These batteries have lots of good characteristics, work well in high heat environments, heavy and deep cycling, work well when not fully recharged--they tend to operate best between 80% an 20% State of Charge (SOC). They are also lighter for the amount of power they provide. Disadvantage--need a special charger--can be damaged by over charging.
I am particularly impressed by the thermal conductivity of the materials, which account for their performance in high heat environments, and in faster charging scenarios.
Invented in the R&D Labs of Caterpillar, by the brilliant founder and CTO of Firefly Energy - Kurtis Kelley.
A sample of Firefly's battery
Novel Carbon Foam Technology, yields more uniform heat distribution resulting
in significant inhibition of grid corrosion, producing much longer battery
Furthermore, Carbon Foam significantly delays typical destructive and irreversible sulfation, which is common to lead acid batteries. ( we sulfate in particles mostly, common lead acid sulfates in hard to reverse Films of sulfation )
Firefly's Carbon Foam is notably more Electrically and Thermally Conductive than conventional lead plates,
and is completely immune to acid attack.
5C discharge thermal image signature of Firefly is compared to a conventional battery
( conventional battery w hot spots - Firefly is cool as a cumber ) in attached "Slide 1" versus a std lead acid's lead plate.
Substantially higher cycle life - J2185 tests (SAE Soc. Auto Engineers), run hot, at 50C/122F, show that we have 2X - 5X better charge cycling lifetime than any other sealed lead acid battery.
See the 1 page J2185 summary [2 charts], and pages 2 & 3 of the 8 page Cycle Life versus Depth of Discharge report.
If your customers pound on marine batteries, for primary power, extended cycling from electrical
accessories, hybrid propulsion and dc microgrid, we take a beating and come back for more.
No marketing hype, no exaggeration, engineering data backing up historic lead acid breakthrough claims.
All from the brilliant expertise of Firefly's CTO Kurtis Kelley starting back in the R&D labs of Caterpillar.
You thought no one would ever make a lead acid service life breakthrough that was compelling?
Here we are shipping, restarted in production since a year ago !
Strongly resistant to heat damage - Firefly OASIS 3D operates easily in extremely high temperatures, far exceeding desert heat life performance of any lead acid battery. The Oasis battery is currently used by two Department of Defense subcontractors. One of which ordered 450 batteries this past year to avoid common quality lead acid short
desert life issues, which were solved by the Firefly OASIS 3D battery. Plus submitted to a new DoD RFP.
In lab tests, after 1200 cycles of 80% deep cycling, Firefly's charge capacity was almost unchanged from the start of test (except for a very gentle slope of tiny capacity loss at 1200 cycles).
The engineering destructive teardown showed the interior had no latent damage.
See last page of 20 page "Intro To Firefly Kurtis and Mat "report
for the capacity versus 1200 cycle deep cycling chart. Very little fade @1200 !!
Low self-discharge characteristics (2.5% /mo) and unprecedented ability to recover after a long period of inactivity/non-use. More specifically, the Oasis 3D battery is nearly immune to significant permanent damage from 6 month extended fully discharged storage in most instances avoiding very high heat.
When storing for 6 months @ zero charge, the battery can be started up upon first charge,
regains 90% of full capacity after approximately five cycles, increasing slightly in capacity recovery thereafter.
Extended Zero state of charge storage Capacity Recovery, impossible in any conventional lead acid,
and a notable distinction of Firefly.
Engineering calculations show operation at 50% depth of partial discharge gains 3600 cycles on its lifetime based on the 1200 cycle data at 80% DoD. ( see attached Cycle Life versus Depth of Discharge report )
Absorbent Glass Mat separators prevent spilling of acid and resist damage from vibration.
The unique stable Glassy Carbon Foam negative electrode, provides a 2000X increase of base electrode surface area, with 60-80% increase in active lead oxide electrochemical surface area, versus common weak flat plate conventional lead negative base electrodes.
Lower lifetime cost due to superior 2x-5x gains in battery service life
60% of room temperature charge capacity sustained at -20c
Lowest voltage droop versus SoC State of Charge. Common Standard Lead Acid at
50% SoC, at times will exhibit 10.5 volts, even lower voltage droop, at yet smaller remaining SoC.
Firefly out to low residual 20% SoC (80% empty) typically outputs 11.4volts,
again extraordinary, unusual for lead acid.
Capable of Ac Welding Fast Charging / huge charge acceptance. between 20% SoC and 80% SoC, if properly configured, single batteries can reliably sustain 250 amp charging to 80% SoC. ( final test at factory charges at 250 amps all of our batteries - ALL ) Past 80% SoC - slow down ....
We do not recommend blindly charging strings at 250 amps per Group 31 series string, but we assume decently matched Group 31 strings can charge at between 100-200 amps, conservatively, but needing monitoring - possibly an advanced BMS we are looking into sourcing ( early now ). If you can rig up voltage and or temperature monitoring you can catch problems in fast charging, we urge this be done for safety.
If all you need is extraordinary long life, and want fastest charging turnaround, charge to 80% SoC and do this in 30 minutes with highest power 250 amp chargers ( run lower initially and if fastest use sophisticated BMS battery monitoring systems interlocked to charger ). Try that in any other group 31, try that in Lithium Ion and you might
risk a fire !
Above 80% SoC charging, water electrolysis kicks in, monotonically increasing parasitic resistance losses, slowing charging in last 20% of topping off ( which we recommend against if avoidable ) See the 2 graphs in the Sweet Spot PSOC presentation of resistance and losses versus SoC State of Charge. ( around pg 5?)