Originally Posted by smac999
Gel was a failure years ago so they created agm.
Really? You got sources for that myth..?
Originally Posted by smac999
Gels are a pain to use. Everything needs to be setup for it. Like external alt regulators etc
AGM's are just as tough to use and set up properly
GEL's are very easy to use they just need proper charging
. When you do this the average life of a GEL battery will almost always exceed that of AGM. In the real world I have yet to see a properly charged AGM battery bank out last a properly charged GEL battery bank... The key word for both is "properly charged"...
All one has to do is take one look at a manufacturer who makes both types of batteries and their own cycle life ratings for their own batteries.
BTW the Rolls AGM's were/are made in China
to Rolls specifications. There has been talk of building them in Canada
but I don't know if that has happened yet. I don't see enough of them to form an any opinion on longevity...
I can only offer my real world
experience across many hundreds of vessels. You certainly can
maximize the cycle life of AGM batteries but it can get expensive to do it right. I still install a LOT of AGM batteries but they are always installed and addressed as a compete system not just a drop in replacement for flooded batteries. The fact that Lifeline AGM's can be equalized makes them a clear winner for me in the AGM market but Odyssey is a close second.
John Harries has written extensively about AGM's and it is a must read for anyone considering AGM:
Morgan's Cloud AGM's
Perhaps the best way to see how a battery should perform is to look at a manufacturer who makes all types. For the Deka/East Penn brand this is how they rate their own
Only ratings within a brand
are useful. Cross brand cycle life data is useless because there is no industry standard for testing. Much of the cycle life data from manufacturers is Disney fairy tale stuff.. Most all of them are fantasy level data
when applied to real world marine
use. Only in-house manufacturer testing across their own batteries can be compared for guidelines
-GEL Cycles to 50% = *1000 Cycles
-6V Flooded Golf Cart - Cycles to 50% = *700-1000 Cycles
-12V Flooded 4D, 8D, 24, 27, 31 - Cycled to 50% = *350 Cycles
-AGM Cycled to 50% = *300 Cycles
These are usually not what you will see in the "real world".. Deka rates their batteries more conservatively/honestly than most..
That is not my data but Deka's own data across their own batteries.... As can clearly be seen;
*They rate their 12V DC wets at 50 more cycles than AGM. (not a true deep cycle)
*They rate their 6V DC wets at 400 - 700 more cycles than AGM
*They rate GEL at 700 more cycles than AGM...
The problem with GEL batteries was the folks who marketed them not the batteries themselves. GEL was having a hard time gaining foot hold due to the lower charging
voltages (14.1V) so they began telling everyone it was okay to charge them with flooded equipment
. BIG MISTAKE! It gave GELS a black eye and allowed the AGM makers to gain a stronger foot hold. They then began a misleading marketing
campaign about depth
of discharge (recommended 80% DOD to justify cost now they recommend 50% max DOD) suggested a lack of sulfation etc., etc... They too gave themselves a black eye and had to adjust
much of the early marketing
If I was choosing a cruising bank of valve regulated lead acid batteries for my own vessel hands down it would be GEL over AGM.....
I have numerous GEL banks on cruising boats beyond 11 years and one at 15....