Firefly Oasis : 2 years old and dead

[john61ct]

Originally Posted by newhaul

Rolls has something completely different to say about it

If you are talking AGM?

Lifeline & Northstar are the makers that specify a 0.2C minimum, Odyssey's is 0.4C. You should be able to google those yourself.

Obviously even those high CAR chemistries will rapidly reduce the current accepted as SoC climbs; except for GEL, lead is basically self-regulating and will not accept a harmfully high current, most "maximum charge rate" specs are bogus, just put there by the lawyers for liability protection since most owners don't have robust enough wiring infrastructure to handle high currents.

Rolls is not any more well proven as a quality maker than Full River, who likely is their OEM.

Yes, their FLA units are the best.

[john61ct]

4C discharge rates are routine for propulsion, in fact very low for modern LI chemistries other than LFP.

Obviously reduces lifespan by a lot, and requires sophisticated engineered thermal management systems.

Will by definition run the bank down in 10min or so, so not meant to be continuous.

And of course not possible with most packs pre-fitted with a limiting BMS.

Note also that LFP only has high density compared to lead. About half that of other modern LI chemistries.

But bottom line, irrelevant in a House bank context.

[newhaul]

Originally Posted by john61ct

If you are talking AGM?

Lifeline & Northstar are the makers that specify a 0.2C minimum, Odyssey's is 0.4C. You should be able to google those yourself.

Obviously even those high CAR chemistries will rapidly reduce the current accepted as SoC climbs; except for GEL, lead is basically self-regulating and will not accept a harmfully high current, most "maximum charge rate" specs are bogus, just put there by the lawyers for liability protection since most owners don't have robust enough wiring infrastructure to handle high currents.

Rolls is not any more well proven as a quality maker than Full River, who likely is their OEM.

Yes, their FLA units are the best.

post the technical links to your assertions .
I post mine

[newhaul]

Originally Posted by john61ct

4C discharge rates are routine for propulsion, in fact very low for modern LI chemistries other than LFP.

Obviously reduces lifespan by a lot, and requires sophisticated engineered thermal management systems.

Will by definition run the bank down in 10min or so, so not meant to be continuous.

And of course not possible with most packs pre-fitted with a limiting BMS.

Note also that LFP only has high density compared to lead. About half that of other modern LI chemistries.

But bottom line, irrelevant in a House bank context.

my Lfp specs call for up to 10C discharge rate and a max of 20C occasional charge rate.

What are the c rates on your Lfp bank?

[Cpt Pat]

I have two Odyssey and two Lifeline AGMs on board. They are nine years old. They still test above 80% capacity. However,...

They have never been discharged below 50% SoC. They have always been recharged to Full within a day or two of use. They have always been discharged and charged at moderate rates (less than 0.5C), and they have been continually floated at temperature-compensated voltages. They have never been exposed to temperatures above 85 F (30 C) or below freezing, and were stored at an average temperature of 65 F (18 C).

Treated gently, AGMs can last a long time. I imagine any battery design will suffer from abuse. Without including the operating and storage conditions, it's impossible to evaluate battery brands and formulations. And if you weren't monitoring and know these conditions, I would assume by default the batteries were being abused. Abuse avoidance requires conscious effort.

Having said that, I have seen several reports of leaky Firefly batteries. If I had a leaky battery, I'd return it at once and permanently avoid the brand regardless of its other advantages. Loose electrolyte doesn't belong on my boat. Bouncing in a seaway, it's only a matter of time before that acid attacks something important: my eyes for example. If I knew there were reports by others that a brand of battery had this problem, I wouldn't buy it in the first place.

I treat fundamental product defects like a criminal record - I'm going to need to see honest transparency from the manufacturer, convincing evidence of corrective action, and a long pattern of good behavior to redeem my opinion of that brand.

[john61ct]

https://bit.ly/2LbCj6A

Maine Sail: http://www.trawlerforum.com/forums/s...86&postcount=4

[newhaul]

Originally Posted by john61ct

https://bit.ly/2LbCj6A

Maine Sail: Trawler Forum - View Single Post - Battery charger for AGM batteries

links to actual tech papers not Google searches.
anocedal posts from other people regardless of their credibility are not the technical papers ..

[john61ct]

Originally Posted by Cpt Pat

Having said that, I have seen several reports of leaky Firefly batteries. If I had a leaky battery, I'd return it at once and permanently avoid the brand regardless of its other advantages. Loose electrolyte doesn't belong on my boat. If I knew there are reports by others that a brand of battery has this problem, I wouldn't buy it in the first place. I treat fundamental product defects like a criminal record - I'm going to need to see a long pattern of good behavior to redeem my opinion of that brand.

As stated above, it was a temporary QA issue, long overcome and if ever repeated at the factory, I believe would not make it through Bruce's inspection process.

[john61ct]

Originally Posted by newhaul

links to actual tech papers

You funny

[ranger58sb]

Originally Posted by john61ct

If you are talking AGM?
Lifeline & Northstar are the makers that specify a 0.2C minimum, Odyssey's is 0.4C. You should be able to google those yourself.

Originally Posted by newhaul

post the technical links to your assertions .
I post mine

Lifeline and Odyssey recommendations -- minimum .2C and .4C respectively for best longevity -- are in their manuals, available on their websites.

-Chris

[Cpt Pat]

Originally Posted by john61ct

As stated above, it was a temporary QA issue, long overcome and if ever repeated at the factory, I believe would not make it through Bruce's inspection process.

OK. Provided Firefly:

• issued a safety advisory to the public admitting the problem
• described how to identify it
• explained how they fixed the manufacturing process
• offered to replace defective batteries
• explained what went wrong with their QA process and how that problem was corrected
• and 5 years or so elapse without another single reported occurrence

-- I'd consider revising my opinion.

People rightly assume sealed batteries don't leak when not abused. Leaking electrolyte is a safety issue. Unsafe products require extraordinary proof of corrective action.

[kenbo]

Originally Posted by ranger42c

Lifeline and Odyssey recommendations -- minimum .2C and .4C respectively for best longevity -- are in their manuals, available on their websites.

-Chris

Not claiming any technical expertise in regards to AGMs, but would those requirements rule out charging AGMs with most solar arrays?

[john61ct]

No, they are just not optimizing for longevity.

As is the case with multiple other factors on 97.4% of boats with House banks out on the water.

In general, FLA should be used anyway, unless a sealed bank is truly required.

[Cpt Pat]

Originally Posted by kenbo

Not claiming any technical expertise in regards to AGMs, but would those requirements rule out charging AGMs with most solar arrays?

Yes, it would ... if it was true.

I've somehow managed to preserve my AGMs for 9 years while charging them underway with solar at much lower rates, sometimes at nearly zero rates. I called Lifeline support and challenged them on that "minimum charge current" assertion. I was told that in fact to recover a badly discharged battery, they recommend using very low charge currents (0.05C - see Section 5.6 here: http://lifelinebatteries.com/wp-content/uploads/2015/12/6-0101-Rev-E-Lifeline-Technical-Manual.pdf).

The stated "minimum" charge rates are intended to limit the amount of time that a deeply discharged and therefore abused battery (below 50% SoC) remains in that discharged state. Time is a factor in destructive sulfation. It's a limited-time-in-a-discharged-state issue to prevent permanent irreversible sulfation. If you never go below 50% SoC, and recharge (at any reasonable rate) promptly, sulfation is greatly reduced.

My absorption voltage for the Odysseys is 14.7 volts, and for the Lifelines it's 14.4 volts (at 25 C), with temperature compensation, by the way.

Since I've stated capacity numbers, I suppose I should describe how I measure battery capacity. Capacity in amp/hours is stated by both manufacturers at the "20 hour rate." For a 100 amp/hour battery, that's 5 amps discharge over 20 hours. Testing at any other discharge rate involves complex corrections to account for the Peukert coefficient. Not wanting to ever discharge my batteries below 50% SoC, I measure capacity to 50% SoC like this:

I discharge at an essentially constant-current (slightly approximated) rate of 5 amps through a total of 2.5 ohms (a 2.4 ohm 300 watt resistor and 0.1 ohm of wiring resistance). Discharge time is recorded by a Honeywell accumulated time counter. When the battery terminal voltage reaches 12.1 volts (corresponding to the resting voltage at 50% SoC), a voltage sensor turns the load off. The clock then stops. The battery terminal voltage, now resting with no load, rises if the battery has more than a 50% SoC remaining, and the voltage sensor turns the 5 amp load back on. The clock resumes counting. This process continues to "walk the battery down" until the battery finally rests at 12.1 volts with no load. Then, I note the amount of time the load was on. 10 hours = 100% capacity (10 hours to reach 50% SoC). I'm getting about 8.5 hours now, or 85% capacity. After nine years. Not bad. The whole testing process takes about 24 hours, while the battery gradually walks down.

I'm getting impatient. I want to replace the rest of my batteries with lithiums, while keeping only one lead-acid battery on each bus. My patience may run out before the lead-acids age out.

[LeaseOnLife]

Originally Posted by ranger42c

Lifeline and Odyssey recommendations -- minimum .2C and .4C respectively for best longevity -- are in their manuals, available on their websites.

-Chris

Not helpful! And probably not correct.



Here is what I find in my Lifeline Technical Manual, page 20 (it doesn't let me copy and paste the text, so I have to use images). Since we avoid discharging deeper than 50%, the point of a needed 0.2C charging capability is not supported by (this section) of the manual. If you find something, please do provide a citation, not just "find it yourself".