When AGM batteries die is it always suddenly?

[OVERKILL]

Originally Posted By: dailydriver
Originally Posted By: kc8adu
while it is made with continuous grids they have several connecting points on each that all line up once the plate pair is wound.those get cast together as part of an interconnect or post.
the big killer is water loss that accelerates corrosion.this takes out an interconnect.
remember the acid becomes more concentrated as you lose water.i get these types of battery often that are testing poorly but have an unusually high oc voltage at rest after being fully charged.i carefully add small amounts of water and let it soak in.then do an impedance test.if still poor i give each cell another dose of water.if its still not improving its just worn out.most improve a lot.many like new.
Originally Posted By: SHOZ
The spiral cells have one major drawback. There is only one grid per cell. It that breaks loose at the internal busbar, or internally in the wrapped cell the battery goes OC.


HOW do you get the water in there, through the dense sponge covered vents in the top???

Was wondering the same thing!

 

[SHOZ]

Originally Posted By: dailydriver
Originally Posted By: kc8adu
while it is made with continuous grids they have several connecting points on each that all line up once the plate pair is wound.those get cast together as part of an interconnect or post.
the big killer is water loss that accelerates corrosion.this takes out an interconnect.
remember the acid becomes more concentrated as you lose water.i get these types of battery often that are testing poorly but have an unusually high oc voltage at rest after being fully charged.i carefully add small amounts of water and let it soak in.then do an impedance test.if still poor i give each cell another dose of water.if its still not improving its just worn out.most improve a lot.many like new.
Originally Posted By: SHOZ
The spiral cells have one major drawback. There is only one grid per cell. It that breaks loose at the internal busbar, or internally in the wrapped cell the battery goes OC.


HOW do you get the water in there, through the dense sponge covered vents in the top???

We made large stationary batteries in the typical fork truck like individual cells. The smallest one was 55A per 8 hr discharge per positive plate. The largest was 180A per 8 hour discharge rate. You would then combine 2 pos plates and 3 neg plates for the smallest up to 31 positive plates and 33 negative plates for the largest cell.

So a 55A5 was the smallest cell we made and had an 8 hr discharge rate of 110A (55x2)per hour. And then combined with six cells to make a 12V battery.

The Absorbent Glass Mat (AGM) was used to wrap the positive plates much like the old fiberglass separators. But it was fiberglass mat and not a ribbed sheet like the old seperators made up of nano glass tubes. These tubes were 1-3 nanometers in diameter. A sheet of this stuff would suck up more liquid than a baby diaper.

I don't know how the small car battery types are made, with the normal flooded car battery it was filled with a weaker acid and then charged for whatever time needed, some water was driven off during this time.. Then the acid is dumped out and they go through a trough of final specific gravity acid, caps put in and rinsed off, then labels put on and out the door.

With the cells we made, we had large reservoir tubes put on each cell, then the tube was filled with a calibrated amount of 1.250 acid. These would then cook for 3 days at different amp rates, driving the water off and if everything went right the acid in the cell would all be absorbed into the mat and a final specific gravity of around 1.315 or so.

Then the tubes were taken off and caps put in and they went through an 8 hour discharge test, adjusted for temperature.

 

[kc8adu]

on optima's i drill tiny holes 1 above each cell.
when i finish i seal with 5m jbweld.
most others are easy to get at the cps or the regulating valves.
east penn/deka are easy.
peel off the bit of hot glue on each cap and unscrew with a socket.

 

[dailydriver]

Originally Posted By: kc8adu
on optima's i drill tiny holes 1 above each cell.
when i finish i seal with 5m jbweld.


I am guessing that this is done LONG after the 3 year full replacement warranty is gone??