PSOC definition

[john61ct]

Originally Posted by sailinglegend

From their instruction manual.

Maybe you need to start reading a bit more to get your facts right.

This is honestly funny.

Show me.

I know for a fact that Full River does not recommend equalizing, and this is reflected in their docs.

Same with the Rolls / Surette rebadged version.

As with any batt, for rebalancing purposes, or just to mix things up if you notice performance slagginf, you could bump up a bit to 14.8V or even 15V at lower currents.

But nothing like a real conditioning cycle.

Lifeline as I said are the only AGM that spec that.

As to the rest, you really should not be relying on Battery University 8-)

We are talking deep cycling batts here.

The three lead types are

FLA, which inherently means have caps get watered

And two VRLA, GEL and AGM.

The distinction between SLA and FLA is watering caps or not.

Any SLA that are not VRLA are not true deep cycling.

[john61ct]

Nobody should care about "total energy delivered over lifetime".

What is important is how many cycles do you get.

Mfg charts do not reflect real life performance at all.

[kmacdonald]

Originally Posted by john61ct

Nobody should care about "total energy delivered over lifetime".

What is important is how many cycles do you get.

Mfg charts do not reflect real life performance at all.

Well folks, there you have it. No need to say more.

[StuM]

Originally Posted by kmacdonald

Well folks, there you have it. No need to say more.

Yep, he's right.



Assuming you cycle daily as is common with solar plus morning top up by alternator/generator if required, Your daily usage can vary widely depending on whether you are at anchor, day sailing, passage making.


Especially with large banks that you keep at a reasonably high SOC most of the time, the manufacturers total Ah based on DOD x cycles is fairly meaningless. We don't buy batteries based on getting 400,000 Ah out of them, we buy them based on getting 2000+ cycles ( 6 years) .

[john61ct]

And say the user decides to go to a 2-3 day cycle with their lead bank for some reason.

DoD is greater.

Average time spent at low PSOC - failing to get back to Full - is greater.

Might be the same total AH in/out

but much faster wearing out of the bank, fewer cycles total lifetime,

"murdered earlier by the abuse" is the judgment al phrase. But only for those focused on Longevity as an important goal and value.

**for them**

Getting back to Full as quickly as possible is important.

Staying there as long as possible is the ideal.

Discharging not too deeply is important.

Total AH cycled through the bank is irrelevant, a red herring invented to justify

going deep DoD, buying smaller banks.

The irony is such a strategy needs no rationalizing. Just declare it as your preference and own the consequence

replacing more often.

Your boat your choice.

[john61ct]

And wrt to terminology, my use of PSOC above may seem to be "wrong" as per the earlier discussion.

But the fact it's used to highlight "the PSOC problem" context is what makes the usage correct IMO.

[Dockhead]

Originally Posted by john61ct

Average time spent at low PSOC - failing to get back to Full - is greater.

Might be the same total AH in/out

but much faster wearing out of the bank, fewer cycles total lifetime,

"murdered earlier by the abuse" is the judgment al phrase. But only for those focused on Longevity as an important goal and value.

**for them**

Getting back to Full as quickly as possible is important.

Staying there as long as possible is the ideal.

Discharging not too deeply is important.

Total AH cycled through the bank is irrelevant, a red herring invented to justify

going deep DoD, buying smaller banks.

The irony is such a strategy needs no rationalizing. Just declare it as your preference and own the consequence

replacing more often.

Your boat your choice.

I believe that this is true, but I think we have to admit that we never found any hard quantitative data to prove it, and we never figured out the science to more than an approximation.



I did hear enough circumstantial evidence to be convinced, personally, that the capacity of lead batteries below 50% DOD is not capacity which can be profitably used on a regular basis.

[kmacdonald]

Originally Posted by StuM

Yep, he's right.



Assuming you cycle daily as is common with solar plus morning top up by alternator/generator if required, Your daily usage can vary widely depending on whether you are at anchor, day sailing, passage making.


Especially with large banks that you keep at a reasonably high SOC most of the time, the manufacturers total Ah based on DOD x cycles is fairly meaningless. We don't buy batteries based on getting 400,000 Ah out of them, we buy them based on getting 2000+ cycles ( 6 years) .

Well great. Everyone should fill the bilge with a ton of batteries, cycle down to 95% SOC and grow old with their batteries.

Fact is, the purpose of batteries is to store energy and then deliver it when needed. If you are buying batteries with the sole objective of getting maximum cycles you don't understand energy management. Cycle life is only a part of the equation. I know, multi-variable functions are difficult for some, but it does take an understanding of them to be able to make an informed decision. It's just not a binary, cycles only, function.

[kmacdonald]

Originally Posted by john61ct

And say the user decides to go to a 2-3 day cycle with their lead bank for some reason.

DoD is greater.

Average time spent at low PSOC - failing to get back to Full - is greater.

Might be the same total AH in/out

but much faster wearing out of the bank, fewer cycles total lifetime,

"murdered earlier by the abuse" is the judgment al phrase. But only for those focused on Longevity as an important goal and value.

**for them**

Getting back to Full as quickly as possible is important.

Staying there as long as possible is the ideal.

Discharging not too deeply is important.

Total AH cycled through the bank is irrelevant, a red herring invented to justify

going deep DoD, buying smaller banks.

The irony is such a strategy needs no rationalizing. Just declare it as your preference and own the consequence

replacing more often.

Your boat your choice.

Funny and total lack of understanding of the topic. It's been pointed out by numerous readers. By the way, I didn't "invent" lifetime energy capacity.

I certainly agree that most cruisers are interested in maximum cycles, which is easy to achieve even by fly-by-night service providers. Just oversize the heck out of the bank. Of course that doesn't use the full capacity of the batteries, adds unnecessary weight, takes up space, is hard to fully recharge, etc. Simple solutions for simple minds I suppose.

[StuM]

Originally Posted by kmacdonald

Well great. Everyone should fill the bilge with a ton of batteries, cycle down to 95% SOC and grow old with their batteries.

Depends where you are. Fine if you are in the US and can get relatively cheap batteries on demand. In many parts of the world, it's best to go through the major hassle of sourcing and replacing batteries as infrequently as possible

[StuM]

Originally Posted by kmacdonald

Just oversize the heck out of the bank. Of course that doesn't use the full capacity of the batteries, adds unnecessary weight, takes up space, is hard to fully recharge, etc.

The last 400Ah of my 1000Ah bank only adds about 120kg, the space it takes up is irrelevant since it would be unused otherwise, I have no problem fully recharging most days, it provides a good reserve when required and probably doubles the number of lifetime cycles.


Of course my use case is a lot different to yours.

[kmacdonald]

Originally Posted by StuM

Depends where you are. Fine if you are in the US and can get relatively cheap batteries on demand. In many parts of the world, it's best to go through the major hassle of sourcing and replacing batteries as infrequently as possible

I agree. That should be one of the variables to consider. People even replace good batteries before a long cruise because they know batteries won't be readily available where they are going or will be crazy expensive.

[kmacdonald]

Originally Posted by StuM

The last 400Ah of my 1000Ah bank only adds about 120kg, the space it takes up is irrelevant since it would be unused otherwise, I have no problem fully recharging most days, it provides a good reserve when required and probably doubles the number of lifetime cycles.


Of course my use case is a lot different to yours.

Yes. Everyone will have a different use profile, priorities, etc and therefore different solutions.

[hzcruiser]

Originally Posted by tanglewood

Maybe it's just me, but I don't really agree with your definitions. PSOC is just an SOC less than 100%. That's it. In particular, it does not mean that the battery ALWAYS operates at a SOC less than 100%, and you seem to be saying it does in both your examples.

+1 on that one. No need to overomplicate things nor try to define some term where you'll never know if the one using the acronym is aware of this definition _and_ uses it correctly.

[Delfin]

Originally Posted by john61ct

This is honestly funny.

Show me.

I know for a fact that Full River does not recommend equalizing, and this is reflected in their docs.

Well, not exactly. What they say is this:

"If Fullriver batteries are properly charged they should never require an equalizing charge. "

Saying that if you charge a battery a certain way means you shouldn't have to equalize is hardly the same as "not recommending" equalization, as you suggest. And what they recommend for charging is that you keep pumping current to their batteries until the acceptance rate drops to 2% of capacity, which they opine shouldn't take more than 8 hours.

John, when you make declarative statements if would be helpful if they were grounded in fact. Just a suggestion.

http://resources.fullriverbattery.co.../batteries.pdf