Questions and concerns about SX190 not starting

[jet_boater_paul]

Hello - I recently purchased a 2012 SX190 and on 2 occasions, I had a situation in which the engine wouldn't start while out on the water. The first time it happened, we had been out on the water all day, music playing, and went to start it, but the starter could not get the engine to fire up. The LCD screen then displayed an error: LOW BATTERY with a long, loud beep. A few minutes later, tried again, and this time it started up. The funny thing is, the voltmeter on the LCD read 14.3 V. Got back to the dock just fine. I removed the battery to inspect it, and the sticker showed that it was from 2013 (it was an Everstart with 690 MCA). To be safe, I just bought a new one. I got an Everstart Marine Max with 1000 MCA. Installed it, and it worked great for our next outing. But towards the end of that outing, the same exact thing happened. Boat wouldn't start. Got LOW-BATTERY message. Waited, tried again, didn't start, waited some more, and eventually it started. Almost immediately the voltmeter read 14.3 V. On this outing, I didn't have the stereo on whatsoever - so I know I didn't have any extra electronics going that would drain the battery. I also checked the new battery before installing with my multimeter - read as 12.7 V - so I'm very confident the new battery was just fine.

When I was testing out the SX190, the owner told me that in order for the magneto on the engine to properly charge the battery, you have to be going at least 7,000 RPM. Wanted to ask the community if this info is accurate? If it is, I guess that would explain what happened to me on the water those 2 times, because on those outings we were doing a lot of tubing and skiing, and generally keeping the boat in the 18-20 mph range, and RPMs were definitely lower than 7,000. So maybe the battery was getting drained because I didn't have enough RPM to charge-it while going?

Another question is, is it normal for the LCD voltmeter to read as 14.3 V while the boat is going? Obviously this is a 12 V marine battery --- I assume with the magneto putting juice back into the battery, that that would explain the 14.3 reading? Am I correct to assume that?

Since these 2 episodes, I bought two things: one of those NOCO battery boost jumper kits to keep on the boat, and I bought a trickle charger to charge my battery while it's in storage during the week. But I would like to ask this community if what I experienced is normal? I.e., is it normal that I'll drain the battery to the point where there's not enough juice to start it, due to a long day of low-RPM boating? Or should I be taking more drastic action (taking the boat in to get checked / serviced)?

Thanks!

-Paul

 

[FLBulldogger]

WELCOME aboard to the best dearn forums on the ole interwebs. You are going down the right path with the new battery, NOCO, and the charger. With that said I would take a CLOSE look at the battery cables and inspect for rust, corrosion, scaling, etc. Sand down to a shine any rough look areas. Also look around the battery compartment and make sure all cables and wires are attached and make sure they are TIGHT. Last week at the ramp a fellow boater backed down untrailered the boat and then nothing, I saw he was dead in the water and offered to let him jump using my battery booster, I walked onto his boat and as I was connecting the booster I checked his connections and sure enough they were loose, I tightened them down with a wrench I had and viola she fired right up. If you can trace them back and check the other ends. This might be the cause of the sporatic starts. As far as the ALARM that might be a remnant of the previous alarms, sometimes just disconnecting the battery overnight can clear the alarm, others like myself have had to get 3 or 4 clean starts to clear the alarms. The motors have a stator not an alternator and for the lack of technical jargon they kind of trickle charge when you are running, haven't heard of the 7k RPM thing so I can't speak to that, but I am sure some of more technical folks on here will jump in. Good luck and let us know how it turns out!

 

[jjmparsons]

I've never heard that about the RPMs at 7k either and needless to say it kind of raises my eyebrow a little. When we go out on the boat, our general cruising speed is around 28-30 Knots and that is tops for us. Not because the boat wont do it, we just like to gingerly cruise. Having said that, our RPMs go nowhere near 7k and we spend literal hours on the river just floating with the radio on. Definitely curious to hear what the mechanical and more experienced gurus have to say on this topic.

 

[marcham]

When you read 14.3V, was that before or after starting the engine?

If after, that is not unusual. 13.8V to 14.5V with engine running is normal. While charging, the voltmeter cannot be used to determine the battery state of charge, you would need an ammeter to do that. The voltage remains relatively constant under charge and the current gradually decreases. This is how the regulator/rectifier functions (we don't have alternators on our boats, we have a stators that provide high voltage variable frequency into regulator/rectifier which converts it to DC. Extra power from the stator is normally shunted to ground which converts it into heat). The regulator is really only sending 5-15A to the battery. With a severely depleted battery, the stator and regulator may never fully top-up the battery, as that could take 8-10 hrs. The stator is really only designed to replenish the battery after a start, not after running the radio for hours on end with the engine off. They are very simple charging devices, not like the 3-4 stage chargers that you can use when plugged into 120VAC (shore power).

Technical Article: How a Motorcycle Charging System Works - ElectroSpo

ELECTROSPORT presents a Technical Article explaining in detail how a motorcycle charging system works.

www.electrosport.com

Ex:

If you draw 10A for 4 hrs with the stereo, (40 Amp-Hrs), it could take 4-8 hrs to get that energy back into the battery while the engine is running. A group 24 battery has a rating of about 65 to 80 Amp-Hr (20 hr rate). For optimal battery life, you should avoid using more than 50% of that capacity. Also, flooded lead-acid (unlike AGM or Lithium) typically will only accept a rate of charge of about 10-15% of their rated capacity due to internal resistance. A higher capacity stator does not result in faster charging.

If you're using a radio / amp with the engine off, then a stand alone battery charger would be a good investment for maintaining the batteries at their full potential.

Here's a great ressource on batteries and charging (if you have a few days to spare!): Basic to Advanced Battery Information from Battery University

 

[jet_boater_paul]

The 14.3V reading was *after* - while the engine was running. Thanks for the explanations. I keep my boat stored during the week at a dry location where's no access to power; so I also bought and setup one of those solar power trickle chargers. Will also double check and make sure all the connectors are clean and tight.

 

[marcham]

What might have happened (with a weak battery) is attempting to start the engine warmed up the battery. That reduces it's internal resistance slightly and is probably why it started after a few minutes rest.

Of all the things I trust the least on a boat is the battery. I know, 100 year old technology should be reliable by now right? The reality is that most batteries are killed, they don't die. Meaning they are not properly maintained. Maintenance involves checking the water level every 3 months (more often if the boat is in daily use), topping it off with distilled water (not tap water) and at least every 30 days fully charging the battery with a 3 stage charger. Then there's the vibrations of the environment which can cause small segments of the plates to break off or sulfated plates to short out. This is very important for batteries that are used for deep cycling (meaning used while the engine is off).

The first thing I did after buying the boat was installing a second marine (hybrid) battery and mounting both on a 3/8" rubber mat (horse stall mat).

 

[marcham]

The 14.3V reading was *after* - while the engine was running. Thanks for the explanations. I keep my boat stored during the week at a dry location where's no access to power; so I also bought and setup one of those solar power trickle chargers. Will also double check and make sure all the connectors are clean and tight.

7 years is very good for a boat starting battery! It was due to be retired.

You can also use a solar panel while you're using the radio. That will avoid deeply discharging the battery. Do you have a single or dual battery system? Mine is very simple with a 1 - both - 2 - off switch. Other systems can seperate the house load (stereo) from the starting load (engines) while in use but connects both together while charging with an automatic relay (ACR or VSR). Your situation (no shore power available) would be a good use case for an automatic charging relay with a seperated house and starting battery:

Mini Add-A-Battery Kit - 65A - Blue Sea Systems

Simplifies switching and automates charging for a complete two battery bank solution.

www.bluesea.com

 

[jet_boater_paul]

I just have the single battery, but will probably start researching how to do a 2-battery setup.

 

[buckbuck]

It is also possible that the 1.8 engine was hot when you shut it down. They have a reputation of not wanting to fire back up when hot. Running the blower while tubing or working the engine can help reduce engine bay temps and can lessen the issue. Did the engine spin over ok during the issue?

 

[jet_boater_paul]

Just wanted to provide an update on this. Was out on the water Friday and Saturday, and I did not experience a single won't-start event. This was after I took a wire brush and cleaned the connectors, and really made sure they were tightened-down very tight on the battery terminals. So, thinking that corrosion / loose-battery-connection was the culprit.

 

[IvanRZB]

I have the same year SX190 and battery drain over a few days' time has been an issue since day 1, so even though you found a loose connection you may run into this again. I followed the same measures you have: NOCO jump starter and a trickle-charger, but I also installed a battery cutoff switch which for some reason wasn't done on these boats (I think later 190's do have it).

What we figured out is that the factory head unit always draws a small amount of current, so if you're in a situation where you can't plug in the trickle charger while in storage you could pull the power cable from the stereo.