FireFly Battery Operational User Notes

[RickG]

1.5 amps per battery.

[rgleason]

I had this in another thread, taken from the recent documentation.

5. Charging Bulk to 14.4v continue until current drops to 0.5a

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

From the Firefly Manual Firefly Manual for G31 Firefly

1. Max discharge current 0.7C for long periods, short periods 3C
2. Max charge current 0.5C continuous, 1C sporadic, but can harm bats
3. Peukarts constant 10hr and 20hr rate= 1.07, 6.5hr and 1.8hr rate=1.12
4. Temperature Constant 24mV/C
5. Charging Bulk to 14.4v continue until current drops to 0.5a
6. Float Charging 13.4v to 13.5v for extended periods (solar or alt motoring)
7. Operating Temp 77 degreesF every 14-18 degreesF halves the cycle life
8. Storage maximum time at 68 degreeF before checking is 12 months. Best to remove batteries in the winter for longevity.
9. 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.
10. Restoration Charge, do Fast Complete charge, discharge to 10.5v and repeat 2-3 times.

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]

well not all that is true or even practical, I started a new thread

[rgleason]

Originally Posted by sailorboy1

well not all that is true or even practical, I started a new thread

It appears to me that you are claiming that the new manual from Ocean Planet is incorrect. It is clear that these batteries can exist for some period of time at psoc, and will be revived as per the manf specs, but the manfacturer specs refer to specific intervals for full charge.

Some of these requirements are not practical for moored boats without adequate solar.

[rgleason]

Despite what you say, I read the new specs and understand them, and brought them to your attention.

It appears to me from your report on the other thread that a good sized alternator run at .4C for a small or medium bank (200-350ah) for a number of hours and combined with decent solar for the trailing current such an ocassional "full charge" might be possible.

The revisions definitely show that they are still learning about these batteries.

[sailorboy1]

Originally Posted by rgleason

It appears to me that you are claiming that the new manual from Ocean Planet is incorrect. It is clear that these batteries can exist for some period of time at psoc, and will be revived as per the manf specs, but the manfacturer specs refer to specific intervals for full charge.

Some of these requirements are not practical for moored boats without adequate solar.

not claiming that at all

nothing really is "clear"

little direct reports exist for "revived batteries" and I have read only 1 account

how much solar can you install?????????????? my small for a 40'+ cruiser of 464AH (4 G31s) would need at least 1200W of solar for just a 0.2C rate

do you really think ruisers are going to, or can do, this deep discharge procedure every 30 days as in the manual?

I am trying to provide practical operational info for real life. If you want to remain a manual parrot just stop reading!

[rgleason]

No, I agree, I don't think cruisers will do a full discharge and charge every month.

.2c with that size bank is certainly difficult with solar. Perhaps an alternator 435 x .2 = 87a x oversized for hot continuous use and longevity 1.3 = about 115a plus your average house loads would help.

[BAD ORCA]

Sailorboy, this is probably not exactly the type of info you were hoping to collect but i figured i'd add my usage experience as maybe sort of an extreme example. Maybe there will be something useful in my usage/abuse of my Firefly that can help someone either not kill theirs or to help define the boundaries of what we can get away with.

I currently have a single Firefly G-31. I dont have a 'house bank' yet as my boat is under construction at the moment. I plan to create my house bank from 4-5 G-31 Fireflys later this year. This single battery is sufficient for now since my only loads are LED lights and a fresh water pump. So currently im using this single G-31 Firefly as my start/house bank.

Im also using it as a 'test subject' intentionally abusing it to see what it can handle.

I'm currently on shore power and have Sterling Pro Charge Ultra charger. Its a 60Amp charger but i turned it down to 30Amps for charging the Firefly, so slightly less than .3C. I monitor the battery voltage/SOC with an SG-200 monitor. I have absorption set at 14.4 volts and float at 13.4. I dont allow the battery to go into float because in the manual it says its not needed unless a restoration charge is being performed.

My usage routine typically is that im at the boat and stay aboard overnight 2-3 nights per week. When im aboard the battery sees an average load of about 2.5 amps for 4-6 hours give or take. So im probably drawing 25-30 amps per week. The battery is about three months old. I intentionally let the battery drain down over the course of about two weeks to a voltage of about 12.1 before switching on the charger.

My charging routine for the first two or three cycles was to charge the battery until absorption voltage went to about 1 amp then i turned off the charger. I dont float the battery. Also this is about where the Sterling charger switches from absorption to float anyways. The past few charge cycles have been intentionally erratic. I would re-charge only until the bulk phase was over and then would only let it sit in absorption until it hit somewhere around 10ish amps. On the last charge cycle i only let it get through bulk charge then shut the charger off.

I have definitely noticed a slight walk down in useable amp hours compared to when it was new but thats no surprise, im guessing my usage pattern would be considered extreme. All the test reports iv'e read also report similar behavior until a restoration charge is performed.

I'm not really set up aboard right now to do precise testing, but currently the battery voltage sits at about 12.0 after about 40ish Ah's withdrawn over the course of about a week and a half, but the last charge cycle it was only allowed to finish bulk charge and i turned off the charger as soon as it hit absorption so thats not too bad.

This weekend i will perform a full charge at 45 amps so just under .4C and let it float for 24 hours. I cant really draw it down to 10.5 and do the recommended restoration cycle so this will be an experiment. I'll report back in a couple of weeks after using it the way i normally do and try and track withdrawn amp hours using the SG-200 until it gets back down to 12.1 volts.

After this test, if the usable capacity seems to have diminished, i will try and set something up aboard my boat so i can do the restorative charge the way its supposed to be done according to the manual and possibly an accurate 20 Ah capacity test, however if the useable capacity seems to be back close to normal i may just continue using/charging it the way i have been and see how it fares and what sort of abuse it can take.

[steve77]

Originally Posted by mitiempo

Which Xantrex chargers are you referring to?


Here's the link to Wakespeed - the most advanced alternator regulator available. Wakespeed Products

Good afternoon. I was not familiar with the WS500, thanks for posting information about it. After reading, I'm still not clear how the WS500 is to be configured to match the charging profile given in the Firefly User's Manual.

The last page of the WS500 manual gives details on the preset charge profiles for this regulator. For Firefly batteries the value for Bulk/Absorption Exit Current is given as 1.4%.

What is 1.4%? Is this 1.4% of C? I see that the battery capacity is set by DIP switches. So if I select a battery capacity of 250-500 Ah, what value (in Amps) will the WS500 use to switch from Bulk to Float?

Cheers!

Steve

[sailorboy1]

RE the 40%C charge rate

In emails with Ocean Energy they say 20% is enough.

I tested how this could be done the other day by a cruiser.

Starting at 68% SOC I ran my generator and 70amp battery charger + the engine with it's 100 amp alternator (belt reduced to 70 amps) + solar was putting out 20amps. I was using using 6 amps of house loads. So I had 70+70+20-6= 154 amps available.

My 464AH FireFly battery bank accepted 130amps of that for 28% C with the batteries at 68%.

The 130A acceptance dropped to 105 in 20 minutes. At 1 hour it was down to 95 amp and I turned off the engine as silly to run a 54HP engine to provide 10 amps.

I was able to charge that day to under 1.5%C acceptance.

This was first time in a year 1.5 of FF ownership I tried this "fast" charge rate thing that people seem concerned about. My batteries weren't showing any sign of lost capacity and 5 days after doing this seem just the same as before.

[sailorboy1]

This morning my batteries were the lowest I have ever had them at 57% and 11.9V (under 8 amp load). So I repeated the above. The batteries again would only accept 130A/0.28C , which is not as much as I could provide them. So they were charge acceptance limited to that with a charge voltage at the time of about 13.1V.

If anyone has acturally managed to charge a FireFly house battery bank at the 0.4C the manual talks about lets hear it.

[sailorboy1]

On the flip side I have been in a slip the last week after 6 months and have shore power. I am not using the battery charger, just solar/batteries for the 12V loads. But all AC loads are being powered from shore power and that has resulted in a savings at night of around 30Ah. As such, solar has been getting the batteries charged sooner and staying in absorption for 6 hours. Even hours after my battery monitor has hit 0Ah out the batteries are still accepting about 1.5%C, which is a lot more than the manual recovery procedure of 0.5amps/ G31 (which is 0.43%C).

[RickG]

We’re shaded in the morning and afternoon by our small mountains. We see 8 hours of sun in the winter. We’re up to 10 hours of sun now in the spring. 2 more hours of sun makes a big difference. The current version of Victron solar controller firmware keeps us from premature float. We hit 98%-100% and then stay in absorption. The Fireflys have us very happy now. Happier than winter!

Cheers, RickG