AGM DC for cranking battery?? Suzuki 250SS

[Warreye]

Considering revamp of my battery setup for starting and electronics configuration.

Motor - Suzuki 250ss
Electronics - 2 solix 12's, garmin 1222 w/ livescope, lights, livewells, talons

Can I safely and effectively....
Run 2 Sam's/Duracell 31 DC AGM's in parallel to power as a starting battery for the Suzuki 250ss (they list 1000 ca) as well as run all my electronics? Is that a good setup, or am I asking for trouble?

Yes, we still fish w/ motor off for long hours, night fish w/o motor running, etc., so there will be times when the electronics and livewell are running 5-7 hrs straight without alternator charge. Also would be good if alternator was charging all electronics when we do start the motor and change spots. No, I do not have a power pole charge or isolator/battery switches figured into the set up. Just the two DC AGM batteries in parallel w/ 2 bank charger when at home.

According to the interweb, some folks state AGM's are no bueno for cranking battery. Also see some chatter about alternator on the 250ss charging at a heavier rate than ideal for AGM, or the potential to overcharge while running motor if batteries are already at 100%.

Pros/cons, alternative setups and "good" advice appreciated

I know I can separate starting from electronics batteries, but running them in parallel gives me a LOT of electronics run time and ability to charge while running. Just don't wanna still potentially pull so much I don't have enough juice to crank that beast after a long sit.

[Plunker]

That's the same system I am installing right now on my rig. The AGM's have a higher CCA and MCA than the 2 crummy Interstates I had in there before, which were also wired in parallel.

[Hot Runr Guy]

Warreye,
Have you looked into whether your Suzuki has an auxiliary battery charging circuit available on that motor? This way, you could have the 2 batteries, but charge each independently, and devote the 2nd battery to electronics,,,,

https://www.brownspoint.com/store/pc...t-83p66076.htm

HRG

[Warreye]

Won't work. Suzuki DF250SS. Site lists DF250AP which is different motor. Seems to be much disagreement on the interweb between folks that will say running an AGM as a cranking battery on the larger Zuki motors isn't good for the motor or the battery (some of these are boat dealers) and the polar opposite crowd where some state they have ran exact setup for years without problems.

Originally Posted by Hot Runr Guy

Warreye,
Have you looked into whether your Suzuki has an auxiliary battery charging circuit available on that motor? This way, you could have the 2 batteries, but charge each independently, and devote the 2nd battery to electronics,,,,

https://www.brownspoint.com/store/pc...t-83p66076.htm

HRG

[Ltrain]

Get the Duracell Platinum Marine and RV AGM batteries. Suitable for a cranking battery .

" Marine AGM batteries are specially designed for engine starting and the long, deep discharges typical of marine applications. The maintenance-free AGM design immobilizes electrolytes, making these batteries spillproof and leakproof, so they’re safe to use no matter how much your ship gets tossed.*

They are available in all popular marine sizes with abundant cranking power for quick, easy starting and all the reserve power necessary to keep your auxiliary equipment running strong. And they're backed by an 18-month free replacement guarantee*. "

Right off the site. Should be no problem wiring them in parallel that i can imagine.

[Keuka]

There's a post on the Hull Truth Forum related to this. According to what I'm reading in this blog, Suzuki does not recommend using AGM type batteries as cranking batteries on their "larger" outboard engines. The consultants' reply to the question however, indicates that some people have been using AGMs on large Suzukis with no problems and the reply indicates the responder feels correct size battery cable installation "may" correct potential problems using AGMs.

AGM batteries are much less capable of handling overcharging than are thick plated flooded type batteries. AGM chargers, that I'm familiar with, utilize a Smart Charging System that reduces the charging amperage down to trickle charge once the charger detects the AGM is 90% fully charged. Once fully charged, Smart Chargers, go into maintenance mode and no charging amperage is continued until the charger detects the battery needs recharging. My understanding is that most large outboards put out large amperage and this can or will result in an overcharged AGM battery and will likely result in premature damage and battery failure.

Just to be clear, I have no personal experience with a Suzuki charging system so I have no first hand knowledge. I'm just throwing this out as information I've read related to your question.

[Warreye]

I have read the same thread, which is what is causing my concern about using the DC AGM as a crank battery. While I would LOVE to have what would result in nearly endless electronics usage via the two 31 DC AGM's (w/ 1000 mca) ran in parallel, plus the ability to add charge while engine is running, I fear the heavy charge of the big alternator on the Zuki "might" damage the batteries.

There seems to be much confusion (mine included) on the interweb regarding this topic. Some folks use it without issue. Others warn against battery damage or damage to engine electronics. I'm at a loss still..... Easy fix is get a single interstate 24 marine cranking w/ the 1000 MCA's and isolate that battery for engine only. Then run 100% of electronics off a 31 AGM DC and see if I run out of juice after a full day pulling hard on the DC w/ livescope, 12" Birds, livewells, etc.

What to do? What to do??? I wanna make the right decision the 1st time, not the 2nd or 3rd. Hence my "Ask the Internet"

Originally Posted by Keuka

There's a post on the Hull Truth Forum related to this. According to what I'm reading in this blog, Suzuki does not recommend using AGM type batteries as cranking batteries on their "larger" outboard engines. The consultants' reply to the question however, indicates that some people have been using AGMs on large Suzukis with no problems and the reply indicates the responder feels correct size battery cable installation "may" correct potential problems using AGMs.

AGM batteries are much less capable of handling overcharging than are thick plated flooded type batteries. AGM chargers, that I'm familiar with, utilize a Smart Charging System that reduces the charging amperage down to trickle charge once the charger detects the AGM is 90% fully charged. Once fully charged, Smart Chargers, go into maintenance mode and no charging amperage is continued until the charger detects the battery needs recharging. My understanding is that most large outboards put out large amperage and this can or will result in an overcharged AGM battery and will likely result in premature damage and battery failure.

Just to be clear, I have no personal experience with a Suzuki charging system so I have no first hand knowledge. I'm just throwing this out as information I've read related to your question.

[Ltrain]

Originally Posted by Warreye

I have read the same thread, which is what is causing my concern about using the DC AGM as a crank battery. While I would LOVE to have what would result in nearly endless electronics usage via the two 31 DC AGM's (w/ 1000 mca) ran in parallel, plus the ability to add charge while engine is running, I fear the heavy charge of the big alternator on the Zuki "might" damage the batteries.

There seems to be much confusion (mine included) on the interweb regarding this topic. Some folks use it without issue. Others warn against battery damage or damage to engine electronics. I'm at a loss still..... Easy fix is get a single interstate 24 marine cranking w/ the 1000 MCA's and isolate that battery for engine only. Then run 100% of electronics off a 31 AGM DC and see if I run out of juice after a full day pulling hard on the DC w/ livescope, 12" Birds, livewells, etc.

What to do? What to do??? I wanna make the right decision the 1st time, not the 2nd or 3rd. Hence my "Ask the Internet"

Okay, I see now this might be a specific Suzuki charging problem with AGM batteries. How about this- get two Lead acid Duracell ( for example) multipurpose group 31 batteries. These multipurpose batteries are dual purpose cranking and deep cell batteries, then run them in parallel. You'll get your max available amp hours running the 31's in parallel plus they'll still get the charging from the big motor when you are traveling.

[Keuka]

I'd say your on the right page considering a two battery system with an isolated crank battery for the engine and a deep cycle for the electronics. Myself, I'd be hesitant connecting an AGM to the changing system as stated before. I have AGM's running my trolling motor but they are charged using an onboard AC Smart Charger and they are not connected to my outboard. If I were connecting them to my alternator, I'd stay with a quality flooded type battery system.

Most alternator charging systems don't put out any amps below a certain engine RPM level, approximately 1100 RPMs, but this is different with different engine manufactures. So if you're trolling at low RPMs while using electronic dowriggers or other electronics you may be running the cranking battery down. The short run at high RPMs back to port doesn't fully recharge your batteries so you're likely slowly depleating and damaging the cranking battery. I learned this the hard way. I would suggest it may pay you to do some research into either a battery "combiner" or battery "isolator" device. I think the Hull Truth also did a section on the pros and cons of each of these devices.

There are also Hybrid batteries available that serve as both a crank and deep cycle battery. In my limited opinion they work but not as efficiently as either a designated cranking or deep cycle battery in their respective designs. If I were running a smaller engine, I might consider a hybrid as a viable alternative. However you're running a 250 hp engine and I'm not convinced a hybrid would serve you well with that size engine requirements. I'm sure others may disagree.

Just in addition, I've run a deep cycle Interstate flooded type battery, located in the transom of my boat, and I've had no problems. Many boats are locating battery compartments up in the front of the hull where they are subjected to a lot more vibration and pounding in rough water. I have no idea under what conditions you're running your boat but flooded type batteries will not take the same amount of pounding and vibration that AGM type batteries can endure so there are pros and cons with each battery type. One type battery doesn't fit all circumstances.

[Warreye]

Wide open plains reservoirs in a very windy state. Our standard "walleye chop" is 15-25 and 2-3' rollers most days. All batteries belong near the transom here.