Cranking Battery Getting Drained New Z520C Ranger

[carolina_cowboy01]

2021 Mercury 250 PXS4 TQM #3B008468

So I posted this a while back (8/1/2021) in the Ranger Forum and thought it would be of interest for this group:

I’m having an issue with a new 2021 Z520C Ranger from Pro’s Choice (not their issue, just saying where it came from) where the cranking battery was getting killed in half a day of fishing. Went about it in three steps so far and still having issues.

1) Was leaving the 12 Live at the console running, while fishing up front with that Live unit left running, battery was dying and impacting 4S motor operation
2) Started putting the console unit in standby mode when up front, battery was still dying (just a little later) and impacting 4S motor operation
3) Replaced the Interstate Dual P 31AGM with an X2 Dual P 31AGM - the “gold” standard for ProXS cranking batteries, battery was still getting run WAY down when tester was used after getting off of the water
4) Added a supplemental charger with built in tester to ensure cranking battery was being fully charged as I had a tournament this weekend and had read that the built in Dual Pro Li capable capable chargers would often only charge an AGM cranking battery to ~75% (which it was in fact doing) - by adding this the battery was getting a 100% charge - Tournament day followed all of my standby routines and added putting the unit up front in standby when not needing it as I was worried about the 100+ mile run (round trip) and getting back. All went according to plan however 1/2 mile from check-in the engine went into safe mode which it will do on Low Voltage. Luckily it happened when I was this close to check-in so no tournament issues. Got the boat back home and put it on the tester, sure enough drained almost completely.

So now I need to figure out what is going on and if it is the C Monster issue referenced in another thread. Anyway I can check this on my own, or if there are any other things to look at? Brand new, and smart gauge indicates no engine issues.

8/6 Update: Will keep everyone updated - all switches are fine - spoke to my mechanic and he has three Mercs being treated for the same issue - speculation is alternator made in .... yep you guessed it land of the CCP ... going in the shop for diagnosis tomorrow

8/7 Update: Well here is an interesting turn of events - My mechanic (an authorized Mercury dealer and mechanic) discovered that none of these three alternators (including mine) were grounded AT ALL - the grounding strap was missing from the factory. Mine also had a shredded belt. This was initial inspection dropping off this am - will post more after service.

9/3 Update: Forgot to post the latest: Grounding strap installed, belt replaced under warranty, now after a full day of use the X2 takes <20 minutes to get back to full charge. Count me a happy camper. As a side note he said that Mercury Maintenance manuals were the best, but when he looked it up, there were no instructions for the Ground Strap install, however the part appeared in the Parts Diagram Drawings. Really odd and might be contributing to a factory assembly issue (new personnel training, or...)

[EuropeanAM]

Hmmm… don’t recall seeing even 1 groundstrap (have had quite a few off
during other repairs).

[thommo59]

I would like to hear more about this, I can't find an "alternator ground strap" anywhere in the parts cataloque and Don can't recall seeing one. Do you know where exactly he is referring to this strap is installed?

[BarryFL]

Sounds like you may have replaced a perfectly good battery. Mercury should reimburse you for that, IMO. QC is dying quickly across a lot of industries.

[carolina_cowboy01]

I would like to hear more about this, I can't find an "alternator ground strap" anywhere in the parts cataloque and Don can't recall seeing one. Do you know where exactly he is referring to this strap is installed?

I’ll ask

[carolina_cowboy01]

Sounds like you may have replaced a perfectly good battery. Mercury should reimburse you for that, IMO. QC is dying quickly across a lot of industries.

I was moving to an X2 anyways - Meets the needs of the motor much better

[thommo59]

I’ll ask

Thank you

[EuropeanAM]

Does not use a ground strap, would be the reason it's not in the parts catalog (or on the engine).

[carolina_cowboy01]

Does not use a ground strap, would be the reason it's not in the parts catalog (or on the engine).

This is what my mechanic provided as it is in the parts display / catalog, but not in the maintenance / install manual - I realize this is for a V6s, but he said was the same for V8s. Part no. 10 Ground Continuity Cable

Merc Alt Ground Strap.jpg

[EuropeanAM]

The V6 uses a different bracket on that side of the engine (composite as I recall), thus a ground strap is installed (and shown) for V6 models.

Not used on the V8's.

[basspro57]

I wonder if the block paint and the threadlock on the alternator mounting bolts was creating enough insulation that the alternator wasn't grounded properly (and poor charging when running). In my full time profession, grounding of electronics is very important. We also see what works in design doesn't always work well in production. The prototypes are not always built the same as the unit going through the assembly line. If Mercury believes that they can save a few dollars and not use a ground strap...then they will leave it out. The technician fixed the problem with a ground strap and seen it 3 times so its good information for those who work on them (and maybe that feedback needs to go back to Mercury engineering).

[EuropeanAM]

I'll definitely pay closer attention to that bracket on the V6 the next time I have one in here. It is also feasibly possible that a couple of the V6 brackets got mixed up (which would act like an isolator and require the ground strap).

Definitely must have a good ground. Good info.

[carolina_cowboy01]

I wonder if the block paint and the threadlock on the alternator mounting bolts was creating enough insulation that the alternator wasn't grounded properly (and poor charging when running). In my full time profession, grounding of electronics is very important. We also see what works in design doesn't always work well in production. The prototypes are not always built the same as the unit going through the assembly line. If Mercury believes that they can save a few dollars and not use a ground strap...then they will leave it out. The technician fixed the problem with a ground strap and seen it 3 times so its good information for those who work on them (and maybe that feedback needs to go back to Mercury engineering).

Thanks for that - I spoke to my mechanic again (BTW it is Neal at R&K Marine in Knightdale, NC) and he called Mercury about it, they told him the V8 should be the same and installing the strap would be appropriate. All I know is I run my boat. I brought it home June 18th and it already has ~60 hours on it. When it comes off the water now the X2 barely needs charging and the volts onboard read 14.6-7 constantly, i.e. problem solved.

[EuropeanAM]

I do not doubt that adding the ground solved YOUR engine's problem. That indicates something on that engine varied from the components it should have.

The ground strap is used SPECIFICALLY on the V6 products as they have different lower alternator brackets, AND use RUBBER mounts. The ProXS V8 models do not require the separate ground strap, UNLESS something has been introduced to the engine that should not be present (brackets or alternator mounts).

[EuropeanAM]

UPDATE: Beginning in late 2021 (November-December timeframe), V8 Fourstroke flywheels began to switch over to a SOLID flywheel (no rubber dampner).

Engines equipped with the solid flywheel (V6/V8) will have rubber mounts for the alternator bracket, AND a Ground Strap for the alternator (going forward).

Anytime the flywheel is replaced (or the powerhead) on V8's with production dates prior to 1/1/22, the installer will likely need to install the updated alternator mount kit.

Dealers should reference Reference SB 2021-24 for part numbers/details.

[thommo59]

Looks like you had a great mechanic that both had the initiative and genuine skills and interest to resolve your problem. Now that we know there was this earth strap and bracket update very close to your serial number, maybe you got 1 of the first pre production brackets.
It’s so encouraging to actually hear that it was diagnosed, fixed and not just “the computer shows no faults” therefore it must be user error.
Enjoy your time on the water