New AGMs to replace lead acid?

[Tango_51]

Hmm. sounds like y'all use to much electric... I do 2 Exide megacycle AGM 200 (100 ah) as house coupled to a 150 watt (9 amp) solar cells... I have no problems with power..
of course - I've changed every thing to LED and thought-out the microwave no 120v appliances cook on a pressurized alcohol stove. biggest power user is the 12v refrigerator. which i put a battery operated fan in so it cycles less.. if i want AC.. start up the portable gen... or do the swamp cooler trick with the fans..
simplicity

[donradcliffe]

Rather than natter on about the various technologies available, if we are really going to help the OP, we need to help him understand the system that he has. So far, he thinks his fridge/freezers take 10 amps at 120 volts AC, and his 1000 watt solar system is at 24v. He has a 57 ft boat with AC, a big generator, watermaker, washer/dryer and induction cooking. I'm guessing he has a powerboat or catamaran, but that's fine with me.

Just trying to understand the elephant, if he needs to run the genny 4 hours per day for water, at 25 gal/hr, that would be 100 gal/day consumption. Not out of the question for 6 people using fresh water flushed toilets and a clothes washer. During that 4 hours, he can do his cooking, washing, and charge his batteries.

The 1200 watt average refrigeration load seems way too high. A new 22 cu ft home refrigerator/freezer has an average power consumption of less than 60 watts, and a good 12v boat system will be more like 40 watts.

So, more information on the boat systems would be a good start. Battery bank voltage, inverter/charger size, alternator(s) size, watermaker output rate, 12 vs 120v refrigeration, solar panel bank and controller voltages, etc. Don't be embarrassed if you don't know all this stuff--you will be much less dependent on technicians if you learn it.

[john61ct]

Originally Posted by donradcliffe

if he needs to run the genny 4 hours per day for water, at 25 gal/hr, that would be 100 gal/day consumption. Not out of the question for 6 people using fresh water flushed toilets and a clothes washer. During that 4 hours, he can do his cooking, washing, and charge his batteries.

**Partially** charge his batteries. Best if that genny run is done before the sun gets too high, then give the panels a full day to complete to 100%.

[sailorman33]

I have been trying to decide between Lifeline AGM 6 volt batteries and Oasis Firefly. I have decided to go with the Oasis Firefly because I believe the upfront and long term cost is less.

Lifeline AGM should not be discharged below 50%. Firefly Oasis can be discharged down to 20%.

I need approximately 440 amp hours of useable battery capacity.

Lifeline AGM 6 volt battery is rated at 220 amp hours. Only 50% of that is useable. It will take eight 6 volt batteries to give me 12 volts of 880 amp hours.
Again, only 50% of that is useable, so I end up with 440 useable amp hours.
The cost of 8 Lifeline AGM batteries is approximately $2850.00.

Firefly Oasis 12 volt battery is rated at 110 amp hours. 80% of that is useable. It will take five 12 volt batteries to give me 550 amp hours. Only 80% of that is usable, so I end up with 440 useable amp hours.
The cost of 5 Firefly Oasis batteries is approximately $2430.00

It costs $420.00 less to purchase the Firefly Oasis battery when looking at the same useable amp hours.

[rwells36]

Originally Posted by sailorman33

I have been trying to decide between Lifeline AGM 6 volt batteries and Oasis Firefly. I have decided to go with the Oasis Firefly because I believe the upfront and long term cost is less.

Lifeline AGM should not be discharged below 50%. Firefly Oasis can be discharged down to 20%.

I need approximately 440 amp hours of useable battery capacity.

Lifeline AGM 6 volt battery is rated at 220 amp hours. Only 50% of that is useable. It will take eight 6 volt batteries to give me 12 volts of 880 amp hours.
Again, only 50% of that is useable, so I end up with 440 useable amp hours.
The cost of 8 Lifeline AGM batteries is approximately $2850.00.

Firefly Oasis 12 volt battery is rated at 110 amp hours. 80% of that is useable. It will take five 12 volt batteries to give me 550 amp hours. Only 80% of that is usable, so I end up with 440 useable amp hours.
The cost of 5 Firefly Oasis batteries is approximately $2430.00

It costs $420.00 less to purchase the Firefly Oasis battery when looking at the same useable amp hours.

There is another benefit to Oasis Firefly. They will accept much higher AMP which reduces charging time significantly. The specs show they will accept 250A charge. Thus, to fully benefit from your new purchase you should take into consideration your charging regimen. I installed 8 FO and am super pleased.

[john61ct]

The real USP for Firefly is the tolerance for PSOC abuse, just like LFP you don't need to get back to 100% full if it's not convenient. If I **knew** I could get all the way full every day, I would likely go Lifeline, certainly well-proven much more widely over a longer period.

Plus, I would caution that drawing them down to 80% DoD in **normal** use will massively reduce their lifetime cycles. Better to size the bank so you think you'll need to only sometimes go below 50%.

Another wrinkle is depending on your location, FF may be a long wait, most dealers are backordered months.

Bruce at OceanPlanet is NA master distributor if you want to learn more.

[sailorman33]

{quote}Plus, I would caution that drawing them down to 80% DoD in **normal** use will massively reduce their lifetime cycles. Better to size the bank so you think you'll need to only sometimes go below 50%.{end quote}

I have been told that Firefly Oasis can be discharged 80% without {massively reduce their lifetime cycles}. I thought there would be very little harm to the life of the battery.

Am I wrong?

[Catmandu]

Went around and around myself on this issue when we added an generator and Aircon to the boat: What type of generator (variable speed DC or constant speed AC)? What type of batteries: FLA, Lipo, FF AGM ??? The original bank was made up of 8 225ah (980ah total) 6V Trojan T-105 Golf Cart batteries.

I was very tempted by the Lithium but the cost was over $10,000 from some reputable marine vendors (mastervolt). I was temped by Firefly but at a cost of $4,000+ to upgrade the bank. In the end I couldn't pass up the sale price at a local golf cart shop for new Trojan T-105's. The total cost was $935.00 for 8 batteries and at that price I can replace the bank four times for what the fireflys cost and more than 12 times for what lithium costs. If the FireFly's could last twelve years we would break even on cost ...

So I went the "use it, abuse it, toss it" mode ...

Once the Lithium price drops (5-10 years given Elon musk's push and investment) and become safer we will look at those once again.




Paid the an extra $160.00 for the trojan watering caps/system which is worth every penny.

[john61ct]

Originally Posted by Catmandu

What type of batteries: FLA, Lipo, FF AGM ???
...
I was very tempted by the Lithium

NBD but FYI, LiFePO4 or LFP are the right terms for the type you're talking about.

Lithium and lithium-ion are too general.

Lipo means Lithium Polymer, an entirely different chemistry.

Originally Posted by Catmandu

The original bank was made up of 8 225ah (980ah total) 6V Trojan T-105 Golf Cart batteries.

Actually a very fine bank, no shame there, and certainly not the cheapest. Properly cared for many owners getting over a decade from them.

Originally Posted by Catmandu

So I went the "use it, abuse it, toss it" mode ...

The batt for that philosophy wound be Sam's GC2s at several hundred cheaper.

Not saying yours aren't good value mind you, but many owners have to (read: should) replace every year or two, and IMO Trojan's a bit pricey for that.

Originally Posted by Catmandu

Once the Lithium price drops

Won't be happening, unless new supplies of the scarce raw materials are discovered. In fact greater demand well may boost prices.

Originally Posted by Catmandu

become safer

Once again you're mixing your chemistries, LFP itself doesn't have any the thermal runaway issues specific to other lithium-ion chemistries.

That is, beyond those of any large battery tech, biggest danger being the loose nut behind the wheel, too light gauge wiring, improper connections, chafing/vibration issues, earthing etc.

[svlamorocha]

Originally Posted by john61ct

Won't be happening, unless new supplies of the scarce raw materials are discovered. In fact greater demand well may boost prices.

The price of lithium carbonate contained in a battery (say US$10/kg lithium carbonate aka LC x about 1.0 kg LC per kWh of battery capacity = about US$10/kWh of battery capacity) has almost no impact on the price of a battery (say US$300/kWh of battery capacity).

If LC price does not drop below 10 US$/kg and given time to develop, supply of LC is not an issue. The recent supply hiccups are only due to problems at startups that promised lower costs than the established producers (SQM, Albermarle, FMC et al). Now that all the BS of costs below US$2/kg from 100% solar evap process is gone (and some shirts have been lost) the credible players are bumping up capacity to produce with known process routes than can make money at US$5/kg.

Another story is the profitability of battery manufacturers. I do not know for how long can we expect them to keep cutting prices, losing money and investing, all at the same time.

[Catmandu]

Yes, corrected. I meant Lithum Iron not Polymer ... got my batteries mixed up with my son's R/C airplane's batteries ...

Still, bang for the buck I have yet to find something better than these Trojan Golf Cart batteries. If someone knows of something better please chime in.

[john61ct]

Lithium is the least of it. All the top vendor's chemistries use other rare Earth minerals.

I'd be happy to place a substantial ten-year bet that LFP will not be cheaper in real terms USD.

[sailorman33]

I have done some further research regarding discharging Firefly Oasis batteries down to 20% capacity.

Firefly Oasis states in their literature that their battery is good for 3600 cycles at 50% discharge and 1000 cycles at 80% discharge.

Lifeline Agm states in their literature that their battery is good for 1000 cycles at 50% discharge and 500 cycles at 80% discharge.

It is true that the cycles on a Firefly Oasis batteries will be substantially reduced when discharged to 80% (3600 vs 1000).

It is also true that when comparing Oasis Firefly and Lifeline, Firefly will give 1000 cycles at 80% discharge and Lifeline will give 1000 cycles at 50% discharge.

A Firefly Oasis battery discharged to 80% will give as many cycles as a lifeline battery discharged to 50%.

Because Firefly Oasis has a much larger useable capacity the battery bank does not need to be as large. Cost saving and weight saving.

When on anchor you are probably only able to charge your battery to 85%. With a discharge down to 50% you have a useable capacity of 35%. With a discharge down to 20% you have a useable capacity of 60%

The ability to discharge down to 20% will almost double your useable capacity when you are only charging to 85% (from 35% to 60%).

[Catmandu]

I have not had the privilege of actually testing the FireFly batteries but from what I have read of those that have tested them they are preferred to AGM. The only advantage that AGM's seem to have is in those rare cases where the batteries must be mounted in some non-upright position.

As for the firefly's vs. the Trojans my back of the envelope calculations indicate that you get about 3x more energy per dollar out of the Trojans over the lifespan of the banks.

The conclusion I came to: When I head out for an extended round the world trip the extra expense for the firefly's might be worth it if they are able to operate as advertised in psoc. While cruising near the USA its hard to beat the Trojans.

[john61ct]

Originally Posted by sailorman33

Firefly Oasis states in their literature that their battery is good for 3600 cycles at 50% discharge and 1000 cycles at 80% discharge.

Yes that's good stuff, should also check out Odyssey, I think they're the last oldschool AGM still claiming OK to draw down that deep. At least as good on general quality rep too.

Originally Posted by sailorman33

A Firefly Oasis battery discharged to 80% will give as many cycles as a lifeline battery discharged to 50%.

Because Firefly Oasis has a much larger useable capacity the battery bank does not need to be as large. Cost saving and weight saving.

I think if you do the math you'll find going to only 50% is well worth the extra money. Obviously there are situations where it may be unavoidable, but as an up-front design parameter. . .

Unless you really can't carry the extra weight/space, in which case IMO worth checking out LFP.

Originally Posted by sailorman33

When on anchor you are probably only able to charge your battery to 85%.

Wut? That's crazy talk IMO. All it takes is a little genny, some panels and a SmartGauge.

And if it **is** true for someone regularly stays on the hook, then investing in anything more expensive than Sam's GC2 is throwing money away!

Just a few cycles out of 31, OK no problem, but not as a regular thing. . .

Except of course for the Firefly, that's their thing.

Or all the way up to LFP. . .