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Old 06-07-2012, 01:53 PM   #12
ben2go
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City: Upstate,SC
Vessel Name: Shipoopi
Vessel Model: derilic sailboat
Join Date: May 2012
Posts: 2,884
Quote:
Originally Posted by rwidman View Post
Other than up front cost, there are no "cons" to AGM batteries for marine use. A lot of folks (including me) feel that the Sears Die Hard Platinum Marine group 31 AGM is the best without dealing with costly specialty batteries.

If you are building a boat, the additional cost of AGM batteries will be insignificant compared to the cost of the boat.
I had wondered about those Sears batteries.My local Sears doesn't carry them but they have a display and can order them.I guess they don't stock them because few people around here use them.They are stuck on those crappy Walfart batteries.

Yeah,I'm kind of lucky on my boat build.I have a lot of resources available to me that will drastically lower my build cost,so I could spend some on other areas that I may other wise skimp on.


Quote:
Originally Posted by Fighterpilot View Post
They have flooded battereis now days that are "sealed" in a limit fashion. No way to add water, and in theory, no need to. Since my start bank is almost impossible to get to I have a pair and will see how they work. Sam's sells them among others. My battery charger won't handle a mixture of batteries so I went cheap with the flooded batteries. Don't have a big load since we don't live aboard or camp, but I do have two 6 volts in series that do have covers that I can get off to service. They are easier to get to.
I have used those before.The longest I have had them last is a couple of years.I'd rather have standard flooded if I go that route.I like being able to keep an eye on electrolyte levels.It's key to longevity.


Quote:
Originally Posted by Delfin View Post
One advantage of AGMs that tipped me in that direction is their superior absorption rate. You can have all the charging capacity in the world, but if the batteries won't soak up the current you still spend a long time charging. Perhaps the higher cost is offset somewhat by less charging time than flooded.
That is a selling point that I didn't think of last night when I made this post.I was tired and it shows.



Quote:
Originally Posted by Budds Outlet View Post
We are beginning our 8th season with a set of Excide Orbital AGM batteries. One starting battery and two house batteries, all three manufactured in August of 2004.

We love the fact there is no unabsorbed acid. Absolutely no corrosion to battery terminals. No charging odor. No chance of spillage or leak or ruined battery trays.This is one reason I enjoy my current AGM batteries.

AGM's don't self discharge as rapidly as flooded batteries so they don't self distruct from sitting discharged as quickly.I have found this to be 100% true with my AGM equipment batteries.

Great to know they absorb charge faster than flooded. I'm a convert.That's always a huge plus.


Quote:
Originally Posted by Scary View Post
I can speak to longevity, the two 8d AGM's on my last boats thruster are over 8 years old and still working. Maybe the longevity offsets the price.
I would think so.

Quote:
Originally Posted by psneeld View Post
The consensus of most boaters and marina tecs I have talked to that flooded is the way to go.Most here push AGM but that may be due to the higher price thus more profit.

Unless you have a special needs..like a bluewater sailboat that may take a knockdown or an unusual battey space that requires wird mounting (on their side or something)...flooded can't be beat forgeneral use if COST IS a consideration.I had considered putting them in a locker,under the floor, in the rear cabin.

Problems with charging are a function of your charging system and battery use...not the batteries. If you have problems with flooded...then you may have the same of other issues with AGMs.

Battery banks and charging systems can be very simple and carefree...or you can make them complicated trying to power your boat forever through a massive system that requires an EE degree to keep it functioning...not that that approach is bad...you just have to understand what is going on with YOUR system and most advice from others is useless unless you provide a detailed schematic and specs on every componenet.Keeping it simple.I want to enjoy boating not messing with gadgets or watching something on a screen.


Quote:
Originally Posted by Keith View Post
I love my AGMs. One less thing... as Forrest would say. Install and forget.

Good ole Forrest and the K.I.S.S. principle.

Quote:
Originally Posted by David O View Post
I have a bank of 8 6 volt AGMs connected to a Magnum Energy inverter/charger that is 3 years old. I have never "equalized" them. Is it required or necessary?

I have never discharged them more than 25%.
Thanks for your details.I had considered a dedicated inverter charger for the house bank.I'll have to see when I start laying out the electrical schematic for the boat.

I plan to research the equalization issue much further.My Trojan charger desulfates and equalizes flooded batteries.I know AGM can't be desulfated and I am unsure on the equalization issue.


Quote:
Originally Posted by Phil Fill View Post
AGM is recommend for house, not start. Floods are still the best for starting, 500 to 1000 vs. AGM of 650. If you compare the AGM with a flood Deep Cycle they compare about the same. Moat of the new floods have screw on caps which makes them less maintains. Also the charging requirements are different between flood and AGM which might require two chargers as I think AGM require a volts, and if you do not charge them correctly it voids the warranty, so make sure you have the correct charger. If I use flooded, I would use the hydrolink caps and plumb a small tank with distilled water to them.


My last flood last 7 years. So if you have flood start batteries, then you might was well have flood house. Oh, lastly for house Gel is rated higher than AGM as they have twice the charging cycle. AGM and Flood are about the same. In the West Marine catalog there is a table comparing the direct kind of batteries or go to a battery store and talk them about batteries.I will check out West Marine's battery chart.

I been there done that 3 times now and still with gook old cheap reliable flood batteries.

Thanks for all the input.A lot of good info.
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