Best battery for EFI motor
I need a new cranking battery for my 1998 200 EFI Mercury. I've heard gel battery or deep cycles will hurt the stator or the voltage regulators. What battery do you guys suggest and is this true. I can't afford lithiums and I'm not buying the 400$ everyone posts on here!
That's correct. No AGM or deep cycle. I bought mine at Advance Auto Parts and it's been flawless for over a year now. Not sure exactly which one it is (I'm not at home to look), but it was under $100.
So are AGM and deep cycle always the same? I am pretty sure you can get a deep cycle battery that is not AGM technology.
Kevin | 2000 Champion 191 | 2000 Yamaha OX66 200hp
No they aren't the same. As far as plates, an AGM is built like a cranking battery, but the glass mats allow it to be used as a deep-cycle without the damage that would be done to a normal cranking battery.Originally Posted by 1bluemcm
The bottom line on this topic is that these engines weren't built with the electrical load of a modern bass boat in mind.
Mercury's recommendation against deep-cycles is pretty much nonsense on this. The reasoning is that the large capacity of a deep-cycle would overload the charging system. In reality, taking 50AH out of any battery places the same load on the charging system to replace, whether that battery is a deep-cycle or not. It's the electrical usage on the boat that is the problem.
Mercury's argument against AGMs is that because of their lower internal resistance they place a higher demand on the charging system. My take is that with heavy use ANY battery will fully load the 40A charging system early in the charge cycle, but the lower internal resistance means the AGM is actually using most of the output of the engine to charge the battery instead of wasting half of it as heat like a conventional battery does. My feeling is that the AGM will spend less time placing a full load on the charging system than the conventional battery because it will charge much faster, and I'm sure that the total amount of power drawn from the charging system will be substantially lower for the AGM.
My advice, and I practice it because I have an older EFI, is to use whatever battery meets your needs, keep it fully charged when off the water, and keep an eye on your regulators and wiring for signs of overheating. If your regulators aren't Quicksilver brand, replace them. If one shows signs of heat, replace them both. Anything you can do to reduce the demand on your charging system is good.
If you have integrity, nothing else matters. If you don't have integrity,
nothing else matters.
Every answer against AGMs makes sense. Then again that argument there also makes sense I had the worst luck ever out of adavanced auto battery's I'll never do that again.
The other way to look at it is what is hard on a charging system or makes a regulator fail? I know heat is a big enemy, otherwise, I'm not entirely sure what is worse, a higher rate of charge output, or longer duration of high amp output, maybe both. You would think that a battery with a lower internal resistance and ability to charge faster would be easier on a charging system, but there may be more to it than that.
Kevin | 2000 Champion 191 | 2000 Yamaha OX66 200hp
AGM starting battery is fine for an EFI. I've been using them for years. Heavy buggers though.
Optima D31M
On my 1991 2.5 200 I use a WalMart group 26 battery and no problem at all .....i run 2 LCX 113c units all day with out any problem for 3 1/2 yrs now .
I dont run the live wells as i just fish for fun . If i did ,i would go with the group 29 they have . I run 2 of them for the tm with out any problem .
I use a group 31 AGM, and keep it charged at all times when not in use.
I would think a smaller but marginal (sulfated) lead acid battery that could be 50% or more discharged would be a lot harder on the charging system than a larger AGM that is at most 20% discharged at any point during its use.
Last edited by LOSTTEXAN; 08-10-2017 at 08:58 PM.
You Don't Know what you Don't Know until you Know.
1984 Champion 201/Yamaha 175
1986 Ranger 390v/Yamaha 200
2002 Viper Cobra Coosa 216/Mercury 225EFI
2002 ProSports ProKat 2200/Twin Yamaha 150HPDIs
I have used deep cycle cranking batteries for years. Never started having problems with charging systems until, and I have Dual Pro on board 3 bank, which charges the cranking battery first then goes to the other three batteries. That being said I switched 2 of the trolling motor batteries to AGM. My system is separated into Cranking, Accessories, and trolling motor. Since I put the AGM's in I have had to repair or replace my alternator twice now in 4 years. I have a 225 Mercury EFI. with a 55 amp alternator. Now the batteries work great because I also charge them with a 110 v. Dual Pro 4 bank 15 amp charger. So I replace the alternator at less than a hundred dollar bill every two years or spend more money and replace the batteries with deep cycle batteries. Alternator is available on line for less than a hundred dollars. Now I do, do the work myself. And yes those AGM's are very heavy.
How many batteries is your outboard charging? Usually they are connected to just one but some have that second lead for charging a second battery.
Kevin | 2000 Champion 191 | 2000 Yamaha OX66 200hp
I have it set up to charge all my batteries. Reason I go to places in Mexico where there are not 110 v. hook up unless I take a generator. So my engine alternator charges through a dual pro onboard charger. Which is separated from the shore charger. Really simple if you deal with Dual Pro. So as I said since I switched to Glass mats I have had alternator problems. Is that the reason, I am not sure at this point. Because it works well for so long.
Last edited by western angler; 08-10-2017 at 11:12 PM. Reason: additional info
Duracell AGM from Sam's, I have a efi,no problems at all
That thread is basically listing batteries that Merc says SHOULDNT be used on a stator motor.
If you have integrity, nothing else matters. If you don't have integrity,
nothing else matters.
Don Weed of European Marine has forgotten more about Merc motors than most people will learn in a lifetime. He say's they're a good fit for an Opti or EFI. I trust him 1000%.
No, Don says those batteries should absolutely not be used on an EFI with a stator.
If you have integrity, nothing else matters. If you don't have integrity,
nothing else matters.
The second line: Although these batteries were tested for use with the Verado Engines, their superior Reserve Capacity Ratings would make them an EXCELLENT choice for Optimax or EFI engines used in a Bass Application!
don't want to steal the thread but since we are talking batteries and the merc efi engines thought I would pass along something I think would be helpful.try to never boost from the engines starting battery.if you do boost, try not to have any sparks around the booster cables or the battery.i know of two different times where booster cables were used and both times the ecm board(behind the efi cover)had to be rebuilt.$800.00 to $1000.00 to have rebuilt.$1800.00 new
"keep your blood thin,you will live longer"
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