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pgmrdan
10-04-2011, 09:46 AM
Can you point me to some good information on maintaining deep-cycle (marine?) and automotive lead acid batteries?

I'd like some accurate guidelines on charging, discharging, battery chargers, etc.

Thanks,
Dan

Willy
10-04-2011, 10:27 AM
Here's a couple to get you started...no pun intended.:)

http://marine-electronics.net/techarticle/battery_faq/b_faq.htm


http://pursuit.bravehost.com/pdf/RV_Battery_Savvy.pdf

bborr01
10-04-2011, 10:46 AM
The key to keeping lead acid batteries good is to keep them charged up fully and keeping the water/acid at the proper level.

A 12 volt battery that has 12 volts charge in it is considered fully discharged. A discharged battery will develop lead sulphate on the plates and that is what ruins most batteries.

Battery tender type trickle chargers work well for this. I just picked up a couple of them from Sears for a little over $20 on sale.

Brian

moe1942
10-04-2011, 10:47 AM
Keep them on a float charger.

Metalmelter
10-04-2011, 11:04 AM
$20 and one of these does the trick for me:
http://www.walmart.com/ip/Schumacher-SpeedCharge-Battery-Maintainer-and-Charger/13005742

The idea is to trickle charge the battery to keep the plates from sulfating which renders the battery useless. I installed one in my backhoe and both of my trucks. Works like a charm ;)

Black_Moons
10-04-2011, 11:04 AM
Get a float charger that keeps them at 13.6 to 13.8v and no higher (idealy closer to 13.6v), lower is also not very good.

Leave it on them 24/7.. Or at least connect it for a few days every month if you wanna rotate it between batterys.

Scottike
10-04-2011, 11:13 AM
In addition to what's been said above, don't allow the batteries to set directly on a concrete floor, put a piece of wood under them if you do.
Something about it seems to encourage discharge. (temperature differential?)

lakeside53
10-04-2011, 11:22 AM
Continuous "dumb" float (the old way, but still around) isn't great for batteries either. "Marine" chargers are often 3 or 4 stage - they monitor the state of the battery and adjust the charge conditions to suit. One of my chargers will also pulse charge a zero volt battery - I've bought a few back from deader then dead!

I put quality multistage chargers on all my intermittent use devices - mower, generator, etc... I'm now into year 8 on all batteries. Prior , I was lucky to get 2-3 years. Oh... these are cheap UI size lawn tractor batteries that only have a 6 month or one year warranty. Neighbor now has the same chargers on all his collector cars.

This is the charger I buy : http://www.batterystuff.com/battery-chargers/brands/soneil/Son1206S.html

here's an extract from the blurb :

Multi Stage charging cycle

Stage 1: Deep Discharge Charging Pulse Mode
The Charger starts charging at 0.5V and give pulse current up to 5V. This has effect of removing loose sulphation formed during deep discharge state of the battery.

Stage 2: Constant Current Mode (CC)
The charger changes to constant current 3A. When the battery voltage reaches to 14.4V, the charging stage changes from (CC) Constant Current to CV (Constant Voltage) mode.

Stage 3: Constant Voltage Mode (CV)
The charger holds the battery at 14.4V and the current slowly reduces. When the current reaches at 0.5 C (C= Battery Capacity), this point called the Switching Point. The Switching Point is one of the great features of this battery charger that it can adjust the current automatically according to the battery capacity. Other chargers without microprocessors are not capable to adjust the current automatically.

Stage 4: Standby Voltage Mode
The charger maintains the battery voltage at 13.8V and current slowly reduces to zero. Charger can be left connected indefinitely without harming the battery.

Recharging:
If the battery voltage drops to 12.5V, the charger changes from any mode to Constant Current mode and restart charging. The charging cycle will go through Stage 2 to Stage 4.

P.A.R.
10-04-2011, 11:40 AM
Sir batteries can be fickle things and if you have mixed types you need a special charger.A standard car battery vs a trolling motor battery vs a gelled electrolyte cell charge at different rates(c rates varies with amperage) I use an Exide fully automatic charger that will charge most every thing and has a trickle charger built in they are not cheep.
A gentlemen above mentioned lead sulphate and he is correct the sulfate may be driven back into solution by temporarily over charging the cell, older service station models are able to do this the over charge is not much and the battery's temp must be monitored.If you have a Ham Radio friend the handbook goes into great detail on battery's in general and how to drive the sulfate back into the solution.Battery's can explode so be very careful.

EVguru
10-04-2011, 01:28 PM
Every single time you discharge a Lead Acid battery (of any type, wet, gel, or AGM) you are forming Lead Sulphate. That's just how the chemistry works.

If you leave a battery sitting around at a partial state of charge, then some of tha Lead sulphate is disolving and re-crystalising. This leads to the growth of large Sulphate crystals that are hard to persuade back into solution under charge. I've heard the terms soft sulphation and hard sulphation used to distinguish between the two.

If a battery that was otherwise in very good condition has been left discharged for a while and has hard sulphated and won't take a charge, then I've had some good results from and electronic de-sulphater/battery rejuvinator. They usually spout some rot about hitting the resonant frequency of the sulphate bonds, but certainly the fast rise pulse (they're just a simple flyback psu with no feedback) does seem to work.

A special case can occour with an AGM type battery. Lead Sulphate is an insulator and you can almost completely coat the very thin plates used in AGM batteries if you overdischarge or leave a heavily discharged AGM battery sitting. This can make them almost impossible to recharge with an ordinary charger. I've had to use around 60 volt on a 12 volt AGM to get it to pull any current. With a good bench supply, I can just set the current to say 100mA and leave it to recover. The de-sulphators seem to do the job a little faster.

The advice about not leaving batteries on a concrete floor is mostly true for the old rubber cased types. They would loose charge. Modern batteries will loose capacity simply by being cold, which is more likely if they're sitting on a concrete floor.

SGW
10-04-2011, 05:01 PM
I bought a Yuasa battery maintenance charger some years ago and leave it connected to my generator's battery all the time. Aside from ensuring the generator will start when needed, it keeps the battery in good shape. It wasn't particularly expensive.

J Tiers
10-04-2011, 09:35 PM
As for the comment about a "dumb" float.....

There is NO SUCH THING AS A FLOAT CHARGER

"Floating" the battery means matching its EMF with the external supply (following temp changes) so that there is NO charging going on....

When the load exceeds the external supply capability, the battery supplies current. THEN it gets recharged when the draw goes below the external supply capability.

batteries in that condition (railroad signal used to be like that, also phone company batteries, etc) will last a LONG time.

The other folks are correct.... sulphate is created in discharging the cell, and you need to recharge soon.

The pulse "reforming" chargers probably work by putting a high enough pulse current in that the "disconnected" sulphate is converted by the field in the water.

lakeside53
10-04-2011, 10:08 PM
Hmmm... semantics .. there is... dumb chargers that have no smart precision regulation (little more then a bridge rectifier and a tranfomer) which tries to float by approximating the transfomer voltage to the battery requirements... and often allow the voltage to rise too high too high and "over-charge" by definition... They are still sold and yes, are misleading to Joe consumer. Mabye a better name is dumb charger.

Over-charging is bad for battery longevity. The marine guys figured this out 20 years ago, Telco - 75 years ago.

tdmidget
10-04-2011, 10:10 PM
In addition to what's been said above, don't allow the batteries to set directly on a concrete floor, put a piece of wood under them if you do.
Something about it seems to encourage discharge. (temperature differential?)

I this crap is the best you have to offer, you should keep it to yourself. The OP did not ask for old wives tales and BS.

J Tiers
10-05-2011, 12:04 AM
There is no "float charger" because either the battery is being "floated", OR it is being charged, and the two are not one thing.

That said, you can "charge" a battery at a low rate about forever, and it will come to no harm..... The "low" rate being C/50 or less..... so 2 amperes max for a 100 ampere hour battery. Less being better.

No doubt a chorus will say "no way", but I have had batteries being charged at a similar low rate for almost 20 years..... they last about 12 years for me that way. They are in a solar power setup in the shed. The lowest charge rate is about 2 or 3 A, and there are 400 AH of batteries, so about C/100.

lakeside53
10-05-2011, 12:31 AM
Sure... you can charge a battery indefinitely at a certain low rate, but if you exceed that low rate for a given battery (which will change as the battery ages) you will raise the voltage and overcharge. Some smarts are required to stop this, and cheap generic battery chargers that have little other than a two position switch (say 2amp/10amp), or some approximate output voltage, isn't the answer for all batteries.


My only point was that multistage "smart" chargers solve many of the problems in maintaining battery condition and longevity. That you have one array that is nicely balanced and can survive for 12 years is a data point, but doesn't cover the masses of other uses.

kd4gij
10-05-2011, 01:49 AM
I this crap is the best you have to offer, you should keep it to yourself. The OP did not ask for old wives tales and BS.


While it is an old myth. There is no need to be rude about it.:eek: Lot's of service stations and dealers worned about that for many years. I even had a Yale battery rep void the warinty on my intire stock becouse 8 batteries sitting under the shelf on the concreat. There is alot of people that still beleive it.;)

J Tiers
10-05-2011, 08:53 AM
While it is an old myth. There is no need to be rude about it.:eek: Lot's of service stations and dealers worned about that for many years. I even had a Yale battery rep void the warinty on my intire stock becouse 8 batteries sitting under the shelf on the concreat. There is alot of people that still beleive it.;)

They stay colder in contact with the floor, which does reduce apparent capacity. Even when heated by discharge or charge, they lose heat faster to the floor,.... On a shelf they tend to be at average ambient temp.

On the floor, as opposed to up on a shelf, they tend to get dust on top, much of which may be alkaline concrete dust, which if it works its way into the cells will neutralize acid.

Even non-conductive, non-alkaline dust acts as a potential discharge path, wicking spilled acid across the surface. Batteries commonly have some acid on top.

On the floor, batteries tend to be less well taken care of, not cleaned of dust and acid, etc, etc.....

I don't know if the "old electrician's tale" is entirely without merit..... but the fact of being on the floor is probably not the issue..... the real deal is likely to be things associated with being down there.

Ideas like that typically don't come out of nowhere, they tend to be "observed"... but often entirely wrong reasons are claimed, even if the observed behavior is a true fact (in this case, poorer performance of the battery).

Black_Moons
10-05-2011, 01:09 PM
They stay colder in contact with the floor, which does reduce apparent capacity.

On the floor, batteries tend to be less well taken care of, not cleaned of dust and acid, etc, etc.....

I don't know if the "old electrician's tale" is entirely without merit..... but the fact of being on the floor is probably not the issue..... the real deal is likely to be things associated with being down there.

Ideas like that typically don't come out of nowhere, they tend to be "observed"... but often entirely wrong reasons are claimed, even if the observed behavior is a true fact (in this case, poorer performance of the battery).

I believe this is the real cause, as well as a slight incress in condensation due to being colder that will wet the dust on the top of the battery causing a conductive path that can self discharge a battery faster then normal. Left self discharged, a lead acid battery will die quickly.

Scottike
10-05-2011, 07:29 PM
I this crap is the best you have to offer, you should keep it to yourself. The OP did not ask for old wives tales and BS.

If that's the best you can do for a response to someone's post that you disagree with, you've got the problem, not me.
After some further research, the consensous I found in the battery industry is that modern battery case materials do not permit the accelerated discharge due to voltage leakage when a battery is placed on a concrete floor that was common with some of the earlier case materals. So, Perhaps my information is outdated, but that doesn't make it an "Old Wives Tale".
A known problem with lead acid batteries, especially large batteries, is electrolyte stratification. Large temperature differentials within the battery help to promote stratification, and it's resultant sulfation on the lower part of the plates due to the higher acid concentrations in the lower part of the battery.
So, while setting a battery on a concrete floor in and of itself may not be a bad thing, the possible temperature differentials that might result within the battery may contribute to electrolyte stratification, a condition that lead acid batteries are already suseceptable to when they are being stored.
My earlier advice to keep car batteries off of a concrete floor may not be entirely correct, it's certainly not BS, and actually does have some justification, unlike your response

Bill736
10-05-2011, 08:58 PM
My understanding about placing batteries on concrete floors stems from the early days ( i.e. Model T) when batteries had wooden cases. They would tend to leak electrolyte , and the wet concrete would create a mild short between the positive and negative poles. Of course, the wet wood might cause even greater current leakage, so I do have some reservations about this bit of old wisdom. However, concrete floors may actually be warmer than the ambient air temperature during the winter months, so I'm not sure about the cold concrete theory either.

JoeLee
10-05-2011, 10:03 PM
They do have battery desulfators that help to break up and prevent the formation of crystals. I guss these may have been called conditioners by some of the other posters??? They are easy to build but you can buy them cheap. I had a post going last year inquiring about them, I was wondering if they really do any good.

JL................

J Tiers
10-05-2011, 10:22 PM
However, concrete floors may actually be warmer than the ambient air temperature during the winter months, so I'm not sure about the cold concrete theory either.

Possibly..... but in a garage, the floor tends to be cold anyhow, and the rest of the year, it may be colder than the air....

In any case, it just goes to show that there are sensible reasons, maybe not correct ones, that could justify the "legend".

That's usually the way of it..... people make an assumption about some old legend that actually stems from an "observed" phenomenon, and dismiss it out-of-hand. Later, it is found that the "legend" is either quite true, or has a basis of truth in some circumstances.

The "scientists" laughed at Semmelwiess..... said his claim was a legend, imaginary, with no basis in fact or science. We know who was right about THAT. This is of somewhat less moment, but is none the worse for that.

JoeCB
10-05-2011, 10:51 PM
As for cold vs warm... Yes cold temperature will reduce the output of a battery under load. However in idle storage I suspect that lower temperature would be a good thing as the natural degradation of the battery is a chemical reaction and lower temperatures slow chemical reactions. Just don't let it get so cold that it freezes. All my idle battries spend the Michigan winter in the unheated garage, the charger makes the rounds every few weeks or so.... no problems.
Joe B

J Tiers
10-05-2011, 11:05 PM
I assumed on floor but being USED...... storage is another issue.