I understand the appeal of AGM and the price from Batteries Plus seems pretty reasonable.
Does anyone have any experience with Firefly Oasis carbon foam batteries?
Firefly International Energy - 12V G31 Battery
They are purported to be very tolerant of deeper discharges, have excellent cycling characteristics and can be left unattended for long periods. But they are not cheap.
I would urge you to go find the May and August 2015 issues of Practical Sailor where PSoC (partial state of charge cycling) was tested.. Suffice it to say there are major differences in the quality and deep cycling capabilities of AGM batteries. Pay close attention to the East Penn AGM's in that test. These East Penn batteries are re-stickered by Batteries Plus, NAPA, Sam's Club, West Marine, Sears etc. etc. etc.) They are not a good deep cycle AGM because they were designed as a dual purpose battery. If you want a high cycling battery from East Penn their GEL batteries are amazing, their AGM's, not so much.
The Firefly Carbon foam AGM's are hands down the best AGM battery to tolerate marine type use, and yes we install all of them and test them as they age.. They are also designed and intended to be cycled to 80% DoD something that renders most AGM batteries useless in a matter of months. The Firefly battery used in that article is still going strong, despite tons of abuse, (I even left it at 80% DoD in a hot garden shed (uninsulated black asphalt roof) for four months straight). Today, at 6 years old it is still delivering 99.3% of rated capacity (as of the last capacity test).
When considering Firefly keep in mind that you typically need one less battery than all the competitors, it will cycle longer, and in the end will be less costly, not more.
As for chargers we really like the Sterling ProCharge Ultra with its 5 year warranty and near impeccable reliability track record. We have sold many hundreds of these chargers and warranty issues are pretty much non-existent.
