What's the best deep cycle AGM battery for 2021?

[GrouchyOldMan]

Greetings Forum Battery Gurus!

I'm currently running dual 12VDC 80 AH deep cycle AGM batteries wired parallel. When new they provided us with 3-4 days of normal use without resorting to the genset. We got four years out of them but the capacity is dropping now and it's time for replacement.

I have researched the latest lithium offerings and WOW, the price has come way down and the capacity is up.... but the required upgrades to my Victron monitor, charging system and some protection for cold weather charging and avoiding damage to my alternator all vote for simply replacing with like-kind, 100 AH deep cycle AGM.

Looks like that will set me back around $400 which is acceptable. So, my question is what brand is currently leading the pack and are then any specs or features I should consider?

Many thanks in advance for your advice.

-Grouchy

[Veebyes]

MEXICOWANDERER wrote:
Try and beat this...heh heh heh

Lifeline in storage, DISCONNECTED for one and a half years

12.58 volts measured Saturday.

Good one, but not surprised. In 2019 my 4D Lifeline AGM went from end of October 2019 to August 2020, Disconnected, & had power to operate landing legs without a top up charge.

Typical storage runs from end of October to mid April, disconnected with no battery tender.

[MEXICOWANDERER]

Try and beat this...heh heh heh

Lifeline in storage, DISCONNECTED for one and a half years

12.58 volts measured Saturday.

[GrouchyOldMan]

UPDATE:
I really appreciate you folks weighing in and after due consideration....

I found a local source for two Trojan T-105 GC-2 batteries for $199 each.
If you think that is expensive, beware the "Supply Chain" and Inflation because both are in play here. Lifeline really does advise three months plus delivery dates to their distributors . And the same Lifeline batteries I price-checked a year ago are up 20+ percent.

With the two Trojan GC-2 batts connected in series, I'll have about 125Ah of reliable juice that will last for many years if I take care of them. Which I surely will. That pesty Victron battery monitor squeals like a pampered child when I even approach 50% drawdown!

AND, I don't have to change a single thing in my electrical system! Which is a "Good Thing" in my Coachmen Freelander because the Converter/Battery Charger isn't adjustable for battery types.

So, Kudos to you LiFePo...whatevers, you are definitely Next Gen. Hats off but I'm sticking with lead acid this go round.

Paz y amor hermanos,

-Grouchy

[MNRon]

I highly recommend Lifeline’s. I just checked batteryguys.com (where I found cheapest prices 3yrs ago, no affiliation) and it looks like they have in stock to ship.

If you instead decide on LA, I’d recommend Sam’s Club or Costco GCs at about $1/AHr

[Skibane]

^Two T-105 Plus batteries connected in series will give you 225 AH at 12 volts, which means that if you only draw 100 AH out of them between recharges, they should last for many hundreds of cycles.

Given proper care, there's no reason why those conventional flooded-cell batteries won't last just as long as a good set of AGM batteries.

Biggest disadvantages are that:

1. They can only be located someplace with good ventilation,

2. They don't accept high charging current as well as AGM batteries do (which means that you can't rapid-charge them as quickly),

3. They require occasional water replenishment and terminal-cleaning.

If you can accept those limitations, they are an excellent choice.

ETA: $215 apiece sounds way high. I assume your local dealer has better prices?

[GrouchyOldMan]

An update on my search:

- Lifeline distributors say 14 months for new orders!

- The Trojan T105 6v GC-2 battery appears to be locally available. Here's the spec sheet.
https://www.trojanbattery.com/product/t-105_plus/

Would two of these (in series) provide me with about 100 usable 12VDC amp hours in "normal" boondocking activities, say 30 AH per day?

- How many years could I expect from these if the lived in the RV during winter with an intelligent trickle charger?

- Would I get much more lifetime out of the Lead Acid version over AGM under the same conditions?

Appreciating the education here... Respect.

(Whoops, just realized the T 105 is a flooded not AGM! Questions still valid. Price on AMZ = $215 each.)

[StirCrazy]

Im going to say rolls surrett, been the best made deep cycle for decades, but you do pay a bit more for them.

[Veebyes]

I am on my second Lifeline 4D 215ah 12V battery. The first one had a lifespan of nine years. We are not bigtime dry campers but certainly do not shy away from dry camping.

Lots of years still in the current one, all going well, but I have been poking around doing research on lithium when the time comes to replace the AGM.

The advantages of lithium over AGM are like AGM over wet cells.

[GrouchyOldMan]

Thanks everybody, I'm going to investigate Lifeline, and also the GC-2 batteries.

[MNRon]

Lifeline. Give them a call, their tech support and info is top notch. If you care for them you should expect 10yr+.

[pianotuna]

Best bang for the buck is telcom batteries that have been "pulled" because one battery in a string has failed.

The interstate stores sell them for $1 per amp-hour. I'm on year 5 with mine. They are maintained by solar between trips.

[Skibane]

GrouchyOldMan wrote:
Question: is Warranty even something to be considered in this purchase?

Many folks abuse their RV batteries.

If you take care of them, they'll probably either outlast the warranty, or die shortly after purchase.

Just about any manufacturer will replace a battery that fails shortly after purchase - and battery "infant mortality" is not unheard of.

The warranties on deep-cycle/trolling motor/RV batteries tend to be pretty short anyway, mostly because the way those particular batteries are used and maintained is unpredictable.

[Ltrip]

corvettekent wrote:
I have used both AGM and FLA batteries. I only get 3 or 4 years of service life out of AGM batteries. I 7 years out of flooded lead acid batteries.
As for brand I like Interstate and Trojan.

I think the useful life of a battery is largely due to how well you care for them. You have done a great job taking care of your FLA batteries!

[corvettekent]

I have used both AGM and FLA batteries. I only get 3 or 4 years of service life out of AGM batteries. I 7 years out of flooded lead acid batteries.
As for brand I like Interstate and Trojan.