AGM Batteries

[sluggoe]

anybody have experience with AGM batteries?

i am replacing my 3 exide nautilus batteries on my sailfish which are 5 years old and wondering if it is worth the extra dough for AGM's.

Also, my electronics guy said my existing on-board charger can charge the AGM's....anybody have experience with this??

 

[CJBROWN]

Wikipedia has a decent write up on batteries, AGM vs lead acid, etc.
http://en.wikipedia.org/wiki/Absorbed_Glass_Mat

Seems to me OPTIMA's and ODYSSEY's are AGM, both are fantastic products although very expensive. I believe they are more than double regular batteries. Optimas are easier to find, Costco even used to have them. They are excellent batteries.
Here's the Odyssey site: http://www.odysseyfactory.com
Oddyssey's have a wider selection of sizes and styles. Get yer checkbook out though...

I'm a cheap guy so I use lead-acid batteries. They are cheap to buy, easy to maintain, you can check the water level and charge level from the acid, and they work dependably. I keep a cranking battery unused for emergency starting, otherwise everything runs off a deepcycle.

For tons of reserve capacity for 'house batteries' the 6V golf cart types in series work exceedingly well. You see them more in RV's but boats get them from time to time as well. Again, they are cheap to buy and maintain, and give almost 200AH of reserve power. No regular deep cycle can do that, or pair of them.

For larger vessels the 8D is popular. I had one in an old wooden sailboat, we never plugged in.

Perhaps some of the members with your setup can recommend some options for configuring your three. For me, it would be marine grade lead-acid types, one each cranking batteries for the motors, and a pair of 6V's for the house, or a pair of deepcycle 12's as large as I could fit in there. There needs to be a way to charge your house batteries while you run though, without having to switch your selector all the time. My choice is to run off the house all the time, start the motors too, and keep the crankers for when/if your house can't/wont' start them. You just need to have the dual charging circuits from your alternators to keep the crankers topped up.

 

[LI Grady]

I've never heard a bad thing about AGM other then price, but I beleive that some battery chargers aren't compatible with them.

 

[TunaT]

Becareful with AGM's had 2 Odysseys and had issue with starting ..... was told by shop that the AGM's are NOT recommended for Yahama outboards and that I needed to change to regular starting batteries. I have swapped back over but still carry a spare AGM for emergency power ... just incase I lose a starting battery I'm covered. I had a sheet from the shop showing that
the Gel batteries were not recommended for use with the larger motors 4-strokes , but have misplaced it or wife threw out on me. Now, I have 4-stokes if your motors are 2-stroke it might be difference. I would inquire with Yahama before you make such a large $$$ expense. Maybe you can find proof saying the opposite that we can use......would make me happy.

 

[gwwannabe]

Most motorhomers evaluate house batteries (deep cycle) based on cost and amp hours. AGMs lose most of the time because they don't have the amp hour capacity and they cost so much. Further, they don't seem to have the life of a wet cell battery so they get you all the way around.

Some people buy them in spite of all this because they truely are a lazy man's dream - you never have to worry about the water level.

You do have to be careful with chargers, as many motorhomers found out the hard way. Older chargers without an AGM setting will fry the battery in a period of several months, sometimes just a couple. And there is no warranty coverage for this.

CJ, I'm with you. I have 4 house batteries and 2 cranking batteries in my motorhome and they're all lead acid. It's hard to beat a Trojan T-105 for coast, amp hours and longevity in a house application.

Gary 89 Overnighter

 

[CJBROWN]

>snip
It's hard to beat a Trojan T-105 for cost, amp hours and longevity in a house application.

Gary 89 Overnighter

Trojans are the shiznit. They do cost a little more, and can be hard to find. But they are built hell for stout, and have the best reputation of all batteries, period. Their 12volt versions are really nice as well.

Frankly, I think if I wanted to spend a little more dough and get a nice battery(s) I'd go with Trojans or something similar, rather than opt for the fancy gel and agm styles.

Costco and Sams/Walmart sell batteries made by Johnson Controls. They are less expensive but sufficiently made. Lead keeps going up so it doesn't make sense to quote old costs, but at least you can get some comparo from the various retailers, including your local battery dealer that can offer Trojans.

The Sears Diehard used to be a big name, not sure who makes it, but in tests it they do seem to hold up well against some of the more common brands, like Interstate, Exide, etc. Interstate is really big out here, but I've never been a huge fan of them - they never seeem to last that long.

Batteries seems to be a big issue for boaters and RV'rs because the subject comes up in the forums all the time. The most important thing is to keep them fully charged at all times. The more they are discharged, and the deeper they are discharged, the shorter their life. It's really that simple. Oh, and if they're lead-acid, keep them topped up with DISTILLED water (only). Top them up once they're fully charged.

Everything you ever wanted to know about 12volt systems is in a neat little book called THE 12 VOLT BIBLE FOR BOATS by MINER BROTHERTON.
You can get it from Amazon.com for about $12. I think the copyright date in mine is from the 80's
http://www.amazon.com/12-Volt-Bible-Boa ... 191&sr=8-1
Hmmm...looks like they even have an online version you can buy now - pretty cool. There are others too.

Here's a pretty good online text on batteries I just found:
http://www.phrannie.org/battery.html

Here's another I had bookmarked at home:
http://www.windsun.com/Batteries/Battery_FAQ.htm

 

[wahoo33417]

I use AGMs mostly for the peice of mind. Found them on sale so they were about 50% more than lead-acid, as opposed to twice as much. I have also read that Yamaha recommends against gel batteries for its four-strokes. However, it is my Yammy mechanic who recommended AGMs (but not gel).

AGMs have been great. Put them in and pretty much forget about them for a few years.

Rob

 

[Parthery]

Costco here in the ATL sells them...I think they are around $150 or so apiece.

I put them in my 226 and forgot about them...when the time comes to replace the batteries in the 180 I'll likely do the same.

 

[Bama96]

The Cabela's AGMs are great batteries. I have three on my bass rig and when the 4 in my Marlin are ready to replace that is what I am going with. Yamaha runs fine on AGMs. They have been great reliable batteries. 3 years old now.

 

[fishie1]

AGMs are NOT gel batteries. AGMs, (Absorbed Glass Mat) have the same charging requirements as a lead acid (wet cell) battery. Gel batteries are more sensitive to charging voltage ranges and this may be a problem for your charger.

Yamaha does not recommend AGMs because they never tested them. When I had to change my batteries on my pair of F225s I called them, twice, and got the same answer both times - that they are okay to use as long as they met the minimum specs required by the motors. I installed them and there has never been an issue, not one over five seasons.

AGMs are safer than wet cells because they can't leak or spill, even if broken, self-drain slower in the off season so require less maintenance and you never have to add water. Their life span is typically longer. Because they have thicker lead plates they can often funtion as a dual purpose battery so those of you who do not have dedicated banks or house batteries in their setup can benefit.

They do cost more though - sometimes a lot more. Cabelas has pretty good ones that go one sale often and the Diehards have been winning praise. BotH are at the lower end of the price spectrum.

Start here for more info:

http://www.windsun.com/Batteries/Batter ... 0batteries

 

[sluggoe]

great...thx for all the advice.

will probably go with the AGM's when i replace my Exide's.

--sluggoe.

 

[JUST-IN-TIME]

i have had 6 fail on me this year at the shop!!!

a wet cell will always out perform them

2 bad things about AGM

they only can be charged at 10amps some at 15 amps

other is when they go dead or over charge, you just burn a hole in the mat

 

[bc282]

Been doing a bit or research and reading on this kind of stuff myself lately.
Wet cells are great batteries but do require maintenance and proper charging to yield their potential performance and longevity. Most boaters do not properly charge and maintain their batteries so never realize a wet cell batteries' full potential. AGM's cost more, no maintenance but require charging although not as frequently as wet cells to maintain their charge (might be able to use same charger but AGM`s do charge at different voltages than wet cells--proper charging will yield longer life of any battery). AGM`s are fine to use as a cranking battery, but most likely you will need to go up in size to achieve the same cranking amps as a wet crank battery. AGM`s deep cycle very well and can be used as cranking units.
Next year i plan to replace the (3) 27 series west marine wet cells for AGMs.

 

[258 Grady]

AGM's

Go with the AGM's and never look back. If you charge them correctly you will have them for 10+ years. No gasses, spills and corrosion. Just pay the money and get the best.