Flooded,AGM or Gel deep cycle batteries 12volt

harold1946 wrote:
"Almost never" implies that extreme conditions can and do exist.

Oh just STOP please.

Your original statement sounded like it is common place for a battery to self discharge at a rate of 40% per month.....and nothing could be farther from the truth.

A healthy battery that is not defective NEVER does that under normal conditions....NEVER.

You can make anything fail by abusing it. That proves nothing about it's normal performance.

It is a fact that most AGM batteries self-discharge at a much slower rate than most wet cell models, sometimes only 10% as fast but usually closer to 20%.

What this means in a practical sense is: A healthy, fully charged AGM battery can sit at 70 F or less for 4 to 6 months with no noticeable loss of power. Many (or most) wet cells would be down significantly in that same time period.

I quit.

"Almost never" implies that extreme conditions can and do exist. That is the reason for testing at extremes. To improve on existing technology and develop new. All product development is done by testing at extremes, as you are well aware.
Tell those that live and work in extreme climates that they don't exist.
You are allowed your opinion and it is respected.

PS. I actively participated in battery testing at extremes from Fort Greely Alaska to the Yuma Proving Grounds for 39 years.

Those interested on how temperature can affect battery performance and life go to = www.batteryuniversity.com

harold1946 wrote:
It is not unusual for battery bays or under hood temperatures to exceed 180 F.

In what part of the battery industry were/are you engaged?

This is the problem with quoting "facts" out of context.

Batteries don't STAY at those kinds of temperatures in consumer applications except when being actively charged.....usually.....so you are combining two circumstances that will almost never occur together; very high temperatures and no charging.

In my opinion simply stating "some new batteries will self-discharge at 40% a month" is grossly misleading because the conditions that would cause that will almost NEVER be encountered.

I am/was an Electronics Engineering Technician for about 50 years, although not specifically in the battery industry.

Vulcan Rider wrote:

harold1946 wrote:
Exide wet cells is one that stands out as the worst to my memory,

And I think your memory is failing a bit.

So what temperature was necessary to create a 40% per month self-discharge in a new battery ??

In my memory NO PRODUCTION battery came anywhere near to that figure in temperatures where a human being can exist.

I have no doubt my memory is failing a bit. Thanks for reminding me :B
IEC tests only new production batteries in temperature ranges from -80f to + 150F. most wet cell batteries start falling off at ranges from 1-2% per day in temperatures exceeding 100F, and doubles for each 50 degrees F above 86F. It is not unusual for battery bays or under hood temperatures to exceed 180 F.
At Furnace Creek I recorded 240 F in the battery bay when the ambient was 116F and there are people living there year round.
Don't take my word for it, contact the IEC.
In what part of the battery industry were/are you engaged?

harold1946 wrote:
Exide wet cells is one that stands out as the worst to my memory,

And I think your memory is failing a bit.

So what temperature was necessary to create a 40% per month self-discharge in a new battery ??

In my memory NO PRODUCTION battery came anywhere near to that figure in temperatures where a human being can exist.

Exide wet cells is one that stands out as the worst to my memory, but every battery tested decreased in capacity progressively as temperatures rose above 70F, some more than others.
Test results for every battery tested are available from the IEC (International Electrotechnical Commission).
The IEC does testing for most manufacturers.

harold1946 wrote:

Vulcan Rider wrote:

harold1946 wrote:
I have seen discharge rates as high as 40%/month in new wet cell batteries.

Please tell us what brand of battery that was so we can stay away from them.

It has far less to do with the manufacturer although there are several that are inferior.

2nd request.

Please tell us what battery it was that exhibited a 40% per month self-discharge rate when new.

Vulcan Rider wrote:

harold1946 wrote:
I have seen discharge rates as high as 40%/month in new wet cell batteries.

Please tell us what brand of battery that was so we can stay away from them.

In 40+ years of dealing with wet cell batteries, that is the first and only claim I have ever seen of a self discharge rate anywhere near that bad in a "new" battery.

You are right that there is an inherent rate when new due to the chemistry and construction......which is pretty much constant over the useful life of the battery. It is the chemistry CHANGE mostly due to sulfation that makes the self discharge rate become worse over time.

Add to that high temperatures. The higher the temperature the faster the self discharge rate even with a "new" or "healthy" battery. It has far less to do with the manufacturer although there are several that are inferior.

pnichols wrote:

Vulcan Rider wrote:
And I am telling you that you can get a "multi-stage" charger without temp. compensation but not the other way around, as far as I know.

Please open and study the documents in the links that I provided above related to the 4400 and 5400 Parallax charger lines. Both series of chargers are in fact two-stage chargers, with both their lower voltage float range and their higher voltage boost range adjusted over wide variations in voltage - depending upon temperature - but with each of the ranges falling within two bands differing from each other depending what stage the battery is ready for.

As I said earlier, the 5400 series even adds power factor correction to their design.

I like the temperature monitoring of those series and their ability to adjust the charge voltage to the optimum value for hot or cold temperature. What I don't like is the seeming lack of current monitoring in boost mode. The converter stays in boost mode for a fixed 4 hours when powered on, even if the batteries are already fully charged.

It is a typical scenario if you are driving to a plug-in site. You may leave home fully charged, the alternator keeps the batteries fully charged en route, or recharging if not fully charged. Then you arrive and plug in and the converter immediate goes to boost mode for 4 hours, where float mode is what is needed.

With generator recharging during dry camping it will do the right thing.

There is another issue shown in the documentation for the higher powered models, such as the 5400 series 65 amp unit: the cooling fan runs continuously, no matter what the load is.

EsoxLucius wrote:

harold1946 wrote:

EsoxLucius wrote:

harold1946 wrote:
It is best not to charge any battery at more than 13.8 volts unless de-sulfating or de-stratifying.

Say what? My batteries accept 14.7 volts for bulk and absorption charging, and 13.7 volts in float. Such generalizations do no one any good.

I'll try to make it clearer.
Bringing a 12 volt battery to full charge using a voltage over 13.8 will damage the battery. That is why we use a charger that steps down in stages as the battery nears full charge and uses a float rate of 13.8 or less. bringing a battery to full charge is not done at higher rates, (such as 14.7) because it will damage the battery.
A charger that has a maximum output of 13.8 can only charge to that voltage. Once it is reached, charging stops.

Then sir you previously ignored what I wrote in the quote of me above. However, you wrote that it is best not to charge any battery at more than 13.8 volts unless de-sulfating or de-stratifying. I pointed out that that statement is false as bulk and absorption charging can occur at 14.2 to 14.8 volts depending on the battery. Thank you for correcting your false generalization with subsequent clarification, or stating the obvious.

No it is not false. I did however unintentionally leave out the word fully.
Typo, nothing more.
Attempting to fully charge a battery at 14.7 volts will damage it. Doing so at 13.8 will not.
I will in the future proofread so there is no misunderstanding.

I did not ignore you statement. I felt there was no need to reply after your derogatory comments, as it would serve no purpose.