Gunny said:
Those that have experience have tried mightily to educate me and while I am not stupid I must admit this high charge, low charge, ambient charge or just plain old charge boggles my mind.
Think of a battery as a full bucket of water.
Pour out half of it.
Now take a garden hose with water on low flow, and fill it back up right to the top of the brim, no more, no less.
Time your removal of the flow so that nothing ran over, and the level of the water is EXACTLY at the brim.
Pretty easy, but it takes a bit of time to do. Lets say, 2 minutes.
After a few days, if the water level has dropped due to evaporation or a dog slurping up a drink, add a tiny bit more water until the level is perfectly at the brim. No more, no less.
Now you have the idea behind the way a standard, flat rate charger with maintenance, or float, would work.
Starting again...
Pour out half the water.
Take another bucket, same size, but 1/4 full of water.
Pour it in rapidly. Dump it all in!
Now the bucket is 75% full. Quickly take the hose with water flowing rapidly, and fill it to 90%.
Turn the water flow down to very low flow again, and top off the water to right at the brim.
You now have a bucket full of water but it only took say, 30 seconds from 50% to 100%, instead of 2 minutes.
Again, add a little water every few days to keep the level at exactly 100%.
Now you have the idea of how a multistage, automatic charger works.
Bulk is the major fill from the other bucket.
Absorption is the high flow from the hose.
Float is the low flow from the hose as it reaches the very top of the brim.
And adding a bit of water every few days is like the maintenance stage...just keeping it level.
On flooded batteries, you can have another stage, called equalization. This would be like spraying a wide steam over several square buckets aligned so that the overfill from one bucket will add to the next bucket.
And finally, you might see a de-sulphation (or sometimes called de-stratification) stage for flooded batteries on some chargers, usually used once a month, or manually with the press of a button. These are often present on a home system using flooded batteries that never move. Batteries in a vehicle that is driven regularly do not need this stage, nor do gel or sealed AGM.
De-sulphation, (de-stratification), used in our bucket of water, is done by taking the hose on the highest flow possible, and dropping the nozzle into the bottom, and purposely over filling the bucket to over-flowing. This stirs up or agitates the water, and keeps it well mixed and fresh.
In a flooded battery that sits perfectly still for months at a time, the battery acid can develop 'gas' bubbles during the charging process and those cause the plate surfaces within the bubbles to 'dry out'. This can cause the beginning of sulphation, and it needs to be addressed or the battery will be damaged eventually. So the desulpahation or de-stratification stage FORCES a very high voltage into the battery, with lots of current, to cause the acid to basically start to boil...its a controlled boil, causing off-gassing, and only done for a short period of time. But its enough to 'stir' the acid, and recombine all the fluid and force the bubbles to the top of the acid level and vent off.
You dont want to be breathing those fumes while its happening! But it restores the fluid to a well-mixed consistency inside the battery.
Now for the those who understand all of this, this is highly simplified....but maybe it helped make it clearer for those who are new to all of this stuff.
I learn something new every day!
