Logo
FULL SITE MENU

12 vdc out of a Merc 25 HP EFI ?

D

davecason

New member
Hi Folks,

I just got my first tin boat and outboard ever a few weeks ago. It came with a 2016 Merc 25 HP EFI 4 Stroke and it's a 1A25213EK model.

I've been out a few times and now have a silly? idea for the engine. Is there a way to get 12 vdc out of those motors when they're running?
I've got a small fish finder I'd like to power and get some LED Nav lights on the boat.

I'd like to toss in a small sealed lead acid battery in to the boat to run those things, maybe something like a small Powersonic PS-12180NB Battery.
So I'm just wondering if I can buy that engine harness plus and tap the 12vdc output (if it exists ) and feed that to a regulator to keep the battery up?

Nothing else going IN TO the motor or anything like that - just wondering if I can get 12vdc out someplace?

Cheers'
Dave
 
davecason said:
Hi Folks,

I just got my first tin boat and outboard ever a few weeks ago. It came with a 2016 Merc 25 HP EFI 4 Stroke and it's a 1A25213EK model.

I've been out a few times and now have a silly? idea for the engine. Is there a way to get 12 vdc out of those motors when they're running?
I've got a small fish finder I'd like to power and get some LED Nav lights on the boat.

I'd like to toss in a small sealed lead acid battery in to the boat to run those things, maybe something like a small Powersonic PS-12180NB Battery.
So I'm just wondering if I can buy that engine harness plus and tap the 12vdc output (if it exists ) and feed that to a regulator to keep the battery up?

Nothing else going IN TO the motor or anything like that - just wondering if I can get 12vdc out someplace?

Cheers'
Dave
Click to expand...

You already have a battery- use that. Other accessories don't "go into' the motor. Depending on how long you're on the water, on average, you could use that small battery but make sure it doesn't kill it too quickly. If you have a multimeter, measure the Current used by the fish finder and size the battery using that.

You don't need to go to Digikey- these can be bought at lower price and it doesn't need to be that brand.
 
Well I may not ! I found this kit everywhere for the bargain price of $400-$500 bucks........ (grin)

It might be: CHARGING KIT Battery P/N 898103A90

The Mercury part number 898103A90 is a Battery Charging Kit, and the direct replacement is the same part number, 898103A90,
as it is the official part itself. This kit is designed for manual start 25-30 Hp EFI Four-Stroke outboards with serial number 0R106999
and above.

What it is: A genuine Mercury Marine battery charging kit that provides a 15-amp charge to a 12-volt battery at wide open throttle.

What's included: The kit typically includes a voltage rectifier, wiring, and mounting hardware.
Compatibility: It is specifically for 25-30 Hp EFI Four-Stroke outboards with serial numbers 0R106999 and above.

For that price I might skip it ...... that's steep! But I do need to check the S/N anyway so it may not fit ......

Cheers'
Dave
 
davecason said:
Well I may not ! I found this kit everywhere for the bargain price of $400-$500 bucks........ (grin)

It might be: CHARGING KIT Battery P/N 898103A90

The Mercury part number 898103A90 is a Battery Charging Kit, and the direct replacement is the same part number, 898103A90,
as it is the official part itself. This kit is designed for manual start 25-30 Hp EFI Four-Stroke outboards with serial number 0R106999
and above.

What it is: A genuine Mercury Marine battery charging kit that provides a 15-amp charge to a 12-volt battery at wide open throttle.

What's included: The kit typically includes a voltage rectifier, wiring, and mounting hardware.
Compatibility: It is specifically for 25-30 Hp EFI Four-Stroke outboards with serial numbers 0R106999 and above.

For that price I might skip it ...... that's steep! But I do need to check the S/N anyway so it may not fit ......

Cheers'
Dave
Click to expand...
A marine battery is very different from the one you're looking at- the small one wants to be charged at about 2.4Amps, not 15Amps.

It will cost a lot less if you use a 12V battery for a lawn mower and recharge it after use.
 
jimn said:
A marine battery is very different from the one you're looking at- the small one wants to be charged at about 2.4Amps, not 15Amps.

It will cost a lot less if you use a 12V battery for a lawn mower and recharge it after use.
Click to expand...

Yep, for the price of that harness and regulator I suspect you're right !! :)

Cheers'
Dave
 
jimn said:
A marine battery is very different from the one you're looking at- the small one wants to be charged at about 2.4Amps, not 15Amps.

It will cost a lot less if you use a 12V battery for a lawn mower and recharge it after use.
Click to expand...
Just because an alternator has an output of 15 amps does not mean that any particular battery will be receiving a current of 15 amps.

The alternator kit provides for up to 15 amperes of output. The battery will take what the battery will take given the battery's state of charge.
 
Last edited:
davecason said:
Hi Folks,

I just got my first tin boat and outboard ever a few weeks ago. It came with a 2016 Merc 25 HP EFI 4 Stroke and it's a 1A25213EK model.

I've been out a few times and now have a silly? idea for the engine. Is there a way to get 12 vdc out of those motors when they're running?
I've got a small fish finder I'd like to power and get some LED Nav lights on the boat.

I'd like to toss in a small sealed lead acid battery in to the boat to run those things, maybe something like a small Powersonic PS-12180NB Battery.
So I'm just wondering if I can buy that engine harness plus and tap the 12vdc output (if it exists ) and feed that to a regulator to keep the battery up?

Nothing else going IN TO the motor or anything like that - just wondering if I can get 12vdc out someplace?

Cheers'
Dave
Click to expand...
Please confirm your engine serial number please.
 
davecason said:
Well I may not ! I found this kit everywhere for the bargain price of $400-$500 bucks........ (grin)

It might be: CHARGING KIT Battery P/N 898103A90

The Mercury part number 898103A90 is a Battery Charging Kit, and the direct replacement is the same part number, 898103A90,
as it is the official part itself. This kit is designed for manual start 25-30 Hp EFI Four-Stroke outboards with serial number 0R106999
and above.

What it is: A genuine Mercury Marine battery charging kit that provides a 15-amp charge to a 12-volt battery at wide open throttle.

What's included: The kit typically includes a voltage rectifier, wiring, and mounting hardware.
Compatibility: It is specifically for 25-30 Hp EFI Four-Stroke outboards with serial numbers 0R106999 and above.

For that price I might skip it ...... that's steep! But I do need to check the S/N anyway so it may not fit ......

Cheers'
Dave
Click to expand...
There is no replacement kit. The kit is the same as it has always been.

 
boscoe said:
Just because an alternator has an output of 15 amps does not mean that any particular battery will be receiving a current of 15 amps.
Click to expand...

Well yes and no, the output of an alternator or power source is not as relevant as the input a battery can take but you can fix that.

For example my battery box I built is four 270Ah LiFePo4 batteries on a12 vdc JK BMS ..... I set it up so I can charge it up with solar, or DC to DC charging from a vehicle that's switchable from 2-4-or 8 amps and I can also charge it up with 120VAC in.

That's just using a Circuit Test PSF240-12 its just a 120 VAC Power Supply that puts out a max of 20 amps. If the batteries are low, the BMS lets it charge at about 18 amps in and as the batteries charge and it "gets full" it eventually drops down to 6 and then 2.3 and by the time each cell is at 3.4 vdc that I want, the BMS it only inputs about 1/2 an amp and that's also balancing the entire time.

Using a small single PowerSonic or a AGM or a marine battery in the boat is one thing - I've have to see what's in that kit and mostly what's in that regulator that the kit comes with? I kinds doubt that they'd leave it stamped with a manufacturers part number on it so good luck seeing the schematic or what's in it.

It's all moot anyway because I sure as heck won't pay the $400-$500 bucks most marine shops are asking for a bit of wire and a rectifier. I'd sooner build something .........

It would be project time tho, wiring kit pin-out, then rectifier schematic hunt, and then source a regulator for the whole thing! That sounds way toooooo much like work! At idle I'd be guessing that I'd see an amp or two out of the engine, and at full throttle they say it'll hit 15 amps. So, if the XYZ battery is full - it'll bitch like heck if it see's 15 amps in ..... (grin)

Like Jimm said before ..... go get a battery of your favorite flavor and drop it in the boat for the day, power whatever, and then yank it and charge it up overnight . Rinse and repeat .......
 
davecason said:
Oh it is a 1A25213EK from 2016 but I'm not gonna get that wiring kit so it's moot. We'll see how bored I get this summer ....... :)
Click to expand...
Mercury serial numbers usually have six digits following the letter designator. For instance

"This kit is designed for manual start 25-30 Hp EFI Four-Stroke outboards with serial number 0R106999
and above."

1A25213EK does not come up in the Mercury Marine system.

 
All you need is to wire the AC output from your alternator stator to the voltage regulator. Two wires.

Then connect the two output wires from the rectifier/regulator (red and black) to your battery.
 
boscoe said:
Just because an alternator has an output of 15 amps does not mean that any particular battery will be receiving a current of 15 amps.

The alternator kit provides for up to 15 amperes of output. The battery will take what the battery will take given the battery's state of charge.
Click to expand...
That's true, but if the regulator goes bad, the battery would be damaged.
 
jimn said:
That's true, but if the regulator goes bad, the battery would be damaged.
Click to expand...
There are many different ways that an alternator can fail. If the regulator fails with no current output then the battery won't be harmed. If the regulator fails with excessive voltage output then possibly the battery could be damaged.

But is that any different than any model of motor that has an alternator?

Most seem to die in a manner that simply provides no output. In which case no harm no foul other than the expense of replacing a failed part.
 
Well you know as Boscoe cleverly found (AND THANKS) they're are aftermarket regulators you can get and THATS actually a fair price too!

So for sure that one would be worth considering, as for the part failing, yea, it could but there are devices I can put in line to handle that
sort of event anyway. There not much to a regulator actually ......

Will it fit? Who knows? My serial number is an OR753XXX one and that other number was/is the model of the motor MOD # 1A25213EK.

We'll see - its new boat to me so I have a billion things to do to it next season, she's put up for the winter now so we'll see how ambitious I get next season! (grin)

Thanks for the post tho, I'm gonna go look at that regulator ...... for that price its definitely worth a glance !
 
You can call Dbelectrical and maybe they can tell you/sell you the precise part number for a Mercury Marine regulator for your specific motor.
 
Back
Top