Superjet Dead Battery Issue

[user_error]

Hi all, I’m looking for some confirmation of a theory that my battery is bad.

Backstory:
This past weekend I was playing around on the sj jumping boat wakes all weekend. Launched off one, came down, lanyard popped out, ski dies.

Try to restart, no power. Very faint click from starter solenoid is all. End of weekend.

At this point I suspect that my ground cable broke, or something similar. Back at home I add a second ground cable and use a jump box to get the ski going. It immediately starts.

Next, I remove the “added” ground cable and use the jump box, ski starts immediately. So, my original ground cable is good.

I take the battery and place it on a battery-tender. After a little while it turns to green, indicating a full charge.

Ski will not start with just the battery, it needs the jump box to start. Jump box leads are connected to the battery cables and it starts perfectly. So, no cdi issues, no cable or grounding issues.

Next, I tried a test. Battery is removed from ski, jump box is connected to battery cables, and I start the ski. Then, I switch the jump box power to “off” and the ski immediately dies.

I had suspected that the stator voltage would keep the ski going after jump box power was disconnected, but this was not the case.

Additional info: I had the battery load-tested at a local battery supply store. At home the battery showed full charge on the tender. At the store it only read 8.3 volts and 34 cranking amps out of the rated 310 cranking amps.
Battery is a sealed Yuasa ytx20 battery new at the beginning of the season.

My question:
It seems obvious that the battery is bad based on its load test results. However, do I have another issue going on with the ski not being able to run on it’s own once the jump box power is disconnected?

I am not well-versed enough in the circuitry of these things to definitively say whether it should run on its own without a power source or not.

Is my stator or voltage regulator likely bad, or did I merely end up with a bad battery? I would like to hear some input before I go forward tearing into things I don’t need to be messing with.

The ski is question is a 2015 sj lites spec. It is stock engine, stock exhaust, stock carbs, running a 61x stator/flywheel and a msd enhancer.

 

[camper357]

Put a multimeter on your battery and start your ski up. While running does the voltage jump back up to a normal level? If the voltage jumps back to a normal level while the ski s running you most likely do not have a charging problem. If you have a charging problem your battery is most likely just severely discharged. You can google the procedure to revive a dead agm battery. You may or may not be able to save it.

 

[user_error]

Put a multimeter on your battery and start your ski up. While running does the voltage jump back up to a normal level? If the voltage jumps back to a normal level while the ski s running you most likely have a charging problem. If you have a charging problem your battery is most likely just severely discharged. You can google the procedure to revive a dead agm battery. You may or may not be able to save it.

Just to confirm, if I put the battery back in the ski and start it and notice the voltage jump to a "normal" (12+ volts?) level, then something in the charging system is bad?

That sounds counter-intuitive. Wouldn't it imply that the charging system is good if the voltage jumps to a normal level when running?

 

[mikidymac]

I could be wrong but I think you have to have the battery in as it completes the electrical circuit for the ski to run, even if the battery is bad. The easy way to check the charging system is to start the ski and with it reved up to around 4,500 rpm you should see at least 13.5 volts on your multi-meter. Not sure about the Yamaha's but on a some skis the jump packs can fry the computers/cdi.

 

[camper357]

Just to confirm, if I put the battery back in the ski and start it and notice the voltage jump to a "normal" (12+ volts?) level, then something in the charging system is bad?

That sounds counter-intuitive. Wouldn't it imply that the charging system is good if the voltage jumps to a normal level when running?

Sorry typed too fast. If voltage jump up then charging system is ok.

 

[user_error]

Testing the battery voltage while running leads me to believe the charging system is bad.

I charged the battery and put it in the ski. Before starting the ski the voltage across the battery measured 9.3. Obviously this is too low.

I used the jump box to assist with starting the ski. Once it was started, I disconnected the jump box and let the ski run. I put the multimeter leads in the terminals while it was running and still only measured 9.3v +/- .5v. It would bounce around a little bit but not much. I also measured voltage while raising engine rpms and the voltage remained in the same range (low to mid 9 volt range).

So, my charging system is no good.

This leads me to either the voltage regulator or the stator lighting coil.

I will report back the values I find after testing them.

Update:
Using my cheap multimeter I measured the following values:

1.5 ohms across the lighting coil (2 green wires from stator). Service manual calls for 1.14 to 1.40 ohms at 68*. Temperature at time of test is higher than 68*.

355 ohms across the charge coil (brown/ white wire and ground (black) wire from stator). 61x specs call for 365 ohms +/- 10% at 68*.

15.4 ohms across the pulser coil (white/red wire and ground (black) wire from stator). Specs call for 12.6 to 15.4 ohms at 68*.

I also performed a cranking voltage test on the lighting coil. With the jump box attached I am only getting 2.6 volts AC when the engine turns over. Multiple sources say this should be 6 volts minimum.

With that info I believe my lighting coil is bad in my stator.

 

[camper357]

Now you need to put your agm battery on a dumb charger to see if you can bring it back to life. Newer chargers with electronics will not charge a really low battery. Just because your battery has been severely discharged does not necessarily mean it is now garbage. Throw it on an old school charger for 10 minutes and see if it is raises the voltage. When it get over 12 volts then you can put it back on your trickle charger so you do not overcharge it. Then let it rest and see if it will hold a charge again.

 

[user_error]

I will try that, thanks for the tip. I'd hate to toss this battery already because it was a brand new Yuasa sealed AGM purchased about 4 months ago.

 

[Rushford_Ripper]

Had similar issues this past weekend. Big air off a wave, landed, fell off, dead nothing not even a click and the bilge wouldn’t even work! Swapped the battery and started right up. I believe a cell cracked internally.

 

[user_error]

Likewise, I believe I had 2 issues at once. The battery is done for and the stator was not charging.

I replaced the non-working stator with a backup that passed both static (ohms test) and dynamic (cranking voltage and voltage while running) tests and replaced the bad battery. The superjet worked just like normal again last weekend.

 

[Pro-pulsion]

I would say that your battery is the most likely culprit. I did this too a few years ago...maybe even as far as 4 or 5 years ago, brand new battery, third run out and landed on the left side of the hull a little bit harsh. It popped off the lanyard and when I reconnected I had the virtually non-existent solenoid click. There was only enough capability there to keep my bilge running. I went out and replaced that cheap Walmart battery with a Yuasa conventional battery and am still running it today. As for the voltage regulator test, I just did this test recently on my ski vs. another regulator from a Blaster, very similar results and both systems work just fine but those test results did not come anywhere close to what Yamaha shows in the manual. I have also experienced this with their CDI tests. I am currently in the process of building a comparative sheet for what the everyday multimeter results are vs. the manual specs. I have also experienced this nonsense with Kawi and their specs on CDI's in the manuals. I am assuming that the OEMs are using some specific tester that they expect the dealers to buy at an unrealistic premium so you can get the test results they claim in the manuals. It doesn't make sense that between 3 different testers I have, all three show the same exact measurements on 2 different CDI's but all three testers are nowhere near what is stated in the manual.

I would say get a conventional Harbor Freight resistor style battery load tester and give the battery a good load testing. I'm counting on it being a done duck. The reason your engine won't stay running when you flipped the switch on the boost box is because you do need a continuous circuit through the battery from the charging system. Your battery is your electrical system's variable resistor and the starting ciruit does supply the rest of the electronics on the startup. There is a positive lead juming off of the start solenoid over to the voltage regulator and from there to the CDI etc. When you break the connection between the battery it's about the same as touching the stop button. I'll try yo get you some values on 2 different 62t ebox voltage regulators tomorrow and show the comparison between them and the manual. This way you can decide if your results are showing a good regulator or not. I should have you some results by about noon tomorrow.

 

[Pro-pulsion]

Ok, so I was able to test a known good regulator/rectifier. Below are the specs identified in the manual, further past that are the results I acquired from 2 different mutlimeters.

Service Manual Specs all in K-ohms :
+ test lead first, - on following wire :

Red - Black = infinite
Red - Green 1 = infinite
Red - Green 2 = infinite

Black - Red = 2~20 k
Black - Green 1 = 1~10 K
Black - Green 2 = 1~10 K

Green 1 - Red = 1~10 K
Green 1 - Black = 2~15 K
Green 1 - Green 2 = 3~30 K

Green 2 - Red = 1~10 K
Green 2 - Black = 2~15 K
Green 2 - Green 1 = 3~30 K

Meter One Results:

Red - Black = 1.19 M
Red - Green 1 = 0.39 M
Red - Green 2 = 0.19 M

Black - Red = 1.47 M
Black - Green 1 = 3.10 M
Black - Green 2 = 1.17 M

Green 1 - Red = 2.85 M
Green 1 - Black = 4.35 M
Green 1 - Green 2 = 3.51 M

Green 2 - Red = 1.64 M
Green 2 - Black = 1.16 M
Green 2 - Green 1 = 1.32 M

Meter Two Results:

Red - Black = 2.29 M
Red - Green 1 = 1.11 M
Red - Green 2 = 1.69 M

Black - Red = 1.24 M
Black - Green 1 = 0.93 M
Black - Green 2 = 0.84 M

Green 1 - Red = 0.92 M
Green 1 - Black = 1.27 M
Green 1 - Green 2 = 1.48 M

Green 2 - Red = 1.00 M
Green 2 - Black = 0.88 M
Green 2 - Green 1 = 0.79 M

Obviously there are some widely differing numbers here but the common threads are it is a known good regulator/rectifier and all results are in the Mega-ohms values where the service manual claims they should either be infinite or in the Kilo-ohms values. This is why I believe the OEMs are using something specific that will cost you part of your house to own just to get their numbers. I wanted to test a second regulator/rectifier but it's currently being used in my ebox and I know the last time I tested it which was only a couple of weeks ago it came up with the same approximate values, all in the Mega-ohms values on three different meters. If I had more time to test today I would have used the third meter but this was just to show that the standard meters we can get/afford, which is what most techs will be using too, vary immensely from what the OEMs will list. I have seen this same scenario with Kawi CDI's and regulators.

 

[Jetfiend]

Likewise, I believe I had 2 issues at once. The battery is done for and the stator was not charging.

I replaced the non-working stator with a backup that passed both static (ohms test) and dynamic (cranking voltage and voltage while running) tests and replaced the bad battery. The superjet worked just like normal again last weekend.

This thread has a lot of good info for people with E-issues, I'm saving this stuff.

If that Yuasa is only 4 months old, you should be able to get a replacement under warranty (depending where you bought it).