# Group 31 Battery Capacity



## lbdavis (Apr 23, 2007)

I need to upgrade my house bank. I'd like to have between 225 and 300 Ah. (that's 3X and 4X my daily consumption, respectively). My budget is tight so I had been thinking of going with 6V golf cart batteries, but my existing battery boxes (each: 8"W x 14"L x 10"H) won't except 4 of them. But they will take a couple of group 31's.

I found this wet-cell and was wondering what people thought. This seems like a high amount of amp hours for a G31 battery to me. Is the weight (62.4 lbs) too light? Am I crazy to order batteries off the net? Are these likely to have less cycles to them?

Thanks!


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## TSOJOURNER (Dec 16, 1999)

Shipping costs for 70 lbs? 

And don't you have a local store near your house?


I'd try a Mr. Google, he's been known to be very helpful at times like these............


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## sailingdog (Mar 19, 2006)

That sounds awfully high for a Group 31 battery. Most of the Group 31 batteries I'm familiar with have a rating closer to 100-120 Amp-hours at the 20 hour rate. These say they're rated at 140 Amp-hours... which is 16-40% more capacity than other Group 31 batteries. I'm also not too familiar with that particular brand, but defender.com generally sells decent products.


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## Freesail99 (Feb 13, 2006)

Take a look at Interstate Batteries. A lot of bang for the buck.


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## TSOJOURNER (Dec 16, 1999)

Freesail99 said:


> Take a look at Interstate Batteries. A lot of bang for the buck.


Anyone know if it's still true (as of the late 90's at least) that there are actually only 3 lead acid battery mnfgs. in the States? I was told this more than thrice............


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## artbyjody (Jan 4, 2008)

Personally, the one aspect of West Marine I do like - is their batteries and replacement policy. I have had three batteries fully replaced with no questions asked (when I first bought my Cat the 2 batteries died (well less than optimum charge retention) they just replaced them as they were within the warranty period) and if you compare the cost of shipping + cost of a battery via the net - you really can't beat the knowing you can lug them to a store and 30 minutes later have new batteries and be ready to go....


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## lbdavis (Apr 23, 2007)

> These say they're rated at 140 Amp-hours...


Yea, this is the part that intrigues/scares me the most. $115 for 140 amp hours is pretty darn cheap!! (shipping aside.) Seems to good to be true and we know what we like to say about that...

I do agree with Jody as well; brick and mortar can have it's advantages.


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## artbyjody (Jan 4, 2008)

I bet those batteries have been sitting for a while so the price is more reflective of the 'not ready for clearance or recycling program'. Considering the average Group 31s run around $179 brick and mortar...

Defender however is a top notch place from people I know that order stuff from them - but - I would ask about return policy on the batteries as well as checking the date of manufacture for the batteries. That does seem a bit too good to be true unless it is just a auto battery with a marine label on it....


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## lbdavis (Apr 23, 2007)

> I bet those batteries have been sitting for a while so the price is more reflective of the 'not ready for clearance or recycling program'. Considering the average Group 31s run around $179 brick and mortar...
> 
> Defender however is a top notch place from people I know that order stuff from them - but - I would ask about return policy on the batteries as well as checking the date of manufacture for the batteries. That does seem a bit too good to be true unless it is just a auto battery with a marine label on it....


This may be a naive question, but how long can a battery sit on a shelf? I know it'll lose a few percentage points of charge each day if left idle, but when unused, do the plates just deteriorate over time?


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## sailingdog (Mar 19, 2006)

The warranty on those batteries looks a bit weak compared to the normal warranties other batteries have.

As for wet-cell batteries... if they're just sitting on the shelf, the plates will start to sulfate as the charge level slowly drops. Wet-cell batteries don't tolerate sitting for long periods of time very well.


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## artbyjody (Jan 4, 2008)

If just sitting on the shelf - the avg loss is 3-8% per month. Depends on the battery though - 6 months to a year on average (poor to high quality). If connected (ie in a boat) less than quoted if batteries are connected up to anything and not being trickle charged. High humidity, temperature, if the battery is connected to anything, etc also influence 'shelf' or 'non-use' life... The whole premise of a battery is it is a storage system and therefore needs to be excited on a regular basis to maintain usage....

For instance when my boat was just moored at the marina - I didn't have shore power connected as I wasn't going to be on the boat. Freezing temps - the batteries went into 'shock' and I had to have one replaced due to a bad cell.

Hence why I am an advocate of if you have the ability to trickle charge and use a charging system - just keep it on.



lbdavis said:


> This may be a naive question, but how long can a battery sit on a shelf? I know it'll lose a few percentage points of charge each day if left idle, but when unused, do the plates just deteriorate over time?


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## Maine Sail (Jan 6, 2003)

*You may laugh..*

You guys may laugh but my brother is going on three years with a pair of deep cycle marine batteries from Wal*Mart. The stated warranty on these is fairly good too when compared to West Marine or even the other local auto parts stores. The MAXX 29's are made by Johnson Controls for Wal*Mart.

The batteries are called Everstart marine MAXX 29 deep cycle. From memory I think they are 125ah each and are under $100.00 ea.. Unless you're buying real batteries like Trojan's or Rolls batteries they are all pretty much made by just a hand full of manufacturers to vendor spec.

Here's what Consumer Reports has to say;

_*"WHAT'S AVAILABLE*_ 
_ Most auto batteries are made by just three manufacturers, Delphi, Exide, and Johnson Controls Industries. Each makes batteries sold under several different brand names. Delphi makes ACDelco and some EverStart (Wal-Mart) models. Exide makes Champion, Exide, Napa, and some EverStart batteries. Johnson Controls makes Diehard (Sears), Duralast (AutoZone), Interstate, Kirkland (Costco), Motorcraft (Ford), and some EverStarts."_


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## Aasem (Sep 3, 2006)

Good question, LBD! I've been eying those this week, and thinking about buying 3 for a house bank. It seemed like a good alternative to two group 8 AGM's! (Uh, financially, that is.)


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## lbdavis (Apr 23, 2007)

> "WHAT'S AVAILABLE
> *Most *auto batteries are made by just three manufacturers, Delphi, Exide, and Johnson Controls Industries. Each makes batteries sold under several different brand names. Delphi makes ACDelco and some EverStart (Wal-Mart) models. Exide makes Champion, Exide, Napa, and some EverStart batteries. Johnson Controls makes Diehard (Sears), Duralast (AutoZone), Interstate, Kirkland (Costco), Motorcraft (Ford), and *some *EverStarts."


The *most* and *some* part makes me a little nervous, but 250ah for under $200 might make these worth the risk.

Halekai - do you know the dimensions of this Everstart marine MAXX 29 deep cycle? I can't find that on my internets...


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## Maine Sail (Jan 6, 2003)

*Lb..*



lbdavis said:


> The *most* and *some* part makes me a little nervous, but 250ah for under $200 might make these worth the risk.
> 
> Halekai - do you know the dimensions of this Everstart marine MAXX 29 deep cycle? I can't find that on my internets...


You'll have to go to Wal*Mart for that. They are a Johnson Controls group 29 though so you might be able to find dimensions for another private labeled Johnson battery. I'm running two six volters but have actually considered making the switch to three of the MAXX 29's when these need to be replaced as I can't fit four 6V batts plus a start.

I laughed when my brother bought them but now he's the one laughing.

P.S. He even left these on his boat in the winter for the previous two years disconnected and not on a charger and they held up surprisingly well. If you do make the decision to buy them use the Scarborough store as that store turns marine batts faster than any other local Wal*Mart but do wait until spring to be guaranteed freshies. Ed's batteries in Westbrook is where I buy my batteries.


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## artbyjody (Jan 4, 2008)

halekai36:

While I really like your posts and scientific endeavors - you should really re-think the battery post or clarify what your brother does as a routine with his boat in regards to battery usage.

Batteries are used for different uses, and people use them differently. If all your brother does is use the battery to start his boat -- then yes I can see why it lasts so long. My diesel pickup that I drive once every 3 months - the batteries lasted 5 years, but when they died they both did at the same time.

If you are cruising (or want to keep your battery optimally charged) - then you have to be wary of the 80% and 50% and 20% rules of capacity for batteries. IE: the original poster stated exactly how many amp hours they needed. When batteries are drawn below the 20% - you incrementally destroy your battery. If all you are using a battery for is starting an engine and playing a radio - yep - your battery will get further, but with 250 amps required.. running radar etc...then you just can not take that chance...you'll boil your batteries ...

And you are right - there are only a few battery manufactures however, again it is important to state - the brand of battery is directly relative to the performance of the battery for a good reason. Each *brand* that sells its own label battery has certain *criteria* that the batteries must have, for a certain *price point*. Not all batteries from one manufacturer, have the same behaviorally characteristics even if that manufacturers produces say both DieHard and Exide labels - both labels are indeed different batteries...Hence cheaper batteries have less than desirable warranties - others go 2 - 5 years... yep you pay for it, but also in the design of the particular label battery - they put emphasis on quality because they do not want warranty returns...

Kinda like your seacock discussion - just because you can buy it for super cheap and others say it works - doesn't mean if you sit down and do the math - that it is the right thing to do....

Batteries in my opinion are one of the most important purchases a person on the water can make as it directly relates to the operational ability of the vessel while underway as well as when in situations of duress....


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## Maine Sail (Jan 6, 2003)

artbyjody said:


> halekai36:
> 
> While I really like your posts and scientific endeavors - you should really re-think the battery post or clarify what your brother does as a routine with his boat in regards to battery usage.
> 
> ...


Well actually my brother does use these batteries as a house bank. He's the polar opposite of me in that he will discharge them then sail back to the mooring, dump his boat for two weeks then show up run the motor for 15 minutes and do another over night. In short he has beat the tar out of these batteries that's why I said I laughed now he's laughing. I did insist that his start battery was a Trojan though..

Having been directly involved in dealings with the Wal*Mart purchasing division I can tell you from an insiders perspective that they screw you to the wall and then have you pay UP FRONT for warranties/returns based on their numbers not yours.

If your product goes above their "returns data calculation assesment" you are penalized at a rate that would stop freight train dead in it's tracks! It is in the WORST interest of any manufacturer, including a battery manufacturer like Johnson Controls, to sell Wal*Mart a cheaper or inferior product!

I could write pages on Wal*Marts buying practices but suffice it to say the warranty they put on batteries is good and I can assure you with almost 100% certainty that if Johnson was selling Wal*Mart an inferior product they would not be doing it for very long. I fully understand that Johnson may build 15 different batteries in the same case each with a different spec but these MAXX's, from what I've witnessed, seem to be a very decent battery with a good warranty regardless of their price.

As we all know an n of 2 does NOT make solid scientific data and my advice is probably worth what you paid for it regarding the MAXX batteries..!

That being said I personally use Trojans, and have for years, but after seeing the abuse the MAXX's took and the performance the MAXX's gave my brother I may just consider them in the future..

P.S. LBW if you want really, really great batteries Ed's Batteries is the local Trojan distributor and they are located in Westbrook. You'll certainly be able to sleep at night with Trojan's...


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## Valiente (Jun 16, 2006)

I have to mention here that in 2006 I put in a pair of fresh SeaVolt 6V wetcells, plus the 12V 1100 CCA starter (the P.O. worked at West Marine and paid for them). The remarkable thing was that I pulled out at that time a pair of 12 V Trojan T-105s (Group 27s, I think) that were failing to hold a full charge _that were 18 years old_. Yep, went in with the engine in 1988, ten years before I took up sailing. I don't know if they were babied or not, but the boat was a liveaboard in the summer, so I suspect not.

People on Lake Ontario usually just buy whatever's on sale at the auto shop, but the most I ever got out of that standard was six years...and I do two specific gravity/distilled water procedures a year.


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## camaraderie (May 22, 2002)

No way that spec is true for the group 31's...thedon't weigh any more than anyone else's. Suggest you call defender and find out who makes them...then go to their spec sheets for the same size battery. I am guessing 100-110ah max.


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## Stillraining (Jan 11, 2008)

*Although it may be true*

that there is only 3 manufactures of battries, that dosent mean much. A lot has to do with the specks that the individual brands ask for. Case Teneco and Catapillar for instance have probably the best battries you can buy for off highway construction equipment. The pounding and shaking thease battries take is unbelievabal. Inertstate's wont cut it for long, nor will Pacific Power battries, A cat battrie is 200 bucks you get what you pay for most of the time. But thats not my point, There isin't jut 3 battries with different stickers on them in different sizes. They are coustom specked buy the engineers of the brand label or most are anyway. Some are just the same as others as anything else like oil filters for example. Most likely the lower end ones.

PS: Mainsail , you seem a little more down to earth on this site. Nice boat !

PSS: If the acid hasent been put in the battrie as they cant ship the acid, it really dosent matter if its a year or two older battrie.


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## artbyjody (Jan 4, 2008)

halekai36 said:


> Having been directly involved in dealings with the Wal*Mart purchasing division I can tell you from an insiders perspective that they screw you to the wall and then have you pay UP FRONT for warranties/returns based on their numbers not yours.
> 
> If your product goes above their "returns data calculation assesment" you are penalized at a rate that would stop freight train dead in it's tracks! It is in the WORST interest of any manufacturer, including a battery manufacturer like Johnson Controls, to sell Wal*Mart a cheaper or inferior product!


I have actually lost any respect for you based on that post... For someone that comes across questioning everything - I am beginning to think you do so only when it warrants...

I know about retail - and your claim of "returns data calculation assesment" and your dealings with Wal*Mart.... There is something to be said about the purchasing power of such a company - and the fact that Wal*marty is not known for return policies...they buy in bulk and the price of their batteries and lack of a substantial warranty is actually linear to the product quality. Maybe your brother got lucky or maybe he runs his motor more than you know... they cater to a certain segment of the spectrum and rightfully so. People that "BUY" warranties are suckers - a real product actually has a reasonable warranty because they rarely have warranty returns (called quality control btw)...and those warranties are full-filled because the company stands behind the product...

So please do not sling Wal*Mart (I shop there too because I can buy disposable items without shelling out the big bucks.. but its not quality..Wally is called discount store for a reason...) ... however, there are some items in life I am not willing to stretch the penny for the sake of saving one...

You never actually stated he drained the batteries... I know alot of sailors that go out and the only thing they have a battery for is charging their phone and listening to tunes... Others however, run full nav stations, radar etc... all of the later which run the battery down below 50 or even 20 % of battery capacity... And it should be noted that batteries are rated by the number of cycles that they can handle reaching less than 20% discharge...

So, please do follow your brother's lead and report back regularly... From experience, there is something that does not exactly measure up here... Call me a skeptic (and kinda thought you were one too)... but it doesn't add up....


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## Maine Sail (Jan 6, 2003)

artbyjody said:


> You never actually stated he drained the batteries... I know alot of sailors that go out and the only thing they have a battery for is charging their phone and listening to tunes... Others however, run full nav stations, radar etc... all of the later which run the battery down below 50 or even 20 % of battery capacity... And it should be noted that batteries are rated by the number of cycles that they can handle reaching less than 20% discharge...


Well that's because I don't know how deeply he drains them as he thinks a Xantrex XBM or Link 10 are a waste of money and I'm not one to just make things up on a whim. He is very much a "well if my main batteries die I'll just switch to my start battery" type of guy.

Usually when we sail on his boat he's running a plotter, stereo, VHF and 12V refrigeration (cold beer). On over nights they run cabin lights for about two hours and a incandescent anchor light all night if anchored which they usually are. He usually does turn off the 12V refrig at about 9:00 or 10:00 and then turns it back on very early in the am. Sometimes they use a 12V portable DVD player for my nephew too. The bottom line is that he runs the motor very little, roughly 32 hours all last season, and is on a mooring.

As I stated he beats the tar out of these and by that I include leaving them on his boat, disconnected, for an entire winter in temps reaching as low as 15 bellow zero F and they are still actually working. This alone surprised the crap out of me!

Trust me, I know all about cycling, sulfation, equalizing et.al and proper care and feeding of a battery system. I have yet to have a Trojan actually fail on me before I replaced it at my four year replacement interval but then again I treat my batts much better than my brother does. I know 4 years is an over kill replacement model, for Trojan's, but as you stated "batteries are one of the most important components"..

Again, I did not TELL anyone to buy the MAXX's and only reported on the surprising success my brother has had with them despite the abuse he's given them.

Jody,

I wish you actually had some scientific evidence or data to support your argument that because a battery is sold at Wal*Mart it must be of a lesser quality. I'd be the first one to read it. I'd really love to see a direct head to head between the very pricey West Marine group 29 and the Wally World group 29 just for the fun of it but I know it does not exist. I wonder if there would be a significant difference in performance, plate thickness, weight, height, rated cycles etc. etc...

No where in any of my posts did I state these batteries were of equal quality to a top quality battery like a Trojan or a Rolls or even to a Die Hard for that matter. I simply stated my brothers success with two of them.

Please remember how I opened my first post on this issue:
_"You guys may laugh but my brother is going on three years with a pair of deep cycle marine batteries from Wal*Mart. The stated warranty on these is fairly good too when compared to West Marine or even the other local auto parts stores. The MAXX 29's are made by Johnson Controls for Wal*Mart."_
I also said (by the way an n of 2 is sample size):_
"As we all know an n of 2 does NOT make solid scientific data and my advice is probably worth what you paid for it regarding the MAXX batteries..!
That being said I personally use Trojans, and have for years, but after seeing the abuse the MAXX's took and the performance the MAXX's gave my brother I may just consider them in the future.."

_
On another note:
You said:
_"Batteries in my opinion are one of the most important purchases a person on the water can make as it directly relates to the operational ability of the vessel while underway as well as when in situations of duress...."

_Considering my first five years of sailing/cruising, as a child, on my grandfathers wooden boat, was all done with no electrical system. We used very traditional means including oil lamps, compass, sextant, DED/DEAD reckoning, paper charts, hand pumps for water and head and a "push boat" (dinghy with an old seagul motor) if we needed a motor. I've also been "pooped" before on a boat with an electrical system and lost electrical power..

My point is this. An electrical system should not be counted on as ones only source of safety measure in situations of duress. In today's day and age one should also carry a hand held GPS with alkaline or lithuim back up batteries, hand held VHF with spare batteries, paper charts and the many other items one may need in the event you lose electrical power which can and does happen regardless of the type of battery you have installed.

As I very clearly stated above: If you want really, really great batteries Ed's Batteries is the local Trojan distributor and they are located in Westbrook. You'll certainly be able to sleep at night with Trojan's..

P.S. Quote: _"I have actually lost any respect for you based on that post... For someone that comes across questioning everything - I am beginning to think you do so only when it warrants..."

_Jody,That was over the top! Let's leave personal attacks in the off topic forum unless it's truly warranted.


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## lbdavis (Apr 23, 2007)

It seems to me that people have stronger feelings about battery choices/electrical systems than they do about most anything else. Ground tackle probably comes in second.

Could it be because there are so many options out there and a nearly infinite amount of possibilities on how to create and restore a reserve of electrical power.

Or is it because it's one of the more complex, annoying and expensive systems on a boat that people are frustrated as soon as they start working on them (or maybe that's just me)?

Maybe for some it's fear of not having access to the creature comforts of home?

Halekai - I didn't take your posts about the wally world batteries as an endorsement - only as one option of MANY. (one i kinda like right now).



> No way that spec is true for the group 31's...thedon't weigh any more than anyone else's. Suggest you call defender and find out who makes them...then go to their spec sheets for the same size battery. I am guessing 100-110ah max.


Thanks, Cam, I'll do just that.


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## lbdavis (Apr 23, 2007)

*horse's mouth*

I called Defender's distributer (mid-state). Mid-state tells me they get the battery from Superior Battery in Kentucky. I call Superior and learn that they actual manufacture the battery right there. Not Delphi, Exide, or Johnson Controls.

I got transfered to a nice, slow speaking, young man that regurgitated all the specs he could find on this battery:

850 cca
1060 ca
215 min of reserve @ 25 a
240 min of reserve @ 23 a
weight: 63 lbs.
12 7/8" x 6 3/4" x 9 5/16" (to top of post)

He did not have a way of telling me the ah of this battery. Is there a way to calculate this from the data above?


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## jrd22 (Nov 14, 2000)

Jody- You are getting a completely different message from Halekais' post than I do. I've read the thread twice and still don't find anywhere that he is pushing to buy, or advocating using, Wal Mart batteries(he buys Trojans). His brother has had good luck with them(Wal Mart), and seems to be trying to kill them ) Seemed pretty strightforward and informational to me.









John


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## Maine Sail (Jan 6, 2003)

*Lb*

LB,

Superior indeed does build their own batteries as does Trojan and they are of a decent quality. Ed's Batteries is a Superior distributor and they do stock the superior group 31 deep cycle battery you referenced on the Defender site although it has a different sticker and quite possibly a slightly different spec. I'm with Cam in that I've yet to see a group 31 with an honest rating of 140ah's.

The 20 hour ah rating on the Superior group 31 that Ed's sells is 130ah. Ed's sells this battery for $95.00 and you can pick it up right here in Westbrook *without shipping!*

By the way Ed's brother spun off and owns Battery World and he also sells high quality batteries. Between he and his brother they sell and services a fair majority of the boat yards, factories & manufacturers such as LL Bean (who according to Ed use a ton of Trojan's), and car repair shops in Maine.

Battery World (Ed's brother) also has the best prices I've ever come across on quality tinned marine grade wire, connectors, heat shrink tubing and battery lugs. Both of these guys are THE place to buy a battery in Maine! I buy my tinned cable from Battery World and my Trojan's from Ed's

*Battery World
148 Walton Street
Portland, ME 04103
207-797-7764*

*Ed's Batteries
334 Spring Street
Westbrook, ME 04092
207-854-9418*

P.S.

An option to the Superior:
The comparable Trojan is the SCS225 ($195.00 Ed's Price)
Length: 13 15/16
Width: 6 3/4
Height: 9 7/8
Weight: 66lbs
Reserve minutes @25 amps: 225
20 Hour ah rating: 130

Both the Trojan and the Superior have a 1 year full replacement warranty


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## cardiacpaul (Jun 20, 2006)

or, this one doesn't look too bad (grp 31)

SKU Number: 0470904

Heavy Duty Type; 12 V; Lead, Acid, Polypropylene Material; Black Color; 13 x 6 13/16 x 9 5/16 in; For Tractor/Heavy Duty, Commercial heavy duty. Corrosive. 
925 CCA 1050 CA 180 min RC
PRICE: $74.88
I had 2 in a cat 27 (pretty hard use) for over 2 yrs. Current owner of boat still uses them


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## camaraderie (May 22, 2002)

None of Superiors spec sheets on their own brand marine batteries even lists a 20 hour rate so I am guessing that no real testing has been done at this level and the AH ratings we are seeing are guesstimates. Nothing else about the battery specs are "superior" to similar group31's from others AND there is no weight difference. They may be a good buy...but plan on 105AH performance not 140AH.

I actually have some (long ago) experience in the private label battery business from a retail buying perspective. My guess is not much has changed. Most battery mfrs. would be happy to slap a label on their batteries for you or change the color of the case but would NOT change the actual battery unless you contracted for a specific minimum production run, with specific specs etc.. Thus...if a battery label is sold at more than one retailer...you can be reasonably confident that the specs are the same as the original manufacturers brand. If a bettery is sold under a private label...the retailer MAY choose to have it designed to different specs OR with a different warranty which is FUNDED by the selling price of the battery rather than any performance difference. The failure rates are known and you can simply "insure" a longer warranty by building it into the price of the battery rather than as a separate extended warranty. Makes the customer think they got a BETTER battery than the competition has even when the batteries are exactly the same! 

Finally...I will associate myself with Halekai on Wall-marts' buying office protocols and demands on vendors. They will not compromise on quality BUT they may design private label products to a specific set of features specs that may not be directly comparable to other stuff on the market. 
Their Maxx automotive starting batteries were tied for last place in Consumer reports review. So...you can't make generalizations when it comes to private label products there EXCEPT that the product will meet or exceed the designed specs.


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## lbdavis (Apr 23, 2007)

halekai36 said:


> LB,
> 
> Superior indeed does build their own batteries as does Trojan and they are of a decent quality. Ed's Batteries is a Superior distributor and they do stock the superior group 31 deep cycle battery you referenced on the Defender site although it has a different sticker and quite possibly a slightly different spec. I'm with Cam in that I've yet to see a group 31 with an honest rating of 140ah's.
> 
> ...


This is fantastic info, thanks Halekai!


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## witzgall (Jan 9, 2007)

An option that I am looking into is the Trojan T-1275. It will fit the length and width of my battery trays, which held Prevalier g31 gels for 17 years (wow). 
They are taller then most, though. 10 17/25". 150ah at the 20hr rate. 

Power Battery also has a taller AGM/gel composite that is rated at 117ah at the 20 hr rate. The 31T. The rate is not listed on their website, I called and talked to a rep to get that number.

Chris


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## xort (Aug 4, 2006)

halekai36 said:


> ...Let's leave personal attacks in the off topic forum...


You mean like...

"You're a hypocrite as far as I'm concerned... 
...mindless, rude, childish and very un-sailor like. Perhaps you were a power boater in a previous life??"
__________________
*-Maine Sail*


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## brak (Jan 5, 2007)

camaraderie said:


> None of Superiors spec sheets on their own brand marine batteries even lists a 20 hour rate so I am guessing that no real testing has been done at this level and the AH ratings we are seeing are guesstimates. Nothing else about the battery specs are "superior" to similar group31's from others AND there is no weight difference. They may be a good buy...but plan on 105AH performance not 140AH.


I will lift this thread if you don't mind as I am battery shopping (still). 
Thanks to this thread I've got to Superior site (calling Midstate did not produce the desired result). However, I can't seem to find Superior spec sheets on it. If you know where I can get them - I'd appreciate it.

Based on the numbers above (and listed by Midstate and Defender) these batteries are both heavier than "regular" group 31 (64-65lbs vs 59lbs for what's sold at West Marine or listed by Deka) and have longer minutes at 23 and 25 amps. So, I wouldn't necessarily think 140ah is out of question.

For comparison, Deka lists their marine group 31 to have:
225 min. at 23 amp
185 min. at 25 amp (amazing how 2 amp make a difference)
20 ah rate - 105

So, if what the message above said about Superior is correct:
240 min of reserve @ 23 a
215 min of reserve @ 25 a
weight: 63 lbs.
Then higher ah rating isn't out of question. Note how much better they do at 25 amp, presumably. 
But I'd really like to see it listed by original manufacturer.

I am trying to replace a set of 4 6 volt batteries. After some calculations, it looks like I won't get as many hours with 12v no matter what, but I would save 60lbs of weight by going with 3 group 31s (and a bit of cash if I find them locally).

Anyway, help would be appreciated!


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## Rockter (Sep 11, 2006)

brak...

Everything depends on how quickly you attempt to take the energy from the battery. 
Batteries adore slow demand rates, and they will last far longer at slow demand rates. 
They will deliver far more energy slowly than they will quickly. Give the battery time to deliver, and it delivers much more energy, and it does not heat so much internally.
A steady load of 20 A I would describe as brutal. No way would I run that for long on my ship's 275 Ahr house battery.
If I start the ship's Eberspacher heater, it will draw 20 A in little "kicks", but not for long. Most of the time, when in port, I get nervous if I am drawing much more than about 5 A. Perhaps it's paranoia, but the ship's house battery seems to last and last.
I have a dedicated starter battery, for the brutal starter currents. very few batteries can cope with those for long.

Rockter.


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## brak (Jan 5, 2007)

Understood about the slow rates. I've been reading battery data sheets from a number of manufacturers or suppliers all day long and by now my head is spinning  Sometimes one will be better in one measurement and worse in another (i.e. somehow reserve capacity will be more and 20 hour rate - less, etc). 

All I am trying to do is - shave off weight and expense of one battery, if I am not loosing too many amp-hours (i.e. 400ah vs 440ah is not a big loss). Staying with current 6v setup would be easier, since I won't have to modify battery box - but 60lbs is a lot of weight.


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## sailingdog (Mar 19, 2006)

Brak-

If you think 60 lbs. is a lot of weight, you really don't want to even think about 4D or 8D batteries. 

The numbers you really should be looking at are the 20 hour discharge ratings.


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## brak (Jan 5, 2007)

well, I have either 4 65lbs 6v batteries or, hopefully, 3 64lbs 12v group 31s. Thats the savings - but the total weight is still a lot  

20 hour discharge rate is, presumably, the same as "amp hour" rating? 

I am still not sold on the Superior battery idea - I found message board where their employees discuss the company and it does not look like a well run business (yes, I dig deep  ). East penn, that makes Deka, on the other hand is one of "the best companies to work for". I don't know if that makes a difference in product quality or me trusting their specifications


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## sailingdog (Mar 19, 2006)

Brak-

The amp hour rating can be measured at various discharge time periods. The one most commonly used for house battery comparisons is the 20 hour rate IIRC. 

BTW, I don't see how three 64 lb. batteries can have the same storage capacity as four 65 lb. batteries, regardless of voltage. Simple physics/chemistry is probably against that being the case if they're both the same kind of battery--wet cell vs. wetcell...etc.


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## camaraderie (May 22, 2002)

brak...


31D29

2156412.886.759.31$146.03
These are the specs I got from their own distributor site...so the 215 reserve capacity minutres and 64lbs. you quote is correct. Again...there is NO 20hr. amp rating. I have visited every one of their distributor websites and found no reference to a 20 hr. rate there or on Superior's home site. I would NOT believe the 140ah claim since:
1. A similar number is not claimed on any of Superiors own product that I can find. My assumption is this testing was not done and is simply extrapolated from the standard ratings they give...which also seem a bit hyped.
2. No OTHER group 31 has this kind of 20hr. capacity including Odyssey and Lifeline and Trojan AGM's which all rate from 100-110AH's and clearly have premium pricing and construction features.

Rock is correct...taking 25 amps from a battery and seeing how long it will last is VASTLY different than taking 5-5.5 amps for 20 hours. I remain extremely skeptical that you will get anywhere close to 140AH from this battery.


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## brak (Jan 5, 2007)

215 reserve capacity is measured at 25 amps, I beleive - so 215 minutes is 3.5 hours of 25 amps or about 90 amp-hours.

240 at 23 amps means 4 hours * 23 = 92 amp-hours. 
Yep, it's a bit far from 140 - I guess it is too good to be true, and it is.

Well, that seals it - I am going back to 4 6v batteries. I really wanted to save some weight (especially because of how they are installed - essentially on a wood tray which has nothing underneath until all the way down the bilge - long way down). But, I am not going to do that at the expense of quarter of my battery capacity.


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## Rockter (Sep 11, 2006)

If you don't have to run a fridge... in Scotland I use Loch Ness for that one, beer bag on a string, like 7 degC, and 6 billion tons of water... you don't really need much in the way of a battery bank. I get by easily with a single 275 Ahr.
The problem.... understandable in the hotter climates... is the (for me, 5 A) draw for the fridge. That one can add up.


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