AGM or GEL batteries

Jun 2, 2004
121
Hunter 430 Shelter bay, Panama
and why? is there a way to tell if an existing inverter is appropriate for these batteries. I have a heart interface, original to boat 1997. And is there a good place on line to order these batteries?
 
Sep 25, 2008
7,076
Alden 50 Sarasota, Florida
Horse before the cart....

Unless you are planning to invert the boat or can't periodically check fluid level, why not use 6 v or 12 v wet cell batteries?
Gell batteries require a different charge voltage and rate than most old chargers can accommodate and AGMs, which offer little advantage, are often significantly more expensive than wet cells.

Perhaps someone might amplify on the above. Alternatively, there are a myriad of internet sites at which you can find lots of information to guide you.
 
Feb 26, 2004
22,760
Catalina 34 224 Maple Bay, BC, Canada
Feb 14, 2014
7,399
Hunter 430 Waveland, MS
I have a heart interface, original to boat 1997
Since we have the same boat, The Heart Interface has a SETUP for both wet cell, gel and AGM.

Yes, it does make a difference for our Inverter/Charger.

I have used Wet Cells only. I can go to boat for the setup procedure manual, if you don't have the manual.
Jim...

PS: Come over and see us if you get a chance.
 
Oct 19, 2017
7,732
O'Day 19 Littleton, NH
It is my understanding that wet cell batteries leak a lot more gas then closed cell batteries like agm or gel. I hope you have good ventilation or there are health issues too.
- Will (Dragonfly)
 

SG

.
Feb 11, 2017
1,670
J/Boat J/160 Annapolis
Gel Cel batteries do "out gas" a very little -- you can get by with very little ventilation; but not really seal them in.
AGM out gas ONLY if you try to equalize them. (Only Lifeline recommends that you equalize your AGM's).

I had a Sabre 42, Hull #4 which had Gel Cells after I had one my conventional Surette's go bad. (Yes, I checked my electrolyte levels religiously, etc., etc.) After I got my Gel Cells, I very went back on the Sabre.

I have had AGM's on our current J/Boat for 19 seasons. I'm going to Lithium Ion, but that's a different, expensive story. I wouldn't recommend the current Lifeline Batteries as maintenance free.

To answer you question of a source: IF you're in the US, on the EastCoast, you could try DC Battery out of Miami. I think they're the least expensive, even after you factor in their shipping. If you are in Panama, I have NFI.
 
Apr 8, 2010
1,942
Ericson Yachts Olson 34 28400 Portland OR
"Horses for courses" is one way to put it. Different battery technologies have different positives and negatives (pun alert...).
We installed a spiral cell AGM in a custom frp box beneath our aft cabin berth over a decade ago. Main reason was that we had no other really useable place to park an "emergency/starting" battery - and in that location it is not possible to check or add water to a flooded battery.
Given the very low self discharge rate of that type, it ordinarily gets no charging from the engine when we are on vacation, altho I do switch the charge over to it for 30 minutes once in a while. If you study the different charge requirements for the main chemistry types you have mentioned you will notice that the input voltage is close for flooded and AGM. (but different for gel)
Our main house bank is a pair of Trojan T-145+ six volt golf cart batteries. They take a little distilled water a couple times a year, and seem happy with the 20 amp shore power 'smart' charger, and also with our 50 amp Moto engine alternator. Last year I did replace a 9 year old set of Trojan's with new ones.
The AGM (Optima) is ten years old.

My experiences are probably not "best practice" but they do work for me. These forums are great for compiling real-world results and answers, IMHO.

Unsolicited advice: buy Quality.
Batteries are awfully heavy and dangerous to your back to lift and install or transport. Saving a few dollars on a cheapie that dies quickly will not seem like such a smart idea if you next have to buy Advil by the bucket full.

Advice dispensed daily... or sometimes "weakly"... deposit one cent! :)
 
Oct 1, 2007
1,856
Boston Whaler Super Sport Pt. Judith
As a data point, my boat was delivered new with 3 gel house batts and 1 gel start batt in 2007. We are still on the original batts 10 years later. They are fine, hold charge and charge quickly. We take very good care of them and keep them charged.
 
Apr 8, 2010
1,942
Ericson Yachts Olson 34 28400 Portland OR
It is my understanding that wet cell batteries leak a lot more gas then closed cell batteries like agm or gel. I hope you have good ventilation or there are health issues too.
- Will (Dragonfly)
While this is a possibility, consider that some folks are also using poor quality or defective battery chargers that are causing out-gassing. Ventilation is required, but there are factors that can exacerbate the problem. Our flooded batteries have bubbled a little bit the few times we have re-charged from days on the hook, but they are in a ventilated compartment. We check them regularly for water level, as well.
Apropos of whatever, I really like the name "Dragonfly" !) :)
 
Oct 19, 2017
7,732
O'Day 19 Littleton, NH
Thanks FastOlson, my wife suggested it and, as you can see from my avatar pic, made for great imagery when I made my new hatch boards. They are one of my first attempt at pyrograghy. Now, I do it for a living.
I have been looking into batteries to install an electrical system on Dragonfly and I am interested in LiPo because they are so much lighter. For a 19'2" mariner, that makes more sense. However, they are so much more expensive. Have been considering ordering from a factory in China off AliBaba but you need an order of 5 batteries to get pricing around the same as lead acid. Don't know about the shipping.
- Will (Dragonfly)
 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
AGMs are superior to flooded in many ways, not least of which is that they:
  • require zero maintenance, while flooded need be monitored for water level and need be equalized periodically;
  • can be discharged deeper, without damage;
  • have much lower self discharge rate.
I venture to guess that most boaters occasionally 'discover' their batteries need water, and find plates exposed to air; and, never equalize. Just guessing.

There are certainly ways that flooded can be superior in capacity, but unless they are well maintained, including watering and not discharging too deeply, this advantage is not realized.
 

SG

.
Feb 11, 2017
1,670
J/Boat J/160 Annapolis
. Have been considering ordering from a factory in China off AliBaba but you need an order of 5 batteries to get pricing around the same as lead acid.
Be careful, the Relion batteries I've ordered, which are Chines made, are certified. The Lithion batteries that are marine rated, like Mastervolts and Relion have a safety shutoff module built in to each battery.

The Mastervolts are more than double the cost of the Relion's.normal price of almost $12/ah. You can do a bit better.

There are huge advantages to a Lithium Ion system (as long as it doesn't burn up ;^))) ):
  • You get 90+ % functional use available for your rated capacity, not 50% for lead acid, AGM, or gel cells.
  • You have essentially constant voltage through the use cycle (i.e., you don't start out at 12.8 volts and them migrate downward to 12 volts, before going towards 11 whatever.
  • You can charge them at very high amperage rates as long as you don't exceed 15.5 volts
  • They weigh a lot less
  • They last a long time
I'm replacing dis functional 800 plus AH AGM batteries with 2 300AH batteries. (I will still have my two engine and generator start Optima AGMs which our Mastervolt Combi charges separately from the two house banks.

Anyway, I'd be careful with a non marine standard battery.
 

SG

.
Feb 11, 2017
1,670
J/Boat J/160 Annapolis
You get more than 50% with AGM, more like 75% to 80%.
In theory you can; however i) It cuts down the life of the battery a lot; ii) you increase the likelihood of sulphation if you don't really charge them up to full frequently; ii) the last 90% of the AGM, especially the last 7% takes forever to "top-out" the used amp hours. The actual acceptance rate of the batteries goes way down as they "top-out".
When we go to beyond 60%, the loads had better be pretty low in total ah/hour. The voltage drops a lot (watts = amps x volts) and you get declining benefits per amp hour. If you are running refrigeration (motor load) or a bunch of electronics (radar, computer, displays, etc.), or pumps (water or bilge) the last amp hours are painful.

With Li Ion, you have pretty constant voltage through the whole usage until the battery "collapses" (is used-up); and they supposedly don't tend to "imprint" (sulphation) their load like a lead or AGM or Gel Cell.

There are really on two downsides: Initial cost is much greater; and, if you don't a decent and disciplined charger -- you run the risk of some very nasty fire. The quality Li Ion marine batteries have protection boards built-in which is supposed to block over charging. They also use a someone different chemistry from the computer and phone batteries which is more restrained and less prone to overheating. (ANYWAY, that's my understanding.)
 
Jun 1, 2009
1,737
Hunter 49 toronto
Here is my 2 cents worth.
Virtually every battery review you read says that at the end of the day, the best bang for the buck are 6 volt golf cart batteries.
I absolutely agree with this
Now, if you go this route , get the water miser battery caps. You might need to add a slight bit of water per season. They ate fantastic.
Now, my next bit of advice which is likely to draw the ire of several folks.
The way to increase the efficiency of your xantrex freedom unit is as follows:
Take a 5/8" 200' line.
Tie it around the unit.
Drop it overboard, and note what a great anchor it makes.
While you are are admiring the ground tackle holding efficiency, order in a Magnum Energy unit.
Here is what I can tell you for sure:
I went through 3 xantrex units.
Customer service was abysmal.
Their technology is a generation old.
Magnum gives amazing customer support. Their remote head gives fantastic stats on your battery, and you are never guessing on state of charge, etc.
It is by far the best marine charger /inverter on the market.
Btw,,,
Needed some questions answered last week.
Called their 800 number.
Was talking to a tech in <3 minutes.
Resolved all my questions
Immediately sent me a follow up email with an updated manual.
First class
 
Jan 1, 2006
7,039
Slickcraft 26 Sailfish
5/8's line seems a little too light. And 200'! It seems like you never want to see that unit again.
 

SG

.
Feb 11, 2017
1,670
J/Boat J/160 Annapolis
I can't speak for the recent Xantrex units; but the old Heart Interface units weren't junk. They may not be technologically advanced (I'm speaking of the modified sine wave units) -- but they were very reliable for me and many thousands of other units.

The company clearly became something different when Heart disappeared and Xantrex took the reins.
 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
You get more than 50% with AGM, more like 75% to 80%.
In theory you can; however i) It cuts down the life of the battery a lot; ii) you increase the likelihood of sulphation if you don't really charge them up to full frequently; ii) the last 90% of the AGM, especially the last 7% takes forever to "top-out" the used amp hours. The actual acceptance rate of the batteries goes way down as they "top-out".
When we go to beyond 60%, the loads had better be pretty low in total ah/hour. The voltage drops a lot (watts = amps x volts) and you get declining benefits per amp hour. If you are running refrigeration (motor load) or a bunch of electronics (radar, computer, displays, etc.), or pumps (water or bilge) the last amp hours are painful.

With Li Ion, you have pretty constant voltage through the whole usage until the battery "collapses" (is used-up); and they supposedly don't tend to "imprint" (sulphation) their load like a lead or AGM or Gel Cell.

There are really on two downsides: Initial cost is much greater; and, if you don't a decent and disciplined charger -- you run the risk of some very nasty fire. The quality Li Ion marine batteries have protection boards built-in which is supposed to block over charging. They also use a someone different chemistry from the computer and phone batteries which is more restrained and less prone to overheating. (ANYWAY, that's my understanding.)
Regarding your comments on AGM, I would like to see a reference that supports that. What I have read from authoritative sources is in contradiction, specifically, that AGM charge faster, and go to 80% depth of discharge for the same life cycle as flooded taken to 50%.
  • You say "forever." Can you be more quantitative, please? I haven't seen in the literature that it takes 'forever' to put back the last 7%, and - compared to what technology?
  • You say you increase the likelihood of sulfating if you don't charge them up frequently, yet, AGM are known to have better storage characteristics, and lower self-discharge than flooded.
  • The paragraph that starts "When we go to beyond 60%," doesn't make any sense to me at all. There's a lot of qualitative criticism, like "a lot," "declining," and "painful," but nothing one can really go on. Perhaps you can elaborate?
Here;'s the source I usually start with, on this topic:
http://batteryuniversity.com/learn/article/absorbent_glass_mat_agm
Quoted, in part:
AGM has very low internal resistance, is capable to deliver high currents on demand and offers a relatively long service life, even when deep cycled. AGM is maintenance free, provides good electrical reliability and is lighter than the flooded lead acid type. While regular lead acid batteries need a topping charge every six months to prevent the buildup of sulfation, AGM batteries are less prone to sulfation and can sit in storage for longer before a charge becomes necessary. The battery stands up well to low temperatures and has a low self-discharge.

The leading advantages of AGM are a charge that is up to five times faster than the flooded version, and the ability to deep cycle. AGM offers a depth-of-discharge of 80 percent; the flooded, on the other hand, is specified at 50 percent DoD to attain the same cycle life. The negatives are slightly lower specific energy and higher manufacturing costs than the flooded, but cheaper than the gel battery.
I agree that lithium ion are denser technology, but at about five times the price per Amp-hour, a necessary change of charging system, and a finite, non-zero probability they will burst into flames, I'll stick with AGM for now.