Wiring In Series (pro vs con)

[ramblinrod]

Originally Posted by ranger42c

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

Well, I do not use data that I know to be faulty and cannot verify has any relevance whatsoever, to base decisions on.

So what I have used, is personal experience.

To date my experience has been that when comparing similar levels of quality, golf car batteries and GRP 27s, seem to last about equal, in a real boat house bank application, EVERYTHING ELSE BEING EQUAL (similar capacity, DOD, PSOC duration, charging algorithm, and maintenance).

Due to the requirement to use even numbers of batteries in a 12 Vdc bank, when perhaps an odd number fits without or with minimum mods, and the drastic loss of capacity if one cell shorts, I shy away from 6 Vdc golf car batteries in favour of 12 Vdc DC batteries.

[ramblinrod]

Originally Posted by ranger42c

Just double-checked my memory about installation in the available space. The Trojan G27 AGMs (for example) are actually almost close to fitting. Tray or box would have to have near-zero clearance, and even then... not sure.

But I also see they're rated as 89Ah each (20-hr rate) so 4x would only give a total of 356 Ah. Not really competitive with 440... I think that's why I eliminated those early on... but yes, would have been appropriate for me to cite G27s as a possibility in my earlier post.

-Chris

What battery model are you using, that gives you 220 A-hr a 20 hrs in a 6 Vdc AGM (question mark).

[ranger58sb]

Originally Posted by ramblinrod

What battery model are you using, that gives you 220 A-hr a 20 hrs in a 6 Vdc AGM (question mark).

Intending to use Lifeline GPL-4CTs.

-Chris

[ramblinrod]

Originally Posted by ranger42c

Intending to use Lifeline GPL-4CTs.

-Chris

Intending... (question mark).

What do you have now (question mark).

[B.Babs]

our life experience for cruise 12v 27 groupe trojan batterie is poor. in the 1994 I was afforded to sabbatical over 5 years. we lived eight month per annum on cruise. cruise location specific to newfoundland nova scotia labrador and include north east usa.

first cruise year start with new 27 groupe hotel batterie with sum of 460 ampere hour. by the six month time the 27 groupe trojan hotel batteries are not hold a charge even if with long motor running. turn down motor and volts drop down lower than 11.5v. the cape dory had ample system generator with smart regulation a smart system of the time. when hotel battery demise we replace it with same 27 groupe trojan. next hotel system deliver 8 month prior to voltage collapse.

second 27 groupe demise happens at plancentia bay newfoundland kings island. took us a bit of a week to flag ride to st. john. st. johns battery vendor sells to us 225 ampere hour 6v batterie for hotel load and made cable for us and hook up illustration. it took 11 days to begin the cruise again. 11 day of running crank batterie it was not best so we purchase new crank batterie at same time. the st john 6v hotel batterie set still was working when we sell the boat four and one half years after hotel in service time. the 27 groupe lasted not longer then eight month of cruise duty. 6v hotel it last 3 more years of the cruise and one more year weekends useage. 6v hotel still was working when we sold the boat. we did not make changes to system rather then 6v hotel batterie.

[ramblinrod]

Originally Posted by B.Babs

our life experience for cruise 12v 27 groupe trojan batterie is poor. in the 1994 I was afforded to sabbatical over 5 years. we lived eight month per annum on cruise. cruise location specific to newfoundland nova scotia labrador and include north east usa.

first cruise year start with new 27 groupe hotel batterie with sum of 460 ampere hour. by the six month time the 27 groupe trojan hotel batteries are not hold a charge even if with long motor running. turn down motor and volts drop down lower than 11.5v. the cape dory had ample system generator with smart regulation a smart system of the time. when hotel battery demise we replace it with same 27 groupe trojan. next hotel system deliver 8 month prior to voltage collapse.

second 27 groupe demise happens at plancentia bay newfoundland kings island. took us a bit of a week to flag ride to st. john. st. johns battery vendor sells to us 225 ampere hour 6v batterie for hotel load and made cable for us and hook up illustration. it took 11 days to begin the cruise again. 11 day of running crank batterie it was not best so we purchase new crank batterie at same time. the st john 6v hotel batterie set still was working when we sell the boat four and one half years after hotel in service time. the 27 groupe lasted not longer then eight month of cruise duty. 6v hotel it last 3 more years of the cruise and one more year weekends useage. 6v hotel still was working when we sold the boat. we did not make changes to system rather then 6v hotel batterie.

Excellent. Thank you for contributing some real world experience with details.

Only 8 months service using Trojan Grp 27s that are well cared for is very contrary to my experience. I was not there to investigate at the time but here are some thoughts as to why your experience with them was so poor and radically different from 6 volts of approx. same capacity.

1. Wiring issue that was corrected (perhaps unbeknownst) when wiring was changed to suit 6 Vdc batteries.

2. Grp 27s defective from get go.

3. Grp 27s old manufacture date.

4. Battery maintenance improved when 6Vdc installed.

5. Battery charging practices improved when 6 Vdc installed.

[ranger58sb]

Originally Posted by ramblinrod

Intending... (question mark).

What do you have now (question mark).

3x Odyssey PC-2150 12V AGM. Installed April 2006.

I'm very satisfied with their performance and longevity, but need more capacity... and can't fit 4x G31s in the available space.

Changeover should happen sometime after May 15th, since we're semi-busy in a fishing season until then.

-Chris

[GrowleyMonster]

Originally Posted by ramblinrod

Excellent. Thank you for contributing some real world experience with details.

Only 8 months service using Trojan Grp 27s that are well cared for is very contrary to my experience. I was not there to investigate at the time but here are some thoughts as to why your experience with them was so poor and radically different from 6 volts of approx. same capacity.

1. Wiring issue that was corrected (perhaps unbeknownst) when wiring was changed to suit 6 Vdc batteries.

2. Grp 27s defective from get go.

3. Grp 27s old manufacture date.

4. Battery maintenance improved when 6Vdc installed.

5. Battery charging practices improved when 6 Vdc installed.

I was thinking along similar lines. Trojans with decent care, whatever the voltage or case size, should last a lot longer than that. I wonder if maybe they were put in a sailboat, and installed with the ends fore and aft. Different form factor, different orientation, maybe, and then the 6v were oriented correctly? Flooded batteries don't last long when the top corners of the plates come out of the electrolyte every time the boat heels over. Just sayin.

[ramblinrod]

Originally Posted by GrowleyMonster

I was thinking along similar lines. Trojans with decent care, whatever the voltage or case size, should last a lot longer than that. I wonder if maybe they were put in a sailboat, and installed with the ends fore and aft. Different form factor, different orientation, maybe, and then the 6v were oriented correctly? Flooded batteries don't last long when the top corners of the plates come out of the electrolyte every time the boat heels over. Just sayin.

Yes, I considered the battery fore-aft orientation, but that is much more likely to detrimentally affect 6 Vdc batteries than 12 Vdc.

If we reference the Compass Marine article...

What Is A "Deep Cycle" Battery? Photo Gallery by Compass Marine How To at pbase.com

On page 2 we see a photo of a 6 Vdc and 12Vdc battery cut-away. While the 6 Vdc batteries have more reservoir under the plates to handle material shed (and they have much more material to shed) they have far less reservoir above the plates.

So if water levels are maintained properly, 12 Vdc Deep Cycle batteries are far less likely to have plate exposure issues in ANY orientation than 6 Vdc batteries.

A 12 Vdc battery fore-aft should handle about as much healing as a 6 Vdc battery athwartship.

So my best guess for cause is as posted prior.

[ramblinrod]

Originally Posted by ramblinrod

Yes, I considered the battery fore-aft orientation, but that is much more likely to detrimentally affect 6 Vdc batteries than 12 Vdc.

If we reference the Compass Marine article...

What Is A "Deep Cycle" Battery? Photo Gallery by Compass Marine How To at pbase.com

On page 2 we see a photo of a 6 Vdc and 12Vdc battery cut-away. While the 6 Vdc batteries have more reservoir under the plates to handle material shed (and they have much more material to shed) they have far less reservoir above the plates.

So if water levels are maintained properly, 12 Vdc Deep Cycle batteries are far less likely to have plate exposure issues in ANY orientation than 6 Vdc batteries.

A 12 Vdc battery fore-aft should handle about as much healing as a 6 Vdc battery athwartship.

So my best guess for cause is as posted prior.

Just another quick little note about this.

Which is more likely to happen:

A) a sailboat to heel or powerboat to carve?

B) a 12Vdc battery in otherwise good health to develop a shorted cell?

If you answered A) consider 12 Vdc batteries instead of 6 Vdc batteries, due to the superior electrolyte reservoir of a 12 Vdc battery for marine applications.

;-)

[ramblinrod]

Originally Posted by ranger42c

3x Odyssey PC-2150 12V AGM. Installed April 2006.

I'm very satisfied with their performance and longevity, but need more capacity... and can't fit 4x G31s in the available space.

Changeover should happen sometime after May 15th, since we're semi-busy in a fishing season until then.

-Chris

Good batteries on all accounts.

It appears your plans have been well thought out.

As we all know, there are pros and cons to every aspect of a vessel design, including the house bank configuration.

My reason for persisting throughout this thread, is that there have been many preaching the virtues of batteries in series, and golf car batteries in specific, and few presenting the flip side.

When one reviews all of the pros and cons, and eliminates all the rhetoric, for most marine house bank applications, there is really no "clear winner".

In a specific case like yours, if there is no 12 Vdc battery solution that will fit in the space available, that meets your quality and performance expectations (I haven't checked), then a switch from 12 Vdc to 6 Vdc may be a good choice, if all pros and cons are considered and weigh in favour of the change.

In some cases, (perhaps even many cases) switching from 12 Vdc batteries to 6 Vdc, 4 Vdc, or 2 Vdc batteries may be a bad move, ALL THINGS CONSIDERED.

IMHO, anyone who claims that in general, switching from 12 Vdc batteries, or a parallel bank to a series bank is a "no brainer", simply means that they have not bothered to apply any grey matter to the decision making process, or they simply don't understand all of the implications.

Further, suggesting any particular configuration without direct knowledge of the vessel construction, existing house bank configuration, available battery compartment space (with or without mods), loads (existing and planned changes), charging systems (existing and planned changes) is a disservice to anyone seeking advice on "What's best for my circumstance"?

[ranger58sb]

Originally Posted by ramblinrod

In a specific case like yours, if there is no 12 Vdc battery solution that will fit in the space available, that meets your quality and performance expectations (I haven't checked), then a switch from 12 Vdc to 6 Vdc may be a good choice, if all pros and cons are considered and weigh in favour of the change.

Further, suggesting any particular configuration without direct knowledge of the vessel construction, existing house bank configuration, available battery compartment space (with or without mods), loads (existing and planned changes), charging systems (existing and planned changes) is a disservice to anyone seeking advice on "What's best for my circumstance"?

It's taken me several years to gravitate toward this coming solution. And even then, I didn't want to make the change before I actually needed to make the change (which is now) so I've been holding it in reserve for about two years...

The specific issue I was most concerned about has to do with the dual-purpose design of our main battery banks, each currently 3x Odyssey PC-2150s.

Each bank starts a main engine, runs approx half the house (one fridge each), and services a bridge function (electronics on one, electrics on the other). The bank I'm replacing services our electronics suite... and that's all fairly power hungry, with potential impacts from when we troll on the other engine (this engine off) without the genset running. More capacity on that specific bank was the goal...

But there's that pesky starting thing. Once I figured out I could meet the engine (and engine maker's) minimum cranking amp requirements with some to spare using the GPL-4CTs... I still thought it best to get some adult supervision... so I asked Lifeline and their tech confirmed I should be good to go for that.

And I have a parallel switch, so I can actually momentarily combine both main banks to start engines anyway, so I'm not particularly worried about that (so far).

-Chris

[s/v Jedi]

Originally Posted by ranger42c

Intending to use Lifeline GPL-4CTs.

-Chris

Great choice; Lifeline takes a good position between affordability and quality. They even have that battery in the much better single-cell configuration for just a couple dollars more but you need space for six of them in that case

GPL-4CT-2V - Lifeline Batteries

[ranger58sb]

Originally Posted by s/v Jedi

Great choice; Lifeline takes a good position between affordability and quality. They even have that battery in the much better single-cell configuration for just a couple dollars more but you need space for six of them in that case

Yeah... earlier on, I hadn't realized that could be worth a look, but as it is, I can only stuff 4x of that case size in the space available.

I looked at their taller 6V versions too, but there's an overhead obstruction so can't do that either...

-Chris

[s/v Jedi]

Originally Posted by ranger42c

Yeah... earlier on, I hadn't realized that could be worth a look, but as it is, I can only stuff 4x of that case size in the space available.

I looked at their taller 6V versions too, but there's an overhead obstruction so can't do that either...

-Chris

I have the 6CT's and they perform like a dream so I'm sure the 4CT's will make you happy