Batteries

Delfin said:

If actual information about LiFePO batteries is of interest, Maine Sail's blog post on the topic might be of interest:

LiFePO4 Batteries - Thoughts & Musings Photo Gallery by Compass Marine How To at pbase.com

Or perhaps this article: https://www.batterystuff.com/kb/articles/battery-articles/lithium-battery-overview.html

"The LiFePO4 batteries are the safest type of Lithium batteries as they will not overheat, and even if punctured they will not catch on fire. The cathode material in LiFePO4 batteries is not hazardous, and so poses no negative health hazards or environmental hazards. Due to the oxygen being bonded tightly to the molecule, there is no danger of the battery erupting into flames like there is with Lithium-Ion."

If confusing the battery in your cell phone with the technology appropriate for a marine application is preferred, then the above will not be of interest.

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Thanks for the links Delfin. Some good info in there.

I think some folks eyes start to glaze over at the word 'lithium' and mentally they get no further. Maine Sail's blog is still a work in progress, but highlights the need for informed decisions and an understanding of the differences to other battery setup and operating parameters.

Insequent said:

Thanks for the links Delfin. Some good info in there.

I think some folks eyes start to glaze over at the word 'lithium' and mentally they get no further. Maine Sail's blog is still a work in progress, but highlights the need for informed decisions and an understanding of the differences to other battery setup and operating parameters.

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Apparently so.

I have been noodling whether to build a bank of LiFePO or install a small night generator - 5 kw - and carbon foam. The nice thing about the lithium is their acceptance rate doesn't drop off, plus 80% discharge is easy on them, plus they last 3,000 cycles. Take out 200 amps and you can put it back in at a rate of 200 amps without much taper. So, you can get by with a smaller bank.

The carbon foam have one really nice characteristic compared to AGM and that is their ability to be partially recharged over and over again without their capacity diminishing. Not sure which path I'll go. Building the lithium bank looks like fun.

FF said:

To not run the engine for hot water as often , would not a 4X larger (as required) HW capacity , with extra wrapped insulation be a simpler choice?

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You can raise the temperature, and add a tempering valve and achieve the same goal with the same size hot water tank. That way you don't lose the space and add the additional weight of a larger tank.

"You can raise the temperature,'

Boat HW heaters are fine with 180F or more as that is the temperature of the coolant.

Home style units are out of luck at those temps , a RHEEM commercial 50G unit with "forever" GRP inner tank is fine at those temps .

Well insulated it only drops 5deg F in 24 hours.

But BIG!!! and costly.Although far cheaper than noisemaker made power.

Baker said:

All good points and I agree. I bought my boat 3 years ago with wet batteries. I then replaced them with AGMs and no trouble so far.

My charger was OEM 2001 so no AGM profile. It is a Charles 80 amp. I called Odyssey(batter maker) and asked them if the Lead Acid setting would be sufficient. They said that it would be fine. The biggest issue was that AGMs desulfate by a rapid charge rate and the LA setting is a little bit slow. Anyway, they said it was a nominal(theoretical) issue and shouldn't worry about it.

There is a good thread on here that I started when I was shopping batteries. I will see if I can dig it up.

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Baker said:

Here you go....same questions and some good stuff!!!

http://www.trawlerforum.com/forums/s4/batteries-11513.html

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Our 2002 OEM charger, ditto, I called Odyssey, ditto... and so now our oldest bank of Odyssey G31 AGMs (PC-2150s) have been through 10 seasons, and voltage still meters pretty good, and the low self-discharge rate during winter lay-up on the hard (although we don't often do that) is still as advertised.

Our battery set-up is two dual-purpose G31 banks (~300 Ah, each bank) plus separate genset battery. Each main bank starts one engine, runs approx. half the house (including on fridge on each), and runs approx. half the bridge (electrics on one bank, electronics on the other). Two levels of starting back-up: a parallel switch at the helm for starting an engine using both main battery banks simultaneously, and the separate genset battery and 3-bank charger.


It's not impossible to check fluids, but it's a pain in the neck... exacerbated by the OEM cabling which obscured some of the caps on the original flooded batteries. I chose to treat myself to slightly less periodic maintenance, and to reduced off-gassing. All good, so far.

But... that original (starboard) bank is also powering all our electronics, which matters when we're trolling on only the port engine or for overnight anchoring with some of the components still on... and I'd also like to add an inverter for some light duty... but there's only space for either three G31s (~300 Ah) or four 6V golf cart batteries (~440 Ah).

G31 Carbon Foam Firefly batteries look good especially because of their PSOC capabilities, but in our case I think 440 Ah trumps 300 Ah... and Bruce Schwab has only been able to say they've taken the (many?) requests for 6V GC versions under advisement. I suspect that means they're at capacity, not really able to increase production...

So our plan is to probably switch that one particular bank to probably Lifeline 6V AGMs whenever the time comes. This after analysis of our Cummins starting requirements (minimum CCA/MCA specs) and discussion with Lifeline, both confirming viability.

Adding an inverter/charger on that one bank for some house functions would just be gravy.

But I'm guessing 6V Carbon Foam would be even better for our particular purposes, assuming willingness to bite the cost bullet.


I haven't been enthused about LiFePO yet, partly because of initial cost but mostly because of the BMS complexity that also apparently becomes required to manage such a system.

-Chris

Cat developed the carbon foam battery. A decade or more ago they were recommending the battery for heavy equipment especially for very hot and very cold locations. Think Alberta tar sands or Arizona copper mines. The manufacturing process was viewed as difficult, expensive and not Cat's forte.

They spun it off with the next company facing new product hurdles and a terrible capital market, eventually going bankrupt. Lithium batteries had become the rage and standard AGMs a lesser cost alternative. Enter the RV market and renewed interest. The reborn Firefly plant in Peoria (Cat history again) began operating at capacity to fill that market as noted by Ranger.

The story line is good but with current purchase costs where they are and no sign of Li or "lesser" lead batteries fading into the sunset, carbon foam lead batteries are an item for the wealthy or those who have a very high use and discharge cycle. Like a blue water build.

All this said, I'd go with carbon foam lead before Li for many reasons. I just may especially if prices come down if/as other battery makers jump into the fray.

sunchaser said:

All this said, I'd go with carbon foam lead before Li for many reasons. I just may especially if prices come down if/as other battery makers jump into the fray.

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I was tempted by LiFePO4 but went with 6v golf cart batteries because if anything went wrong way out in the middle on nowhere on BC's north coast, replacement parts wouldn't have to be flown in from Vancouver. Carbon foam batteries give almost as good performance characteristics as LiFePO4, but can be used with readily available components.

Hopefully they gain traction and lower their cost a bit...

Baker said:

Yikes!!! Maybe running your hot water heater on your inverter might be the reason for the early demise of your batteries??? That is pretty heavy service to expect from your batteries....especially 50 gallons!!! I would much rather start my generator to heat water than subject my batteries to that sort of punishment. I state this ignorantly as I do not know your set up. But a water heater, especially a 50 gallon one, is one of the highest drawing AC appliances on the boat.

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Yes and No.

You are right, but when I do turn it on, I do so for only short periods, maybe 10 minutes.

Also, as I said, I turn it on when I have excess power.

Lastly, the Raritan is very efficient, so if I turn it on, after running the energy, the load is pretty small to keep the hot water hot.

And of course for the silent boat folks the RV folks have efficient 120V and propane HW heaters with about a 6-10G tank.

Step back and look at the problem.

Taking 12-24 vDC and inverting it to sine wave A/C 110/220 v and handing it to a resistance heating element for heating water.

Has anyone thought about a 12v heating element?

Also, what about the heat loss from the inverter.

Then, to charge up the batteries run down by the inverter to heat water, you start an engine...

that's insane.

Someone makes a 12V water heater now.

"Has anyone thought about a 12v heating element?"

Resistance is resistance , all the heating elements will operate at a lower voltage.

Many off grid folks with big wind or hydro power dump excess energy to the HW heater.

Its just a switch setup that is required.

50A at 14 V is still only a few hundred watts , so its not fast.