Wiring In Series (pro vs con)

[TeddyDiver]

Originally Posted by ranger42c

Haven't been able to find info about predicted cycles on all of them, and truthfully haven't spent much time shopping on these since horizontal dimensions are problematic for my installation...

But without cycle info, the relationship seems backwards to me: a fair amount more capacity (29%) weighs (slightly) less in these examples. All three marketed as "deep cycle" but I didn't see specific info about plate thickness for each.

The 29% claim seems a bit adventurous, anyway. (ur current G31s are rated at 100 Ah and weigh 78-lbs each, compared to these G27s at 60, 61, and 62-lbs respectively.

I realize overall weight isn't a very perfect predictor, though...

-Chris

The capasity correlates better with plate area and the volume of electrolyte, not plate thickness. There's physical limits how thin a plate can be and how much of the thickness is usable during a cycle.

BR Teddy

[john61ct]

And avoid any batteries where the actual manufacturer won't supply detailed tech specs & charts on life cycling vs DoD.

These can't be used to compare with batteries from other vendors though.

[tuberider]

when wiring series and parallel you should do Ah's first then series. So if you have 9- 4v batteries and you want 12v you parallel three sets of 3 batteries and then series them. this way you're only have three banks in series. I deal a lot in 3.2v batteries and the rule of thumb is for 12v you series only 4 times and for 24v you series 8 times. in my case I have 16 3.2v batteries that are 40 Ah's apiece and I want 80 Ah's at 24v. I parallel 8 sets of two batteries and then put them in series. that's the way the battery manufacture says it has to be done.

[ramblinrod]

Originally Posted by ranger42c

Yeah, but they start getting longer, too. The Trojan 27MTH and the SCS200 say 115 Ah (20 hr rate), but they're also each 3/4" longer and minor as that seems, that makes them essentially the same size as our current G31s and it means I could only stuff three of them in there. And as I said, four of the slightly smaller 27 AGMs -- still more like a 20% difference in capacity -- may only barely fit, given each is only an inch less long than the current 3x G31s I've got in there now.

Seems odd to me that Trojan's various "deep cycle" (their label) G27s can vary so widely in capacity. 115 Ah vs 89 Ah? (When many manufacturers rate their normal G31s at either 100 or 105 Ah, or 111 in Trojan's 31 AGM instance).

Seems odd to me the flooded 27MTH @ 115 Ah weighs 1-lb less, and the SCS200 weighs 2-lbs less, than the 27 AGM @ 89 Ah. Same as it seems odd to me a G27 can offer more capacity than slightly larger G31s.

Flooded batteries would be a pain in the neck to service, in our installation. I can't really get to the outboard batteries easily enough, and one of the batteries is obstructed overhead. While a watering system might be feasible (or not; not sure I'd have overhead clearance over that one battery), pretty much eliminating battery service altogether with AGMs means I can divert my labor hours to other stuff.

I suspect you're willing to start with "I'll wire 12V batteries in parallel, now how much capacity can I get." I've started with "How much capacity can I stuff in there, and how must I wire it to get there from here."

-Chris

I'm not sure, but it seems like you are mixing a lot of variables in your comparisons to best suit your arguments or your information sources are incorrect.

For Trojan 12 Vdc Marine / RV Standard FLAs Deep Cyclces

http://www.trojanbattery.com/pdf/ProdSpecGuide.pdf

Grp 24, 12 Vdc, 100 A-hr @ 20 hrs, 11.3"L x 6.7"W x 9.8" H, 50 lbs
Grp 27, 12 Vdc, 115 A-hr @ 20 hrs, 12.8"L x 6.7"W x 9.8" H, 60 lbs
Grp 30H, 12 Vdc, 130 A-hrs @ 20 hrs, 13.9"L x 6.8"W x 10" H, 66 lbs

As compared to East Penn Deka Marine/ RV FLA Deep Cycles

http://www.eastpennmanufacturing.com...Sheet-0194.pdf

DC24, 12 Vdc, 75 A-hr @ 20 hrs, 10.8"L x 6.8"W x 9.4" H, 46 lbs
DC27, 12 Vdc, 90 A-hr @ 20 hrs, 12.5"L x 6.8"W x 9.4" H, 54 lbs
DC31, 12 Vdc, 105 A-hr @ 20 hrs, 13"L x 6.8"W x 9.5" H, 60 lbs

Clearly, Trojans have slightly larger physical dimensions, weight, and significantly higher A-hr ratings than Dekas, (which if I recall previous research correctly, has fairly recently reduced the A-hr rating of their DC batteries, which I recall as 85, 100, 115 A-hrs, so I'm not sure what is going on there.)

Rod (Mainsail) recently advised that some FLAs he was testing could not meet their specs; maybe related, perhaps he was using old spec sheets, or East Penn hadn't published revised specs yet.

[ramblinrod]

Originally Posted by ranger42c

Yes, lab cycles are different than real world cycles, but given lack of better data for comparison... it's better than nothing.

-Chris

Perhaps, perhaps not.

It is possible that there is absolutely no logical correlation between lab cycles and real world application cycles. Then the comparison is worth less than nothing; it's actually counter to good decision making.

We have absolutely no verifiable evidence this correlation exists, other than via dock speak, which according to the Mainsail article being commonly referenced, CANNOT BE TRUSTED.

Regarding manufacturer lab cycle testing, I suspect there may be all kinds of issues with the testing protocol within a manufacturer and compared to other manufacturers. (Which is something I reviewed in a former life, to ensure proper product validation before release to production.)

One issue I have related to this thread, is the use of battery test water bath.

My suspicion, and I would need testing and proof otherwise to condone it, is that this may alter battery performance from real world conditions, and may artificially favour batteries which are poorer at dissipating heat through natural convection in air. (Such as taller batteries of equal or smaller comparative footprint, or those having differing bulk density, or those having greater casing thermal insulating properties.)

I am very skeptical (and for very good reason based on many examples throughout my career) of any declaration or data that is not supported by properly documented and repeatable scientific analysis and methodology detailing how conclusions were drawn.

It is very important that one apply "critical thinking" to any improperly supported correlation, especially including anything posted on the internet.

Do lab cycles correlate across manufacturers?

We are pretty sure this is false, and until proven true, I assume false.

Do lab cycles correlate in any way, shape, or form to real world cycles?

We have absolutely no reliable, verifiable evidence to support that this is true, and until proven true, I assume false.

It is reasonable to conclude that lab cycles data within a manufacturer are reasonably accurately reported and correlate directly to what occurred in the lab under the test conditions.

Even at that, we saw a fine example recently in a certain car manufacturer, who purposely deceived the public and government agencies, by modifying performance under test conditions, compared to real world operation.

Lab cycles may or may not have anything to do with how the battery performs, in air, on a boat, with variable discharge depth, rate, duration, temperature, charging algorithm regime, etc.

[ramblinrod]

Originally Posted by ranger42c

Yes, lab cycles are different than real world cycles, but given lack of better data for comparison... it's better than nothing.

-Chris

Perhaps, perhaps not.

It is possible that there is absolutely no logical correlation between lab cycles and real world application cycles. Then the comparison is worth less than nothing; it's actually counter to good decision making.

We have absolutely no verifiable evidence this correlation exists, other than via dock speak, which according to the Mainsail article being commonly referenced, CANNOT BE TRUSTED.

Regarding manufacturer lab cycle testing, I suspect there may be all kinds of issues with the testing protocol within a manufacturer and compared to other manufacturers. (Which is something I reviewed in a former life, to ensure proper product validation before release to production.)

One issue I have related to this thread, is the use of battery test water bath.

My suspicion, and I would need testing and proof otherwise to condone it, is that this may alter battery performance from real world conditions, and may artificially favour batteries which are poorer at dissipating heat through natural convection in air. (Such as taller batteries of equal or smaller comparative footprint, or those having differing bulk density, or those having greater casing thermal insulating properties.)

I am very skeptical (and for very good reason based on many examples throughout my career) of any declaration or data that is not supported by properly documented and repeatable scientific analysis and methodology detailing how conclusions were drawn.

It is very important that one apply "critical thinking" to any improperly supported correlation, especially including anything posted on the internet.

Do lab cycles correlate across manufacturers?

We are pretty sure this is false, and until proven true, I assume false.

Do lab cycles correlate in any way, shape, or form to real world cycles?

We have absolutely no reliable, verifiable evidence to support that this is true, and until proven true, I assume false.

It is reasonable to conclude that lab cycles data within a manufacturer are reasonably accurately reported and correlate directly to what occurred in the lab under the test conditions.

Even at that, we saw a fine example recently in a certain car manufacturer, who purposely deceived the public and government agencies, by modifying performance under test conditions, compared to real world operation.

Lab cycles may or may not have anything to do with how the battery performs, in air, on a boat, with variable discharge depth, rate, duration, temperature, charging algorithm regime, etc.

[ramblinrod]

Originally Posted by ramblinrod

Clearly, Trojans have slightly larger physical dimensions, weight, and significantly higher A-hr ratings than Dekas, (which if I recall previous research correctly, has fairly recently reduced the A-hr rating of their DC batteries, which I recall as 85, 100, 115 A-hrs, so I'm not sure what is going on there.)

Upon review of a previously downloaded Deka spec sheet, the specs for their Marine DC models have not changed since Feb. 2, 2015.

[ramblinrod]

Another element related to this thread, also according the MainSail article commonly referenced throughout this and other threads, it declares that manufacturer published specs cannot be absolutely trusted, and in some case may be calculated from other data which may not be a direct correlation.

I also have much experience with product data that is assumed correct by engineers based on theory, but which there has been no practical testing by technicians to verify, and when that testing was finally performed, proved the published specifications as supplied by engineering to be completely FALSE.

This is often the cause of product recalls, when actual "real world" product testing is performed by unsuspecting customers, and it is proven that the facts provided by the engineering department was pure caca. Example: Samsung 7 and there are an incredible number more that nobody ever hears about.

[TeddyDiver]

Originally Posted by ramblinrod

My suspicion, and I would need testing and proof otherwise to condone it, is that this may alter battery performance from real world conditions, and may artificially favour batteries which are poorer at dissipating heat through natural convection in air. (Such as taller batteries of equal or smaller comparative footprint, or those having differing bulk density, or those having greater casing thermal insulating properties.).

Please explain, That statement is totally false unless batteries are installed too tight preventing air circulation between batteries. Every manufacturer have the minimum distances in their installation manuals..

BR Teddy

[ramblinrod]

Originally Posted by TeddyDiver

Please explain, That statement is totally false unless batteries are installed too tight preventing air circulation between batteries. Every manufacturer have the minimum distances in their installation manuals..

BR Teddy

The statement that my suspicion that a water bath may alter test results from a real world application in air, is absolutely true.

That the manufacturer may specify an air space (I'm pretty sure not all do) is irrelevant to my point, other than to suggest that anything (such as a water batch) that alters normal heat dissipation, likely skews results.

[TeddyDiver]

Originally Posted by ramblinrod

The statement that my suspicion that a water bath may alter test results from a real world application in air, is absolutely true.

Yes, but to get any kind of comparable data the environment has to be standardized, thus water bath..

That the manufacturer may specify an air space (I'm pretty sure not all do) is irrelevant to my point, other than to suggest that anything (such as a water batch) that alters normal heat dissipation, likely skews results.

Irrelevant? can that be understood that you doesn't care if there's an air cap between batteries or not in your installation? That I think is quite obvios as you recommended in earlier post to use batteries which are pretty tight fit..

And a bit not so of topic reading about facts
Why Facts Don’t Change Our Minds - The New Yorker

BR Teddy

[ranger58sb]

Originally Posted by ramblinrod

I'm not sure, but it seems like you are mixing a lot of variables in your comparisons to best suit your arguments or your information sources are incorrect.

For Trojan 12 Vdc Marine / RV Standard FLAs Deep Cyclces

http://www.trojanbattery.com/pdf/ProdSpecGuide.pdf

Grp 24, 12 Vdc, 100 A-hr @ 20 hrs, 11.3"L x 6.7"W x 9.8" H, 50 lbs
Grp 27, 12 Vdc, 115 A-hr @ 20 hrs, 12.8"L x 6.7"W x 9.8" H, 60 lbs
Grp 30H, 12 Vdc, 130 A-hrs @ 20 hrs, 13.9"L x 6.8"W x 10" H, 66 lbs

Well, I don't really have an "argument" for/against any of this. As I said earlier, G27s won't fit where I need them to be, so I didn't spend lots of time shopping all the various brands of G27s. And otherwise, putting the most AGM capacity in the space I have solves my requirements -- even though series and parallel wiring both seem to have pros and cons.

Note on that same ref you posted -- 27 AGM (down toward the bottom, 89 Ah. I was only surprised that it weighs more than their 115-Ah G27s... but it was merely surprise, since I don't really care one way or the other. IOW, I don't have much of a dawg in the discussion.

Note also on that same ref that Trojan G27s are not all the same dimensions. Would have thought BCI Group "standardization" meant something, but apparently there's some slop in there. Again, merely surprise, neither for nor against...

-Chris

[ranger58sb]

Originally Posted by ramblinrod

Perhaps, perhaps not.

It is possible that there is absolutely no logical correlation between lab cycles and real world application cycles. Then the comparison is worth less than nothing; it's actually counter to good decision making.

Et cetera...

My point was simply that we often have nothing better to use for comparison.

I can do "critical thinking" 'til the cows come home, but when we only have one predictive for comparison, and it's known to be shakey, all the comparison in the free world is maybe a crap shoot.

Unless you know of some other predictive factoid about all batteries that is published somewhere by a reputable authority so I could look it up -- for nearly every battery I might consider at any given time?

-Chris

[ramblinrod]

Please do not put other statements within quotes by others.

RR: The statement that my suspicion that a water bath may alter test results from a real world application in air, is absolutely true.

Originally Posted by TeddyDiver

Yes, but to get any kind of comparable data the environment has to be standardized, thus water bath..

So standardize the test conditions on air, with relative air gap and relative air circulation LIKE A REAL WORLD APPLICATION.

RR: That the manufacturer may specify an air space (I'm pretty sure not all do) is irrelevant to my point, other than to suggest that anything (such as a water batch) that alters normal heat dissipation, likely skews results.

Originally Posted by TeddyDiver

Irrelevant? can that be understood that you doesn't care if there's an air cap between batteries or not in your installation? That I think is quite obvios as you recommended in earlier post to use batteries which are pretty tight fit....

Well I cannot help it if that is your comprehension of my post, but no that should not be understood as your statement.

Exactly as I said, that the manufacturer may specify an air gap for real world installation, is irrelevant to my statement (or perhaps even supports it) that testing to simulate real world conditions via methods that will not artificially skew results from those conditions should NOT INCLUDE A WATER BATH.

I dont know about how you install batteries on your boat, but on my boat, and all of my customers boats, I install batteries in proper boxes, surrounded by air. I have never seen batteries installed in a water well on a boat.

The ventilation within those purpose made boxes sucks, and the ventilation within the battery box compartment may also be poor.

So any lab test that immerses batteries in water most likely affects the batteries ability to dissipate heat, and I suspect favours those batteries with smaller footprints and greater height, greater bulk density, and having cases of greater thermal insulating properties.

I used to review engineering department produced test protocols and had to often object and have them revised due to the flaws or intended elements that would skew results in favour of releasing a product that may not meet performance specs in real world applications.

Yes, that can be the difference between an engineer and a technician.

I then performed the tests and reported all the flaws in the engineering design.

[TeddyDiver]

Originally Posted by ramblinrod

Exactly as I said, that the manufacturer may specify an air gap for real world installation, is irrelevant to my statement (or perhaps even supports it) that testing to simulate real world conditions via methods that will not artificially skew results from those conditions should NOT INCLUDE A WATER BATH.

I dont know about how you install batteries on your boat, but on my boat, and all of my customers boats, I install batteries in proper boxes, surrounded by air. I have never seen batteries installed in a water well on a boat.

The ventilation within those purpose made boxes sucks, and the ventilation within the battery box compartment may also be poor.

So you instal a temperature sensor then?
Have to admit, installing batteries in a cramped damp hot inaccessible box being cheap is the winner. But as said before this site is cruiser forum, not lay by the pier the whole year and get a couple of hours motoring out once forum..