Optima
Here is a quote from Jeepforum.com under the cj section. Again this is a quote from a guy I don't know from Adam.
(start quote)
How about some information from a guy that owned and operated a starter, alternator & battery shop, mostly for heavy equipment, for about 10 years....
'Optima' is what is known as an 'Activated Glass Matt Battery'.
AGM for short.
AGM doesn't use a liquid electrolyte.
Instead, it uses a fiberglass mat, saturated with a gell type electrolyte.
The lead plates and AGM are piled up on one another, then rolled into a cylinder shape.
Battery guys call them 'Jelly Rolls'
That's what gives the AGM batteries their 'Six Pack' design.
There are problems with the fiberglass design, and the failure rate for them when I handled them was about 80%.
Now I understand it's about 50%, but that's not very good either, when every other one is going to die in service.
The problem begins with the pates converting chemical energy (Acid acting on the plate material, creating an electrical current) into electrical energy.
When this happens, bubbles are created.
Those bubbles are now a dead spot on the plate and can't conduct electricity anymore.
With a true 'Gell' cell, you can heat the electrolyte paste in a controlled environment, and liquefy the paste to release the gasses, but with a rolled AGM, the gasses are just stuck there against the plates, working as an insulator.
Capacity of the battery is reduced because of the bubbles, so it the areas of plate that are still in contact with the electrolyte have to work harder, causing bubbles to form there...
And the cycle repeats until the battery is useless.
The same is true with over charging.
Overcharging will form bubbles at the plates, and render the batteries useless.
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Now, some things to think about...
1. Warranty on a Optima is only one year (12 months), and up to 50% of these won't live through that warranty period...
2. Optima's are around $125 each (discounted), with a one year warranty.
That's about $10.50 a month just for the privilege of saying you have an 'Optima' under the hood.
(Average liquid electrolyte batteries will run you about 0.75¢ a month over an average 60 month warranty)
3. There is a 50% chance your expensive battery will fail in the first year, and over a 90% chance the battery will fail inside of 3 years.
4. Discount, off the shelf liquid electrolyte batteries are under $50 and have a 5 year or more warranty.
5. Discount batteries are normally 'Spill Resistant' and leak none or very little when inverted for a short period of time.
6. The normal 'Jeeper' DOES NOT invert their vehicle on a regular basis, so a 'Leak Proof' battery isn't required.
7. If you are a profession rock climber, or just someone that can't keep your wheels on the ground, a true 'Gell Cell' battery is absolutely leak proof.
8. A true 'Gell Cell' is absolutely Shock Proof.
You will fracture the case before you break a plate loose.
9. A true 'Gell Cell' is comparable in price for the cranking amps produced by the AGM batteries.
10. "PROPER USE" of an AGM or Gell Cell battery is slow discharge, like for battery back up of computers or telephones.
Rapid discharge, like starting a vehicle engine or running a winch, is absolutely going to damage a single AGM battery.
Rapid discharge, and subsiquant rapid recharge will create the bubbles mentioned earlier.
You might stand a chance with TWO AGM batteries in parallel, but I believe (from experience) you will damage both, just much slower.
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I purchased two liquid electrolyte batteries, made a custom battery tray, made custom battery cables, and installed a battery isolator relay for the cost of just one AGM battery locally.
Now I'm redundant on batteries,
I can jump start myself,
Weld off the batteries since liquid electrolyte will allow for that rapid of a discharge,
I can finish the day wheeling if my alternator give out on the trail (and it has) by just turning off the extra stuff, radios, electric fan, ect.,
And I have no fear of winter starts!
Twice the cold cranking amps with the twist of the starter switch...
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