Carbon foam batteries

[Dave Neptune]

Hi guys, does anyone here have any experience with the "Fire Fly" carbon foam AGM style batteries. They really look good, almost to good to be true. The cost effectiveness is somewhat offset by the recommended "discharged levels" before charging, IE getting almost another 30% capacity from the same rating. Two of their group 31's have almost the same discharge before charging capacity as a pair of 4D's which are almost exactly double in size. A pair of 31's are about the same "footprint & height" of a 4D.

Comments welcome.

Dave Neptune

[Al Schober]

I'd be curious to know what happens if they get pulled right down to 0 SOC - ie: 4V across the terminals. I did that to a pair of Gp 31 flooded and they never did recover to more than 65% capacity. Expensive mistake..
Read an analysis of AGMs some years ago that seemed to make sense. The AGM batteries make their cost worthwhile due to their short high current recharge characteristics, saving money on the cost of generator hours. But, you have to be living aboard to make it worthwhile.

[Dave Neptune]

Al, they state that it is absolutely no problem or loss of capacity going to zero. They also recommend charging at 20% not the usual 50% remaining amperage. The additional capacity seems well worth it when considering cost to amp hours available.

They almost sound to good to be true and I am trying to find a downside.

I also see that Bruce Schwab is promoting them and he is mostly associated with really top notch stuff.

Dave Neptune

[ndutton]

We chatted up the Firefly Oasis late last year
http://www.moyermarine.com/forums/showthread.php?t=1418

No conclusions though

[joe_db]

They seem great. By the time my current battery needs replacing I hope there is enough field experience with them to be confident about buying them. I have heard nothing but good things so far.
IMHO it will be a race between this and lithium batteries getting cheaper and reliable enough for mass market consumption.
BTW - taking a battery to 0 is not realistic for any lead-acid battery. It would not have enough voltage to do anything useful well before 0%.

[Dave Neptune]

Joe, in there specs they say at 20% charge they still have cranking capacity albeit not for long. I like the idea that two grp31's can yield as many amp hours as 2 4D's.

My new boat has room for a pair of 4D's or 4 grp31's. Three of the 31's would out perform the 4D's with less space and less trips to the chiropractor after wrestling them into place.

Giving some serious thought to these. As there voltage/charging levels are the same as AGM's, I wonder if they could be used together? After all they are both AGM's.

In my new boat I found 2 new grp 31 AGM's. The shore charger sets at about 14v when charged however I don't think he changed the regulator as I have only seen about 13.5v after motoring for hours. Just stuff to figure out and get done right.

Dave Neptune

[joe_db]

I would seriously consider it. 4Ds hurt my back. There is a manual somewhere on charging voltages. I can tell you right off 14 volts is low for an AGM system.

[BunnyPlanet169]

I've read reviews on both the Panbo website and in Practical Sailor. As Joe says, the ONLY hesitation from either review was the lack of full service life history. Otherwise, they performed as advertised, which is pretty remarkable.