LA Battery Report

[sailorboy1]

Originally Posted by mat jam

The point sailorboy is this is a forum for sharing ideas.

BTW - I think you are arguing with the wrong person and maybe you should go back and read the thread and find out who you should be focusing on with the posting you have aimed at me. I will accept a "thanks" privately when you realize

[RaymondR]

Originally Posted by sailorboy1

If I get 5 years out of my current house battery bank the batteries will have cost me $110/year. That's only $9.16/month!

That may be so and it would be nice to be able to put ones hand in ones pocket every month and pay the $9.16, but.

We don't do it that way, we replace at least a bank at a time and this is generally a big enough wallet assault to cause pain.

[noelex 77]

Originally Posted by john61ct

which is required at least a couple times per week in order to get optimum longevity

has been outlined in hundreds of threads, as well as on the sites we often reference here. If you want to have it explained yet again let us know.

His is often repeated, but is unrealistic.

We could also say keep a LA battery at a near constant 100% SOC for maximum battery life, or keep a Lithium bank at perhaps a constant 60% SOC for maximum battery life. This is true, but not practical. Batteries are no use unless we use some of their capacity. The real question is how much reduction in life results when we deviate from these ideals.

AGM batteries are more sensitive in this regard, but most lead acid batteries do fine with nothing remotely close to reaching 100% SOC a couple of times a week.

In the days before solar panels were available the battery bank of long distance cruising sailors would only very rarely achieve 100% SOC. Cycles from around 50% to 80% were the usual practice. Battery banks often lived nearly all their life within these parameters.

These days solar makes achieving 100% SOC a regular and practical event. This is good for LA battery life, but it has not resulted in dramatic lifespan increase, suggesting while helpful the need to acieve 100% is not of major importance, at least not with anything like the frequency of a couple of times a week.

[john61ct]

Yes I agree, the need being critical for AGM longevity is yet another reason among many for sticking to quality FLA if reasonably priced in your market.

But since as you say it has become increasingly easy to actually get to true 100% Full, then why not strive for optimum as a goal?

Those reporting 14-16 years before swapping out are likely doing at least close to that.

Obviously for those (fewer and fewer as time goes by) who just can't do it that often, well them so be it.

Similar with the "simplification guideline" of try to stay above 50% DoD.

You do what you can, to the degree longevity is important to you - I'm not saying go beyond what you're inclined to do, but make it an informed choice,

most owners aren't even aware of the issue.

[sailorboy1]

Originally Posted by RaymondR

That may be so and it would be nice to be able to put ones hand in ones pocket every month and pay the $9.16, but.

We don't do it that way, we replace at least a bank at a time and this is generally a big enough wallet assault to cause pain.

I understand and I didn't like it last time I replaced my batteries (that probably still had a year plus of life). But the fact remains we are talking the cost of a 6-pack of good beer a month! That's nothing in the costs of boat ownership and operation.

I have no problem with people spending extra money on batteries for other reasons. I recently spend about $900 to upgrade my solar from 290w to 640w just so I didn't need to run the generator to supplement battery charging. This made no real sense at all as I had already calculated that the cost would would have paid for 900 days of fuel to run the generator. But I decided it was worth it to me not to have to listen to the generator run.



BTW - I only really needed to run the generator every 3 days or so to get fully charged and that's with never getting the batteries below 70% SOC. So those 900 days equals 2700 boat days that also didn't involve motoring etc for some other reason.

[sailorboy1]

Getting batteries to their optimum goal is only of concern to those interested in saying they do so. I'm much more interested in getting the best financial cost, and life effort, out of my batteries life span. That may be shorter life of the batteries, but reduced costs and hassles to maintain them. The battery replacement cost may accurately be less expensive than chasing optimum charging and SOC numbers given the costs and effort required.

[sailinglegend]

Originally Posted by noelex 77

....We could also say keep a LA battery at a near constant 100% SOC for maximum battery life,.... Batteries are no use unless we use some of their capacity....

A very astute comment.

Originally Posted by noelex 77

....The real question is how much reduction in life results when we deviate from these ideals.

This has been well documented in lots of articles and graphs - the bottom line is the less you discharge, and the more regularly you recharge to a true 100%, the longer they last. But all boats are different!

Lifeline graphs show 10% discharge gives 5000 cycles, 50% discharge gives 1000 cycles.

Sandia article "PV Hybrid Battery Tests on L-16 Batteries" said recharge once a week - but it also said all batteries are different.

So all generalisations can just complicate things.

In my case my large bank - 1050 Ah Lifeline AGMs - lasted 14 years. They cost me £1725 so that makes their monthly costs £10.26. At todays money that is about $13/month - only a tiny bit more than Sailorboy1's - and yet I have had the many large benefits of having AGMs, but that's another very long thread somewhere.

[daletournier]

Originally Posted by sailinglegend

A very astute comment.



This has been well documented in lots of articles and graphs - the bottom line is the less you discharge, and the more regularly you recharge to a true 100%, the longer they last. But all boats are different!

Lifeline graphs show 10% discharge gives 5000 cycles, 50% discharge gives 1000 cycles.

Sandia article "PV Hybrid Battery Tests on L-16 Batteries" said recharge once a week - but it also said all batteries are different.

So all generalisations can just complicate things.

In my case my large bank - 1050 Ah Lifeline AGMs - lasted 14 years. They cost me £1725 so that makes their monthly costs £10.26. At todays money that is about $13/month - only a tiny bit more than Sailorboy1's - and yet I have had the many large benefits of having AGMs, but that's another very long thread somewhere.

It also depends on how you cruise. You got an incredible run out of your batteries but if i remember rightly (and I may not) you go to a marina regularly and plug in? this is being very nice to your batteties, but marinas cost money.

Many live on the hook very rarely plugging in, some do ocean passages, ocean passages can be brutal on batteries.

As Sailorboy says financially for some it makes alot more sense to treat batteries as a consumable.

I to are trained to keep my batteries up,Ill be starting the generator shortly BUT the truth is im partcipating in false economics, and I know it.

[john61ct]

Originally Posted by sailinglegend

In my case my large bank - 1050 Ah Lifeline AGMs - lasted 14 years.

Amazing. Did you know their final SoH, residual capacity at EoL?

To what do you attribute that lifespan, besides Lifeline's stellar build quality?

[sailinglegend]

Originally Posted by daletournier

It also depends on how you cruise....

I've already said that in a different way in my post - "But all boats are different!!!!!"

Originally Posted by daletournier

You got an incredible run out of your batteries but if i remember rightly (and I may not) you go to a marina regularly and plug in?...

I used to charge to 100% every two weeks on a quay - much cheaper in the Med than a marina. Then Equalised twice a year.

Originally Posted by daletournier

....Many live on the hook very rarely plugging in, some do ocean passages, ocean passages can be brutal on batteries...

We live on the hook and very rarely plugg in. Now with extra solar - up to 450 watts - we haven't needed to go on shore power this year. We can get fully charged every day with only 10% lost capacity overnight. More than that we might run the Gensets once every two weeks. We have also reduced our bank to 630 Ah of Lifelines - I'm not sailing for another 14 years!

Originally Posted by daletournier

....As Sailorboy says financially for some it makes alot more sense to treat batteries as a consumable....

That is exactly how I treat them now - with the extra solar. They sit there doing their own thing until I need to give them a boost.

I spend a lot more time and energy worrying about the charge in my two computers two iPhones iPad and Kindle - but i don't post about that!

[sailinglegend]

Originally Posted by john61ct

Amazing. Did you know their final SoH, residual capacity at EoL?

To what do you attribute that lifespan, besides Lifeline's stellar build quality?

There were each down to about 52% SoH - using a 20 hour test at rated current which of course only took about 10 hours.

This is another amazing feature of Lifeline AGMs as they recommend you don't need to change them until their SoH is down to 50%. Most other batteries recommend change at an SoH of 80% - after that they may suddenly fail.

Their longevity was due to a very low discharge over night - hardly any extended passages or night sailing - living aboard the boat for 8 months of the year - being very careful charging the batteries over winter with the solar charge voltage reduce to 14v for 30 minutes every day, not letting them gas at 14.4v for three hours every day!..... etc., etc.....

....And equalising when I felt they really needed it - and that did allow extra time at anchor before the voltage went too low.

I thought in 2012 they were beginning to show signs of lost capacity but they lasted another 7 years. After all they are just consumables that will eventually fail - but unlike a torch battery it is very inconvenient to replace 5 batteries weighing 65 kilos every 3-4 years, especially if you are on a small island in Greece, or on an extended passage for a month with no sight of land. That's when you need batteries you can trust and eventually realise that this is the end of the season that they must be changed.

KNOW YOUR BOAT

As I said in my post generalisations are confusing as every boat is different and every boat cruises differently. But I did think this was a Cruisers forum, not a Weekend Sailors forum.

[john61ct]

Originally Posted by sailinglegend

This is another amazing feature of Lifeline AGMs as they recommend you don't need to change them until their SoH is down to 50%.

Again wow, something new every day. Shows a lot of self-confidence in their build quality especially in the litigation-crazy US market.

> longevity was due to a very low discharge over night

yes that 20% DoD, much lower average I guess does extend cycles by many times.

Some might not want the extra weight, but certainly works out economically, not to mention saving lots of replacement hassles.

[gauvins]

Interesting facts.

I was wondering if we can get an idea of FLA's health by looking at voltage.

Our use case is 2+months per year at anchor, with a couple of weeks of passage, then on the hard until the following summer.
We have a 210W solar array and Victron charger + monitor.

We've significantly improved refrigeration such that now we consume less than 5Ah overnight, on a bank of close to 700Ah. So, for all practical matters, our batteries are always fully charged, but for a few days (maximum discharge has been less than 10% of nominal capacity).

I would have 2 other questions :

1. Our batteries are inexpensive sealed varta LFD - I've never equalized and tend to believe that the risks outweigh meaningful gains. Right?

2. Two years ago we had a humongous and inefficient fridge that would consume more than 70+Ah/day. Hence a sizeable battery bank. Now I feel that we have a ridiculously oversized bank. There might be a very long passage in rough seas under cloudy conditions where we'll use more power, but I doubt it. What's the current wisdom wrt capacity?

[john61ct]

Originally Posted by gauvins

I was wondering if we can get an idea of FLA's health by looking at voltage.
…
1. Our batteries are inexpensive sealed varta LFD - I've never equalized and tend to believe that the risks outweigh meaningful gains. Right?

2. Two years ago we had a humongous and inefficient fridge that would consume more than 70+Ah/day. Hence a sizeable battery bank. Now I feel that we have a ridiculously oversized bank. There might be a very long passage in rough seas under cloudy conditions where we'll use more power, but I doubt it. What's the current wisdom wrt capacity?

More is better, shallower cycling means less frequent replacement.

Unless weight is an issue. IMO ideal is

rarely go below 50%
AND
never have to stop using anything important because you ran out

Depends how consistent usage is, and the availability of power on demand, both allow for a smaller buffer.

True SoH is residual capacity, needs a constant current load test to determine precisely.

Unless SG-200 works well with your bank.

Bank maker tells you to equalize or not.
Quality sealed, usually not.

[Kenomac]

Originally Posted by RaymondR

That may be so and it would be nice to be able to put ones hand in ones pocket every month and pay the $9.16, but.

We don't do it that way, we replace at least a bank at a time and this is generally a big enough wallet assault to cause pain.

Your point is another fallacy that’s often repeated. Our 450ah 24v bank is now 8 years old and has endured much abuse. I was having problems with it two weeks ago regarding voltage which would have had most on this forum replace the entire bank. With some quick easy testing on my part, I determined that only one Trojan T105 six volt was bad. I replaced the single battery and now all is fine.