Lake Houston Fishing!

Ok, it's now time to replace my Trolling Motor batteries and I think I want to upgrade to AGM's. I'm running a 24V system so only buying 2 isn't nearly as painful as 3 but i'm seeing a lot of varying price ranges. I run Interstate starting batteries and I really like them as a brand, very dependable in my experience. Their 100 AH version of an AGM is gently priced at about $280 each. I also see where you can get a duracell brand at sams for about $100 shy of that with similar specs and a decent warranty. Anyway, just looking for experience suggestions or recommendations. I have a Minn Kota MK210D 2 bank onboard charger that is safe for AGM's so that's not an issue. Any input is appreciated. Thanks.

Duracell is one of the top rated batteries on the circuit as well as interstate.
most are going to the group 31 battery marine deep cycle glass mats will
last twice as any other battery.

AGM Batteries

Pro anglers are switching to Absorbed Glass Mat (AGM) batteries. They can't be filled and are sealed valve regulated. AGM batteries have gel's advantages without the disadvantages. Originally developed in 1985 for military aircraft, where power, weight, safety, and reliability were essential considerations, AGM technology utilizes tightly packed and rigidly mounted Boron-Silicate glass mats between plates to absorb more abuse than gel cells. With no liquid to freeze and expand, they're practically immune from freezing damage.

AGMs are also "starved electrolyte", as the mat is about 95% saturated rather than fully soaked, they won't leak acid even if broken. Withstanding shock and vibration better than standard batteries means they're non-hazardous and shipping costs are lower. AGMs cost about the same as "gels".

Sitting stored in a partly discharged state for a few months is the biggest battery killer. A "float" charge should be maintained on idled batteries. AGMs survive off-season or in-between trips much longer without charging than standard batteries. If left for longer periods, all batteries should be trickle-charged to avoid damage. Sulfated plates may give batteries the appearance of being fully charged, but in reality may go dead very quickly under load. With a low self-discharge, 1% to 3% per month, AGMs are much lower than (up to 15%) "standard" batteries!
AGM's Charger Faster

Charging voltages of AGMs are the same as standard batteries so there's no need for special adjustments or problems with incompatible chargers that gels create. Internal resistance is extremely low, creating almost no battery heating even under heavy charge and discharge currents. Lead-acid batteries charge to 85-95% while deep cycle AGMs approach 98%. Bottom line — AGMs charge faster and fuller! However, most battery chargers are bulk charge only, and have little voltage regulation, fine for a quick low battery boost but not for long periods.

Voltage regulated chargers, such as MinnKota's MK 345 On-Board Charger, deliver rapid recharging and fully automatic 3-stage charging (bulk, absorption and maintenance) operation to provide a full charge every time. MinnKota offers automatic temperature compensation delivering fast charging recovery, even in extreme temperatures, while protecting batteries from overcharging.

Unlike AGMs,
wet batteries do not age gracefully. Capacity decreases and maintenance requirements increase. They require longer charging time and/or higher finish rate (higher amperage at the end of the charge) and they need to be watered more often.

Thanks Sticko,

I decided it was a worthy investment with all the benefits over lead acid. My old batteries are 27's but with the price being so close I'm going to opt for the 31's. it's not a huge jump in life but it will allow the TM to be strong for a little while longer. Glad to know the Duracell has a good reputation.

I have couple of them, had to replace one recently but it was a smaller one and like 650 cranking amps -- it was main starting battery and ran live well -- it made it almost 1 yr before having issues but sams replaced no problem and even upgraded to 1000 cranking amp

I bought 3 deka intimidator group 27 agm batteries about 6 years ago. One went bad 2 years ago and another last year. I replaced both with duracell agm from Sam's because of the convenience. If i could get the dekas easily I'd get them again without a second thought. But no problems or of the duracells yet either.

Pbr that says a lot for the Duracell if you got a year out of
one 650 cranking amps not sure what horse power your motor is
but most recommend 1,0000 marine cranking amps. for a starting battery.
But i guess any can go in a year. glass mat is rated 4-8 years.

Greg Lowes carry the Deka

went on and jumped in with the duracell platinum 31 agm's. I didn't realize the weight difference was so significant but I'm not planning to drag them out anytime soon either. Thanks everyone. Just an FYI, Sam's is running a $20 off deal on saturday on their marine batteries just in case anyone is in the market.

johnson 130hp, was like 2 wks from a year cause was still just barely under warranty. They let me pay the difference to upgrade to the 1000ca and another yr warranty.