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School me on a starting battery

5/16/14 @ 9:16 AM
User since 1/24/02
My starting battery gave up on me this week. In the past I've just bought any old battery and have been ok with that, on smaller rigs. I now have a larger Merc motor that I beleive is pretty sensitive on voltage for the fuel pump\compressor?? or it will not start. I beleove it needs to see at least a solid 11 volts, or something like that. I also run my entire boat off this battery; radio, lights, electronics, etc. I'm not up on battery technology. Wet cell, dry cell, class 3, starting, cranking. I understand that batteries come in many flavors depending on application.

What am I looking for in a reasonable price range?


9/12/14 @ 9:35 PM
User since 9/12/14
Mercury marine states any dfi (optimax) engine has a minimum cold cranking amp requirement of 800 cca. Make sure the terminals are spotless clean all the acc. terms are on top of the main engine ones and throw away the wing nuts and use a wrench. If you run a lot of accessories and have room there is a 27 series starting battery that has a greater reserve capacity.

9/3/14 @ 9:01 PM
MEMBER since 5/12/09
I started it up again today and it seems to be gaining life. Put the volt meter on, and it is reading about 13 volts. I thought is has to be 14 to be "healthy." I'll google parasitic draw and see if I can find the issue.

9/3/14 @ 5:46 PM
User since 10/1/03
if the battery went dead while the boat was sitting and not being run then you either have a bad battery or a parasitic draw. i.e a radio with a clock. google finding a parasitic draw and you'll get info on finding one.

9/2/14 @ 6:47 PM
MEMBER since 5/12/09
I've got a battery question. I bought a new starting battery about a month ago and put the muffs on and started up the motor perfectly. Now, a month later, I brought the boat out for a week long trip in Minnesota next week and the battery is dead. I checked my switches for all the auxiliary power and they were off. I was able to charge it back up and the tester says it is up to specs. With the motor running and the tester on the terminals, the meter did not put the needle in the "charging" white zone. Does this mean my alternator is shot? What do you think it would cost to replace the alternator on a Mirrocraft Outfitter with a 90 Honda on it? I'm not too familiar with this kind of stuff and would appreciate any help.

5/20/14 @ 6:19 AM
MEMBER since 7/9/12
dsinwi, I have the same Optima that I purchased before last season. I was very pleased with it last year. I use it for all the boat electronics and troller. It came with a good warranty. I think you will like it.

5/19/14 @ 7:05 AM
User since 1/24/02
Thanks for all the info guys, way more than I expected. After reading most of this and talking with the rep at the store I ended up going with a blue top 27 Optima. It was qutie a bit more than I wanted to spend but I would expect it to serve me well over the long haul. I've got 4 more dedicated to the trolling motor that will probably need replacing in the next year or two, not looking forward to that expense.

5/19/14 @ 5:30 AM
B Fish
User since 6/26/10
You can get a lot of good and different responses on this page. But if I were you I would call a battery manufacture and ask to speak with a tech.

Northen Batteries is located in Madison Wis and actually makes (most of the batteries out there - there web page shows them). They are very easy to work with and nice people who know what they are talking about.


That's what I would do if I were you.

Good luck and have a good day Big Smile

5/19/14 @ 1:54 AM
MEMBER since 12/19/01
The only issue with using a deep cycle as a starting battery is the charging voltage put out by the alternator on the motor, which is a bit too high for (flooded-type) deep cycles, and may result in a lot of gassing and water loss. (Depending on how you use your boat - mostly trolling vs. mostly anchoring.)

AGM (sealed) batteries can generally tolerate the higher voltage, so if I were to make a recommendation for someone with a smaller (<100Hp) motor and only 1 battery, make it an AGM type.

The only reason for the high CCA rating requirement of some motors is the very poor starting efficiency. There is no good reason a marine motor should need the same CCA as your car's battery, since nobody tries to start their outboard when it is -20F.

So, for the record, Fishing Bum is pretty much correct.

BSEE UW-Madison '83, and charging industrial lead-acid batteries since '95 or so...

5/18/14 @ 9:37 PM
User since 10/13/04
Not sure if the motor manufactures requirement for CCA is high or not, but I have been using deep cycle for starting-electronics-accessory battery for years. This is with a F115 yamaha. I do carry jumper cables just in case to jump from my trolling batteries but have never needed them. I get way longer life on the battery in years and in time using electronics-accesories. My kicker does not have an alternator and I use a lot of juice if trolling between electronics radio etc. edit I used a 27 series.

5/18/14 @ 5:59 PM
MEMBER since 6/15/01
thanks wet-net for the link... knew there was a difference and a reason, but not knowing why exactly, just had to go on best practices

that explained it clearly, at least for me

still learning...willing to learn... thanks all

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