AGM Battery - which is the best option.

[WindLove]

I know there are countless threads about AGMs and the technical differences and I don't want to invest a ton of time into something others here can advise me on. I have Group 31 size:

Duracell AGM Deep Cycle Marine and RV Battery are about $179 each. They are manufactured by East Penn.

Lifeline GPL-31T are about $350 each. I know they are good, but expensive

Is there a clear advantage to spending twice the money for the lifelines? I'm not looking for a "best anchor" style debate. I am just trying to make a reasonable calculation.

[WindLove]

I did just check at Sam's Club and they appear to be out of the Duracells. Is there a shortage of AGM batteries, maybe because of COVID?

[jeff356]

I have Lifeline GPL 31XT's at 125 amp hours, got them at the boat show for less than $300 per.

Look at the number of cycles and being able to equalize...

[MikeHoncho]

Originally Posted by WindLove

I know there are countless threads about AGMs and the technical differences and I don't want to invest a ton of time into something others here can advise me on. I have Group 31 size:

Duracell AGM Deep Cycle Marine and RV Battery are about $179 each. They are manufactured by East Penn.

Lifeline GPL-31T are about $350 each. I know they are good, but expensive

Is there a clear advantage to spending twice the money for the lifelines? I'm not looking for a "best anchor" style debate. I am just trying to make a reasonable calculation.

I’d say yes given my research…….

[Pegu Club]

I use two group 31 Firefly batteries going on four years old, very good AGMs the best imo.

Fair winds,

[ranger58sb]

WL, depending on your purpose, you might also compare the Odyssey PC-2150s (G31s) and also pairs of Lifeline's GPL-4CT or 6CT 6V batteries. Former, more cranking amps. Latter, deeper cycle.

-Chris

[Maine Sail]

Do yourself a favor and read the May and August 2015 issues of Practical Sailor.

Deka GEL Batteries = Top Notch Deep Cycle Product (needs proper charging)

Deka AGM Batteries = Poor Deep Cycle Performance (we will only install/use them as starting batteries)

[CarinaPDX]

Batteries are a big investment, but very important to cruising. Replacing batteries in distant places can be a nightmare so go for the most durable. While many cruisers use AGMs, and specifically Lifelines, I would not recommend them for you. AGMs need special care; specifically they suffer from sustained partial charge levels (PSOC, or partial state of charge) and really want to be reset to 100% charge frequently, which means constantly managing them. Gel batteries, and specifically Sonnenschein, East Penn, and Exide brands, are better in that regard and at least as good in other ways. But the Firefly carbon foam are probably the best in both performance and resilience (which is why I bought them to replace my Sonnenschein gels).

Quality batteries cost a lot of money, but cheaper ones almost never perform nearly as well and in the end frequently cost more due to frequent replacement. There are several quality sources for proper deep cycle flooded (old-fashioned liquid, or FLA) batteries, and they are the least expensive quality batteries but still up there in price. The quaity AGM (Lifeline), gel, and carbon foam all cost about the same (about $500 for a group 29/31 battery). Cheaper AGM and gels just don't match up, and I am not talking about a small difference. If you only plan on owning the boat for a couple more years or are planning on staying close to home and don't mind more frequent replacement then save some money, but if this is your boat for distant cruising then batteries are not the place to skimp. Given the similar pricing for the sealed batteries I recommend the Firefly carbon foam, secondly gel, and lastly AGM - but all from the best brands only. N.B.: Lithium may be the best answer from a technical point of view but are more expensive and require more technical knowledge so probably not for you.

Greg

[goboatingnow]

I’m of the view now that “ reasonable “ priced FLAs are best suited for me. I get about 5 to 7 years , easily replaced almost anywhere and prices tend to be competitive

[George DuBose]

Skylark has five series 31 batteries. I had five Optima Yellow Tops, but after 10 years, I replaced the house bank with three Full River Series 31s.

You might want to look into the Full River line. They are not spiral wound AGMs like the Optiimas, but they are heavier...and not expensive.

https://www.fullriverbattery.com/

[Simi 60]

Originally Posted by MikeHoncho

She doesn’t want to research. She wants you to do it and answer her question

It's a minefield of information full of commentators with vested interests.
Sometimes it's better to ask info from those who hopefully, have actually used what they tout and had results .

[WindLove]

Originally Posted by Simi 60

It's a minefield of information full of commentators with vested interests.
Sometimes it's better to ask info from those who hopefully, have actually used what they tout and had results .

Thank you. Yes, I am not being lazy about research, it's just that if you really get into it there are so many conflicting opinions. My original fact was that Sam sells Duracell AGMs at < $200 and they say for marine use, 105 Amp Hours. Why is that not a good deal? I am shocked by battery prices and to me Duracell is a good name selling a marine battery for 1/2 the price (or so) of Lifeline.

So that's my issue in a nutshell. Thanks everybody!

[CarinaPDX]

Here is a specific discussion on the Duracell/Deka AGM batteries: https://www.sailnet.com/threads/anyo...teries.185785/ . Some points to note are 1) they have a rated lifetime of 300-350 cycles while other deep cycle batteries are two to three times longer life in deep cycle use, 2) both AGM and gel batteries require specific charging and float voltages. At first glance it appears that you get what you pay for, so pay 2-3 times the price and you get 2-3 times the lifetime (more or less). If you are not going distant cruising the Duracells are a reasonable tradeoff for the time being; if you are nearing departure try to go with the better batteries. The other issue is what are the capabilities of your charging systems? Most modern battery chargers have the ability to set the proper voltages for various battery types but there are still some installed that don't, and these old units might be hard on AGM or gel batteries. If you are charging with the engine's alternator you will want an external regulator on it for best battery care and fastest charging. I would consider opting for the cheaper batteries if you don't yet have an alternator regulator, as no point in shortening the life of expensive batteries. OTOH if you have an alternator regulator and a charger that can provide the desired voltages, and are close to going cruising, it might be time for something better.

Greg

[AuroraGH]

Originally Posted by WindLove

I did just check at Sam's Club and they appear to be out of the Duracells. Is there a shortage of AGM batteries, maybe because of COVID?

One of my 20+ year old LifeLine 27T's gave up the ghost this week and as I'm fixing to leave the country I figure it is time to swap em both out.

When I bought them 20 years ago they were very expensive. They've come down to around $320-$360 per. They have been very solid performers but this is the second one I have killed and you kill them by running them down and leaving them down. One died running a bilge pump all winter on a mooring.

Anyhow, I called my local battery guy and he says they are very backed up due to Covid. Might be a couple months to get a pair (he has one right now).

I've got time to wait a bit an I'm sticking to the LifeLines (will be adding DIY LiFeP04's for supplemental house anyhow).

[sailinglegend]

Originally Posted by WindLove

AGM Battery - which is the best option.

Your original question should have been .....which is the worst option?

Simple - that's anything that calls itself a marine battery, which is usually a compromise between a starter battery and a service/house battery and does neither very well.

The answer to your original question requires a book just on batteries, so do follow up the links given here.