Installation & Orientation of Flooded Batteries

Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
Port to Starboard Orientation
In the photo below I am simulating a sailboat heeling with flooded batteries. For years I have been wanting to write this article but until my friend Dave let me shoot these polycarbonate cased UPS batteries it was going to be tough to explain. A picture is worth a thousand words. This one may be worth more than a thousand...

Here we can see the three individual cells of this 6V battery. A 12V battery would have 6 cells. Even heeled like this the positive and negative plates are not and have not "uncovered" and this is good. The vents are also not having electrolyte try to escape out the vent holes. In a port starboard orientation, like this, the cells are in their "thin" orientation compared to port or starboard tacks. In 6V golf cart batteries, as well as groups 24, 27 & 31 12 volt batteries, cells oriented port to starboard, not bow to stern, is the preferred method for installing flooded batteries on a monohull sailing vessel.

Sorry for just telling you this now, if you have them oriented non-optimally, but I needed the pics before the article could happen. I apologize that you've also not heard about this from the industry experts either. Thousands of regurgitated articles in sailing magazines but I've never seen a single article deal with the the proper orientation of flooded batteries on monohull sailboats.. Sad really...

This is a problem I discovered back in the late 80's. I was on a friends fathers boat that we had put a "state of the art" charging system on due to chronic short battery life. At the time we incorrectly assumed it was "overcharging" or what we through at the time was "overcharging"... Even after the new alternator and regulator he still had short battery life.

He went through the first bank in less than a season. One day while helping him work on it I noticed electrolyte spilled in the cases. The plastic cases for the batteries were black and so were the battery boxes so it was tough to see.

I removed the batteries and discovered quite a bit of electrolyte. I cleaned it out, neutralized the acid, and we went for a sail with no charging. We put her up on ear beating to weather and sure enough electrolyte began to drain out of the batteries fill/vent ports.. The cases were not cracked or leaking but it was spilling out when heeled.

It then dawned on me that the orientation of batteries on sailboats mattered. Doh'........

I looked at the cell layout, and fill/vent ports, and simply rotated these batteries to port/stbd. After that quick fix he never again had a single drop of spilled electrolyte. This may NOT be an easy fix on all boats as many builders really stiff you one this...

If I recall that bank lasted 5 or 6 years, after those first few days of spilling. This after multiple years of replacing batteries almost annually. I can't say all the issues were related to the exposing of his battery plates, and chronically low electrolyte, but it certainly did not help any.

This problem is only compounded with batteries that have "off set" fill caps meaning they are closer to the edge of the battery than the center. Orient offset cap batteries in a bow/stern orientation and you'll have some real leakage issues on one particular tack....

Exposing the plates, especially under charge or discharge, can lead to shorter battery life. Is a failure immediate and catastrophic? No, but if the opportunity exists to orient them more optimally then it should be something you consider. Monohull sailboats should ideally have flooded batteries installed to minimize electrolyte spillage and to minimize or prevent the positive and negative plates from uncovering during normal sailing activities.
Port to Starboard Orientation





Bow To Stern Orientation
Here we have the same battery only now it is oriented with the cells running bow to stern. As you can easily see the positive and negative battery plates are exposed and uncovered from the electrolyte. On these batteries spilling is not an issue due to the height and design but on the typical 12V "marine" group 24,27,31 etc. this can not only lead to exposed plates but also electrolyte leakage if the heel is extreme enough.

Exposing or uncovering of the positive and negative plates of a battery from the electrolyte, especially when under load or when being charged, is not good for the battery. Even if you are not spilling electrolyte you may be exposing the plates.

Seeing as most sailors are using the batteries to power house loads, while they are sailing, proper orientation of the cells can be that elusive piece of the puzzle that finally leads to longer battery life.

You may have invested thousands of dollars in solar, wind, regulators, alternators, desulphators, temp sensing, fancy chargers, new large gauge wire, bank fusing and more, but if your batteries are not oriented optimally you're likely still missing that last piece of the puzzle...
Bow To Stern Orientation




Side Profile = Uncovered Plates
Here is a close up and side profile of what happens when the batteries are installed non-optimally. This battery was also at the low level for electrolyte. If it was full to where it should be then leakage could have occurred in a good puff. Either way the positive & negative plates are exposed and this is not good for the battery.
Side Profile = Uncovered Plates




Fill Levels
There are differences between 6V batteries and the typical 12V batteries used in marine applications. No one ever discusses these points so I will.

In this photo you can see the blue line representing low mark for electrolyte levels, and this battery needs topping up. The bottom line is the low mark and the top blue line is the full mark. Even at low this battery still has sufficient electrolyte covering the plates to sustain typical heeling angles if properly oriented. This battery is very similar in design to a typical 6V GC2 or 6V T105 type battery.

6V deep cycle batteries are taller than a typical "marine" group 24, 27 or 31 12V batteries. Why? They are sold and used most widely in golf car applications and the added height benefits these batteries in two important ways.

#1 The added height, in some designs but not all, gives more electrolyte depth covering the plates when compared to typical 12V batteries. Golf carts are often driven on hilly terrain, parked at steep angles and this type of movement is closer to what a monohull sailboat undergoes. Only off road jeeps and four wheelers often put flooded batteries through the same pains as a golf car or sailboat, but rarely stay at these angles for hours...... This added case height and electrolyte depth can allow for less chance of the plates uncovering when the golf car moves about on hilly terrain and longer periods of time between watering...

#2 In deep cycling applications, like golf cars or sailboats, sulfation of flooded batteries is just a fact of life. The bottoms of 6V battery cases are deeper allowing for the collection of more shed lead sulfate. This battery shows very little sulfate in the bottom of the clear case but I have seen autopsied batteries with a "snow" covering of lead sulfate in the bottom of the case. 12V batteries can be "shorted" internally sooner than a 6V due to the build up of lead sulfate which eventually can reach the plates and short across them. This is more rare in 6V deep cycle batteries.
Fill Levels




A Proper Orientation
While this picture shows the battery cells lined up port to starboard, this is not how they shipped from the factory. This entire battery compartment was re-configured to allow for a larger house bank of two group 31 12V batteries plus a group 27 starting battery. The factory installation had the batteries bow/stern and only had room for two group 27's..
A Proper Orientation




Port/Starboard
I like this picture because if you look closely you can see the cell divisions dimpled into the top of the plastic battery cases. Look at the faint lines and you can count all six cells on each battery.

This is an example of a good factory installation on an older Sabre 34 MK I. At the Annapolis boat show, this past fall, the Sabre I was on still had properly oriented batteries! Nice job Sabre...

While this battery compartment is small, at least by today's standards, the batteries are properly oriented and that is a good thing..
Port/Starboard




Builder Blunder
I will certainly give kudos to builders who do it right but there is no need to slam an out of business builder by calling them out by name. Those who own this model will know this battery compartment well. Sorry.......

This owner has actually unknowingly did a good thing by installing AGM batteries. Of course they lasted all of two years, on a mooring, but that is a topic for another day. Everything on a boat seems to be a compromise...

Unfortunately this builder left no possibility for a proper installation of flooded batteries short of cutting fiberglass and reconfiguring the battery tray. There is no way, in this tray, to orient the batteries any way other than bow/stern. Doh'....!

On a boat like this GEL or AGM batteries will likely be a good alternative option.
Builder Blunder




Mounting
Any discussion about battery installation would be incomplete without addressing securing the batteries into the vessel.

For this task I often prefer a set of heavy duty pad eyes and some canoe/kayak straps.. The other pad eye in this photo is for the house bank which has not yet been installed into the battery tray. Containment of acid is critical so that any metal tie downs don't get compromised by acid. For containment plastic battery boxes suffice.

Also important is that the battery box not be able to move fore, aft or side to side. In this installation it is entrapped by a 1.5" tall X 1.5" wide mahogany frame on the battery platform. There are many ways to secure your batteries, just be sure you do..

A good way to think about installing your batteries is to mentally visualize your boat in a knock down. So, take a moment to picture your vessel in a knock down................

Now, where are YOUR batteries...? $hit happens so please install your batteries safely. A little spilled acid, if you have flooded batteries, is better than a 65 pound cannon ball flying through your cabin.

I generally dislike the cheap battery hold down straps that come with plastic battery boxes. The AGM photo before this one is a prime example of sub par hold down straps, neither of them was still operable... These cheap straps, with their plastic buckles, are marginal to useless at best.

EMS, LL Bean or Northwest River Supplies (NRS) sell the type of canoe/kayak straps I use. They work extremely well and are very, very strong..
Mounting




Off Set Fill/Vent Caps
Here is a a prime example of a 12V group 31 battery (Deka/East Penn) that absolutely needs to be installed properly. If not they will leak on one tack and this leakage can quickly ruin the batteries..

Here the batteries are properly installed with the neg post facing PORT and the positive post facing STARBOARD.

I can not stress enough how critical proper orientation is with batteries that have offset fill/vent caps as these do..
Off Set Fill/Vent Caps





4D Orientation
With 4D and 8D batteries the placement and orientation of cells is different than a typical 6V GC2 or 12V G24, G27 or G31.

In a 4D battery the cells are rectangular, as shown here with the red lines. As such the cells on 4D batteries are best mounted so the long length of the battery runs bow to stern. This puts the narrowest profile of each cell oriented to minimize positive and negative plate uncovering during sailing conditions..

The red lines represent the cell dividers inside the battery box. Each rectangle/cell is sealed from the others. The battery could also be flipped around so port / starboard are opposite the the long sides of a 4D should face port/starboard...
4D Orientation




8D = NOT OPTIMAL
In this image I have left the red lines off the cell divisions. If you look closely you can see the faint divisions of the cell dividers imprinted/dimpled into the plastic cover.

When you look close at the cell layout of an 8D battery you can clearly see that these cells are SQUARE! The 4D has rectangular cells, which can be better situated, the 8D really has no optimal configuration for a monohull sailboat.

Because of the square cells on an 8D battery there is no orientation that is better than another. Any way you install a flooded 8D battery, on a monohull sailboat, will result in the plates uncovering when heeled. This is never good for the batteries overall longevity.

Use 8D's at your own risk and if short life is an issue, and everything else is 100% correct, you'll know part of the reason.
8D = NOT OPTIMAL



Hope this helps.


This article is also on my web site here:

Installation & Orientation of Flooded Batteries
 
Jan 22, 2008
1,483
Hunter 37 C sloop Punta Gorda FL
another revelation MS. Your work is well worth the price of admission. Thank YOU.
 
Sep 25, 2008
7,077
Alden 50 Sarasota, Florida
Give the realities of storage orientation which is often inflexible, I am curious if there is any empirical or even anecdotal evidence it makes a difference.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
Give the realities of storage orientation which is often inflexible, I am curious if there is any empirical or even anecdotal evidence it makes a difference.
I see lots of anecdotal evidence every day. Spilled electrolyte and exposed plates as the result of improper orientation are very, very common. Once these portions of the plate become exposed they are eventually destroyed and capacity is lost.

Then there is stuff I can actually measure with accurate analyzers. Batteries improperly installed are almost always on the short end of the spectrum of longevity but as I mentioned this is only one piece of the puzzle. I can also measure imbalances in banks that are poorly or incorrectly wired. Often battery life is not caused by one event it is multiple issues leading to short life.

Even on boats were everything was 100% perfect, the owners or yards had done everything correctly from wiring, to battery monitors, to correct chargers and regulators etc. etc. I still see shorter life in banks that can be affected by this.

The only "empiracal" evidence I have comes from my many conversations with engineers at companies like Deka, Trojan, EnerSys, US Battery etc. etc.... They all suggest that exposing plates under charging or discharging is worse than exposing them while idle but the never exposing them is best.

This is how it was explained to be my a major battery manufacturer.

When the electrolyte dips below the tops of the pos & negative plates the exposed parts begin to rapidly sulfate. Some manufacturers say this happens "immediately" and other suggest it happens a little less aggressively than immediately but all agree that it causes irreparable damage to the plates. This is especially true for the negative plate which is a "sponge" lead and has massive amounts of exposed plate surface area,not unlike a sintered bronze grounding plate, that is exposed to the air. It oxidizes quite rapidly when exposed to air and not bathed in electrolyte..

With charging or discharging going on these exposed areas create heat and get hot. They are no longer "cooled" by the electrolyte like the rest of the plate but still "involved" in the work by nature of still being attached to the rest of the plate surface area submerged in the electrolyte..

If this goes on long enough, like a long sail on one particular tack, this action can cause the electrolyte to become very hot. Hot electrolyte attacks the active materials and increases the speed of sulfation of the entire battery not just the parts of the cells that die due to exposure.. The exposure of the plates can be quite dramatic when you consider both tacks. Unlike low electrolyte levels where usually only the very , exposed and damaged, you can expose more surface area to air when sailing on port and stbd tacks. Even without long term exposure the huge surface area of the negative plate is compromised by oxidation. Loss of this surface are results in less capacity.

With regard to spillage going unnoticed, as I see quite regularly, it too is bad for the battery.. I often pull poorly oriented batteries from the plastic boxes with a 1/4" to 3/8" or more of electrolyte in the battery box. I also see poorly oriented batteries with no boxes, not a good idea to not have containment, that have completely rotted out the battery platform they are on due to acid leakage.

When you lose electrolyte due to spillage you lose acid too. You are not just losing the water. Unlike losing electrolyte due to gassing, which only gasses off water vapor, here you are losing actual acid.

When you re-fill the battery with distilled water you are now diluting the electrolyte and causing a degradation of the electrolyte to a level that the battery was never designed for..

Spilled electrolyte is worse than "gassing off" because when your re-fill after a gassing loss the acid concentration does not change much, if any. With spillage it can change dramatically. This is especially true when batteries have off set fill/vent caps.

Given the realities of installations sometimes the decision has to be made to move to another technology or just accept the short battery life. After all everything on boats is a compromise. When spillage and plate exposure are an issue I see the shortest life when just plate exposure is an issue they last a little longer. Again it is hard, if not impossible, to quantify what portion of the short life is driven by plate exposure and leakage but we know it does nothing to help and only serves to hurt the batteries.. I don't know a single battery manufacture that says it is okay for a battery to spill acid in regular use or to expose the plates during use.

I can tell you that our properly installed & wired Wal*Mart batteries finished their sixth season and are still at better than 92% of new AH capacity and still exceeding MCA and CCA specs with both of my analyzers.. ;) They would easily go a seventh season... Too bad I am giving them the boot for a new LiFePO4 bank...:) I know I will find some good use for them....
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
Go figure.
Pays to pay attention to the details
Thanks MS
 
Jan 10, 2009
590
PDQ 32 Deale, MD
It's amazing the things broad expereince teaches. I have a catamaran and would never have thought about this.

A month ago I was asked to re-inspect a large (1 million gallon) oil tank that I had inspected a few years before. It had sprung a leak in the sidewall through 3/8-inch steel in a location I had given a clean bill of health. I pulled out my multi-meter, noted a small stray current, and then got up to walk around the tank. Sure enough, someone had stollen the grounding rods and cable for the copper scrap value, not just from this tank, but from all 17 in the farm. They asked "how did you guess so quickly?" I explained that the first time I ran into this, many years before, it took longer to piece together.

Nice write-up.
 

Jan11

.
Apr 9, 2012
40
Ericson 35 Albany
With charging or discharging going on these exposed areas create heat and get hot. They are no longer "cooled" by the electrolyte like the rest of the plate but still "involved" in the work by nature of still being attached to the rest of the plate surface area submerged in the electrolyte..
I'm kind of curious how you get charging or discharging to go on in sections of the plates without electrolyte. Maybe we don't need the acid at all. :confused:
 

Blitz

.
Jul 10, 2007
672
Seidelmann 34 Atlantic Highlands, NJ
Off Set Fill/Vent Caps
Here is a a prime example of a 12V group 31 battery (Deka/East Penn) that absolutely needs to be installed properly. If not they will leak on one tack and this leakage can quickly ruin the batteries..

Here the batteries are properly installed with the neg post facing PORT and the positive post facing STARBOARD.

I can not stress enough how critical proper orientation is with batteries that have offset fill/vent caps as these do..
Off Set Fill/Vent Caps
Mainesail - Offset fill caps are just caps that are not in the middle or center line of the battery?

My house batteries (2-US Battery Group 31s) are on the PORT side of my boat, with the positive terminals to PORT, and the negative to center or STARBOARD - are you saying this is wrong or is it that in your picture the batteries were on the STARBOARD side of the boat?

Again, Thanks for your posts!
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
I'm kind of curious how you get charging or discharging to go on in sections of the plates without electrolyte. Maybe we don't need the acid at all. :confused:

Sorry that was poorly worded... The charging or discharging is going on in the rest of the plates still bathed in electrolyte but NOT in the exposed areas. The exposed area of the plate can still gets hot because it is still connected to the rest of the plate doing the work but it lacks the cooling effect of the electrolyte.
 
Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
My question has always been why are the sulfated batteries rendered useless. Wouldn't it make sense to recycle them and have the sulfate removed (some stronger acid and done commercially) then used again until the lead is gone? Just thinking green.
All U Get
 
Nov 26, 2008
1,966
Endeavour 42 Cruisin
Uh oh! Here is a picture of my six T 1275 house bank. They are 12 volt golf cart batteries from Trojan, 150 a/h each.

ForumRunner_20130113_105333.jpg


They are very tall, which is why I chose them, they maximize the space available. The box is running tranversely across the boat. The picture is looking from port to starboard. So it appears I installed these "wrong"!
MS, you commented on 6v golf cart batts being good because they are tall, I assume it's the tall aspect of the batts, not the 6 volts?

We're full time living aboard so the batteries do get a good workout. We draw well over 100 amps per day. I'm not burning thru water, I've never seen the plates exposed. So I think we're OK. We don't sail the boat hard so there's not a lot of healing goin on either.

This was an upgrade from 4 T 105s that were installed the same way.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
Uh oh! Here is a picture of my six T 1275 house bank. They are 12 volt golf cart batteries from Trojan, 150 a/h each.

View attachment 60129


They are very tall, which is why I chose them, they maximize the space available. The box is running tranversely across the boat. The picture is looking from port to starboard. So it appears I installed these "wrong"!
MS, you commented on 6v golf cart batts being good because they are tall, I assume it's the tall aspect of the batts, not the 6 volts?

We're full time living aboard so the batteries do get a good workout. We draw well over 100 amps per day. I'm not burning thru water, I've never seen the plates exposed. So I think we're OK. We don't sail the boat hard so there's not a lot of healing goin on either.

This was an upgrade from 4 T 105s that were installed the same way.
The T-1275 is a true deep cycle 12V built with extra top case height and bottom case depth.. They are pretty rare in sailboats but are a good option. Deka/East Penn alo make a 12V GC battery.. Technically those are installed in the wrong direction, and I think I made mention of it when there. With minimal heel and keeping the batts full you may not have any issues.

With enough heel your #1, #3, #4 & #6 cells could potentially leak. #2 & #5 are in the middle of the batts.. You may consider hydro caps for them which will help minimizing any potential for spills..
 

Jan11

.
Apr 9, 2012
40
Ericson 35 Albany
The exposed area of the plate can still get hot because it is still connected to the rest of the plate doing the work but it lacks the cooling effect of the electrolyte.
If there is no heat generated at the exposed areas of the plates they don't get hotter than the immersed working area of the plates.

You're trying to over explain a real problem. Battery plates exposed to air will immediately sulfate according to Rolls.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
If there is no heat generated at the exposed areas of the plates they don't get hotter than the immersed working area of the plates.

You're trying to over explain a real problem. Battery plates exposed to air will immediately sulfate according to Rolls.
I can only share what is in my pages of notes. That same phenomenon was explained to me by three different manufacturers. Perhaps I did not explain it well, but the bottom line is the same. Exposing plates & spilling electrolyte is bad for them.

Proper orientation of the batteries is one part of the longevity puzzle that most have never considered...
 
Oct 17, 2011
2,808
Ericson 29 Southport..
As usual, my thoughts tend to be impracticable as hell; and aside from the obvious problem of space, I'm wondering if gimbaling is an "option"?
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
Mainesail - Offset fill caps are just caps that are not in the middle or center line of the battery?

My house batteries (2-US Battery Group 31s) are on the PORT side of my boat, with the positive terminals to PORT, and the negative to center or STARBOARD - are you saying this is wrong or is it that in your picture the batteries were on the STARBOARD side of the boat?

Again, Thanks for your posts!
Neal,

Sorry I missed this.. Yes, offset caps are oriented towards the sides of the battery or in some cases in a V formation where cells 1, 3,4, & 6 are towards the very edges of the batteries..

For example if the fill caps are on the starboard side of the battery and it is running bow/stern when you are on a port tack they can leak because they are on the low side of the battery. When on starboard tack they don't leak because the fill/vent caps are now on the high side of the battery...

See the post by Gettinthere to see what a "V" formation looks like. Sometimes hydrocaps can help if there is no way to re-orient the batteries.

The US Battery 31DCXC batteries has fill caps that are off set and not in the center. For most group 31 batteries it is though to keep the caps down the center..... If your - & + posts are oriented running port to starboard, you are fine.
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Hasn't this problem already been solved? AGM batteries.
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
AGM batteries present a whole host of other issues so most owners tend to stick with flooded LA batts.
That's why I'm waiting for you to work out the kinks on a LiON battery system! Then I can hire your design/build services, and you can live aboard while you do your work!

Not looking for the "Dreamliner" pyrotechnic option :D