FireFly Battery Long Term Users - Speakup

[sailorboy1]

Originally Posted by nwesterne

If you have these batteries and have been connected to shore power for an extended period PLEASE test them before heading out for a trip.

Were they on the battery charger on float for a year??

[nwesterne]

Originally Posted by sailorboy1

Were they on the battery charger on float for a year??

No, they weren't on a constant float. They would float daily for a short time then the charger would go into standby mode and wouldn't run again until the batteries were run down a bit. The charger was set per Firefly and Magnum's recommendations. They just weren't deeply discharged for an extended period. That said, I had disconnected from shore power while docked for various reasons throughout the year. It was just last month that when disconnected they seemed fine until voltage got down to 12.4 then the voltage just dropped massively. The only amp draw was about 7 amps from our fridge/freezer.

[Dave Lochner]

Originally Posted by nwesterne

No, they weren't on a constant float. They would float daily for a short time then the charger would go into standby mode and wouldn't run again until the batteries were run down a bit. The charger was set per Firefly and Magnum's recommendations. They just weren't deeply discharged for an extended period. That said, I had disconnected from shore power while docked for various reasons throughout the year. It was just last month that when disconnected they seemed fine until voltage got down to 12.4 then the voltage just dropped massively. The only amp draw was about 7 amps from our fridge/freezer.

When you tried to recharge them the last time how much current did you use? Did you try discharging again and then recharging them?

MaineSail mentions this in the linked article below.

https://marinehowto.com/how-fast-can...ry-be-charged/

[nwesterne]

Originally Posted by Dave Lochner

When you tried to recharge them the last time how much current did you use? Did you try discharging again and then recharging them?

MaineSail mentions this in the linked article below.

https://marinehowto.com/how-fast-can...ry-be-charged/

Actually, a former Firefly rep performed the recovery procedure on each battery individually and tested them. It was determined they could not be brought back and were eligible for warranty. Unfortunately at just under 3 years old they would be prorated which meant no money back but I had the option to buy more Fireflys at $200/ea. I don't think that's even an option anymore since there's no way to contact them and the Firefly website is down.

[MondayNever]

This thread is dead, but still may be used by a prospective purchaser, so I'll throw in my 2 cents.

Firefly batteries were a promising technology that have treated a lot of people well, but our experience sucked. We purchased a set of 6 Group 31s in Jan 2020 from eMarine and started noticing capacity loss by that fall. We did restoration charges and that seemed to help, but it got bad again, so in Nov 2021 I removed the batteries from the boat and did extensive bench testing on the individual batteries and found that they ranged from 35-75% of nominal capacity. After aggressive restoration cycles, the batteries returned to ~80% capacity.

I filed a warranty claim with Firefly, which was eventually approved for full replacement at no cost after much advocacy from Ocean Planet Energy (US distributor). However, after many months of Firefly telling OPE that my batteries "will be on the next shipment," the emails started bouncing and the phone lines were dead in May 2022. No batteries for me.

OPE was extremely helpful through the whole process, but what are they going to do if the manufacturer just disappears? They were kind enough to offer me a major discount on other batteries. OPE also stopped even attempting to distribute Firefly around this time, citing many issues like mine in the preceding couple of years.

The batteries fully died several months after that debacle. We were still trying to nurse a little life out of the batteries, hoping to hold out until we were ready to switch to lithium, but they suddenly started heating up to 200*F+ and spewing acid and gas during a shore power charging cycle after a long sail.

All that to say, if you can even find Firefly batteries in the USA, you should go into it knowing that they have QC problems and they will not honor their warranty, even if the claim is approved.

Too bad, as they were a promising bridge technology between traditional lead acids and lithium.

[crayiii]

Yes, we’re pretty much in the same position. We had 6 G31 Firefly batteries installed in 2021 and have treated them exactly the way Firefly specifies.

They now have significant voltage sag even at a 10a draw. With 200 amps of charge ability, the batteries will only take
60 amps even when voltage was 12.3 in the morning. Even then, the 60 amp acceptance drops to 30 in a short amount of time.

It’s such a shame but yeah, Firefly batteries are a big letdown.

[sailorboy1]

As the OP this thread I will say this:

- my 30 month old set of 4 F31 batteries that rarely have been less than 70% state of charge are now showing lower that expected voltage at a given soc and small 5-10 load
- they do take all the current I can charge them with at less than 80%
- their charge profile has always seemed same as my old Trojan T105
- I spent 4x the price of new T105s to not worry about partial state of charge capacity losses. But they seem exactly as expected of only acid based battery that has not always been fully charged each day
- mine are still very usable, but I question their future

Since it seems the Firefly battery supply is dead any owner is going to use till they die and move on.

[crayiii]

Originally Posted by sailorboy1

Since it seems the Firefly battery supply is dead any owner is going to use till they die and move on.

Yup! We are now beating the heck out of them and when they die, lithium goes in.

[Adelie]

Something I realized a couple weeks ago when I heard stocks were currently unavailable was that LiFePo prices have dropped to be almost competitive with Firefly so it would only be a matter of time before Firefly dropped prices significantly or were discontinued.

They may be gone already.

[noelex 77]

Interestingly, Victron has recently released some carbon batteries. The negative plate is replaced by a lead carbon composite. I presume the technology shares some of the properties or perhaps is even analogous to FireFly batteries although details are scarce:

https://www.victronenergy.com/batter...carbon-battery

Perhaps they can solve the poor quality control and supply problems that seem to have plagued FireFly.

[phantomracer]

Originally Posted by noelex 77

Interestingly, Victron has recently released some carbon batteries. The negative plate is replaced by a lead carbon composite. I presume the technology shares some of the properties or perhaps is even analogous to FireFly batteries although details are scarce:

https://www.victronenergy.com/batter...carbon-battery

Perhaps they can solve the poor quality control and supply problems that seem to have plagued FireFly.

Interesting. Will have to consider it when my fireflies die.

Still holding on after 7 seasons now. Seems I am the lucky one in the group.

Was thinking of LFP when they go, but the buy in cost is huge compared to some FLA 6v GC2 batteries from Costco! Even replacing the GC2 every 2-3 years would be like 20 years break even on installing the LFP!

Any real life feedback on these victron batteries?

[ItDepends]

We have had our 24 V, 464 A-hr Firefly bank for two and a half years. Mostly on daily cycle service, but sometimes floated--maybe 20% of the time. Our normal cycle is down to 70% on the first morning, solar charge to 85%, then down to 65% the next morning. Generator charge to 93%, and then solar to ~100%. We do a deep discharge, and recovery charge about every 6 months. We routinely charge at 0.3C (150 A), and during a recovery charge, we up that to over 0.4C (200 A).

Doing a full discharge all the way to 10.5V equivalent at the C10 rate (I am too impatient to do it at C20) means we have a better idea than almost anybody else the REAL capacity of our batteries and how it changes over time.

In each of these total discharges our batteries delivered AT LEAST the specification C10 energy, and sometimes 110% of that. There has been no downward trend at all. To say we are happy with the performance, would be an understatement.

BUT... I know (and had trouble with) the quality control issues. It took us several tries with warrantee replacements to get 8 batteries that all worked. The usual failure mode was an internally shorted cell. The vast majority of users wouldn't notice the symptoms of this until the entire battery bank had been destroyed. It seems to explain a lot of the issues.

It really is a shame that the QC issues sunk this product. When they work they are the best LA batteries on the market--if they were still on the market, that is...

[crayiii]

Originally Posted by noelex 77

Interestingly, Victron has recently released some carbon batteries. The negative plate is replaced by a lead carbon composite. I presume the technology shares some of the properties or perhaps is even analogous to FireFly batteries although details are scarce:

https://www.victronenergy.com/batter...carbon-battery

Perhaps they can solve the poor quality control and supply problems that seem to have plagued FireFly.

Wow, they seem really large for the AH compared to firefly or AGM.

[sailorboy1]

Well my 481ah bank was -135Ah this morning and 11.98v under a 5A discharge. That is not right and not what they have historically been. Limited things can do on anchor.

These batteries just spend the last 8 months being lightly cycled. I was in a slip with the battery charger off cycling the batteries as normal off solar.

[crayiii]

Originally Posted by sailorboy1

Well my 481ah bank was -135Ah this morning and 11.98v under a 5A discharge. That is not right and not what they have historically been. Limited things can do on anchor.

These batteries just spend the last 8 months being lightly cycled. I was in a slip with the battery charger off cycling the batteries as normal off solar.

Yeah, we were duped into believing these were better than AGM. I got the same life out of the Lifeline batteries that these replaced and the lifelines were significantly less money.