Batteries

[JDCAVE]

At 8 years on my FLA bank. 10 T-105’s, cabled series parallel 12 VDC. I can water them in 15 minutes. Not sure why KSanders takes so long! ;-)

As it was early in my boating career when I put them in, there were probably times when I abused them a bit, but they have never gone below 60% SOC. Now they rarely go below 90% SOC. Who knows what the actual capacity of the back is now. 70%, 80% of the 1125 Amp hour bank? It doesn’t really matter as I am still well within safe limits. When the generator goes on it may have declined to 12.55 volts under a 10 amp load. Well within safe parameters.

With solar, I can charge them on an extended Threshold charge past 100% SOC nearly every day. I think the solar has extended their lifetime. I could perhaps get another season but that might be tempting fate, as we do use the microwave on the inverter and that drops the voltage down quite a bit, although it does recover.

When it comes time to replace them, who knows what I’ll do. Probably a smaller bank. Probably FLA. Possibly Firefly? Possibly LFP? Not sure right now.

Jim

 

[Simi 60]

Just guessing, he forgot the tax, travel time, shop fees, environmental fees?

Ideally, he wants to charge the batteries while underway???

You can run the Genset while underway.
Or we can, can't see why others couldn't.

 

[OldDan1943]

You can run the Genset while underway.
Or we can, can't see why others couldn't.

Yes, assuming he/she has a generator and it works. Also, maybe he/she just doesn't want to run the generator.

 

[MYTraveler]

Are the fire dangers originally associated with LFP's now mitigated to the point of no concern? That is one of the biggest considerations holding me back from making the switch. Another is whether my Heart/Interface 3000 watt charger-inverter can be configured to properly charge LFPs. The comments above about alternators has me wondering whether they will create a problem, even though I would expect 90% of the charging to come from my genset. Lastly, if I switch the house bank to LFP, must I also switch the start bank (all currently FLA)? Note that my start bank is automatically paralleled with the house bank to produce 24v when running the thruster or windlass. Should I be concerned about the high amperage draw that entails causing the LFPs to shut down? These concerns make me favor replacing the house bank with FLAs, but if I do it will be another 5-7 years before they will need replacement. Advice?

 

[Simi 60]

Yes, assuming he/she has a generator and it works. Also, maybe he/she just doesn't want to run the generator.

Hey, I hate running the generator as well but I'll gladly use what I have vs shelling out $5k for another set of things that do the same job as the thing I already have.

Other advantage of lifepo4 is that genset time will be reduced as batteries are happy to not be 100% charged.

 

[Simi 60]

Are the fire dangers originally associated with LFP's now mitigated to the point of no concern? That is one of the biggest considerations holding me back from making the switch?

Apparently fire with Lifepo4 was never an issue.
Lithium like used in tesla powerwalls are a different thing altogether

A good video here of trying to kill LFP batteries

I think this video done by Sinopoly can sum up the safety of LFP technology. Those crazy Chinese guys shot, burned, shorted and cooked these cells. Please do not attempt this stuff at home. Take note that a single 60Ah 3.2V cell can throw in excess of 1800A of current into a dead short. WOW! None of the testers got acid burns, were blinded or went home with holes in their clothes.
DIY LiFePO4 Batteries On Boats - Marine How To

 

[rslifkin]

Thinking about it, there's a cheaper solution to the alternator and lithium solution. Let the alternator charge the lead acid start battery and use a DC-DC charger to charge the lithium house bank from there. No fancy alternator and regulator setup needed.

 

[Bigsfish]

Just replaced all my batteries, inverter and battery charger. After 7 years the Lifeline needed replacement ( not all but most so I decided to replace them all. My dealer suggested to do them all and since he is smarter than I we now have new batteries. Good got another 7 years.

Cheers

 

[Redsky49]

I have been quite happy with 6V FLA golf cart batteries in a series/parallel arrangement.

I am surprised that no one has mentioned gel cell batteries, which I think are a better option than AGM.

 

[OldDan1943]

I have been quite happy with 6V FLA golf cart batteries in a series/parallel arrangement.

I am surprised that no one has mentioned gel cell batteries, which I think are a better option than AGM.

Why not fuel cells?

 

[JimW]

Made the jump in AH with the same footprint of my AGM 8D Duracell (Sam’s) house battery by moving to 2 Odyssey PC-1800 AGM batteries . . . Because they can sit/stand/lay in any position, I have room in the same footprint to add another . . . At the end of the day, needs and wherewithal of the boat and owner will dictate best options . . .

Standing by -

 

[MichaelD]

Don’t think anyone here has addressed the FLA watering in tight spaces problem. I have one 8D start and 6 GC house, all difficult to reach. So, one difficult crawl to install a remote watering system that cost <$30 and problem is solved. For the GCs with screw-type caps, I have a self-limiting manifold to water all 18 cells from one connection. For the 8D with press-type caps I have 6 tubes to 6 caps that have a water+level indicator showing who needs the love.

 

[Bustlebomb]

Michael D, Where did you find a remote watering system for less than $30? All the ones I’ve been looking at have been $150+

 

[MichaelD]

Michael D, Where did you find a remote watering system for less than $30? All the ones I’ve been looking at have been $150+

On Amazon, various types, but when I looked I found I was wrong, it was $50. By Flow-Rite.

 

[Coalman]

Plain lead acid
Cheapest to by, high maintenance, short life

THAT IS NOT TRUE AT ALL

I have wet cell and agm, both are good choices for the right purposes

 

[Seevee]

After all the comments, I'm leaning toward the Oasis for the next batteries for the best bang for the buck, but will revisit when the time comes. Also, Oasis are easy to maintain and more robust than the AGMs.



However, one can't go to far wrong with a good AGM like Lifelines.



For "me"... lithium is just not prime time... too complicated and costly for the amps.



And, fwiw.... goal is to get about 400 to 500 amp hours for two nights on the hook, supplemented by solar. Right how I have 360 ah, which is plenty for one night.

 

[catalinajack]

Just replaced all my batteries, inverter and battery charger. After 7 years the Lifeline needed replacement ( not all but most so I decided to replace them all. My dealer suggested to do them all and since he is smarter than I we now have new batteries. Good got another 7 years.



Cheers

Seven years on expensive Lifelines. Flooded batteries easily last just as long and are 1/3 the cost. Unless access is a significant problem, I don't get Lifelines or other AGMs as any advantage.

 

[rslifkin]

Seven years on expensive Lifelines. Flooded batteries easily last just as long and are 1/3 the cost. Unless access is a significant problem, I don't get Lifelines or other AGMs as any advantage.

Lack of access or lack of suitable mounting space to handle the gas production, possible acid leaks, etc. are the biggest reasons for AGM over flooded. But AGMs do typically do better (both charging and discharging) at high currents relative to their size. So for some use cases, that may be an advantage.

 

[Bacchus]

The main reason I originally switched to AGM was for their lower self drain rate vs FLA. My boat gets layed up & covered for NE off season with no possible way to charge during that period.
In addition the no maintenance, no acid corrosion, etc has been a very welcome positive and I'm willing to pay a premium for the above benefits vs having FLA run down in prolonged storage or having to remove & take home for charging.

 

[catalinajack]

The main reason I originally switched to AGM was for their lower self drain rate vs FLA. My boat gets layed up & covered for NE off season with no possible way to charge during that period.
In addition the no maintenance, no acid corrosion, etc has been a very welcome positive and I'm willing to pay a premium for the above benefits vs having FLA run down in prolonged storage or having to remove & take home for charging.

Makes sense in the very cold New England winter environment. In warmer climes and in boats that are on shore power when not in use, AGMs offer no advantage over FLA batteries the exception being lack of access to maintain (water) FLA batteries every three months, give or take.

Yes, AGMs have a higher charge acceptance rate but one needs a charging source large enough to take advantage of that fact. For example, according to the Trojan Battery folks, their AGMs accept at 20% of capacity while FLA takes 13%. Those percentages applied to a bank of 900Ah yields acceptances of up to 180A and 117A respectively. But, one needs an alternator(s) capable of pushing those amounts of current. Same for the battery charger. My Magnum 2812 inverter charger is rated at 125 amps. I have measured the output of my 100 amp alternators while underway. I get 65-70 amps because of alternator temperature derating. So, the idea that one can charge AGMs faster than FLA is functionally untrue in most setups. I do realize that some folks, not many, do have high-output alternators that can take advantage of the higher charge acceptance rate of AGMs.

Battery experts, please correct me if my thinking is wrong.

 

[Bacchus]

Makes sense in the very cold New England winter environment. In warmer climes and in boats that are on shore power when not in use, AGMs offer no advantage over FLA batteries the exception being lack of access to maintain (water) FLA batteries every three months, give or take.

Yes, AGMs have a higher charge acceptance rate but one needs a charging source large enough to take advantage of that fact. For example, according to the Trojan Battery folks, their AGMs accept at 20% of capacity while FLA takes 13%. Those percentages applied to a bank of 900Ah yields acceptances of up to 180A and 117A respectively. But, one needs an alternator(s) capable of pushing those amounts of current. Same for the battery charger. My Magnum 2812 inverter charger is rated at 125 amps. I have measured the output of my 100 amp alternators while underway. I get 65-70 amps because of alternator temperature derating. So, the idea that one can charge AGMs faster than FLA is functionally untrue in most setups. I do realize that some folks, not many, do have high-output alternators that can take advantage of the higher charge acceptance rate of AGMs.

Battery experts, please correct me if my thinking is wrong.

I'm not an expert but agree with your points completely.
CMS has a very complete article on charge rates for AGM that supports your point.
https://marinehowto.com/how-fast-can-an-agm-battery-be-charged/
I guess I'm also a neat freak and basically lazy (at least found myself checking FLAs that had low levels that I'm sure didn't help life).
I've gone all AGM for house battys in my motorhome as well, although I do have power to run maintainers in that case. Refurbing the batty tray was a significant project and swore I would do it once but never again.

 

[TexasBryan]

On the battery discussion, how often are others having to add distilled water?

The battery on my generator seems to require about 2x as much as my other batteries. I'm not sure if that's a battery issue or that it's because that battery is dedicated to the generator?

On the plus side, it's the easiest battery to access.