AGM Batteries

[RCJG228]

Looking for a house battery to power the sound system. I've made up my mind to go with an AGM. My boat dealer is going to do the 2 battery setup for me and they are quoting an Optima battery. I spoke with someone that didn't think highly about Optima, so I'm curious what anyone else thinks.

 

[H20Rat]

Re: AGM Batteries

i'm curious, but why are you going AGM vs a nice big conventional deep cycle?

 

[RCJG228]

Re: AGM Batteries

From what I've read and talking to other people, it is just a better more durable battery that lasts longer than a conventional flooded, and is totally maintenance free. You could even install it on it's side. I have been leaning toward a Sears Platinum that comes with a 3 year warranty. Kinda hard to beat 3 years on a battery warranty.

 

[MTboatguy]

Re: AGM Batteries

I had a optima in my last CJ-7, great battery for a 4x4 with all the off camber moves and bouncing around, I have never used one in a boat, but I can't see where it would be a problem, albeit a bit more expensive.

 

[DuckHunterJon]

Re: AGM Batteries

I run Yuasa AGM's in my motorcycles, snowmobiles, and 4 wheeler as they hold up much better to the vibration and pounding. I have never used one in the boat, but would consider it when it comes time. A friend drag races two cars, and they both have optimas. I know they are good batteries - my question would be are they good for deep cycle use? Typical batteries don't do so good when you run them way down before charging back up.

 

[skargo]

Re: AGM Batteries

I had 3 crappy Optimas in a row a few years back, it was enough to make me swear them off too.

 

[H20Rat]

Re: AGM Batteries

Not many boat batteries need to be installed on their side... Also, maintenance free just means you can't add electrolyte when it gets low. ALL batteries will vent when charged. Also keep in mind that you should use a different charger for a AGM battery, a standard charger will put too much voltage and not enough amperage for it.

Optima used to be very good batteries, but within the last couple of years their quality control has been slipping substantially. (and of course, price goes up.)

 

[Outsider]

Re: AGM Batteries

Also keep in mind that you should use a different charger for a AGM battery

Well, not really. Any conventional charger will function just fine with AGMs, and the same charging cautions apply. At least that's what two different manufacturers have told me. "Gel' batteries do require a specialty charger, but not AGMs ...

 

[RCJG228]

Re: AGM Batteries

I bought a Promariner 20 direct from the factory, and the person that I spoke to there said that this charger would distinguish between a flooded and AGM battery. I was concerned because my stating battery is flooded. The Promariner 20 will also charge "gel" batteries, but it requires changing out some plastic plug that is mounted in the charger. I didn't want to have to replace my flooded battery, because I just bought it last year.

 

[TerryMSU]

Re: AGM Batteries

Also keep in mind that you should use a different charger for a AGM battery

Well, not really. Any conventional charger will function just fine with AGMs, and the same charging cautions apply. At least that's what two different manufacturers have told me. "Gel' batteries do require a specialty charger, but not AGMs ...

Outsider:
I suspect that is not entirely accurate. I have a charger that does have an AGM program built in to it. Why would they offer that function if there is no reason to have an AGM charger? Were these manufacturers of chargers or AGM batteries?

I cannot speak for the long term reliability of the Optima Blue Top as I have only had mine for a couple of seasons. I can say that the self-discharge of the blue top is incredibly low. I put it away for the winter and last spring it was still fully charged. By the way, the first season I did use my old non-agm charger and had no know issues, so yes they can work OK to charge AGM batteries. I bought the charger with the AGM function at a outlet mall store because the price was so good.

TerryMSU

 

[Silvertip]

Re: AGM Batteries

Nobody has mentioned the cost difference between and AGM and a group 27 deep cycle. My local farm store sells a group 27 deep cycle for $75 bucks. They will last three years no sweat. I've been using them for years. when I buy a new boat, the troller gets a Fleet Farm battery. The boat goes down the road 4 or 5 years later with the original battery working fine. One AGM that size will be well into the three figures and will very likely not have the reserve capacity of the deep cycle. The way I look at it is that I can buy two flooded deep cycles for one AGM that probably will not have the same capacity. Read the labels on the AGM carefully and then compare with a deep cycle.

 

[willamettejeff]

Re: AGM Batteries

From what I've read and talking to other people, it is just a better more durable battery that lasts longer than a conventional flooded, and is totally maintenance free. You could even install it on it's side. I have been leaning toward a Sears Platinum that comes with a 3 year warranty. Kinda hard to beat 3 years on a battery warranty.

Just bought a Sears Platinum PM1 on Wednesday - 1150 CCA and 205 minutes reserve - $259.99 at the store. That is 3 years free replacement warranty. Did I need such a large battery? Well no, but just don't want to worry like I did last season that the boat will start especially if I happen to flood the motor. My boat is also small and didn't want to deal with space issues and complications of mounting multiple batteries, so needed one that was both starting and deep cycle which the Sears Platinum is. My decision was then based on simplicity and reliability which are both worth a lot to me. BTW, according to the salesman at the Sears store, you can use a regular charger on an AGM battery, but that will shorten the batteries life as regular charges tend to burn up AGMs. Assume that occurs when charging back up after deep cycling it since others have said they work fine in regular vehicles and wouldn't be drained very much in those situations, but I'm no expert. Others have also made very good points about the price compared to conventional batteries. In the end, it is a personal choice. I'm hoping I'll be happy with mine.

-- Jeff

 

[j_martin]

Re: AGM Batteries

Just bought a Sears Platinum PM1 on Wednesday - 1150 CCA and 205 minutes reserve - $259.99 at the store. That is 3 years free replacement warranty. Did I need such a large battery? Well no, but just don't want to worry like I did last season that the boat will start especially if I happen to flood the motor. My boat is also small and didn't want to deal with space issues and complications of mounting multiple batteries, so needed one that was both starting and deep cycle which the Sears Platinum is. My decision was then based on simplicity and reliability which are both worth a lot to me. BTW, according to the salesman at the Sears store, you can use a regular charger on an AGM battery, but that will shorten the batteries life as regular charges tend to burn up AGMs. Assume that occurs when charging back up after deep cycling it since others have said they work fine in regular vehicles and wouldn't be drained very much in those situations, but I'm no expert. Others have also made very good points about the price compared to conventional batteries. In the end, it is a personal choice. I'm hoping I'll be happy with mine.

-- Jeff

AGM batteries are constructed so they have huge plate area, and thus they will pack a huge current punch in a small package, and also accept a charge at an enormous rate, basically limited only by practicality.

Trolling motor service is relatively slow discharge, and also boat chargers are slow charge, so the two biggest attractions of an AGM are mute. Unless your boat rides so rough that your teeth are in danger, you also don't need the third attraction, ruggedness.

For the price point, I'll stick with the farm store batteries.

Now, If I could get 200 amps off my outboard to charge the trolling batteries, then AGM and smaller size would be the way to go.

my 02
John

 

[infideltarget]

Re: AGM Batteries

Iraq...US Military and DoS Civilians...2500+ armored vehicles (MRAPs, Hummvees, suburbans, LENCO F350s, etc...etc...) 140 degree+ ambient AIR temps...horrible roads...one name brand battery in EVERY vehicle - OPTIMA. Nuff Said.

 

[Silverbullet555]

Re: AGM Batteries

Sears Diehard PM1 Platinum Marine Group 31. Rebadged Odyssey. I want 2 in my boat but haven't justified the price yet. Can be had for about $250 each on sale.

 

[jhebert]

Re: AGM Batteries

An absorbed glass mat (AGM) battery is a lead-acid battery. You can charge an AGM with a charger that works with a lead-acid battery, but you should be careful about having too much float charge voltage.

An AGM battery does not have intrinsically lower self-discharge than a flooded cell battery. The characteristic of a lead-acid battery which gives low self-discharge is the purity of the lead. Only AGM batteries made with high-purity lead will have lower self-discharge than conventional batteries. It is frequently mentioned that an AGM battery has a lower self-discharge rate than other batteries, but there is seldom any figure put to this. I made some measurements of two batteries, one an AGM and the other a quality flooded cell battery, and I found the AGM had a lower self-discharge rate, but the difference was not astounding. The variation was on the order of one or two percent difference. It is unlikely over a typical winter storage period of six months there would be a significant difference between a quality flooded cell battery and an AGM.

The AGM battery is not known for having longer life than conventional flooded cell batteries, and, in fact, just the opposite. AGM batteries are generally considered to have shorter service life than a flooded cell, but the flooded cell may require attention to electrolyte levels and periodic refilling.

Citations of use of AGM batteries in military vehicles are interesting, but I suspect that the principal attraction of the AGM in that application may be its ability to continue to work even if punctured. Use of AGM batteries in aircraft probably is attractive due to lower weight and ability to function in any orientation.

AGM batteries have been required on some outboard engine installations, notably the Mercury VERADO, and I suspect that is for their ability to take high charging current. The Mercury VERADO engine does not become a net provider of charging current until its engine speed is rather high, and then it likes to pour a lot of current back into the battery to make up for all the current it drew out at lower speeds.

AGM batteries tend to cost more than conventional flooded cell batteries. The Sears Marine Platinum DIE HARD batteries are very nice AGM batteries, but at $250 or more they are not a bargain.

Many times comparisons are made between AGM and conventional flooded cell batteries where there is a significant difference in cost. I think if you compare a $250 AGM to a $250 flooded cell battery you will find the quality of the flooded cell battery will be very good. A $250 flooded cell battery should outlast an AGM, and it should provide equivalent service.

 

[infideltarget]

Re: AGM Batteries

Citations of use of AGM batteries in military vehicles are interesting, but I suspect that the principal attraction of the AGM in that application may be its ability to continue to work even if punctured.

That, and the fact that they are must less affected by bouncing and less susceptible to vibration damage. Also, if the vehicle rolls over, it will not spill acid all over the place, and the vehicle can more likely be restarted when it is reoriented. We typically do not get more than about 8-10 months service from an Optima. The flooded cell type batteries that some of these vehicles arrive in theater with, will typically only last 3-6 months, due to the harsh environment. And those batteries are very high dollar flooded cells, with the absolute highest amperage ratings and reserve ratings. So, your statement that "A $250 flooded cell battery should outlast an AGM, and it should provide equivalent service" will depend entirely on the usage, and I would expect a fair amount of bouncing and vibration in a typical marine application. So based on what I have seen here, I would be inclined to disagree with that statement. MY boat will be equipped with Optima batteries when I get home. But that's just me.

 

[jhebert]

Re: AGM Batteries

...The flooded cell type batteries that some of these vehicles arrive in theater with, will typically only last 3-6 months, due to the harsh environment. And those batteries are very high dollar flooded cells, with the absolute highest amperage ratings and reserve ratings. So, your statement that "A $250 flooded cell battery should outlast an AGM, and it should provide equivalent service" will depend entirely on the usage, and I would expect a fair amount of bouncing and vibration in a typical marine application. So based on what I have seen here, I would be inclined to disagree with that statement. MY boat will be equipped with Optima batteries when I get home. But that's just me.

If I were planning to do a lot of boating in a desert with extremely high ambient temperatures I would consider your recommendation to use an AGM.

 

[infideltarget]

Re: AGM Batteries

If I were planning to do a lot of boating in a desert with extremely high ambient temperatures I would consider your recommendation to use an AGM.

Use what you want, man. It's a free country, and I don't work for a battery company, so it makes no difference to me what you use. I think my last statement...which you quoted...says that MY boat will be equipped with Optima batteries when I get home. But that's just me. I actually didn't recommend anything. The OP asked about Optima in particular, and I stated my experiences with them. I think they kick butt. Are they right for everyone? Prolly not. Are they right for ME? You betcha'!

 

[Silvertip]

Re: AGM Batteries

I happened to be at my favorite Fleet Farm store just this morning and I almost always check battery prices while there. The $259 AGM battery referenced earlier with a 205 reserve minutes has a deep cycle counterpart at Fleet Farm for $85 and it too is 1050 CCA and 210 RC. It is a monster group size 31 unit. So three of these for the price of one AGM -- what a deal. The AGM would have to cook my meals, do my laundry, and wipe my nose for that price. If price is no object, go for what lights your fire. In a recreational boat it is simply not necessary. Paralleling the three Fleet Farm batteries would provide 630 RC. Now you could add a stereo system.