FireFly Battery Long Term Users - Speakup

[Stu Jackson]

Originally Posted by Bear-O-Ness

I have three of the Firefly 12v for my house bank. Have had them just over 2 years and have had issues for the past 1.5 years. I have done three restoration charges and am still not able to run refrigeration over night from a 100% charge. My next step is to restore and test each one individually. I know they are suppose to be brought down to 10.5v but is that resting voltage? I cannot find that information anywhere. With a load on the batteries they can be brought to 10.5v but as soon as the load is removed, the voltage goes up, which is to be expected. I can find no information on how to determine the 10.5 volts. Is it with a load or after the battery rests for several hours? Thanks for any experience on this.

Not resting voltage, it is the V you see under load, the V at which you stop the discharge.


20 Hour Capacity Test by Maine Sail

http://forums.sailboatowners.com/ind.../#post-1295253

[Bear-O-Ness]

Originally Posted by sv.antea

I built a battery discharger. Headlight sealed beam, voltage cut off device and a DC watthour meter from the internet. Incandescent bulb actually makes an aproximation of constand current load, as the voltage drops, the resistance does too.

What did you use for the voltage cut off device? I need to do a similar setup to individually restore and test three 12v Firefly's. Also, did you use a battery monitor to measure amp hours? Thanks for your help! I just posted a question as to figure out how low to go for cutoff. With a load on the batteries, it would not be a true 10.5v until the load was removed and the batteries rested for several hours.

[Bear-O-Ness]

Originally Posted by Stu Jackson

Not resting voltage, it is the V you see under load, the V at which you stop the discharge.


20 Hour Capacity Test by Maine Sail

http://forums.sailboatowners.com/ind.../#post-1295253

Thanks Stu, I wish this information was outlined in the Firefly literature. I have been taking my batteries to 10.5v resting before doing a restoration charge, maybe I have already killed them...

[sailorboy1]

Originally Posted by Bear-O-Ness

I have three of the Firefly 12v for my house bank. Have had them just over 2 years and have had issues for the past 1.5 years. I have done three restoration charges and am still not able to run refrigeration over night from a 100% charge.

Wow, you are 1.5 years late in really chasing down the problem. I have a large freezer and refrigerator and combined they avg about 5Ah.

What happens if you don't run your refrigeration at night, does the voltage still drop real low? If yes it is a battery, if no it is your refrigeration.

[Stu Jackson]

Originally Posted by Bear-O-Ness

Thanks Stu, I wish this information was outlined in the Firefly literature. I have been taking my batteries to 10.5v resting before doing a restoration charge, maybe I have already killed them...

You're welcome. My guess is that the 20 hour test is not Firefly-specific so maybe that's why, not knowing, of course, what IS in their literature.


As you could see from this thread alone, folks have trouble figuring out how to even create a load to do the test.


Don't know how long your warranty is, either. Have you checked each individual battery? You could well have one that's done and the others are fine. BTW this is standard fare for checking questionable battery "banks" made up of individual batteries.


Good luck.

[phantomracer]

Originally Posted by Bear-O-Ness

What did you use for the voltage cut off device? I need to do a similar setup to individually restore and test three 12v Firefly's. Also, did you use a battery monitor to measure amp hours? Thanks for your help! I just posted a question as to figure out how low to go for cutoff. With a load on the batteries, it would not be a true 10.5v until the load was removed and the batteries rested for several hours.

Unsure if you saw the thread I started with my testing my firefly batteries. I used a 65w headlight to draw it down, using my camera with time lapse so I could follow the voltage as it drew down, and charged. Used a power supply to manually control the recharge. Have a Victron Battery protect set to disconnect at 10.5v.

https://www.cruisersforum.com/forums...ml#post3569130

[Bear-O-Ness]

Originally Posted by sailorboy1

Wow, you are 1.5 years late in really chasing down the problem. I have a large freezer and refrigerator and combined they avg about 5Ah.

What happens if you don't run your refrigeration at night, does the voltage still drop real low? If yes it is a battery, if no it is your refrigeration.

Hi Sailorboy,
If I do not run refrigeration, stereo, or inverter, just LED lights, I can go for a couple of days. I have an SG200 Battery Monitor and when it gets to 82% all of a sudden it will drop to zero% and 11.5 volts. With a very low load I can get them to last much longer but it will reach a point where it just drops. This is suppose to be a "smart" monitor that is suppose to get smarter the longer it is used. It is on the carbon foam setting but with the way the levels drop so quick, would assume it cannot figure out this system yet. I put the batteries in just before the first Covid shutdown and the boat did not get used much for at least a year while it sat on shorepower, which I know now is not good. It wasn't until last summer that realized I was having issues. Was told by rep for Firefly at Fisheries Supply that I needed to individually recondition and test each battery, which I am now at the point of doing. I also just found that other folks were having issues with these batteries. I was searching "firefly batteries" online rather than "carbon foam" batteries. Other than the supplier information, not much was coming up under Firefly.

[PNWSalmon]

Originally Posted by Bear-O-Ness

Hi Sailorboy,
Was told by rep for Firefly at Fisheries Supply that I needed to individually recondition and test each battery, which I am now at the point of doing. I also just found that other folks were having issues with these batteries. I was searching "firefly batteries" online rather than "carbon foam" batteries. Other than the supplier information, not much was coming up under Firefly.

Sorry to hear this. I had a batch we bought right before the pandemic too, from fisheries and they failed like this. I couldn’t recondition them. Luckily we caught it before the one year full warranty period.

Chances are you have the same “bad batch” what you are describing is the exact failure scenario we saw. It’s not related to your battery monitor.

I took ours off the boat, did the recondition at home with a battery charger. I couldn’t get them to hold a charge. Thankfully fisheries and firefly repelled them all at no cost. It was month 11.

I’m happy to report our new batteries are doing well. We’ve been cruising full time for a year now.

[Bear-O-Ness]

Originally Posted by phantomracer

Unsure if you saw the thread I started with my testing my firefly batteries. I used a 65w headlight to draw it down, using my camera with time lapse so I could follow the voltage as it drew down, and charged. Used a power supply to manually control the recharge. Have a Victron Battery protect set to disconnect at 10.5v.

https://www.cruisersforum.com/forums...ml#post3569130

Thanks Phamtomracer, I did not see this thread. Quite a system you set up! I know my bank as a whole has issues and now need to do individual tests. I guess with a known load, there is no reason to use a shunt for amp hours. Don't have a time lapse camera so trying to figure out how to know when 10.5v is reached. The question I have to deal with for me is it worth going through all this testing and costs for the equipment to find out I have bad batteries out of warranty? I might get some pro rated warranty but not sure I go back to new Firefly's when lithium prices are in line with the new $600 price/each for Firefly. Been researching them for a while now and I have most of the charge system already in place.

[Bear-O-Ness]

Originally Posted by PNWSalmon

Sorry to hear this. I had a batch we bought right before the pandemic too, from fisheries and they failed like this. I couldn’t recondition them. Luckily we caught it before the one year full warranty period.

Chances are you have the same “bad batch” what you are describing is the exact failure scenario we saw. It’s not related to your battery monitor.

I took ours off the boat, did the recondition at home with a battery charger. I couldn’t get them to hold a charge. Thankfully fisheries and firefly repelled them all at no cost. It was month 11.

I’m happy to report our new batteries are doing well. We’ve been cruising full time for a year now.

PNWSalmon, Wow, good you got them replaced under warranty. Full time cruising is my dream but still working 12-16 hour days. I may be SOL as it is now over 2 years since my purchase. I just looked and it seems Fisheries is not even carrying them anymore. I am to a point where I am leaning toward LI batteries. Am going to test and recondition these three in the hopes of maybe having 1-2 good ones that can be used for start battery some point. I still have the Firefly rep's contact so will see what they can do. Glad yours are working out!

[sailorboy1]

Originally Posted by Bear-O-Ness

I put the batteries in just before the first Covid shutdown and the boat did not get used much for at least a year while it sat on shorepower, which I know now is not good.

In this thread this is looking like a common killer.

[phantomracer]

Originally Posted by Bear-O-Ness

Thanks Phamtomracer, I did not see this thread. Quite a system you set up! I know my bank as a whole has issues and now need to do individual tests. I guess with a known load, there is no reason to use a shunt for amp hours. Don't have a time lapse camera so trying to figure out how to know when 10.5v is reached. The question I have to deal with for me is it worth going through all this testing and costs for the equipment to find out I have bad batteries out of warranty? I might get some pro rated warranty but not sure I go back to new Firefly's when lithium prices are in line with the new $600 price/each for Firefly. Been researching them for a while now and I have most of the charge system already in place.

Well, I use the power supply (not expensive) for my battery charger. Nice to be able to have full control when charging the batteries.

Headlight I had laying around.. The only thing I bought was the battery cut off (not expensive either) . had an old digital camera that had that function built in (an old cell phone could work too) , so it was a low cost set up ..

[smac999]

Brought a couple bad ones home to play with. Built a cheap c20 tester with an old free link 10, victron battery protect , and 50w light bulb.

Got 47ah out of one and 45ah out of 2nd one first drain. I’ve now had them charging (40a charger) at 14.4v for over 48h and they are still taking an amp each. Slowing droping from 1.8a to 1a over last 36h. I’m not sure if these will get under 0.5a or not. Maybe in a week?…, Might be too late for these to recover.

I’ll do a few cycles and see what happens.

How long are people normally charging to get them down to 0.5a?

Pic is sideways for some reason…

[phantomracer]

Originally Posted by smac999

Brought a couple bad ones home to play with. Built a cheap c20 tester with an old free link 10, victron battery protect , and 50w light bulb.

Got 47ah out of one and 45ah out of 2nd one first drain. I’ve now had them charging (40a charger) at 14.4v for over 48h and they are still taking an amp each. Slowing droping from 1.8a to 1a over last 36h. I’m not sure if these will get under 0.5a or not. Maybe in a week?…, Might be too late for these to recover.

I’ll do a few cycles and see what happens.

How long are people normally charging to get them down to 0.5a?

Pic is sideways for some reason…

is that a 12v light? or a household 120v light? I used a car headlight to draw down my fireflys when I recently did the test.

which charger? Some chargers won't stay in bulk long enough before it goes into absorption. I usually use a power supply so I can precisely control and monitor the charging. Charging is relatively fast, 10-12 hours or so from flat-flat to .04a or so. using the power supply Unsure if you saw my thread previously posted above about my recent experience doing this.

[smac999]

It’s a 12v bulb. For boats / rvs.

I am now using a 50a promariner pronatic. Custom set to 14.4 bulk and 14.4 float. It’s been holding 14.4v for 2 days.

My 40a truecharge kept going to float.


They are down to 0.7a now but it’s been almost 3 days.