'19 40hp not charging battery

[@Reel_Chris]

At the request of a mod, this is now being posted here after being posted in the electronics forum and then the Mercury forum.

I'm working with a 2019 Tracker Pro 170 with a 40hp (serial 1C552353) and the original group 24 cranking battery. When fully charged, the battery tests at 13.5 volts on a multi-meter immediately after removing the charger and 12.79 an hour later.


After the motor is started, the battery is steady at 12.5 volts via meter. However, when running at 3000 and 5000 rpm, the voltage at the battery stayed at 12.5. This is confirmed at the graphs as well. So, the motor is not sending anything to the battery at all. After running for 12 hours a few days ago, voltage dropped so low the engine quit running, which leads me to believe it's not sending any juice to the EFI either and just relying on the battery to power everything. So, somewhere there's a problem, but I have no idea what. Fuse? Voltage regulator?


Any suggestions on how to diagnose and/or fix the issue would be greatly appreciated!


I would also happily take suggestions on what battery to replace the group 24 with. A group 27 will definitely fit in the space the 24 sits in now. A 31 *might* fit. Thanks again. The present battery is rated at 400CCA.


Thanks!

[Pulsare2020]

There is a lot of data on this site regarding recommended batteries and it is good reading. I would carefully check all you connections, including the battery switch, but if they are good and the voltage at your battery is only 12.5V at 3000 rpm, I doubt your issue is the battery (although it could be compromised after months of this low charging voltage). You can check the voltage directly at the alternator to eliminate the battery / wiring connection issues. You could install another battery (from your car just for this test) and measure the battery voltage at 3000 rpm to eliminate the battery as a possible cause.

[SilverFox579]

I would carefully check all you connections, including the battery switch, but if they are good and the voltage at your battery is only 12.5V at 3000 rpm, I doubt your issue is the battery (although it could be compromised after months of this low charging voltage). You can check the voltage directly at the alternator to eliminate the battery / wiring connection issues.

^^^^+1^^^^

You've already confirmed the battery will take and hold a charge from a remote charger. Fully charge your battery and have it load tested. Since your battery voltage does not increase with engine running, your charging circuit has a problem and where you need to focus your testing. A higher capacity battery won't solve that. Start by making sure all connections are clean and tight first, no wing nuts on battery terminals.

[@Reel_Chris]

I'm looking for a bigger battery to power electronics and other stuff for fishing while the charging system is still out of commission. I've read the list but I'm not finding a lot of the recommended batteries locally. Does anyone know anything about the Exides that home depot carries like these two?

https://www.homedepot.com/p/Nautilus...=aw.ds#overlay

https://www.homedepot.com/p/Nautilus...09649?#overlay

[EuropeanAM]

Have you checked the voltage regulator fuse yet?

[OCBA]

I have not, mostly because I haven't figured out where it is. Is it any of these?

Screen Shot 2022-07-29 at 9.02.03 PM.png

25	FUSE, Mini - Yellow - 20 Ampere (#88-832969T20) Qty Required For Repair: 3 Minimum Order Qty: 5 Supersedes: 88-832969 20	$3.74 $4.40
	25	FUSE, Mini - Clear - 25 Ampere (#88-832969T25) Minimum Order Qty: 5 Supersedes: 88-832969 25	$3.83 $4.50
	25	FUSE, Mini - Tan - 5 Ampere (#88-832969T05) Supersedes: 88-832969 5	$5.44 $6.40
	25	FUSE, Mini - Blue - 15 Ampere (#88-832969T15) Minimum Order Qty: 5 Supersedes: 88-832969 15	$3.32 $3.90
	25	FUSE, Mini - Gray - 2 Ampere (#88-8329692)

[@Reel_Chris]

Today I learned a group 31 battery will absolutely not fit in the space available.

In the course of not fitting a group 31 battery, I made sure all of the existing battery connections were tight and clean.

[@Reel_Chris]

Just got done looking the engine over for a second time trying to find fuses. Found this tucked away:

IMG_20220801_204055934.jpg

At first it looked like they were all ok, but my meter said the 25 amp had no continuity. Upon closer inspection:

IMG_20220801_204710856.jpg

I may have found the problem. I'll find out tomorrow when I get a replacement.

[EuropeanAM]

There you go... now if you have a second blown fuse event, you'll need to start looking for the cause. Overloading the charging system (loosely connected, reversed polarity, bad, severely discharged or simply incompatible battery) is the most common cause.

[@Reel_Chris]

To wrap up the story - with a new fuse, the engine began charging the battery again. Voltage hovered around the mid 13's at idle up to about 14.1 volts at 5800 rpm. The battery finished the day almost full charged. Thanks all for the help.

[EuropeanAM]