Considering battery's for the future

[user 37446]

AGM is certainly more "finicky" than flooded.

But a **lot** more forgiving than GEL

Also compared to LFP, if you are striving for longevity.

Yep, what was said above is true, finicky to what degree is the issue.

I’d wager that as many people have overcharged and boiled off their fla’s or just forgotten about them and ended up with water below the plates, so as to kill them through that or simply chronically undercharging.

How many threads have discussed battery murder through inattention?  Lots.  It all “boils” (pun intended) down to the OP’s willingness to check fluid levels monthly, watch charging parameters, invest in a hydrometer etc.  AGM’s certainly make life easier for the non-technical type, who is just learning on his first set.

As in everything else, it varies. I stand by AGM as being a very good choice for a sector of the community who just aren’t that dedicated to monitoring batteries, much less the venting concerns.

Me, I’m going to dump the lead acid idea (weight and hassle) completely and purchase the (gasp, horrors) all in one 400 watt Lithium Ion box unit, since I have less in the way of requirements with the minivan. It will power a compressor fridg and accepts 100 watt solar panel input, as well as dc charging. If it fails in a year or two oh well, that’s what my temp agency part time work pays for.   Choices.

 

[John61CT]

Boiling AGMs is just as easy as with FLA, at a lower voltage and fatal much more quickly, can't even replace the water lost.

If you're the type to murder batts, buy the cheapest (good) ones, Duracell FLA GC.

Mainly because less $ to lose, harder to kill is a bonus.

 

[user 37446]

Boiling AGMs is just as easy as with FLA, at a lower voltage and fatal much more quickly, can't even replace the water lost.

If you're the type to murder batts,  buy the cheapest (good) ones,  Duracell FLA GC.

Mainly because less $ to lose,  harder to kill is a bonus.

True John, you can overcharge any battery, since AGM's take a different (by a couple tenths) charging rate. It's all about the need to pay attention to your system.  I'll never convince a purist that AGM's are better than FLA's. It's just a balanced amount of information for the OP.  I don't care either way what he uses, each system has its advantages and disadvantages.

From Century Batteries pdf: http://www.centurybatteries.com.au/...alk/issue-2-battery-talk-battery-charging.pdf

"Deep Cycle AGM:- AGM batteries should be charged using a charger with a mode switch for AGM type batteries. It is recommended to use a charger, current limited to 20% or 0.2C of the batteries capacity at a charging voltage of between 14.6 – 14.8V following deep cycle use, or 13.6V – 13.8V for standby use. Charging should be paused if the battery or ambient temperature exceeds 50°C."


From Battery University site: http://batteryuniversity.com/learn/article/absorbent_glass_mat_agm

[font=Arial, Helvetica, sans-serif]"Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell); a direct replacement with a sealed unit could overcharge the battery on a long drive. (See BU-403: Charging Lead Acid.)

AGM and other sealed batteries do not like heat and should be installed away from the engine compartment. Manufacturers recommend halting charge if the battery core reaches 49°C (120°F). Table 1 spells out the advantages and limitations of AGM.
 [/font]

Advantages​

[font=Arial, Helvetica, sans-serif]
Spill-proof through acid encapsulation in matting technology
High specific power, low internal resistance, responsive to load
Up to 5 times faster charge than with flooded technology
Better cycle life than with flooded systems
Water retention (oxygen and hydrogen combine to produce water)
Vibration resistance due to sandwich construction
Stands up well to cold temperature
Less prone to sulfation if not regularly topping charged

Has less electrolyte and lead than the flooded version[/font]

Limitations​

Higher manufacturing cost than flooded 
Sensitive to overcharging (AGM has tighter tolerances than gel)
Capacity has gradual decline (gel has a performance dome)
Low specific energy
Must be stored in charged condition (less critical than flooded)

End of quote


Whatever OP buys, be it golf cart 6v's, high cost deep cycle AGM's, or anything in-between, I hope he gets the needed monitoring instruments so that he doesn't end up killing them in a year.