What type of battery is it? NI-CD/NI-MH/LI-ION? If it is Li-Ion, you must NOT let it fully discharge, or it will lose almost all it's capacity; if not all. For any type of battery that has not been used in a while, you could try some charge/discharge cycles, just remember if it is lithium, not to fully discharge

Sorry, it's a 12 V lead acid deep cycle boat battery. Thought that would be obvious. That's what I get for thinking!

Recharge the battery for at least 12 hours or until the battery tester hygrometer reads full charge.

Hygrometer? What's that? I'm off to purchase one. Mine broke a couple years ago and I haven't replaced it, yet?

Thanks, it's on the charger as I type.

A battery is just a way to store energy with a bucket of chemicals. Batteries hate warm temperatures and will self discharge quicker in warm climates. Also, conventional lead acid batteries, even so called deep discharge ones, should never be deep discharged as full rated recharged capacity will be severely compromised. A good rule of thumb for house batteries is never drop below 75 percent of the battery's amp-hour rated capacity. I have a boat in Florida and it seems like every three years my batteries just konk out and need to be replaced. Batteries up north seem to last forever.

"And, in your location, a solar maintainer charger might be ideal."

Yes, I had solar chargers on both batteries. The problem with them is that they accumulate dirt/sand/bird do/etc. and require periodic cleaning, which I didn't do. The output falls off rapidly if left unattended.

People like me shouldn't own a boat.

Thanks.

GA from me.

After reviewing the GA in this thread, I added a GA for your and Pantaz's posts. The new battery tenders which supply programmed charge & load discharge cycles are amazing. My son uses them and swears by their performance. I thought that these suggestions should stand out for future reviewers.

The kicker is going to be the two Arizona summers. Batteries do not like elevated temperatures. The black floaters are not a good sign. If you are really desperate about saving this battery for whatever reason, your best bet may be to try completely changing the acid, although I suspect your plates are pretty well sulphated at this point...

Charlie Warner has it pretty much on the button. Internal discharge is a direct function of temperature, thus Lynn must put a trickle charge on for summer storage.

One way out of the current problem, although not a complete solution, is to equalise the battery. This means charge it up to 15.5V and allow it to gas vigorously for a few hours (about 4hrs should be enough). It knocks the sulphate off the plates and will restore some of it's former glory, but it will never be what it should have been.

Needless to say this should be done in a well ventilated space as the gas given off is highly explosive. No sparks, no smoking.

If, as is almost certain, sulphation is the problem then the hydrometer will tell you little. The reason for this is that the electrolyte is in a charged condition but the sulphation will not allow it sufficient access to the plates. You should see a correctly charged battery voltage,12.6V @20ºC but it will fall off immediatly you attempt to put a load on.

regards

Chas

Personally I would never trust a lead acid battery that has been left for a long period in an uncharged state and allowed to sulphate, you could end up stranded thinking you had full capacity when in reality the baterry is knackered, invest in a new one.

Very valid point Lemmy,

I was assuming that this battery was for service load (house battery in US parlance) since Lyn states it is deep cycle battery which would not normally be used for starting the engine(s). I woul also guess that it is a lake boat as Arizona is landlocked and is at least 150 miles from the ocean.

Chas

When you buy the replacement battery.....you have some good advice here.

I take my battery into the cellar from our caravan, i can look after it much better there.....make up a transport box and get the muscles in training!!!

Do not use a normal "cheap" charger on the new battery, they ruin batteries every day of the year.... you need one that shuts off well before gassing starts....

As you can see, I think you need a new battery.....

Andy-Help, help, I use car batteries for my backup system here in the tropics. I have a cheap charger, it drops off amps as the battery charges, but they do get warm. I don't see a lot of bubbles. My truck battery died in one cell just because I left it dead for a while when my back was out. Really dead I presume, won't come up. Another battery only has surface charge, all cells show good electrolyte, but no real longevity. Deep cycle batteries cost a fortune here, gel cells no cheaper, a good car battery $100. I have a maintainer, do I use it to bring up a discharged battery?

My backup system is a 450AT ups (APC) with a computer fan to keep it cool, and the car battery hooked up to where the gel was. It protects my computer, tv, vcr, etc. from the power company here that has no shame.

A good charger, with a cut off at say 13.4 volts is simply a must for ANY LA or SLA Battery.

Not "Over" discharging, even if a deep cycle battery, is also a good idea.....car batteries are very sensitive to being below 12.6 volts for any length of time, sulfation starts below 12.6 volts.

I personally would only use a Gel battery where I did not have the possibility to get rid of any gas. Before anyone says it, even SLA batteries can gas under bad circumstances, they have a safety valve to make sure that they cannot explode...!!

I have heard good reports for some years about these small electronic units that are placed across the battery (permanently) and that using the battery power (a tiny amount), give it a high voltage "jolt" every few seconds. I have one over the caravan battery, the battery works like new and it is a 5 year old, unsealed deep cycle battery that rarely gets deep cycled....120 AH..

But whether this battery "saver" has helped or not I cannot categorically say, sorry.....

Car batteries are very sensitive and need to be recharged immediately. They are made in a special way to give high "Cranking" amps......not for deep discharge.

In the RN we learnt how to recover a failed battery, but its complicated and dagerous and you need a properly designed workshop, proper clothes, equipment and safety equipment.....also modern batteries do not lend themselves on an individual cell basis for either testing or repair....

If I can help further just ask.

This Battery zapper workes for me, a cheap soloution to revitilize lead acid batteries, if this does not do it nothing will other than bying a new battery and looking after it, trickle charge etc, never let the go dead flat.

http://www.siliconchip.com.au/cms/A_104827/article.html

How long did you charge it for?

I always wondered how a battery was "Dry charged" now I know! Thanks.

GA from me.

Why do you suggest discarding the the electrolyte? Couldn't it just be stored in an appropriate container, and returned to the battery when needed?

Of course, the electrolyte can be used later. It is the same chemical. However it appears dirty in general.

During the electrolyte is boiling (During charge and discharge) , or during transportation (vehicle batteries) , some remnants of the Plumb Sulphur is soften and got drop down from the plates. They form a sedimented clay at the dip of the battery box. Therefore used and removed electrolyte is always brownish dirty. It's not a good idea to store it in a container and use again in the next service time. Fresh electrolyte is not expensive.

I also strictly advise to wash the inside of the battery with (soft) hot water just after the electrolyte is removed. This rinsing operation will clean the clay of remnants below the plates. This clay is conductive and the cause of battery self discharge even not in use. You can also estimate the remaining battery amp/h capacity. Capacity decreases by the sedimented clay of plumb, of which is seperated out from the plates. (Plates are getting thinned because of the sedimentation during strong (Quick) charges and vibrations of the off roads.)

Regards

Very interesting. I'll experiment with some sick batteries I have. One has one dead cell, it only reads 10.5 volts, and the electrolyte in the last cell is much weaker than the rest. I left it totally discharged for a week, my back was out. What happened to the electrolyte in that cell? Would replacing that electrolyte help renew the battery? I can get new electrolyte at the hardware store. What is that liquid that is sold not as electrolyte, but as battery rejuvenator? I usually buy distilled water for topping off.

The second battery shows 12.5 volts, but doesn't put out for very long. The electrolyte measures ok (I only have one of those five floating ball testers). It ran my monitor ok for a test, but won't drive other stuff very long.

Well put.

The sediment will, if it reaches the bottom of the plates, short out that cell.....a common fault on car batteries that have not have correct usage/maintenance.

Plus, there might not be enough...and it's critical that the electrolyte filling process not be interrupted for any reason...including rushing to the battery store to purchase another (plastic) container-full when the first container runs short.

And, the electrolyte (H₂SO₄) is cheap...as in, inexpensive enough that purchasing new is better than the hassle of storing old fluid...better to let the store (and the recycler) store the stuff instead.

I gave nezihozfirat a GA for the excellent post 32.

However the advice may be valid for a company suitably equipped to deal with the electrolyte but it is not very advisable to try these restoration methods at home. One or two drops of acid on your clothes will ruin them and remove all profit from attempting to save a lost cause anyway.

http://www.abbey-chemicals.co.uk/MSDS/BATTERY%20ACID%20MSDS.pdf

regards

Chas

Capblanc is very right. Thanks for the reminder.

Dealing with pure powerful acids is the business of chemists, of which are well acquainted, having proper background. Otherwise severe burn and hazards may occur.

Especially dealing with pure smoking Suphuric acid is like playing with a smoking gun.

Exposing pure acid with water causes splashing and you may lose your eyes or you can burn yourself.

What we are speaking in this forum is the Battery Electrolyte, the diluted form (30% acid to 70& pure water). This is less harmful, if you use eye protecting goggles and surgeon type rubber gloves.

I have damaged many of my Jeans even I know this. It is not remarkable immediately. But a week later you can see small holes on the cloth.

Regards

Let's deal with your immediate problem: a deep-cycle battery gone dead from overlong storage of the battery itself.

It's going to take a considerable amperage for a considerable duration (as defined in a moment) in order to get your battery going, charging up to full charge in any reasonable amount of time. While there are home (12V) chargers with deep cycle setting these are inadequate for the battery restoration you require. But, commercial automated (computer controlled) battery testers-chargers of the kind that would get it done are not within the $means of a home user...but are available to home users of batteries through numerous, major chain auto-parts outlets and battery distributors--and the benefit of their use is free!

You need to approach the solution like this:

Take the battery in to your auto parts store (something like Auto Zone, for example) and tell them you would like the battery tested to see it it's okay, but...but the battery is discharged so would they be kind enough to charge it first so it can be tested....if you leave the battery with them until tomorrow? They will agree. (They hope to sell a battery...or have you come back when you need a battery.)

The next day, at the appointed time, return to see if the battery has completed charged and has been load tested. If charged only, they can load test it in just a few moments while you wait.

More likely than not your battery will test out in fine condition.

If you ask them to check the amperage setting (which is self setting under computer control) on their charger, you are likely to find that 60, 70...and more amps was required over at least several hours, perhaps 6 or more up to almost a day. Examine the battery for any fluid (electrolyte) overflow and ask them to clean it up before you take it home.

Hence forth, if the battery is discharged turning the prop, or simply by sitting, be sure to charge it up periodically (say, monthly or not less than bi-monthly) using an automatic charger with deep cycle setting that you will purchase. If you buy a hygrometer, you are likely not to use if much if at all, and the specific gravity means of testing is not always that reliable...compared with simply getting your battery sales store test it for you. There are also handheld load testers which don't cost much...probably better than hygrometer...but, in either case, testing specific gravity of electrolyte or load testing better will only be effective on a fully charged battery.

Another thing: "topping off" the water (by which I assume is meant, adding distilled (not spring) water to the full lines) is advisable only to the degree needed to just cover the plates...but no more to the caps as used to be done.

If you did fill it up to the cap tubes, it is likely to have overflowed during charging at the store. So it's more likely you will need to let the battery come to room temperature (it will be very warm if they just took it off the charger) before wiping it and transporting it in your vehicle.

If a battery leaks, just wiping off is not enough, the acid needs to be neutralized in some way as well......

Exactly. The Sulphuric acid , spilled anywhere must be neutralized.

The most common stuff is Caustic Soda. It is an alcaline. Mixing Soda with acid is simply resulting a neutral Salt,

Was referring to overflow, not leak, but, otherwise point well taken. Since baking soda for neutralizing electrolyte (H₂SO₄) overflow is not likely to be available at the merchant location, wiping excess with paper towels might be the only ready option; take along a plastic box, like a litter box, to ensure protection of car during battery transport. (Also, the part about not transporting hot battery is noteworthy, since some electrolyte near the fillers cover will be drawn back inside as the cells cool.) Once home, a wet paste of water and baking soda (bicarbonate of soda) can be wiped over the battery (do not remove filler covers/caps), followed by a general rinsing and wiping dry of the battery case. If desired, wet the "clean" battery case and lightly sprinkle baking soda over it: to neutralize any remaining acid; or to ensure all acid removed...by the fact that the baking soda does not react to (does not foam up) remaining aced...followed by re-rinsing the (baking soda off of) the battery.

Nuff said? Thanks (to both of you) for the insightful correction.

Thanks to one and all for the excellent advice. I didn't find any advice that I'd say was off base.

I've made a command decision, and am buying a new battery for the boat.

I'm putting the old boat battery on my flat bed trailer to supply power to the winch, now running off the vehicle battery. That lets me run smaller wiring back from the alternator to the remote battery.

Thanks for the intelligent responses.

Lyn