Visit our Popular Forums

**skipmac** · 08-12-2020, 11:28

Any recent tests or any long term users have any comments about these? They call them carbon batteries but are a good bit cheaper than Oasis Firefly batteries. But are they just a glorified AGM with little advantage over a standard AGM or are they comparable to the Firefly batteries.

Saw a comment on another forum that these and other batteries that are labeled as carbon batteries are not at all the same as the Firefly.

rgleason · 08-12-2020, 17:56

I dont think it can be charged as fast, but I have never used them.
It appears that they have tried to address the issue of PSoC but it is not entirely clear if they will recover to 100% when fully charged 2 to 3 times as Firefly does.

rslifkin · 08-12-2020, 18:07

The Trojan SPRE appears to be flooded, which likely explains it being cheaper than the AGM Firefly.

sailorboy1 · 09-12-2020, 05:00

Just a FLA battery with a mystery carbon something. Up to 15% more life/8 years. At $400 not much less than Firefly you can get from Maine Warehouse for $429

So no, I don't have any experience with them. But they don't look to be worth the risk. Meanwhile I can say my FireFlys have been working good (haven't been on shorepower for 3 months and haven't even gotten fully charged in 2 weeks)

rgleason · 09-12-2020, 05:46

Thanks. Firefly is a simpler and less expensive than LiFePo4, because BMS, and relays are not needed.

How fast do you charge them? .3C?

How fast can they be charged? .3C?

Is there the same resistance as FLA above 80%?

How long does it take for them to become fully charged?

Typically how long is the absorption stage? 3 hours?

How often does that have to occur?

How far do you draw them down?

What size solar do you have?

What alternator do you have? Manuf and amperage? What is the max output when hot charging a depleted battery bank?

How long do you think it takes to get them full from your lowest state with just solar and no loads?

Or How long do you think it takes to get them full using your lowest state with just your alternator?

How do you use your system normally when you are on board, loads and charging routines, etc. Not on board?

Any install suggestions you might have.

Thanks very much.

Quote:

Originally Posted by sailorboy1

Just a FLA battery with a mystery carbon something. Up to 15% more life/8 years. At $400 not much less than Firefly you can get from Maine Warehouse for $429

So no, I don't have any experience with them. But they don't look to be worth the risk. Meanwhile I can say my FireFlys have been working good (haven't been on shorepower for 3 months and haven't even gotten fully charged in 2 weeks)

**skipmac** · 09-12-2020, 06:34

Quote:

Originally Posted by sailorboy1

Just a FLA battery with a mystery carbon something. Up to 15% more life/8 years. At $400 not much less than Firefly you can get from Maine Warehouse for $429

So no, I don't have any experience with them. But they don't look to be worth the risk. Meanwhile I can say my FireFlys have been working good (haven't been on shorepower for 3 months and haven't even gotten fully charged in 2 weeks)

This is more or less what I have been able to figure out from limited information I've found online.

One question, what kind of voltage drop under load do you see with Fireflies compared to FLA batteries? Ever run an inverter or other heavy load from the batteries?

sailorboy1 · 09-12-2020, 07:45

Quote:

Originally Posted by skipmac

This is more or less what I have been able to figure out from limited information I've found online.

One question, what kind of voltage drop under load do you see with Fireflies compared to FLA batteries? Ever run an inverter or other heavy load from the batteries?

I run the inverter to run the microwave sometimes. It has made the battery monitor alarm on low voltage like it would with my last set of T105. So i would say they appear to have less voltage drop under “large loads”

Random other info
-Most of my charging is with solar and than is about 0.04C. But sometimes will run the generator and battery charger ant that is 0.15C. Have done the batt charger, solar, alternator when in a hurry and that is about 0.24 C
- under the batt charger I don't see a drop from my 70 amp rating toll into the 90+% SOC
- takes about the same amount of time to fully charge as my T105s took, but don't have to get them there which is the point. Can not give a “how long” answer as it depends on too many things but if you have the charge capacity for max acceptance i would say i5 would take 5-6 hours starting at around -100ah
-i have my solar set for 4 hours at absorption or till 14.4v and only 6 amps
- lowest i seen my batteries is 68% soc
- have 640w solar, a 70 amp batt charger using my honda, 100 amp alternator belt load reduced to 70 amp
-am using 150-200ah/day, recharge mostly with solar and the batt charger every couple of days as needed
- still tryin* to forget my fla ways so probably dont discharge as low as i mght because 7nless i plan to motor it still has to be made up for. I try to get them fully charged nce every 2 weeks, bu5 sometimes the sun does cooperate

There a whole thread i started above FireFly batteries

rgleason · 09-12-2020, 08:44

Sailorboy, I do know this link https://www.cruisersforum.com/forums...238410-21.html

Early in it CtHoops wrote "They get a full 100% charge when we motor for several hours."
Through your use have you found differently? From your post below you can bulk charge at 70a up to 90% SoC which is good, and then absorption (big solar PV 640w) down to 6a current for about 4 hrs. Is bulk charge time about (90%-68%Soc x Battery Capacity) / (70a x 0.9)= (.22 x Bat Capacity) / 63a= ??? Bulk Charge time (up to absorption). Also you say it takes about the same time as a bank of T-105 to get to full which take hours and hours too.

What is the Capacity of your Firefly bank?

CtHoops Configuration:
(2) Firefly group 31
(2) 100W Renogy semi-flexible solar panels with (2) Genasun GV-10 controller
70 amp alternator on our Beta 16.
Balmar Smart Gauge to see what percentage is left on the batteries.

From one user post I see that the charge efficiency is about 92-95%

From the Firefly Manual Firefly Manual for G31 Firefly

Max discharge current 0.7C for long periods, short periods 3C
Max charge current 0.5C continuous, 1C sporadic, but can harm bats
Peukarts constant 10hr and 20hr rate= 1.07, 6.5hr and 1.8hr rate=1.12
Temperature Constant 24mV/C
Charging Bulk to 14.4v continue until current drops to 0.5a
Float Charging 13.4v to 13.5v for extended periods (solar or alt motoring)
Operating Temp 77 degreesF every 14-18 degreesF halves the cycle life
Storage maximum time at 68 degreeF before checking is 12 months. Best to remove batteries in the winter for longevity.
Periodic Fast Complete charge to restore capacity at 0.4C (56 amps) at 14.4v until current drops to 0.5a ending with a 24hr float charge at 13.4-13.5v, every week if heavily cycled and minimum every month.
Restoration Charge, do Fast Complete charge, discharge to 10.5v and repeat 2-3 times.

I haven't found anything like these Specs for Trojan.
Max continuous charge (0.5C) is more than most LiFePo (0.3C)
I think 6.8hr peukart rate (1.12) is an efficiency of about (1/1.12) 90%
The kicker here is the need for Fast Complete Charges for a boat on a mooring or traveling. 24 hr Solar charging gets interrupted at night and may not maintain the 13.4v either. LiFePo does not require any of this but a complete system is more expensive and exotic and may affect resale.

sailorboy1 · 09-12-2020, 10:25

I have 4 G31s. No one does that fast charge, but seems everyone gets hung up. It is a recovery event, not a normal event.

I personally know CtHoops. Take her info lightly as her battery monitoring consists of checking the batteries with a meter once in a while. (Its working for them)

The whole and only point of getting the FireFly, or even LFP, is to not have to worry about PSOC. And only people going to be off shorepower need really worry about that the most part. Everything else is nce, but really IMO just battery noise.

If you have anymore FF questions you need to ask on the FF thread as doing it here loses topic readers who may want to know and that is why that thread exists.

sailorboy1 · 09-12-2020, 10:34

Quote:

Originally Posted by sailorboy1

I run the inverter to run the microwave sometimes. It has notmade the battery monitor alarm on low voltage like it would with my last set of T105. So i would say they appear to have less voltage drop under “large loads”

s

Noticed i left out the key word