Carbon foam agm's

[john61ct]

Originally Posted by exMaggieDrum

epiic - totally beautiful installation!!

The issue with carbon foam agm, from what I have read not by experience, is that they still need to be taken up to full charge (99+%) on a frequent basis otherwise they will gradually lose capacity just like a regular agm will.

First, let's just say Firefly Oasis, rather than pretending there is, more than one battery in this "category".

And no, that is exactly what makes them so special. Yes they will **appear** to walk down in capacity, in a PSOC context, but a simple procedure taking 2-3 cycles following the protocol spelled out in their manual fully restore the capacity back to full, no equalization required either.

Yes they will normally lose AH capacity over time and through regular cycling, but not accelerated from the PSOC situation. That is unique in the industry.

Also, they are designed & intended to be used and cycled daily to 80% DOD, and that extra 30% usable capacity largely offsets their higher price per nominal AH compared to other top-notch AGM vendors.

Only Odyssey claims that deeper discharge capacity anymore out of that group.

[exMaggieDrum]

john, absolutely no doubt they are a game changer with huge benefits for cruisers. I seriously considered them, got quotes, etc. but they only came in the Grp31 form factor and that didn't work for me. I just couldn't come up with the space required to make it work. I also was concerned about the 100% charge issue which they confirm in their manual.

I just took a look at their manual. The "restoration charge" they describe in the manual is exactly what I was referring to. They do not say how often that has to be done. Weekly, monthly, every six months? BTW - part of the process requires taking the batteries down to 10.5v a couple of times. That's not very convenient on a cruising boat.

If there is no "push back" as come up to the 0.3A specification for cutoff of the restoration charge, i.e. no extra charge time to get that last bit in, then that is not a big deal. The graph they have shows Brand X and their charge acceptance grow together at the tail of the charge versus capacity and it does not give the last bit from the 1.5A "full charge" point to the 0.6A point for "restoration".

I was only cautioning that one should get the full story on this before saying it is not an issue. It may well not be an issue but I don't know that for sure. If you do, please tell us.

The Compass Marine study was for 30 days, not two years. It was meant to abuse the batteries but I don't think it is equivalent to cruising usage in the real world. Very promising though. More info would be great.

I am NOT saying these are not good batteries and they may well be the best available right now for the reasons you have given. I have just seen far too many cruisers ruin their regular agm's in two years of real cruising. Firefly hasn't gone out of their way to actually give the rest of the story.

The user manual can be found on page 3 at: www.bruceschwab.com/uploads/firefly-users-manual-02-06-17.pdf

[admiralslater]

you are quite right , they do walk down as other agms do. The reason I bought them was their ability to live (within reason ) in the psoc and then recover their full capacity . This along with the high acceptance rate .

[john61ct]

Originally Posted by exMaggieDrum

The "restoration charge" they describe in the manual is exactly what I was referring to. They do not say how often that has to be done. Weekly, monthly, every six months? BTW - part of the process requires taking the batteries down to 10.5v a couple of times.

Actually only once should usually work just fine.

Pending an authoritative answer from Bruce or MS, my guess is "not needed at all if PSOC is not an issue"

And "If chronic PSOC, then once every few weeks" to "if only occasional PSOC issues then once a quarter.

I only see it being a problem in rare instances like medical appliances, solved with a backup/reserve bank, in my case also used for cranking.

Or just do when on shore power.

My main point is that this unique attribute pretty much eliminates the PSOC walkdown from being in fact a problem.

Your statement I responded to implied that PSOC walkdown is actually a problem with FF just like all the other AGM.

[chris95040]

Hey, is the weight (per Ah) any different for these as compared to typical AGMs?

I imagine at the very least weight per *useable* Ah is better since they can be more deeply discharged.

Also, are there any additional dangers (thermal things, exploding if theres an internal short, etc) or are these just as safe as a regular AGM?

[exMaggieDrum]

Originally Posted by chris95040

Hey, is the weight (per Ah) any different for these as compared to typical AGMs?

I imagine at the very least weight per *useable* Ah is better since they can be more deeply discharged.

Also, are there any additional dangers (thermal things, exploding if theres an internal short, etc) or are these just as safe as a regular AGM?

Their primary customers are not marine. They seem to have wide acceptance with the military, bus systems, warehouses, and many others. I have not heard of any dangerous problems. That is not to say there aren't any but I would put them on my boat without any more concern than with regular AGM's and would view lead-acid as slightly more dangerous because of the acid and potential thermal runaway (very, very slight risk).

They are much lighter than regular AGMs per Ah from the specs I have seen. The PSOC and deep discharge specs make them very attractive also. The technology is a leap ahead and there are supposed to be other leaps in the pipeline but they would be years away.

I am not the battery expert that Nigel Calder or Compass Marine or Bruce Schwab or others are but I did do a fair amount of research including reading everything written by them. I might have them on my boat right now except for the limited sizes available in 12v batteries. The other batteries in their product line are for more industrial uses and would be worse in that regard unless you had a lot of space for them.

[john61ct]

Originally Posted by chris95040

I imagine at the very least weight per *useable* Ah is better since they can be more deeply discharged.

Yes, but still made of thick lead plates, google weight per 100AH to compare.

Originally Posted by chris95040

Also, are there any additional dangers (thermal things, exploding if theres an internal short, etc) or are these just as safe as a regular AGM?

At least as safe AFAIK

Note also LiFePO4 doesn't have the same thermal runaway issue as other lithium ion.

I think with lead most "explosions" are gassing FLAs with a spark in insufficiently ventilated holds.

Huge electrical shorts do cause a lot of boat fires though, regardless of chemistry.

[TeddyDiver]

Originally Posted by epiic

I have 7 of the Firefly Oasis batteries and absolutely love them!

They are very fast to recharge.

Dunno but how is the temperature of your batteries when bulk charging or high loads, not much of ventilation nor space between batteries?

[phantomracer]

Also doing my own unscientific test on the firefly batteries on our boat. Keep it on a mooring all season, never gets a full charge during the season. Spends most of its time at a PSOC.

Only have one season on them, so far so good. Since I am well known to totally butcher battery sets in a few seasons.. if they can take my abuse.. they will get my blessing!

The idea of a battery being left at a PSOC and recover 100%+ is very attractive! If the performance is half as good as the marketing material says, I am optimistic.

[Matt Johnson]

Originally Posted by phantomracer

Also doing my own unscientific test on the firefly batteries on our boat. Keep it on a mooring all season, never gets a full charge during the season. Spends most of its time at a PSOC.

Only have one season on them, so far so good. Since I am well known to totally butcher battery sets in a few seasons.. if they can take my abuse.. they will get my blessing!

The idea of a battery being left at a PSOC and recover 100%+ is very attractive! If the performance is half as good as the marketing material says, I am optimistic.

Don't you have a fuel cell installed on your boat? Why are you getting to PSOC still?

Matt

[phantomracer]

Originally Posted by funjohnson

Don't you have a fuel cell installed on your boat? Why are you getting to PSOC still?

Matt

yes we have one.

it don't keep the battery 100% topped off the moment it hits 99%. Sometimes when I turn something high amp (refrigerator, bilge pump,etc) it will stay on long enough that the fuel cell thinks the battery is low, just do to the sudden outrush of amps.

I changed the settings for it to come on at a lower voltage, trying to take advantage of these batteries being able to discharge deeper than L.A., etc.

So it is generally always at a PSOC. The fuel cell didn't save my last set of L.A batteries

[epiic]

I love these batteries so much, I decided to replace my bow thruster/windlass batteries with them.

[john61ct]

Originally Posted by phantomracer

So it is generally always at a PSOC. The fuel cell didn't save my last set of L.A batteries

Couldn't you set the cell to always power loads, only use the bank as backup keeping it at 100% most of the time?

[zboss]

Aren't these batteries very close to the firefly's in terms of PSOC cycling?

https://www.coastalclimatecontrol.co...northstar.html

[Matt Johnson]

Originally Posted by zboss

Aren't these batteries very close to the firefly's in terms of PSOC cycling?

https://www.coastalclimatecontrol.co...northstar.html

Here is another:

https://www.altestore.com/store/deep...attery-p11953/

Mainesail sent me a pretty good response detailing the major difference. I won't quote it, as I never asked if it was ok, but the major difference is in life cycles (600 at 80% DOD to 1000 for Firefly) and recovery from abuse. When abused to way worse conditions than any boat can even do (-.04v and left for 6 weeks), the Fireflys recover to 85% of capacity and improve with each cycle from there..... crazy! Maine recommended not going below 50% for either the Northstar or Outback, so you have lost the 80% dod value of the Fireflys.

Matt