Troubleshooting a 12V problem...

[ssullivan]

Hi Everyone,

I wanted to run a 12V problem past the crowd in the hopes that someone who has experienced a similar problem can keep me from wasting a lot of time going down dead ends. Or maybe if an expert like Rick has seen this many times, he has an idea where to start.

Setup:

I have 4 batteries. 1 is a starting battery and 3 are deep cycle house batteries. They are all in a line and share the same ground. In fact, the neg terminals are all tied together, and a ground runs out from the first house battery to somewhere I can't see.

I have a 100 amp charger (circa 1987) charging this system.

History:

When I purchased this boat, the starting battery had been behaving badly and wouldn't charge. It would only discharge. The previous owner let it drain so much, it was junk. I put a new starting battery on, and it would never charge. So... I rigged a jumper cable to one of the house batteries as a temporary fix until our 1300 mile delivery was over.

Additionally (and possibly related), there is a new wiring "terminal" at the rear section of my Perkins engine that was recently installed at the same time a new starter was put in. This was all done before I bought the boat. A photo of this terminal is here:

http://cruisersforum.com/photopost//...sort=1&thecat=

Now, when I bought the boat, it had a problem where the starting battery would not charge from my main charger OR from the alternator. This problem still exists. Also, there is another problem when you start the engine. When you press the start button, the starter whirrs without the starter gear engaging flywheel. It will whirr, and then "clunk" at the end of its blast of energy, as it engages the flywheel, but is out of momentum. My workaround had been to give it another blast of power just after the clunk, while it was still engaged with the flywheel, thus starting the engine.

Current Problem:

Now I have another 12v problem, adding to the puzzle. It seems that out of my 3 house batteries, the 2 house batteries that do lights and other accessories are only charging up to between 10 and 11 volts (I'm on AC shore power, and charging from the electrical charger, not the alternator). I noticed this problem tonight when my inverter sounded an alarm. However, at the same time, my 3rd house battery, used only for refrigeration, is doing fine at 12-13V charge.

Possible Ideas:

My thoughts, up until tonight, were that the little terminal I showed in the picture was incorrectly wired, causing my starting battery to get no juice from the charging systems, and causing my starter motor to behave incorrectly. Could this be possible based on what I have described?

As of tonight, I am even more confused, and wondering if some bus or something isn't just decaying somewhere and causing all this grief.

Does anyone know where to begin? My boat has no wiring diagram, and all the wires (of course) go under the pesky hull liner. It's one of the main drawbacks of my boat. In general, are there some sanity checks I can do myself before I have someone come in to check it out? I was planning on having someone correct the starter battery/starter issue in a couple months as I watched to learn. Now that my house batteries are barely holding a charge, this has moved up on the priority list.

Thanks in advance to anyone who takes the time to give this some thought. I realize it's long winded and complicated. I also know many of you have better things to do.

[ssullivan]

Also, I should add that there is no deflection at all in my Volt meter for house battery 1 and 2 when I turn the charger on and off.

On the 3rd house battery (the refrigerator one), there is a deflection when I turn the charger on and off.

[Sunspot Baby]

Wow! Lots to digest here but a few questions before I could even try to respond.

1. The picture of the “terminal” looks a lot like a solenoid to me. Probably part of your starting system.
2. You speak of various batteries being used for starting, refrigeration, etc, but say they are all “in line” which implies in series and is almost certainly not the case.
3. The negative sides being tied together is not a problem. They should all share a common ground.
4. Is there no battery switch to isolate the hot side? Without it, you have basically one bank that does everything and shares all charging systems. Seems highly unlikely.
5. While there may be no schematic of the system, this would be a good place to start. It may require crawling is some tight spaces and/or a simple continuity checker.

Any more information related to the questions/comments above?

Sunspot Baby

[Sunspot Baby]

Maybe I should aplogize for my last post. I just looked at your profile and you are obviously experienced. My answer is probably WAY too basic. Sorry if I offend.

Sunspot Baby

[CSY Man]

First thougth:

Do ya have a battery isolator in the system..?

(It allows the all the banks and all the batteries to charge at the same time from the same source, but will only allow drain from a selected source..As in house bank)


If a previous owner wired up a junk system that seems to work, but not quite, ya are better off dismantling it and starting from scratch, otherwise you will have problems for the next 40 years..

Been there, done that, then some.

[NoTies]

The picture sure seems to be a solenoid. This may have been installed to by pass the solenoid on the starter, not an uncommon practice. Pre-engage starters do 2 things with the solenoid. 1/ they force the pinion forward to engage with the flywheel. 2/ they act as a heavy duty switch to energize the starter motor itself. If the solenoid on the starter has developed dirty switch contacts in the past this additional solenoid may have been installed to solve the problem. If the heavy wire from the pictured solenoid leads to the motor side of the solenoid on the starter then I would suggest that the problem is either a pinion that is binding on the motor shaft somehow or that there are problems with electrical contact. First thing would be to remove & clean all terminals associated with the starter. If that doesn't help then it looks like the starter has to come out for repair.
The strange thing about the pisture is that there appears to be no ground wire connected to the solenoid. Can you feel it clicking when someone hits the starter switch? Unless you are 100% confident that you can deal with the problem then I would call in an experienced electrician. Remember that starter circuits are generally not protected and I personally hate the smell of chloride gas as the insulation melts.
There, I've given you a great long ramble and then told you to get someone in to fix it. Too much caffeine I think.

[GordMay]

Sean:

From the photograph, the existing wiring appears to be in poor condition - cheap (unsealed) crimp terminations, painted (brittle-looking) wires, etc. This is very common with pre-1990 boats, most of which are ready for a complete re-wire.

The first step in analyzing your problems (you appear to have multiple, perhaps increasing, problems) is to identify where the wiring goes, and understand what it does (or is supposed to do) -> either you, or your electrician, will have to prepare a wiring diagram. There’s really no way around this. The diagram must be entirely complete & accurate, at least as far as the Distribution Panel Bus’. Branch Circuit wiring diagrams are useful, but (perhaps) not entirely necessary, at this time.

Do I understand correctly ?
1. You’re Previous Owner (PO) had a new Perkins Engine, new Starter, and the new (pictured) Solenoid installed ?
2. He re-used all of the existing wiring, adding a single new wire (terminal) between the new solenoid and what ?
3. The starter circuit has never worked properly, and the Starter Battery never took a Re-Charge?
4. Your House Banks were previously Charging, but conditions are deteriorating, so that now 2 of 3 House Batteries will not Re-Charge (10-11V is a Discharged battery) ?

[ssullivan]

Thanks, guys! I took your advice and really started to methodically go through some of the wiring with my volt meter and found that at least *some* of my problems had to do with 2 blown fuses in the group of 4 fuses for the 4 batteries. This fuse bus is located right next to what I just learned here is called the "battery isolator."

Ironically, when we first were leaving the marina the boat was purchased at, we swapped 2 fuses to see if that was the problem with the starting battery not working. We must have swapped 2 BLOWN fuses. As of right now, all 4 batteries are charging.

This doesn't solve the issue with the starter, but thanks to the post from Pwederell, I think I'm at least understanding how this solenoid works. That's a big step in trying to diagnose the problem with the starter that isn't engaging.

Gord, I wanted to answer your 4 questions:

1)Almost... the PO did not have a new Perkins put in (I wish!). They have the same original equipment Perkins. They had the starter replaced, and the 2 shiny, new items on that engine are the starter itself and that solenoid from the photo. This is what lead me to believe that something wasn't installed correctly wrt that starter. In my past experience, anything I had a boatyard do, has been done wrong and I had to re-do it. So... I suspected the "new" items as being done incorrectly.

2) All wires hooked up to the solenoid are original wires. I can tell since they are moronically painted blue. I see only one wire that could be considered a groud, and that's a very small white wire leading into a large conduit/bus of about a dozen wires. The other 2 wires that are large, and are connected to the large terminals on the solenoid are both red.

3) The starter was replaced just before the boat went up for sale. Apparently, they had some problems with it just before I bought it as well. When I first got the boat, it behaved as it does today. Just a "whirr" (spinning starter motor without engaging the flywheel) when you first hit the start button. At the end of the "whirr", a "clunk", as it engages the flywheel. My workaround was to hit the starter button again just after this clunk, providing power to the starter motor (sine it is engaged from the clunk) and starting the engine. The starter battery had never been able to re-charge, but I have ironed that out and chaulk it up to a blown fuse. It is currently charging right now from the main battery charger.

4) Correct.... but thanks to this forum/post, I went in and figured out where things were wrong. Blown fuses that weren't properly checked were the culprit (for now... we'll see if they blow again).

Thank you very much to everyone who has posted to this thread. It's great to get some advice from people who have "been there" and had problems like this, or more experience in working with these systems.

I will proceed to make a wiring diagram and see if I can't try and reason out this starter issue. Hopefully, the fuses don't blow again. If they do, it does mean an electrical system tear down. If not, I just have the starter issue to contend with.

Thanks again!

[ssullivan]

pwederell once whispered in the wind:
The picture sure seems to be a solenoid. This may have been installed to by pass the solenoid on the starter, not an uncommon practice. Pre-engage starters do 2 things with the solenoid. 1/ they force the pinion forward to engage with the flywheel. 2/ they act as a heavy duty switch to energize the starter motor itself. If the solenoid on the starter has developed dirty switch contacts in the past this additional solenoid may have been installed to solve the problem. If the heavy wire from the pictured solenoid leads to the motor side of the solenoid on the starter then I would suggest that the problem is either a pinion that is binding on the motor shaft somehow or that there are problems with electrical contact. First thing would be to remove & clean all terminals associated with the starter. If that doesn't help then it looks like the starter has to come out for repair.
The strange thing about the pisture is that there appears to be no ground wire connected to the solenoid. Can you feel it clicking when someone hits the starter switch? Unless you are 100% confident that you can deal with the problem then I would call in an experienced electrician. Remember that starter circuits are generally not protected and I personally hate the smell of chloride gas as the insulation melts.
There, I've given you a great long ramble and then told you to get someone in to fix it. Too much caffeine I think.

Thanks for this intro to the external solenoid. I wanted to follow up, since what you wrote here has got me to a point where I can do some testing. It's not that I don't have experience with eletricity - I learned to wire 3 phase power from reading up on the internet a couple years ago.. ha ha ha (used to work at NASA, physics degree, etc.. ). So I have certainly smelled my share of chloride gas.

My personal issue is that I have never seen these particular types of circuits. My last boats either a. didn't have them, or b. didn't have trouble with them. So this is my first time looking at this type of setup.

So with that background, I wanted to just follow up on your post, since it was so informative and helpful. Another bit of background info is that the external solenoid and new starter motor were both installed within a few months of my buying this boat. They don't even have any dust or dirt... they are brand new.

Ok, so given that a pre-engage starter does the 2 things... (1, engage the pinion and 2, energize the starter motor to spin it), mine is failing at #1 from your list (engaging the pinion). Ironically, my starter seems to be doing these 2 items in *reverse order*. It spins the starter motor, and then as the starter motor spins down, I hear a "clunk" as the pinion engages. As a workaround, I have been hitting the start button just after this clunk to re-energize the starter motor, which starts the engine.

So given that the starter and solenoid are brand new, and that it behaves as in the above paragraph, would you tend to think it is a problem with dirty connections, or a mistake in the installation of the starter/solenoid?

Also, I should answer some of the unknowns. Yes, the heavy gauge wire does run to the starter motor's terminals from this external solenoid.

Thanks in advance. I think with your input, I am 80% of the way to understanding this problem.

[NoTies]

Hi Sean,
With a pre-engage starter, the motor should not be able to turn until the pinion is fully engaged. The pinion assembly comprises the solenoid "slug" (iron mass to react to electromagnetism) and also comprises the moving contacts for the switch that energises the motor. Under normal circumstances it is impossible to energise the motor without the pinion engaged but with the addition of the auxillary solenoid this then becomes possible as it will be primarily energising the motor not the pinion. If there is a fault in the wiring to the solenoid on the starter or a mechanical fault with the pinion then your scenario is probable. The fact that the extra solenoid was added at the same time as the new starter leads me to believe that they were chasing a fault and didn't get it quite right. Ie, put the new starter in and it still didn't work so fitted the auxillary solenoid to bypass a voltage drop somewhere. First area I would look is the heavy wire between the battery and starter, including terminals and isolator switch. Put a voltmeter from the starter solenoid output terminal (the one that carries the wire/strap between solenoid & motor to ground. Get someone to hit the starter button and see what happens to the voltage. If it only drops a volt or so then there is probably no problem and it's time to delve a bit further. If the voltage drops significantly then slowly start working your way back along the heavy wire towards the battery, measuring all terminals, isolators etc. When the voltage drop disapperars then you have found your problem.
Damn, just got an email saying my flight north is delayed a day due to bad forecast. Outta here Saturday now.
Good luck, I'm off for a lseep now, back in 12

[Alan Wheeler]

Pete, I hope you catch up with us when you get home again.

Sean, Peter has been very helpfull. If I may add. Firstly, check that your engine start battery is supplying the correct voltage. Because of your charge problems, you maybe chasing a red hearing. ( I will come back to the electrics). Therecan be one other starter type and this typw is what used that solinoid you have fitted. It is simply a motor/shaft with a spiral on the shaft and a gear, that when the motor starts, the gear is thrown down the shaft by a resistance to movment. If the shaft and gear have become dirtyor rusted, this can stop the gear being thrown down the shaft and engaging the flywheel teeth. Thus doing exactly as you have described. To check this, you need to remove the starter and inspect it.
OK, back to the electrics. Fuses on the battery side of things, IMO are bad. If they blow, you have a problem and as you have discovered, it is not easy to now what the problem is. I believe in circuit breakers as essential in this area. You have to be able to see a breaker has tripped and reset the breaker quickly. If it trips again, you need to be able to isolate circuits and reset the breaker. This is essential safety wise. Another helpful tip for fuses and beakers for that matter. An indicator light. Take a wire from each side of the fuse or breaker. It can be a 12V bulb or LED. If the fuse/breaker is connected, the light fails to work. As soon as the breaker/fuse opens, the light comes on. This light can be placed by the breaker/fuse, or can be taken upto the instrument panel for quick and easy ID.

[ssullivan]

Wheels and Pete:

Truly *awesome* advice. I will go ahead and perform the tests Pete suggests. With this info, I will probably be able to come close to a self-diagnosis before hiring a mechanic. Hopefully, I won't have to at all. I'll get to this project sometime over the next few weeks.

Wheels - I agree regarding those fuses on the "supply side" of the battery. Circuit breakers would be a much more elegant solution, and indicator lights... wow! To dream a dream of utopia! Maybe in a couple seasons I could make that upgrade.

As of this moment... still charging well. All batteries are up to 13V with loads on them. I haven't dared to try out the starter quite yet.

I'll give it a shot now just to see. (Then I'll replace the fuses when they blow... ha ha ha) Hopefully, it's a red herring, like you suggest, Wheels. That would be ideal if I just wasn't getting enough power to the starter causing it to malfunction.

[ssullivan]

Well, it looks as though you were right, Wheels. It was a red herring. The starter engaged perfectly and all batteries are reading a solid 13.5V via the alternator now that the engine is on.

I suppose the lesson to be learned from this thread is that everyone needs a wiring diagram and that seemingly small electrical problems can manifest themselves in big ways.

Thanks to everyone who posted. Even if it was a simple problem, I learned a lot about the starter types and electrical system.

[Rick]

I agree with Gord in that you must yourself draw a schematic of your entire system starting with "modules" if you must in sections. Here are a few suggestions which may prove very useful in the long run:
1. Draw lines representing wires without drawing any "loops" to indicate that a wire crosses over another without connecting like some books show for those not famaliar with reading schematics. Where wires cross, draw them at right angles like and intersection. Where wires connect always draw them in a "T" which removes any ambiguity as to whether or not a connection is made. This syntax makes for a clean easy to read schematic. (developed by IBM back in the 50's, I believe)
2. Never assume that "ground is the same everywhere", it is not. Therefore, draw your lines representing wires from point to actual point so that when interpreting and troubleshooting your system you can visualize how heavy currenets flowing in exactly which wires can raise the voltage from one point to another (this is required in order to troubleshoot bonding system wiring, for example). The same discussion applies to positive distribution wiring systems.
3. Make notes regarding the attributes of each component such as "25A switch rating" or "Positive distribution post 3/8" located by the symbol of each component. Attempt to learn symbols rather than using only rectangles to represent anything.
4. Make a master and mark up a copy when making changes to your system. Mark over removed wires with red. Mark added wires with green, mark over the green wires with yellow after you have installed the newly planned wires and verified their connectivity. After any changes are verified as fully operational THEN change your master and note the changes made and date.
5. Use a heirarchical method to keep the schematic clean by placing a box for a schematic subsystem whenever it makes sense to go to another page having its own subfunctions (like a voltage regulator schematic).

NOW you can troubleshoot your schematic in order to determine how to change the wiring to eliminate ground and power loops and other "wired-in" deficiencies exposed by the schematic.

As a note: keep in mind that fuses offer some advantages over breakers, they have, in general, a lower voltage drop than do breakers before tripping. This may be important with SSB transceivers, for example.

[Sunspot Baby]

Sounds like ssullivan has zeroed in on the solenoid issue. There is another possible reason for a second solenoid, isolation. My engines have isolation solenoids so they are only grounded to the common when starting. Tends to reduce corrosion with my aluminum sail drives. This is not likely the case for ssullivan but if others are learning from the posts, this is a not uncommon situation.

Sunspot Baby