Free up valuable storage and AGM advantage

[Robert]

I found this when looking for a little AGM battery at a low price for starting my emergency generator, hurricane season.. My generator battery was less than half the price charged by BatteriesPlus, so I want to pass on this site to you.
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This is for the Mazda Miata, it is very light and compact and provides 475CCA. And the price is very reasonable for the advantages of an AGM battery. This little thing might fit in the little well just inside the transom behind the cover on the inside there, that would free up valuable storage under the seat. The battery posts would provide a connection point to add the cables to the house battery that will lead forward. The low resistance of the short cable from this battery to the outboard and the low internal resistance of the AGM (1/10 the resistance of wet cell) will keep the cranking voltage very high for quick starts.
http://www.westcobattery.com/miata.html

[richandlori]

I just can't bring myself to pay the premeium. For $20 cheaper, I was able to get a 115AH "old school" battery from Costco. I know they are great, mount them upside down, but I just don't know if they pass the bang for the buck yardstick?

Has anyone run some cost numbers for a cost benefit analysis...Moe?

Rich

[Robert]

In my opinion these are the AGM battery advantages for he Mac26X:
1.) no hydrogen gas expelled into bilge/storage
2.) no acid or fumes leaking into bilge/storage or on you
3.) faster more efficient charging with less internal resistance
4.) faster higher starting voltage better for starter life
5.) 2 year shelf life of charge will start your motor in spring
6.) lighter weight for given capacity
7.) smaller size 7.5" x 7" x 5" for this starting battery
8.) AGM starting batteries can withstand severl deep cylces
9.) AGM deep cylces can provide a lot of CCAs
10.) No maintenance, wet cells need to be topped off
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To me item 1, 2, 5 or 10 alone justifies the extra cost, the rest of the advantages make AGM even more attractive compared to wet cell.

[kmclemore]

Umm... just out of curiosity... why the worries about hydrogen gas ending up in the bilge? I see that's one of your key concerns, but I'd think that hydrogen would rise rather rapidly and try to find the nearest exit up and out. I'm pretty sure it's not gonna just lay down there.

[juergen X2524]

...- but sulfuric acid remains in the bilge - ...
I therefore have installed an AGM-Batterie under the cooler
juest next to the centerboard.
juergen

[Robert]

My dad was a auto mechanics instructor most of his life. He wrote many shop manuals and time estimator manuals. He told me often af the dangers of battery gasses with first hand examples. Like the time a student of his that thought he was smart enough to check a battery by placing a tool acroos the terminals to observe the sparks. This one welded two 1/4 socket extensions together rather nicely and ignited the gas above the battery. The flames must have also entered the battery as it exploded covering the student with acid. My dad grabbed him by the big blowy dandilion hair and dragged him to the eyewash then shower. He gave the student a lab coat to wear home. The student returned the next day with his old clothes washed (as my dad requested) and no hair. My dad used the clothes now just a pile of rags with hundreds of holes and the smart new haircut and the welded tools as an example. He told the student he is lucky he was wearing goggles as required for the battery lesson, or he likely would be blind forever. My dad eventually was the guy that planned the classes that the people who would travel the country teaching Mr. Goodwrenches at dealerships would be taught with. He also was the first to add auto mechanics to the VICA contests. http://www.skillsusa.org/ He continued to be important to VICA, teaching the USA finalists for the internationals until he died Feb. 2005. The auto mechanics part of VICA is now the model the other parts of VICA try to match for how well it is run. The top people from VICA flew in from around the country for my dad's funeral.
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What if something in the storage/bilge fell against the battery terminals? An exploded battery in the cabin might launch the admiral off her seat, or maybe the kids playing manage to connect the terminals with the handle of the gaff hook/scrub brush. So, I have a lot of respect for battery acid and the hydrogen gas that comes with them.
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I also have owned a few older cars, 1964 Corvair Eight Door Greenbriar Deluxe Van and others where the battery acid made a rusty mess. So, I also buy AGM for my cars just to eliminate the rust. Then there's the corroded terminals that require similarly corrosive baking soda to clean, having both the acid and then the baking soda all over the battery compartment is such an unnecessary mess.
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How do you control the acid / soda mess when removing the corrosion on the wet cell bucket of acid batteries in the bilge of the Mac26? The Mac26X did not come with a battery box or even a battery drip tray.
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Wet cell batteries come with significant hazards I can do without. I am amazed that MacGregor uses wet cell batteries as standard. Just one liability suit will change that I suppose, force him to provide either proper battery containment or AGMs. AGMs are so much smaller and lighter than a properly enclosed wet cell.

[Jack O'Brien]

My boat came with the standard "no name" batteries, one aft the galley and one under the dinette seat cooler. The latter ate the sailbag, but not the sail inside it, also stored there. I now have 3 identical Lifeline AGM batteries. I love not having to worry about battery gas or juice escaping under any condition, nor having to hang upside down trying to see if they need water or, worse yet, filling them. Plus all the other advantages. Worth every penny. Also, very hard to fault "Prop Man" Robert when he bites into a subject.

[Moe]

AGMs sure pass my bang for the buck test. After 4 years of maintaining flooded cells in the external compartments of our Airstream, including trying to keep the acid mist off the surrounding aluminum, I replaced them with a pair of Group 27 Lifelines. Did the same with the backup sump pump battery in the house. Will do the same with the two batteries in the Mac next year.

[richandlori]

So given that my house bank consists of two 115ah "Wet" batteries, how much would I be looking at extra to get the same battery capacity over replacing with two additional Wet types when the time comes?

Rich

[Chip Hindes]

Why doesn't Mac specify AGMs as standard?

Very simply, because they're not worth it.

It's also not worth the efffort to get into yet another contest with Robert about how great AGMs are and how terrible my buckets of acid are and dire predictions of extensive damage. BTDT on a previous thread. So I'll say it as simply as possible: In five years, none of those things has happened to me.

After five years of good service, this summer both of my original flooded cell batteries decided to give up the ghost. I had a brief attack of, "Maybe it's time to switch to AGMs", but one look at the price cured me of any such desire. Instead I replaced my corrosive, bucket of acid, explosive hazard maintenance headache batteries, which have actually been none of the above, with two more just like them for a grand total of $78 for the pair.

I'm thinking the thing to do, rather than wait for them to die after five years like I did this time, is simply trade them in every two years for brand new ones. After another five years, I'll be on my third set of new batteries. We'll see who's ahead monetarily.

BTW, since we already know what happens if we try to bridge the terminals of a wet cell with a socket wrench, I think one of you AGM owners out there should volunteer to prove AGMs superiority in this aspect by perfoming the same experiment with your battery.

Anyone? Anyone?

I thought not.

[richandlori]

..... ..... ......

[Robert]

AGMs are like insurance. Once you have an battery mess that could have been prevented, then you see the value. You never need insurance until something terrible happens, but everybody buys it anyway.
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I do see that the price is very high for AGMs but it is coming down. Solar / Wind Power arrays and electric cars use AGMs, more and more people are using them. One day the wet cell will just be a memory, because people will stop buying them in favor of better AGM or some other technology batteries.
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Old technology may work just fine, but that does not make it as safe. I heard a story of a guy driving a wonderful vintage Dusenburg (spelling?) car with the family aboard in California. They were in an accident in this very fine old technology car, and they all died because there were no safety items like seat belts. That said, I do not ever want a law to force people not to use old cars or old batteries, those people are taking a chance and have complete ability to decide to take that chance.
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For me the Mac26X wet cell battery was too much on my mind to leave it in. So I changed it out a couple weeks after buying the Mac26X. The old battery went to a friend that made good use of it, in a location that could better tolerate the mess.

[Frank C]

I found this earlier AGM thread very helpful and a little surprising. Jeff's advice was that the imported AGMs from Gruber were just as reliable and long-lasting as domestic brands. But rather than double the price, as an example, the AGM is $70 compared to a similar Costco wet cell for $60. I'm guessing shipping cost will be pretty steep, but I'm sure tempted to give them a try - and my 5-year old batts, like Chip's, are ready for retirement. Looks to me as if the larger Group 31 AGM (for $89) is virtually identical cost per amp-hour as the cheapo wet cells.

If you are looking for AGM batteries try Gruber Power Services. They are my main battery supplier that I use for the power wheelchairs and scooters that I sell. The batteries are foreign made, a lot less expensive, and they last as long as the domestic ones ...Jeff

The "clean & dry" aspect of AGM is certainly appealling, but untill now I've concluded that AGM is simply too expensive. So my choices were these el-cheapo wet-cells ...

• * Walmart's is about $60 with a decent warranty (18 mos. free?)
  * Costco's is about $60 with 3 years, full replacement warranty.

But Jeff's link to Gruber caught my attention too. These three batteries offer curious stats (rounded off for clarity). I suppose the price difference is all in the warranty:

Code: Select all

 75 AH   11"  7"  10"    53 lb   $  70  1 year full
103 AH   13"  7"   8"    83 lb   $ 156  3 year full (Northstar)
110 AH   13"  7"  10"    84 lb   $  89  1 year full

If I could find the way to squeeze a group 31 in my chosen battery compartment (might be too tall), I think the 3rd battery (cited by Joe) hits the Bulls Eye.

[Robert]

I went to the Gruber web site, the batteries don't seem to be rated for CCA (Cold Cranking Amps), so I'd give them a call and ask if those batteries are suited for my purpose before buying from them. Just to be sure the design of the battery will be equal to the service you expect from it.

[Duane Dunn, Allegro]

Cold Cranking Amps (CCA) really has no relevant relationship to our uses. Our motors are so small that almost any battery is up to the task of starting it. It takes next to nothing to turn over a 50hp outboard.

The real relevant number is Amp Hours (Ah). This is the concrete number from which you can calculate how long your batteries will last for a given task. Since it is best to not discharge a battery below 50% of capacity if you want a good number of cycles from it, .5*Ah is what you should use as the empty tank number. Take your loads in amps * time in hours and you can figure out how much you need in Ah capacity.

We make some quite long trips with a good compliment of electronics and other power hungry things from water pumps to the lights left on by the kids. Even so, measured by my very accurate Link 10 amp hour meter we rarely use more than 20Ah a day and usually it is below 15Ah a day. That's playing music, watching movies on the laptop (plugged in via the inverter) and 5 people on board not really trying at all to conserve power.

By the way, don't mix AGM and Std or Gel batteries in a bank. They all have quite different charging requirements, particularly gel cells.

To echo what Chip said, my dual purpose lead acid (The cheapest you can get that is rated for some deep cycles) which cost quite a bit less than Std Deep Cycle batteries let alone Gel or AGM's are still cranking out the power just great after 5 years. I think about upgrading to more amp hours capacity than the small 130Ah (65Ah*2 batteries in a single bank) I have, but we've never even needed that much power even with our long trips.

When they do give up the ghost I will replace them with a pair of 6V GC2 golf cart batteries. They have 215Ah and when wired in series will give me all the power I would ever need.