Should we opt for Lithium Iron batteries (LiFePo) over Lead Acid kind?

[Mako]

I am reminded of the words of Benjamin Franklin
“If you fail to plan, you are planning to fail!”

Hmm, I didn’t know there was a guy named Ben F down in Aussieland. We used to have a guy with the same name here in America ?

 

[sunchaser]

Hmm, I didn’t know there was a guy named Ben F down in Aussieland. We used to have a guy with the same name here in America ?

Up until the Colonialists got burrs under their saddles, Ben was a confidante of British royalty whose wisdom was much sought after by the British rulers of the new country. Captain Cook had yet to set sail for OZ while Ben's pearls of wisdom were floating about England.

 

[LargeMarge]

...In 4-5 years of cruising you will swap your lead acid for new...

.
Real-world:
2003, we built our ExpeditionVehicle.
Nearly two decades full-time live-aboard, our ancient AGM bank is going strong.
.
It powers our induction hot-plates and our water-heaters.
.
We keep it topped with 1,830-Watts photovoltaic.
No petroleum-based genset.
.
I hope this helps.

 

[Simi 60]

Unique in the sense that cost of equipment in Oz is so damned high. Cost-benefit decisions are much different in North America. That is what I meant by unique. So, Simi, you saying, categorically, that lithium is so much cheaper than lead-acid technology is, quite simply, pretty much irrelavant to most others here.

And we went through this on another thread and you didn't back up that claim.

Let me try using trojan T105 in comparison to our EVE 280 lifepo4 24v bank @ 840ah.

Random look on the interwebs has a 6v 220ah T105 trojan @$147 usd

https://advantagebatteries.com/shop/trojan-t105-6v-battery/

4 X makes a 24v @ 220ah = $588
4 X makes a 24v @ 880ah = $2352
BUT
That only gives 440ah usable
To get up to the 840 ah usable that we enjoy with lifepo4 we need to double that trojan bank again

So that makes it T105 6v X 32 for $4704
Plus
A huge amount of space used
896 kg vs 120kg (1975 lb vs 260lb)
And excessive amounts of battery cable and terminals to connect it all.

So on that it seems it's going to be every bit of $5000 USD to get a flooded lead acid bank that can match the usable ah of our lifepo4 bank.

Our lifepo4 bank of 24 X 3.2v cells to make 840ah @ 24 v cost $3670 usd
And that included 3 BMS and all busbars and nuts for connecting the cells.

Looks to me like that's cheaper than flooded lead acid

Screenshot below of Alibaba invoice

 

[Bacchus]

"4 X makes a 24v @ 880ah = $2352

BUT

That only gives 440ah usable

To get up to the 840 ah usable that we enjoy with lifepo4 we need to double that trojan bank again"

That's is not factual... exaggeration at best just wrong in many ways.
Show me a batty mfg cycle life curve that drops off to zero beyond 50%
FLA & AGM easily usable to 70-75% and occasionally a little beyond.
I could care less whether folks LOVE LiFePO but don't sell it with bad info.
If that's your / others rationalization that's fine but there are other exaggerations against but not worth repeating.
LiFePO4 are absolutely great for some people and situations but not universally the right answer for all.

 

[Simi 60]

"4 X makes a 24v @ 880ah = $2352

BUT

That only gives 440ah usable

To get up to the 840 ah usable that we enjoy with lifepo4 we need to double that trojan bank again"

That's is not factual... exaggeration at best just wrong in many ways.
Show me a batty mfg cycle life curve that drops off to zero beyond 50%
FLA & AGM easily usable to 70-75% and occasionally a little beyond.
I could care less whether folks LOVE LiFePO but don't sell it with bad info.
If that's your / others rationalization that's fine but there are other exaggerations against but not worth repeating.
LiFePO4 are absolutely great for some people and situations but not universally the right answer for all.

I have yet to see a FLA or AGM manufacturer who says going below 50% is a good thing for longevity.

And, on our previous AGM bank, voltage sag was noticeable if we got anywhere close to 50%

This Rod Collins "Marine How To" article and pic supports what I said

https://marinehowto.com/under-load-battery-voltage-vs-soc/

 

[Kit_L]

@Simi: that is a truly excellent article; thanks for linking.

 

[Delfin]

Delfin - a couple clarifications.

There is a very good practical reason LiFePO4 batteries may not make a good starter battery: the BMS limits discharge current, usually close to the AH rating of the battery. So a 100AH battery such as the typical BattleBorn can only discharge up to 100A of current. This roughly compares to the CCA (cold cranking amps) of a starter battery which is normally 800A or more. You can parallel multiple LiFePO4 to multiply the available amperage, but that's sort of an expensive workaround. So while electrons are electrons, they are being throttled differently.

LiFePO4 have a much, much different charge profile than a traditional 3-stage charger/regulator. Both Renogy and Victron have LiFePO4 charge settings that are essentially a single stage blast with the BMS modulating a maintenance charge. Because the parasitic discharge on LiFePO4 is near zero vs 2%-3% per month for LA batteries, it really does require a specific charge profile.

Bottom line is the "special charger" and "special alternator" terms are only a slight misnomer. The charge profile is controlled by alternator capacity and the regulated flow. That regulated flow is significantly different for FLA vs LiFePO4. Installing LiFePO4 but not adapting the rest of the system is wasting the potential of LiFePO4.

Peter

I only have my own installation and system to refer to, but the two Lithionics 300 Ah 24vdc in my house bank put out 800 amps continuous and 6,000 amps pulse, supported by the supplied BMS. I happen to use 8Ds as a starter bank, and they are rated for 820 amps @ 24 vdc - in other words, the same as the LFP house bank. Further, the recommended Bulk charge current for 8Ds, at least according to Trojan, is 29.6 vdc. For the Lithionics battery, it is 29.2. Enough of a difference to matter? I doubt it, but not "significantly different", IMO.


5 years in, I use the same charger I had with AGMs, the same voltage regulator and the same alternator. The only change I made was to add 3 30 amp/24vdc Sterling chargers to boost genset charging current to 180 amps so as to take advantage of LFP's much, much, much greater current acceptance and resultant decrease in genset time. The exact same charging system is used for the LA starter bank with no issues. I just use the LFP parameters for charging and they work fine for the LA.


So, based only on my own experience, I think you can see why I find the argument for the need to redo the entire charging system when one converts to LFP to not make a lot of sense. At least to me....


It looks like the Battleborn 100 amp LFP deep cycle puts out 200 amps @ 12 vdc (30 seconds), so I guess different LFP batteries may have different specs and some may not be ideal for a starter bank, but that appears to be a manufacturer, not chemical parameter. Same with the charge voltage - Battleborn says 28.8 vdc for bulk charging.



http://www.trojanbattery.com/pdf/datasheets/SCS225_Trojan_Data_Sheets.pdf


https://lithionicsbattery.com/product/24v-300ah-8d-gt-module/


https://1t1pye1e13di20waq11old70-wp...ent/uploads/2019/01/BBGC2-2021-Spec-Sheet.pdf

 

[sunchaser]

Great information Carl. I'd forgotten how simple a setup you'd installed. Do you have an inverter charger or just rely upon the 3 Sterlings? How did you tie the 3 chargers together? Thanks

 

[Delfin]

Great information Carl. I'd forgotten how simple a setup you'd installed. Do you have an inverter charger or just rely upon the 3 Sterlings? How did you tie the 3 chargers together? Thanks

Tom, I have a Trace 4000 charger inverter that puts out 100 amps, and yes, the Sterlings are just daisy chained so when charging 187 amps is what I read is being absorbed by the LFP. I can't remember how many is the limit of Sterlings that can be put together, but they seem to work just fine and play nicely with the Trace. I have them set to the same value of bulk voltage as the Trace, and keep the Absorption to a max of 30 minutes, which I generally interrupt after 5 minutes or so of reaching target voltage of 29.2 volts. The only time the Sterlings are used is when on anchor and using the genset as they are 240 vac input.

 

[MV Justace]

Hello Guru, (catalinajack)
As your boat is about the same as my Lyscrest 42 and I currently have 8 x 6V US 2200 wet batteries that have lasted 6 years but I'm told that a couple at least aren't healthy now.
Looking to replace with either 225AH 6V Fusion AGM or SSB EV & Golf Buggy ones 226ah which my water top up system would fit onto as it does with the US2200. Only diff will be I drop from 232 AH each to 226 AH and 3 Kg lighter each. Connection setup would remain the same. Can't afford Lifepod at this stage and at 76 years old I probably wont be boating into my 80's but who knows.
Any advice?

 

[mvweebles]

I only have my own installation and system to refer to, but the two Lithionics 300 Ah 24vdc in my house bank put out 800 amps continuous and 6,000 amps pulse, supported by the supplied BMS. I happen to use 8Ds as a starter bank, and they are rated for 820 amps @ 24 vdc - in other words, the same as the LFP house bank. Further, the recommended Bulk charge current for 8Ds, at least according to Trojan, is 29.6 vdc. For the Lithionics battery, it is 29.2. Enough of a difference to matter? I doubt it, but not "significantly different", IMO.


5 years in, I use the same charger I had with AGMs, the same voltage regulator and the same alternator. The only change I made was to add 3 30 amp/24vdc Sterling chargers to boost genset charging current to 180 amps so as to take advantage of LFP's much, much, much greater current acceptance and resultant decrease in genset time. The exact same charging system is used for the LA starter bank with no issues. I just use the LFP parameters for charging and they work fine for the LA.


So, based only on my own experience, I think you can see why I find the argument for the need to redo the entire charging system when one converts to LFP to not make a lot of sense. At least to me....


It looks like the Battleborn 100 amp LFP deep cycle puts out 200 amps @ 12 vdc (30 seconds), so I guess different LFP batteries may have different specs and some may not be ideal for a starter bank, but that appears to be a manufacturer, not chemical parameter. Same with the charge voltage - Battleborn says 28.8 vdc for bulk charging.



http://www.trojanbattery.com/pdf/datasheets/SCS225_Trojan_Data_Sheets.pdf


https://lithionicsbattery.com/product/24v-300ah-8d-gt-module/


https://1t1pye1e13di20waq11old70-wp...ent/uploads/2019/01/BBGC2-2021-Spec-Sheet.pdf

Glad you're happy with your system. Sounds like it works well. It is not representative of an average system so makes sense that you caveat your statements accordingly.

Marine-how-to article explaining why LFP batteries are NOT a drop-replacement for FLA.

https://marinehowto.com/drop-in-lifepo4-be-an-educated-consumer/

Peter

 

[mvweebles]

.

Real-world:

2003, we built our ExpeditionVehicle.

Nearly two decades full-time live-aboard, our ancient AGM bank is going strong.

.

It powers our induction hot-plates and our water-heaters.

.

We keep it topped with 1,830-Watts photovoltaic.

No petroleum-based genset.

.

I hope this helps.

My hunch is you'd admit your experience of getting 20+ years from an AGM bank is exceptional. Excerpt from Marine-How-To article I just posted in previous response. 1480 "Real World" examples (albeit FLA vs AGM, a relatively close cousin),

In a battery use survey conducted on sailboatowners.com, the largest ever of its kind with 1480 users surveyed, the vast majority of boat owners reported they rarely if ever get more than 150 cycles out of their lead acid batteries. 150 cycles!!!!! Many of these are batteries that have claims of 1000 to 1200 cycles or more. Laughable is about the best way to describe it.*

Peter

 

[markpj23]

... So, our decision is to go with LiFePo batteries. The only thing we now worry about is getting it built correctly by the vendor, who in our case is KK...

I would make the same choice in your position. It should be easy enough to oberve the ABYC T13 standard and it's likely that the final version will be out by the time your build reaches that point. Perfect technology for your intended use of the boat.

The rest of this discussion is just the "which anchor is better" crowd on steroids.

 

[sunchaser]

In a battery use survey conducted on sailboatowners.com, the largest ever of its kind with 1480 users surveyed*[/I]
Peter

Aha, sail boaters! Having been on a sailboat or two, it seems logical to expect that battery maintenance and charging systems would be early points of neglect. To whit, Collins's articles on how to operate and take care of your sail boat battery and charging systems. Heed those caveats and house electrical issues will be minimized.

A boat owner who's neglected their LAs is more than likely to neglect their Li setup. A silver bullet for poor boat maintenance and lousy charging systems has yet to be developed.

My take on these excellent TF Li battery threads is there are a few proven vessel owners and trades men worth listening to - and then the rest of us.

 

[hughespat57]

I am very much around but there are days i dont read TF?

Appreciate all who commented on the thread. Please be sure that when I ask a question, it is for a matter that i am about to make decision. While reading TF replies I also tend to do independent research. Experience of many of you broadens my perspective and helps the research process. There are never 100% right decisions. It is all tradeoffs when engineering is involved (and, I am an engineer).

We are buiding a new boat, 60’. Going to live aboard. Not going be moving marina to marinaand given the size more likely to anchored than be on a slip.
So faster charging time is important. With a new build of this size boat, price of battery system is a marginal increase. But, safety matters.
PM with a member who is very experienced indicated that most new build he is advising on is opting for this type of battery. So, our decision is to go with LiFePo batteries. The only thing we now worry about is getting it built correctly by the vendor, who in our case is KK.

Hrk

This could get long so let me first layout who I am...
Retired USCG Machinery technician that worked gas, diesel, DC power generation, AC power generation, HVAC and refrigeration.

I then moved into commercial marine, then Heavy Trucks and equipment. Am an ASE certified Master HD technician. Then I changed careers and am currently an Data Center Infrastructure Architect. I work integrating Commercial power, DC power, Uninterruptible Power Systems, HVAC and computers (mission critical and sensitive loads).

I have full access to ABYC and have read and understand the full TE-13 as well as the full E-11 for all electrical systems.

Note TE-13 only speaks of "Lithium Ion" because ANY battery that uses Lithium is in that class and ABYC doesn't know what specific vendors or chemistry will be involved. And ABYC does not promote a specific solution.
So most of the "standards" refer to following the vendor specifications (for the batteries), and then makes recommendations on design as related to marine use.

The standard does point out real world situations that need to be dealt with. Such as considering a metal battery enclosure. Considering the power to your life safety systems; radio, GPS, chart plotters, radar, etc.

This is because a BMS will have the ability to completely disconnect your battery pack during any abnormal operation (charge or discharge faults).

LET ME BE VERY CLEAR HERE...
And as others have mentioned.
LifePo4 is not inherently any greater risk then LA. A fault is by definition an abnormal operation. A run away battery charger can cook a LA battery to the point of explosion (hydrogen gas is a normal by product of LA charging). Many fires have started in "traditional" marine battery, starting, charging and electrical systems.
E-11 covers all those normally anticipated fault conditions by specifying wire sizing, circuit protection and installation practices.

SO first thing is you have the advantage of a new build. And you know your particular use case, on the hook. Now consider how you want to live and what power requirements that will need. How long do you want to go without the need to run the generator or mains.

Then get with the electrical engineer designing the vessel power and wiring now. As a new build there are numerous things you can do to maximize energy use. First do you want to eliminate the generator? You could with LifePo4. You could select DC powered HVAC rather then straight AC. You may want a 48v system if running larger loads or large inverter. Higher voltages are easier to deal with then 12v at 400 amp (= 48v@100A).

To many think of "dropping in" and staying with 12v because that's our traditional lighting and electronics. But that is not necessary and problematic due to the high current loads @12v

A 48v bank can work in a large system for inverter, HVAC, water heating, cooking even.

Keep a 12v Deep Cycle battery for all you life safety systems and emergency lighting (or all LED lighting). Charge that from the 48v system with a DC/DC charger convertor.

Keep a separate 12/24v bank for very large short use motor loads such as starting, winches and thrusters. The engines are going to have 12v systems OEM anyway (possible 24v) no need to complicate.

 

[Delfin]

Glad you're happy with your system. Sounds like it works well. It is not representative of an average system so makes sense that you caveat your statements accordingly.

Marine-how-to article explaining why LFP batteries are NOT a drop-replacement for FLA.

https://marinehowto.com/drop-in-lifepo4-be-an-educated-consumer/

Peter

Thanks for the link. I am very saddened to hear about Rod Collins' health challenges. Worth noting that this guy is still trying to help boaters cut through the waist deep b.s. that seems to surround LFP with one finger typing and voice to text software. Thank you Rod. Praying for a full recovery.....

If you read the link you provided, I think you'll see that the supposed limitation of LFP as a starter bank is not related to the chemistry of LiFePO4, but of the amperage rating of the BMS. Like I said, there is no particular reason not to use LFP as a starter battery but like all things electrical, you have to have the correct equipment for it to work and a properly rated BMS is one of those for LFP.

Rod also provides a definition of a "drop in LFP battery" as being one with a built in BMS. He specifically excludes LFP with an external BMS as "drop in". He gives the reason - with most batteries with a built in BMS, the BMS is wimpy. Sure, some external BMS units can also be inappropriate, just as counting on an automotive regulator on the alternator would be inappropriate for maintaining a house bank, but you don't have to put trash on your boat of you don't want to.
If hanging an external BMS on the wall makes my batteries not drop in, fine, but dropping them in is what I did.

Bottom line, LFP is a safe chemistry on a boat. If sized correctly for the function, including the BMS, they can be used as a starter bank if you want. I don't generally bother because I first built out my boat with a two bank system with an AGM house bank and FLA for the starter bank, and I use the FLA as the destination bank for charge current underway when the LFP is charged.

 

[Simi 60]

5 years in, I use the same charger I had with AGMs, the same voltage regulator and the same alternator. The only change I made was to add 3 30 amp/24vdc Sterling chargers to boost genset charging current to 180 amps so as to take advantage of LFP's much, much, much greater current acceptance and resultant decrease in genset time. The exact same charging system is used for the LA starter bank with no issues. I just use the LFP parameters for charging and they work fine for the LA.

If not, wouldn't the alternator then be subject to the same loadings that killed off my previous 2 large frame continuously rated alts?

Forgive we if this has already been addressed in a previous post but

Do you still need some sort of smart regulator/cooling for your alt?
I assume so because you are still smashing amps into the starts so it can be sucked out and transfered to the LFP bank by those 3 chargers yes?

 

[Delfin]

Forgive we if this has already been addressed in a previous post but

Do you still need some sort of smart regulator/cooling for your alt?
I assume so because you are still smashing amps into the starts so it can be sucked out and transfered to the LFP bank by those 3 chargers yes?

A Balmar 624 controls the alternator and the Sterling and Trace also have programmable charging. The alternator is de-rated and doesn't need cooling as it is a 150 amp, 24 vdc that I have set for 100 amps via the MC624.



If I understand you second question, your assumption is not right. The FLA and LFP banks are never combined, so there is no sucking of amps going on. My three charging sources - alternator, Sterlings and Trace - all output to a charging buss that can be connected to the LFP via the BMS or the FLA. This is done simply by using the existing rotary switches for each bank that most all boats have and that I installed initially.


When underway, the alternator by itself can top up the LFP and once full, I connect the FLA to the charge buss and disconnect the LFP via the rotary switches and de-powering the BMS. The settings on the MC624 for LFP are just fine for the FLA since I never float the LFPs and can set it for what the FLA would prefer.



When at the dock, the Trace is also connected to the FLA and the LFP sit at around 50% soc.


When at anchor we power the house off the LFP and the FLA sit disconnected from the charging buss. When the LFP need re-charging the genset is started which supplies ac to the Trace that puts out around 100 amps. Since the genset is running, I can engage the 3 Sterlings and add another 90 amps or so allowing us to replenish the LFP in around 90 minutes (daily consumption is around 300 amps.)



This is a very simple setup that requires about two minutes a day to manage. By manage, I mean note the time I start the genset when charging the LFP, the amps consumed and set my watch to give me an alarm when the 90 minutes or so required to recharge are up. When charge acceptance rate <3%, off goes the genset. It also means that if I am recharging the LFP while underway, I quesstimate the time I should be checking the soc of the LFP and when they're full, I connect the charge buss to the FLA and take the LFP off line.



IMHO, the mistake people make is to try to install LFP and have it function just as if they were on LA. I manage mine as if they were a fuel tank. Use the fuel, then refill, and when full, stop filling. Not too tough......

 

[Kit_L]

@Delfin: that is a brilliant, simple system, and perfect for someone who's reasonably mechanically (electrically?) minded. Thank you.

 

[journeyon]

Just an honest question. Who uses a LiPe04 battery to start their diesels? And what battery do you use?


In actuality, I have an Honda 150 outboard, . It is a Accord motor turned on end and which seems to use >200 amps to start. I assume that a diesel uses more, the bigger the better.



I've checked the specs on the LiPe04 battery I installed and it's 100 amps. A Battleborn 100 ah, 12 V is speced at 200 amps for 30 sec as a surge current. Thus it seems to me that one should use a FLA battery to start any motor or risk burning out the LiPe04. And I retained a FLA to start the Honda.


So, the question is: does anybody use a LiFPo4 battery to start their boat engine, gas or diesel? And how did you configure the alternator?



Boris

 

[BruceK]

... I currently have 8 x 6V US 2200 wet batteries that have lasted 6 years but I'm told that a couple at least aren't healthy now.
Looking to replace with either 225AH 6V Fusion AGM or SSB EV & Golf Buggy ones 226ah which my water top up system would fit onto as it does with the US2200. Only diff will be I drop from 232 AH each to 226 AH and 3 Kg lighter each. Connection setup would remain the same. Can't afford Lifepod at this stage and at 76 years old I probably wont be boating into my 80's but who knows.
Any advice?

Sounds sensible looking forward. AGMs won`t need watering. 6AH difference should not be noticeable. 6 years life is an indicator to replace wet with wet but newer tech AGM is worth considering .

 

[Simi 60]

Thanks for the reply

A Balmar 624 controls the alternator and the Sterling and Trace also have programmable charging. The alternator is de-rated and doesn't need cooling as it is a 150 amp, 24 vdc that I have set for 100 amps via the MC624.

Thought as much
Have been trying to avoid the $1000 spend (in Oz) on one of those
+ $500 for a single DC to DC charger
Not worth it for my 50amp alt.

Back to the drawing board for me

If I understand you second question, your assumption is not right. The FLA and LFP banks are never combined, so there is no sucking of amps going on. My three charging sources - alternator, Sterlings and Trace - all output to a charging buss that can be connected to the LFP via the BMS or the FLA. This is done simply by using the existing rotary switches for each bank that most all boats have and that I installed initially.

My mistake
I thought the alt charged FLA start and DC to DC charge went from FLA start to Lifepo4

When underway, the alternator by itself can top up the LFP and once full, I connect the FLA to the charge buss and disconnect the LFP via the rotary switches and de-powering the BMS. The settings on the MC624 for LFP are just fine for the FLA since I never float the LFPs and can set it for what the FLA would prefer.

.
And underway is something I would like to get happening but using the 120amp charger that our victron multiplus has.
I have an additional 50 amp victron Phoenix charger sitting in a locker doing nothing I would like to bring into play as well

Back to looking at the Mecc Alte 10kva belt driven Genset head
That'll run both easily.

When at anchor we power the house off the LFP and the FLA sit disconnected from the charging buss. When the LFP need re-charging the genset is started which supplies ac to the Trace that puts out around 100 amps. Since the genset is running, I can engage the 3 Sterlings and add another 90 amps or so allowing us to replenish the LFP in around 90 minutes (daily consumption is around 300 amps.)

That extra oomph is nice when the Genset is running
Should look at doing same with the spare 50amp Phoenix we have

IMHO, the mistake people make is to try to install LFP and have it function just as if they were on LA. I manage mine as if they were a fuel tank. Use the fuel, then refill, and when full, stop filling. Not too tough.....

It's exactly how we treat ours but getting the bloody things back to full without running the Genset for several hours is the issue
Unseasonal rainy weather has not helped our 2.5kw solar installation.

 

[Kit_L]

@Simi,

I read today that the La Niña event that is making everything so wet on the east coast is due to end by end autumn. A technical question: do your lithiums suffer in any way when the ambient conditions do not allow full charging? On the present vessel with a small FLA system, I use the genset (loaded by water heater, battery charger, cooking, small hot air fan to reduce mould) for an hour, or perhaps 1.5 hours to charge in the evenings, and a small solar panel to do the last 10% or so in the daytime, assuming enough. But in the present situation where your big array is not putting out much power, is there any downside to not fully charging your batteries for a couple of months or so?

 

[Simi 60]

. But in the present situation where your big array is not putting out much power, is there any downside to not fully charging your batteries for a couple of months or so?

No downside at all.
They apparently prefer it if they are kept somewhere between 20% and 80%,

 

[SteveK]

My hunch is you'd admit your experience of getting 20+ years from an AGM bank is exceptional. Excerpt from Marine-How-To article I just posted in previous response. 1480 "Real World" examples (albeit FLA vs AGM, a relatively close cousin),

In a battery use survey conducted on sailboatowners.com, the largest ever of its kind with 1480 users surveyed, the vast majority of boat owners reported they rarely if ever get more than 150 cycles out of their lead acid batteries. 150 cycles!!!!! Many of these are batteries that have claims of 1000 to 1200 cycles or more. Laughable is about the best way to describe it.*

Peter

When I first saw 150 cycles I thought got to be wrong. Most have said their house batteries last an average of 6 years. 150/6=25 cycles per year.
My previous sailboat got 2-3 days with one cycle, so that translates to 50-75 days per year average on inverter. So yes the survey must be accurate.

So does anyone get anywhere near 1000 cycles. Or do the batteries die of old age first. Maybe they would provide 1000 cycles in the first year with heavy use.

 

[sunchaser]

SV
Your sailing experience with 2-3 days per cycle poses a question - what is a cycle and does it really matter?

If a cycle means discharge to 50% over 2-3 days repeatedly that seems an obvious LA battery killer. If it means draw down to 70 to 80% overnight and then recharge fully by shore power, generator, panels or alternator the next day then a cycle is different metric.

Then there is the vessel with generator auto start with batteries seldom falling below 80% posing another scenario. For most I know, cycles are never a topic. Whereas how to keep their house bank fully functional and at a high state of charge seems to dominate any discussion.

Li batteries, ACRs, chargers, inverters, monitoring systems etc get lots of attention. Excepting mention on TF, the number of cycles are but a fleeting topic for the cruisers and blue water crowd we gab with.

 

[SteveK]

a cycle is from fully charged to dead for a sail boater.

 

[mvweebles]

I have no idea what a cycle is or how to count it. I have a Renogy 50 amp DC-DC charger in my van that accepts dual input from engine alternator and MPPT solar (sort of a cool device, though the one from Redarc is a better choice). It seems to count a "cycle" as whenever the battery voltage has reduced - even a moderate amount - and then topped-off. I suppose that's the only way you can measure, but it's not very useful.

When read the MHT article and "cycles," I wondered the same thing, but when I read the entire article, I took it as more analogous than empirical so the context is fine. The author gives plenty of detail elsewhere

Peter

 

[Delfin]

@Simi,

I read today that the La Niña event that is making everything so wet on the east coast is due to end by end autumn. A technical question: do your lithiums suffer in any way when the ambient conditions do not allow full charging? On the present vessel with a small FLA system, I use the genset (loaded by water heater, battery charger, cooking, small hot air fan to reduce mould) for an hour, or perhaps 1.5 hours to charge in the evenings, and a small solar panel to do the last 10% or so in the daytime, assuming enough. But in the present situation where your big array is not putting out much power, is there any downside to not fully charging your batteries for a couple of months or so?

There's some evidence that LFP will develop memory and lose capacity if rarely fully charged, but my impression is that if fully charged and absorbed for 30 minutes that can be rectified. Other than that, no issues that I know of in partial charging.