AGM vs Sealed Deep Cycle

[__ScottyDont]

All,
I've been looking around for different batteries for my house bank and I'm really interested in AGM's because it gives me the ability to not have to worry about the gases (when charging) back in a small compartment where I plan to leave them as well as having an onboard charger I won't have to worry about freezing in the winter so I can just leave it all on the boat and run an extension cord. A few other considerations is no liquid spill, and the ability to take much heavier vibrations. etc. etc. etc. okay, we get the point, they are overall better batteries.

Since this is for a house bank I would prefer to maximize amp hours. Looking at the Group 31M AGM's my eye's got a little big for a second, I mean near $300 a battery? And I'm looking at two?

Overall what I'm looking for is above, a safer battery and the ability to maximize amp hours. Now do I need two Group 31M's or will two 27's be good enough. That's a never ending debate that will typically be dictated by how nice the weather on the sandbar that day is. However what I'm more interested in is AGM really all that its cut out to be or can I get away with a sealed battery. I've had two sealed interstates in my boat all last season without a problem, however I wasn't charging them overnight in that location.

So where have you all seen the best deals online for batteries fitting this bill?

 

[__ScottyDont]

I've been comparing these two batteries, i've read really great things about the Die Hard Platinum's and use two sealed die hard's (Group 27) on our larger Maxum. However the compartment is very well vented and heated during the winter.

DieHard Platinum Group 31 (AGM) - $260.99 (seems to have a different price everytime I'm on the website)
http://www.sears.com/diehard-platin...p-02850131000P?prdNo=1&blockNo=1&blockType=G1

Die Hard Group 31 (Sealed) - $112.49
http://www.sears.com/diehard-marine-deep-cycle-rv-battery-group-size-29hm/p-02827582000P?prdNo=1

Edit:
Optima BlueTop Group 31 - 227.68 (a little better on price, can't find a solid Ah rating)
http://autoplicity.com/products/438...52_161_bluetop_deep_cycle_marine_battery.aspx


Such a huge price difference, hard to really justify my wants for an extra $140 per battery.

But then I see images like this:

 

[davel501]

What switches do you have? Stock VSR can go to group 27 on AGMs but should be 24s.

 

[__ScottyDont]

I have the add a battery kit so the Blue Sea On-Off switch and the SI-ACR

 

[davel501]

That one is supposed to have anti-chatter circuit so you should be fine with 31s. Even 24s are probably fine for most people. Either way, you probably want to add a dual bank charger to keep both batteries in top shape. You can wire that blue seas switch to not parallel the batteries when the charger is running. There are a lot of other posts on this so I won't rehash here.

 

[Murf'n'surf]

2 group 27 agm batts with an onboard charger that is used when the boat sits will be plenty. Jumping Up to group 31 is not nessessary, save the weight and space.

The onboard charger set for agm is key in having long play time and life in your batteries.

 

[__ScottyDont]

@Murf'n'surf I didn't necessarily share what I was powering which is probably a dictator in what size house bank I want.

On the house side I will have all the stock accessories, Fusion Head Unit, two 600 watt amplifiers, and a lot of other low amperage accessories (LED's, GPS, Perfect Pass) The weekends I go out, I roughly boat 10 hour days but do have the ability to charge at the dock every night.

 

[jdonalds]

These are jet ski motors. Jet skis have small, motorcycle sized, batteries (sorry I don't know the numbers). So I've often thought a jet ski battery, costing closer to $60 should work well ( we rarely listen to music so don't drain the battery ). My jump box only has a small AGM battery and I've used it to start both engines.

Comments?

 

[__ScottyDont]

@jdonalds totally understand that. Only plan on using a single group 24 on the start bank. More concerned about house bank and sizing everything correctly as well as weighing AGM vs Sealed.

I've found plenty of AGM and sealed info on the forums and have determined AGM for my situation is best. However reading other posts won't help determine what group batteries I get.

I've tried doing the math and can only assume I'm right, I will post that tomorrow.

 

[jdonalds]

@jdonalds totally understand that. Only plan on using a single group 24 on the start bank. More concerned about house bank and sizing everything correctly as well as weighing AGM vs Sealed.

Ah. Well in my case start bank=house bank as I only have one battery.

 

[davel501]

The stock boats come with group 24s in the 2 battery setup but you lose some amp hours going to AGM. You can do 24s, 27s or 31s. 27 is probably the sweet spot but if the price difference between the 27s and 31s isn't that much then might as well go for it.

I went for the 31s to get more life out of my batteries due to wet slipping. I charge at the slip but I travel a lot and the dock is in a shared area so it gets unplugged from time to time. That said my house battery seems like it is going to go in for warranty replacement in a few weeks.

 

[TechRider]

I went with 2 AGM group 31 batteries. Mostly for any weekend trips I might take and two amps putting out a 1000 watts with 6 speakers and a sub.

 

[Rigger]

Here's another option for ya, 105 Amp Hour Rate ---> http://www.tristatebattery.com/8a31...gh-performance-agm-marine-battery-p-1356.html. When I ordered I asked if I could just pick up from their Gambrills MD location? they said no problem! Saved $60 bucks in shipping. I was hard pressed in my time spent searching to find any AGM with this amp hour (105) at this price $(217) with this good of a reputation (DEKA). Plus they are so damn heavy it'll help with the ballast on the port side of the boat.

 

[jetboater4life]

I just purchased two Deka AGM group 24 intimdators from a local shop in Rochester, MN. It was at a place I had never heard of and only found them because I went onto the Deka website and asked where the closest dealer was.
Price was $169 per battery. I considered the group 27s but the price jumped $50 per battery and that pushed it way over $400... ouch! . I don't think my usage will require 27s. With my dual bank charger and my Blue Sea add a battery kit I've got a nice mod waiting for me to get too when the weather warms and the snow melts.

 

[__ScottyDont]

@Rigger Thats awesome and the price seems great! I could grab that on my way north to Baltimore this Thursday! I'll go right by there! Are you overall satisfied with those batteries?

 

[__ScottyDont]

@jetboater4life have you ever used DEKA's before? any feedback would be greatly appreciated!

 

[jetboater4life]

I have not used Deka before, but my research on the other site and from the web says only that they are excellent batteries.

 

[Rigger]

@Rigger Thats awesome and the price seems great! I could grab that on my way north to Baltimore this Thursday! I'll go right by there! Are you overall satisfied with those batteries?

You'll have to call in your order tomorrow if you want to pick them up on Thursday. They didn't carry them at the MD location so it was a one day transfer from NJ to MD, no cost to the customer. My Deka experience only goes so far. None with the new AGM's but I still have the original DEKA 24M7 lead acid start battery that came in my 2007 SX230 when I bought it new, in July of 2007.

 

[__ScottyDont]

Just ordered the Intimidators! Thanks @Rigger