29chico said:
Maine Sail, the battery guru on Practical Sailor, has been posting about the Firefly battery. Some amazing claims, and actual in boat results, in regards to this new type of lead acid AGM being able to fully recover it's capacity after months at partial discharge.
http://forums.sailboatowners.com/index.php?threads/practical-sailor-firefly-agm-batteries.171123/
The spec sheet:
http://hybridelectricworks.com/wp/wp-content/uploads/2015/02/2014_Firefly_price_sheet1.pdf
If PSoC cycling over and over without capacity loss is indeed true, and we can get a total expected cycle life of the battery confirmed, instead of an 'In progress' report, then that ~420$ price tag for a group31 might very well be worth it.
I heard they can't meet the demand at this point, and we really need to see if these things can be abused and still last for 1000+ deep cycles.
Lots of new batteries make rather ridiculous cycle life claims, and these have mostly been untrue in the extreme in actual usage, away from the 'lab' and the 'lab's' perfect conditions.
Also they stress the 14.4v maximum on them quite vehemently. Many vehicles voltage regulators can and do exceed this. If 14.5v + is cumulatively abusive or if it is a near instant death Knell, is not clear.
Mainesail's knowledge on these matters is pretty much second to none, but I think he still takes campaign contributions from products he endorses if you know what I mean, and sitting down for lunch with the Firefly carbon foam inventor/proprietor might have a little wink wink strategy going on while the total cycle life reports are still not yet available, and repeatable, with the variables known as to success or failure in their treatment.
So, I remain suspicious, because that is my nature. I need more proof, and we don't have that available yet. Just marketing and a couple impressive reports by some big names in the boating world who 'might' be rewarded for their endorsement while the product has not yet been out long enough to live out an actual cycle life in hard usage.
And make no Qualms about it, Vandwelling full time with basic electrical comforts is pretty much a deep cycle every day. The only other off grid system that cycles batteries harder is a blue water sailboat and perhaps golf carts, and they tend to have much larger capacity banks to reduce depth of discharge and as a safety buffer. The golf carts likely get 12+ hours of grid power to recharge fully after a deep cycle. A Van dweller only has limited alternator recharging time and limited solar wattage and hours of sunlight, with the possibility of grid power, or a generator thrown in too.
The 100% recharge required to keep a regular lead acid battery happy is just so time intensive as 80% to 100% takes about 4 hours no matter what. If a Carbon Foam AGM can indeed be cycled deeply and only seldomly require a 100% recharge, it is indeed a Van dwelling game changer, as Van dwelling screams Partial State of Charge cycling.
I can tell you definitively that a regular AGM PSOC cycled deeply nightly, is not long for this world. 4 cycles without a full recharge on My Northstar AGM, and performance loss becomes Obvious to me. When I do need to 'reset' the capacity i have to high amp recharge it from its most depleted state, AND hold 14.46v @77f for well in excess of 4 hours before amps taper to 0.425. The other day required 10 hours at 14.4v before amps tapered to this level. Without a plug in charging source, i would have had to of driven to SantaCruz(8 to 10 hours away) before amps tapered to that level.
I am at about 225 Deep cycles so far on this AGM, and the battery is doing well, but I recharge it well too.
