperes and maintains this load until the string drops to about 75-percent of the full-charge voltage. The time it takes to reach this state of discharge is noted and evaluated as an indicator of the health of the battery string.

The UPS system is designed to maintain power on crucial circuits until our standby 300-kW generator can be (automatically) started and brought on line. The system is designed to allow us about an hour to accomplish that. Typically the generator will start and stabilize in less than a minute.

The VRLA batteries are kept at a "float" voltage of around 13.5-volts. The float current through the string is around an ampere or so. In this service the manufacturer says the battery has a reliable and useful life of about 48-months.

Prior to installation of this sophisticated monitoring, we operated the UPS with our fingers crossed and waited for it to fail one of the monthly capacity tests. Then we would replace all 40 batteries. Historically about 48-months of service was the point at which the battery string would start to show reduced capacity and fail the monthly load test.

Because there are so many batteries connected in series, the string is only as good as the weakest jar. Since installing the more sophisticated monitoring, we can identify individual jars in the string which are showing signs of weakness. Instead of replacing the entire string of 40 batteries, we can replace just the weakest of them. In this way we hope to be able to maintain all 80 jars in a useful condition so that in the event we actually experience a sustained power outage the system will function as intended.

The downside is that we no longer have 80 fairly good VRLA AGM cells to throw out every few years. The upside is that the next time we do a wholesale replacement, I can cherry pick the best battery in the lot for my personal "disposal."

Back to Walmart house brand batteries.

I would say that the general reports of quality are good, and the situation described above wherein the battery fails every 6-months is due to poor maintenance rather than poor quality of the battery.

The last time I was in the market for a new marine battery (May 2006) I went to Walmart to get one of their house brand batteries. They were completely sold out! I guess many boaters are aware of the value offered in Walmart house brand batteries, and they had cleaned them out before I got there.

posted 01-27-2007 10:57 AM ET (US)            

There are a few battery manufacturers in the U.S. and Mexico that make batteries to be relabled for sale by various retail outlets.

A Wall Mart battery with a 48 month guarantee will be the same as an Auto Zone or some other brand with the same guarantee.

If a battery fails after six months, there is something wrong. Most likely, the battery is being overcharged by an outboard with a nonexistent or deficient voltage regulator.

posted 01-27-2007 11:26 AM ET (US)            

I too have a diesel truck with dual batteries. I also have a motorhome with 7 batteries in it. One for starting and the other six are maintained by a wind generator while on the beach and provide our only power for the summer. The wind generator is an Air-X model and it works flawlessly.

In addition to that, our everyday vehicles and the boat also have the same batteries.

If properly maintained, they will all outlive the warranty period by at least one year. Unfortunately, out of sight is out of mind and I have frequently killed every one of them in a winter of non-use. Leaving them in an unused vehicle or boat with any type of drain will do a number on them.

posted 01-27-2007 12:29 PM ET (US)            

Technology sure has come a long way in the thirty some years since I maintained battery banks. That one on the ship had a hand written log book that went back more than 20 years. Most of the batteries were more than 10 years old. When a bad cell was found, that battery was flushed with distilled water and filled with new electrolyte, charged and tested and put back in the rack. I never discarded a battery in the 18 months that I maintained them.

The only problem that I can see with that "supervisory system" is that it can't monitor individual cells. A lead acid battery rarely goes bad as a whole. One of the cells usually starts to fail and that eventually does bring the battery down.

Valve-regulated lead-acid (VRLA) batteries have sealed caps which will not allow individual cell maintenance. This rules out the use of a hydrometer, which is still the best way to perform capacity maintenance.

posted 01-27-2007 08:28 PM ET (US)            

You can do combinations of charging also. Start out at high rate(caps off and watch close) then reduce through the lower rates to get a full charge.

And yes it is better to charge at lower rates because of greater heat at higher charge rates. If your charger has a jump start feature, never use that for charging a battery.

posted 02-04-2007 12:39 AM ET (US)            

http://autos.msn.com/advice/CRArt.aspx?contentid=4023696

posted 01-11-2009 10:23 AM ET (US)            

In a warranty which covers 24-months, if the product fails at 21-months then the product has fulfilled 21/24 or 0.875 of its warranted life. The pro-rated refund of the product's purchase price would then be 0.125-times the original price. Since you received $3, this implies the original price was

$3/0.125 = $24

If you paid more than $24 for the battery, you did not get the proper pro-rated return. It is hard to tell if this is the case at hand because in your narrative you did not mention what price you paid for the battery. The details of the warranty coverage should be specifically stated in a written warranty that accompanied the product.

In addition, as you have pointed out, a battery has an intrinsic scrap value due to the residual value of its lead core. Typically most retailers will give you a core credit of more than $3. In that case, surrendering the battery to WAL-MART for only $3 credit may not have been the best use of the defective battery.

As I noted above, the warranty period offered with the purchase of a new battery is often a good indicator of the quality of the battery. If a manufacturer offers only a 18-month warranty on a battery, this is a good indicator that the manufacturer anticipates that the product will last 18-months but perhaps not much longer. As you discovered with the pro-rata warranty clause, there was little value in the warranty once the 18-month period expired.

Manufacturers of premium grade marine batteries offer ten-year warranties, and you can anticipate that their batteries will last for that amount of time. Again, as I recommended previously:

posted 01-11-2009 12:09 PM ET (US)            

I just bought a battery from Wal-Mart the core charge is 9 bucks.
Did I ever have a battery at Wal-Mart go bad? One. I told them it would not hold a charge, no testing gave me 50% of my money back( ½ thru warranty period) and no core charge on the new one.

posted 01-11-2009 12:31 PM ET (US)            

A battery is not a durable good, and when you buy a battery there is an expectation that there is a certain life span anticipated for the product. As I have mentioned, a reasonable basis for judging the life span of the product is by measurement of the warranty or other guarantee offered by the manufacturer.

To learn that a battery with a warranty of 24-months failed at 21-months is not particularly surprising. As I mentioned, this represents 87.5-percent of the anticipated life span. Also, the retailer apparently made good on the pro-rata refund. Whether or not this result constitutes an alarming variance with the anticipated performance is perhaps more of an individual perception.

posted 04-21-2010 09:21 PM ET (US)            

BASSONLY--Thanks for the update on WAL-MART warranty policy or perhaps LACK of warranty policy.

posted 04-22-2010 11:26 AM ET (US)            

I offered the suggestion because of minitauk85's remark that he is apparently charging his Wal-Mart batteries with a current regulated charger which could be partly to blame for his reduced battery life. The real question here is not the number of months that the battery is expected to last but rather how many discharge cycles the battery is designed to withstand.