Marine Deep Cycle Batteries

[shepaug]

I bought 4 marine deep cycle batteries. New to such they actually tore my shoulder muscles lifting. (oooouch!!!!) OK..get help… So for the interim keep them charged. Every couple months I have made sure they are fully charged. At first it was difficult to get any charger to indicate full charge (and naturally the charger quits when there) After several charges none will fully charge anymore. Wait day after day and no. I have several good rated chargers which should shut down when a certain voltage is detected. I HAVE NOT EVEN USED THESE HEAVY MONSTERS YET!!!! If I open the tops and check fluid level what do I expect ? Only thing possibly you ever do is add distilled water ? EXCIDE brand from Home Depot. I have wrecked them by no use but keeping them charged ? Is not the worst thing is a discharged battery ?

I bought them for portable Amateur Radio usage away from regular electricity. Tender Loving Care and I ruined them ? AGAIN—using chargers that promote smart charging and not some auto battery charger that fast charges something and that’s it. Guess my luck with some large Lithium Batteries that cost a fortune ? I just like to have the education here. Buy 4 Marine Deep Cycle and not familiar they weigh 10,000 pounds I just try to keep them alive by charging every several months.

They do register over 12 volts on a meter but not much over. Rough and Rugged and I kill them by precious care ?

Baffled.

[Nicholson58]

Batteries need a proper multi stage charger to avoid various damage. The final stage is called float. If you use a bargain auto charger you get single stage with no smarts.

[Lake-Effect]

Originally Posted by shepaug

After several charges none will fully charge anymore. Wait day after day and no. I have several good rated chargers which should shut down when a certain voltage is detected. I HAVE NOT EVEN USED THESE HEAVY MONSTERS YET!!!!

How do you know the batteries are ruined? I wouldn't necessarily trust the charger's behaviour. Simplest way to test is with a decent battery conductance meter or analyzer. A good auto battery store will have one. I have been able to get basic health readings with a cheap Far-East conductance meter, though I would then check a problem battery with a better meter before junking it.

(A hard way to check is to draw a reasonable current from them, measure how long they can provide that current before the voltage dips below 12v, and multiplication gives you amp-hours.)

Also, a battery that looks iffy on a conventional auto-battery tester might still be useable in a lower-current scenario. How much battery current do you plan to draw in ham use?

The above is just an oversimplified list of ideas. Lead-acid batteries are complex beasties, and can take a lifetime to understand fully.

[StuM]

Originally Posted by shepaug

Every couple months I have made sure they are fully charged.

There's your mistake.FLA can self discharge up to about 5% per week. After a month they can be down to 80%. In the second month, they can drop to about 60%. Most of the time they are sitting in a partial state of charge.

EXCIDE brand from Home Depot.

Excide Nautilus? If you research them, you will find they are a cheap hybrid battery, they are not true "Deep Cycle" (One give away is that they start off their listed specs with "cranking Amps" - CA, MCA and CCA figures )

I have wrecked them by no use but keeping them charged ?

No, you have possibly wrecked them by NOT keeping them charged.

...using chargers that promote smart charging...I just try to keep them alive by charging every several months.

You should leave them permanently on a smart charger so that they will be held at float.
If it's "every several months" rather than "every couple of months", they'll be sitting at a low SOC for longer and suffer much more sulphation

[CarinaPDX]

Agree with above. Just because they say they are marine deep cycle batteries doesn't mean they are so. Buying Exide at Costco you probably paid half to one third of the price of the real deal. You didn't mention the size, but for argument's sake let's say they are Group 29 or 31; quality batteries of that size for our usage run about $500 apiece, whether they are Lifeline AGM, Prevailer gel, or Firefly carbon foam. A true FLA (flooded) deep cycle battery might save $100-200 off of that (very roughly). Much lower than that and it just isn't in the same ball park.

As for charging, both overcharging and undercharging can be a problem. You want a multi-step charger that will take the battery up to a higher "absorption" voltage (14.1-14.5+V, highly dependent on battery construction) and after some time (usually programmable) they should drop to a "float" voltage, usually somewhere between 13.3-13.8V. The ideal charger will reset every few weeks and do an absorption charge again (advanced topic). If you have a simple charger that goes to 13.8V you may never fully charge the battery, and if it stays up at the absorption voltage too long it can gas and potentially damage the battery. AGM batteries don't like being at a partially discharged state, but also don't self-discharge much. FLA batteries self-discharge and really need a good charging regimen. Gel and carbon foam are both low self-discharge and handle low charge levels better than others. The typical automotive low-maintenance batteries aren't worth discussing...

Whether or not these batteries are damaged can be determined with a proper under-load tester, but if they can't reach full charge voltage that is not a good sign. If you are using a battery manager to determine full charge then that could be very misleading - they have to be adapted to the batteries. They should reset at full charge and then calculate usage/charging but they need setting up and may not be the best info.

Greg

[Edit: the charger needs to be set to the correct absorption and float voltages for your specific batteries - you must do this, and if there is no way to do it, or there isn't a battery type selector switch, you don't have an adequate charger. Also the length of time at absorption voltage is usually set.]

[chasfgr]

My experience; cheap chargers = battery expense.


I bought a charger in 1993, which operates on back EMf and charges the batteries at a maximum of 40 amps and a float of about 0.8 amps.
It starts its charge at 14.5 volts and tapers off to 12.4 @ float.
It's one of the early Sterling chargers - the first two burnt out but Sterling replaced them without quibble - in the end I discovered a duff cell in one of the 3 batteries which was probably the cause.

[rickpyne]

There is a product available in Australia called "INOX battery restorer" where you add a measured amount into each cell to remove the sulphurization on the cell-plates I have used it over the years and have found it very,very good. I add it now, to new Batteries and have extended their lifespan considerably. Well worth the small investment. I highly reccommend this product.

[chasmains]

Would you folks please list brand and model numbers for these advanced chargers? And it would be great to consolidate all the great knowledge into one place, maybe a website book, to capture it for noobies like me. Regular revisions, as the info updates, would be so good. Thanks, C

[sailorboy1]

Seems this isn't really a battery problem thread as much as it is a battery user problem thread. If you don't properly charge them and understand what a proper charge is, you are going to have short battery life. There are 1,000s of battery threads here and I bet at least half indicate people don't understand the how and what that equals a properly charged battery.

[chasmains]

Agree, Sailorboy1. And that is a supporting vote for a consolidated knowledge “book” on this forum. We have lead/acid batteries on my submarines. I know that battery knowledge is essential to keeping them alive. Submarines don’t change batteries often, if at all. I don’t remember any battery cell(s) being changed out. My 20 years experience on subs, not working in Electrical Division did not give me adequate training to apply to my own boat batteries. So Submarine methods apply here. And all the other knowledge from all of you would be a battery gold mine if collected in a single place. C

[Lake-Effect]

Originally Posted by sailorboy1

Seems this isn't really a battery problem thread as much as it is a battery user problem thread. If you don't properly charge them and understand what a proper charge is, you are going to have short battery life. There are 1,000s of battery threads here and I bet at least half indicate people don't understand the how and what that equals a properly charged battery.

Pushing the derail a bit... given how critical the care and feeding of a battery system is, it's still left up to the end user to piece together the optimal system with brand A batteries, brand B alternator, brand C charger, brand D solar, brand E battery monitor, brand F ACR... seems to me that there would be a ready market for an integrated battery system with most or all of the above selected and programmed to work together.

Or at least some cross-reference or specific recommendations: eg the battery maker recommends specific charger models. Last suggestion - maybe the ABYC or NMEA should create performance standards and classifications that all these components can be certified for, so that if you buy batteries certified as class XX, then you know that a charger certified for class XX will properly charge them.

[sandy stone]

Originally Posted by CarinaPDX

The typical automotive low-maintenance batteries aren't worth discussing...

Well, there is the discussion about whether the premium batteries will last 4-5 times as long as Walmart deep-cycle batteries.

[sailorboy1]

Originally Posted by chasmains

Agree, Sailorboy1. And that is a supporting vote for a consolidated knowledge “book” on this forum. We have lead/acid batteries on my submarines. I know that battery knowledge is essential to keeping them alive. Submarines don’t change batteries often, if at all. I don’t remember any battery cell(s) being changed out. My 20 years experience on subs, not working in Electrical Division did not give me adequate training to apply to my own boat batteries. So Submarine methods apply here. And all the other knowledge from all of you would be a battery gold mine if collected in a single place. C

As an ex sub nuc, those batteries are basically always fully charged and on float unless the reactor scrammed. At which time the motor generator drew from them till the diesel got started (10 minutes). After they quickly got recharged and they barely got cycled at all and lived a near perfect life. Nothing like a pleasure boat system at all.

Btw - they did get various types of charges once in a while.

[sailorboy1]

Btw i just found out my 3.5 old start battery is dead. So guess I am not so smart.

[donradcliffe]

I and a friend just went shopping for house batteries for his RV. The cheapest Chinese drop in LiFePO4 batteries on Amazon are getting very competitive with AGMs on an initial dollar per amp-hour basis, but the user feedback says their Battery Management Systems don't work as advertised (if they even exist). The LifePO4 price trend is down, while the AGM price trend is up.

On my advice, he bought two group 31 "marine deep cycle/starting" batteries for $99 apiece at the local auto parts store (compared to $300 apiece for AGMs). With the 300 watts of solar we are installing, they should last a couple of years at least, at which time he will buy better batteries for the long term.