LiFePO4 vs FLA - The Real Deal

[fivecapes]

Originally Posted by ramblinrod

Let’s see, 600 A-hr FLA bank plus 400W wind generator plus 600W flexi panels weights about 500 lbs.

1000 A-hr LiFePO4 bank and 5kW generator plus big charger to charge 300 A-hrs in an hour weighs about 700 lbs. Nope, still no major advantage.

Aren't the bank sizes reversed

[missourisailor]

Originally Posted by jkleins

There is one other advantage and that is more reliable voltage. My Firefly’s do get pretty low under a good load when below 50%. It hasn’t affected me yet but I never have any critical instruments on usually during this time. LFP do seem better in this regard.

Jim

True.
Honestly, early morning, when raising the anchor, is really the only time I have noticed a critical voltage drop. But this is only after a couple of days of low sun light and a brain fart of not turning the power on to the voltage reg...


Most other times, when using the anchor windless, the motor and alt is operating. So it is really a non issue.

[kmacdonald]

Lithium is the clear winner in about all parameters except cost and fault tolerance. In the cruising market it will lose for lack of fault tolerance. It will lose on cost to the weekend and occasional sailor. For the racing sailor it is the clear winner.

[senormechanico]

Originally Posted by ramblinrod

No matter what technology, one has to be able to put back in what they take out.

With lead, + 15%. Ya gotta pay Peukert.
With Lithium, + 1%.


I'd never go back to lead.

[daletournier]

Originally Posted by senormechanico

With lead, + 15%. Ya gotta pay Peukert.
With Lithium, + 1%.


I'd never go back to lead.

Yer, but does it matter? Is the end result much different? If you have enough electricity, you have enough electricity, if your charging capabilites keep up deficiencies and all then it dosent matter.

If im correct one of the contributers here has spent €15,000 on his charge system , that's alot of money to have what I have,electricity!

[daletournier]

Originally Posted by a64pilot

As a lead acid battery users myself, I have to say arguing they they are “better” than Lithium is a lot like arguing that wood is a better boat building material than fiberglass.
I just don’t have that kind of money, and don’t want to have to become a lIthium expert either, so I’ll stay in my old wooden boat, but I recognize fiberglass is superior for most.
Let the early adopters find out and fix any traps, and hopefully by the time my lead dies, it’s not such a Science project, and less expensive.

This is exactly my view. By the time my current batteries die Lifepo is mainstream and cheap, this dimishes the greatly the downside for ne.

A64, if you did go Lifepo how would your cruising day to day real life improve?

[ramblinrod]

Originally Posted by fivecapes

Aren't the bank sizes reversed

No, I did that intentionally to make a point, reserve capacity.

Some tout that LiFePO4 has 80% usable capacity from 90% to 10%.

Well FLA has usable capacity from 100% to 20%. (It will just not last as many years as if one uses it from 100% to 50%.

This is all really smoke and mirrors as one would never design a system with no reserve capacity.

Normally, one will choose a bank A-hr capacity that they can skip a day without charging at all.

Well they might not with LifePO4 because the dang batteries are so expensive.

So the guy with the lower cost higher capacity FLA bank will sleep comfortably, while the guy with the LiFePO4 bank will get up at 2 am when the alarm goes off to start the generator because they had no reserve capacity.

[daletournier]

Hi just read the below in another thread, written by Oceanplanet:

"Regarding Li, I have a simple rule of thumb: If you have enough solar to cover your loads and condition your batteries, Pb will be fine. If your loads are such that you have to charge with fuel, then you should consider Li".

I think this is a good way of looking at the Lifepo vs fla thing. I would swap the "condition your batteries " with getting them to "cruising full".

[gmakhs]

The only reason my lifepo batteries would benefit my boat was the reduction in space and weight , for 200 ah lead I could use 400 lifepo, from the other hand they are problematic and not wide spread .
For my 400 ah bank I had to spent 1000 euros from Chinese source , with the same amount of money I change my lead batteries 5 times so why should I bother ?
I do have 400 watt wind generator and 200 watt of solar .
Now about the power consumption, you can spent the same amount of money you spend for lifepo to cut your power expenses , like buying a windvane so you don't have to use auto pilot , induction cooker ?? Do you really need it ??
Remember electric applications will fail during water ingresion, stay simple .

[gmakhs]

Some.people talking about longetivity , I have seen posts here.with BMS stop working after 4 years , so I am not convinced yet .

[44'cruisingcat]

Virtually zero self-discharge. Try putting lead acid batteries in storage for a couple of years, with no charging source. They're going to be good for ballast, not much else...

Someone I know left LiFePO4 batteries on a shelf for several years while he built his boat. They were still fine when he launched.

There's also the efficiency. Put 100 amphours in, you get very close to 100 amphours back out. With lead, you dont.

So, lighter, more compact, longer lived, faster charging, better voltage stability, more efficient..

You can see why people might think it's cool to be able to say " I have Lithium batteries ".

[ramblinrod]

Originally Posted by CatNewBee

wait a minute...

I would buy them because they are yellow and look so pretty under the berth...


But if you really look for an answer, 4 times the nominal capacity and 6..8x the usable capacity of a FLA regarding weight and space, 10 times the life expectancy (cycles).

And there is no Absorption Amp drop while charging. A LFP 1000Ah battery can be charged from empty to full in 1h with a 15kWh generator, a 1000Ah Fla will still need the whole day to recharge with the same generator. Got the point?

OK, so here's a direct comparison.

LiFePO4 - Battle Born BB100 12.
Size: 12.75" x 6.875" x 9"
Weight: 29 lbs
Capacity: 100 A-hrs.
Cost: US$ 949.00
Shipping: $$$$
Cycles: 3000

Deka DC31DT
Size: 13.00" x 6.75" x 9.5"
Weight: 60 lbs
Capacity: 105 A-hrs
Cost: US$ 166.00
Shipping: Local pick up
Cycles: 1500 (100% - 50%) (Educated Guess)

Assume 250 A-hr / day consumption, 50% reserve capacity

Boat A
5 x BB10012 + shipping, 5kW generator, 30 G Diesel/Month, and 3x100A chargers.

Total Weight: 150 + 270 + 230 + 35 = 685 lbs
Total Cost: $4,750 + $200 + $12,000 + $1650 = $18,600 + $150/month diesel
4 Yr Cost: $25,800

Boat B
5 x DC31DT (local pick up) + 1000 W solar + 400 W wind + 100A charger.

Total Weight: 300 + 40 + 38 + 11 = 389 lbs
Total Cost: $830 + $2000 + $2500 + 550 = $5880
4 Yr Cost: $5,880

Still can't justify LiFePO4, not even close. Not cool at all.

[44'cruisingcat]

Originally Posted by daletournier

This is exactly my view. By the time my current batteries die Lifepo is mainstream and cheap, this dimishes the greatly the downside for ne.

A64, if you did go Lifepo how would your cruising day to day real life improve?

I went with LiFePO4. There's now space for additional gear alongside the batteries in the battery compartment.

In the event I have to move them, it's MUCH easier.

Because of the improved efficiency, it's like having about 10% (or nearly 100 Watts) more solar. They also charge faster off a generator or engine. So less hours running a genny.

All the electric stuff works better. Toilets, pumps, windlass, whatever, they all run better at 13 volts than at 12. And there's virtually no voltage drop under load. The watermaker even makes more water.

If it's been a cloudy day, and the batteries are only at about 60% at bedtime, I don't have to worry about drastically shortening their life if I leave charging them till tomorrow. And I don't have to put up with low voltage alarms from the inverter every time the fridge or freezer starts up.

[44'cruisingcat]

Originally Posted by ramblinrod

OK, so here's a direct comparison.

LiFePO4 - Battle Born BB100 12.
Size: 12.75" x 6.875" x 9"
Weight: 29 lbs
Capacity: 100 A-hrs.
Cost: US$ 949.00
Shipping: $$$$
Cycles: 3000

Deka DC31DT
Size: 13.00" x 6.75" x 9.5"
Weight: 60 lbs
Capacity: 105 A-hrs
Cost: US$ 166.00
Shipping: Local pick up
Cycles: 1500 (100% - 50%) (Educated Guess)

Assume 250 A-hr / day consumption, 50% reserve capacity

Boat A
5 x BB10012 + shipping, 5kW generator, 30 G Diesel/Month, and 3x100A chargers.

Total Weight: 150 + 270 + 230 + 35 = 685 lbs
Total Cost: $4,750 + $200 + $12,000 + $1650 = $18,600 + $150/month diesel
4 Yr Cost: $25,800

Boat B
5 x DC31DT (local pick up) + 1000 W solar + 400 W wind + 100A charger.

Total Weight: 300 + 40 + 38 + 11 = 389 lbs
Total Cost: $830 + $2000 + $2500 + 550 = $5880
4 Yr Cost: $5,880

Still can't justify LiFePO4, not even close. Not cool at all.

Why only a 5kW generator for the boat with lithiums? Surely we all have 500kW gennies? And burn at least $5,000,000 worth of diesel per hour?

Or then there's reality. I have a 1 kW generator, and it hasn't been run for months.

If you're need to invent ridiculous scenarios to attempt to "prove" your point, your point is most likely wrong....

[ramblinrod]

Originally Posted by 44'cruisingcat

Why only a 5kW generator for the boat with lithiums? Surely we all have 500kW gennies? And burn at least $5,000,000 worth of diesel per hour?

Or then there's reality. I have a 1 kW generator, and it hasn't been run for months.

If you're need to invent ridiculous scenarios to attempt to "prove" your point, your point is most likely wrong....

Not ridiculous at all.

A 1 kW generator can reliably drive a 60A @ 12 Vdc charger.

If daily consumption is 250 A-hrs, then to put that back in is going to take 4.2 hours generator run time.

If one is going to charge with a 400W wind generator and 1000W solar, that eliminates any fast charge benefit of LiFePO4, as the charging system will only deliver 60 Amps at the best of times, prolly 15A per hour average over a typical 24 hour period.

So justifying purchase based on fast charge rate doesn't cut it, if the plan is to charge slow.

To justify based on charge rate, one would need a 5kW generator and 3 x 100A chargers, to charge the bank back up in one hour.

The real numbers are pretty frightening when one really looks at them.