Intermitant Non charging on House only

[Sandero]

The fuses are doing nothing. That is one weird bit of wiring. What's the gray thing to the right?

I think you need to re wire your charging system and dispense with the relay.

Have the alternator charge the house bank and get an echo charger to charge FROM the house to the start bank.

[Ex-Calif]

Mark - Don't go buying parts yet. Before any more logical troubleshooting can be done you really need a circuit diagram.

The black item is simply a relay - pins 1-2 when charged activate the coil - then 3-4 are connected - I suspect based on the wire thickness in and out of the black box that this is house bus power (red lines) - I suspect one comes from alternator output and the other goes to the 1-2-both switch or the main bus and then from main bus a line to the 1-2-both switch - this is likely how the alternator charge also gets to teh batteries through the 1-2-both switch.

That cylinder is clearly a solenoid and I guess the double wire going in is solenoid power (blue) and alternator sense brown - but that's a guess (you can check the back of the alternator and see if a brown wire is coming out of the plastic plug that goes in the back of the alt. When you hit the master, the cylinder is charged, the big black wires make contact and then the black box is powered by the blue ware coming off the cylinder to the black relay - That lights up the DC bus. Then watever battery bank (1-2-both) is selected on the manual switch is now supplying one side of the cylinder and out to the starter on the other. The brown wire is now sensing bus voltage, because it is now exposed to the bus due to all teh contacts being closed.

It is here you would check "sense" voltage. You will likely get a good voltage read to ground from brown. This is what the alternator is seeing. If this voltage is low the alternate regulates up. If this voltage is high the alternator regulates down.

You can also check bus voltage on each side of the cylinder - If the voltages are different going in than going out, that solenoid (cylinder) has high resistance. I am betting it is OK because you report the fault only on one bank.

It makes sense that the sense line goes to a unit that is common to both battery banks and "central" to the electrical system - this solenoid appears to be it. The blue line in the double likely goes to the master switch on teh DC bus panel. The blue single goes to the bus realy (black box) andis powered by the master relay (cylinder).

Note there is one big cable going in and one big cable going out of the cylinder. I suspect one of the big cables goes to the 1-2-both switch. The other end likely goes to the starter relay.

So - This cylinder is a single point piece of hardware - i.e. it is operating whether you are on 1-2 or both. Since your fault lies with only one condition (2) then a common piece of hardware to both settings cannot be the fault.

I hope someone with a 393 wiring diagram shows up soon.

BTW - Solenoids get hot. There is a current racing through a coil to keep the solenoid contacts closed and there is current running across the secondary contacts especially right after teh starter has been activated. How hot is too hot takes an experienced hand to figure out. I would say that if you can put your hand on it for up to 5 seconds it is not too hot. If you can fry eggs on it, you have an issue. If it makes smoke it's too late...

BTW - Have Nicolle operate your bus master switch while you listen to this cyclinder - you will hear a loud click when she powers on.

Remember - Your fault is on one bank only. Parts that are common to both banks are not going to be the problem.

At this point I still vote 1-2-both switch or it could be the cable going from house bank to 1-2-both switch. Can you tell the condition of that?

[Therapy]

Originally Posted by DeepFrz

Take a look at the two fuses on the left side of the picture. The wires are connected to the same side. The current isn't flowing through the fuses at all and therefore the wires connected to the fuses are not protected.

Do-nothing fuses.

Very interesting.

[DeepFrz]

It's true that you need a wiring diagram. If you can't get a wiring diagram from the boat builder then you should trace out the wires yourself. That will help you to understand exactly how the charging circuits are wired up.

I do think that the discoloration on the solenoid, as well as the discoloration of the cables and connection hardware, shows that the solenoid is way to hot. The heat could possibly be caused by loose connections though.

Make sure there is no power to the solenoid when you are working on it.

[MarkJ]

OK. I'm thinking


(slowly)

[Caribsailors]

Save yourself the headache of this thread, and hire a certified marine electrician.

The right one will educate you so you know what you live with, at your life at sea.

Cheers

[MarkJ]

Originally Posted by Caribsailors

Save yourself the headache of this thread, and hire a certified marine electrician.

At $98 per hour even if I do eventfully hire one for this problem I wish to be able to reduce his time on the job so its affordable. I can do that by tiring my best, with help from here, to get as close to solving the problem as possible


Mark

[r.furborough]

Mark,

The sytem basically connects and disconnects the house batteries when the engine starts and stops, this protects your cranking battery when the engine is stopped and your house batteries are in use. Then when the engine starts the solenoid is switched by the charge lamp circuit and connects the house batteries into the charge circuit while the engine is running. This can be done by a single relay or a reay and a solenoid for higher charge currents.

The small relay in your picture is a 28RA and the cylindrical metal units is a 2ST solenoid, they are basically the same thing but solenoids switch a much larger current.

I suspect the coil in one of these units has gone open circuit or you have a poor connection somewhere. The circuit for this is really very simple on paper, however, there can be difficulty tracing the circuit in a boat as connection point with the actual circuit may not be as shown in a diagram and this can make it confusing.

I will PM you with a link to a wiring diagram, I cannot post it to the board as it is within an engine operation manual for a line of engines I sell and may infringe the rules of this forum.

Bob

[DeepFrz]

The sytem basically connects and disconnects the house batteries when the engine starts and stops, this protects your cranking battery when the engine is stopped and your house batteries are in use.

Mark, Bob, that is what I meant when I said it was acting as an "Echo Charge" device by connecting the house and start battery.

It is probable that the alternator is connected directly to the start battery and the charge current to the house battery passes through this device. This is opposite to "best practice" that says the alternator should connect to the house battery and then the charge for the start battery should pass through this device. The reason for this is that there is usually much less current required to charge the start battery than is required to charge the house battery.

Bob didn't say where the solenoid could be purchased but I was thinking that a camper (caravan?) shop would probably have them if you can't get it at an auto part store.

After you get the solenoid sorted out your next job Mark, should you choose to accept it , is to trace out the wiring for the two "do nothing" fuses.

[r.furborough]

Originally Posted by DeepFrz

This is opposite to "best practice" that says the alternator should connect to the house battery and then the charge for the start battery should pass through this device.

Yes this is the way I described the circuit as this is the way I think Mark has his boat wired to give priority to the cranking battery in the event of a relay/solenoid failure.

Bob

[MidLandOne]

The discolouration on the solenoid body I would suspect on first guess to be from leakage at some time from what I take to be an anti siphon loop valve beside it (I route the anti siphon reliefs to a safe area myself).

In addition to what others have said the first thing I would do, if not done already is clean and tidy up the terminations on the solenoid relay . I would do that whether the solenoid is likely to be implicated in the problem or not.

[DeepFrz]

Quote by MarkJ:

The thing in the photo that I have arrowed is hot when the engine is on.

When off and I conect the right side large red cable it shows 13.6 volts. But the large red one on the left shows 12.6 volts.
Should they be the same?

I misread the quote. I thought that you had a different voltage on each side when the solenoid was activated, not when off. When off I believe what you are seeing is the house bank on the left and the start battery on the right.

What are the readings when activated?

Looking closely at the discoloration I believe it to be caused by heat, the way it is located between the terminals. If it was spray from the anti siphon valve I think it would be all over the solenoid.

I once repaired a starter solenoid similar to this. It depends on whether you can get the end off. I was able to remove the contacts and dress them with a fine file by drawing the file across the contacts. I was then able to seal the solenoid and get to a city where I could get a replacement.

[DeepFrz]

Well, I hate to admit this but it just dawned on me that if you place your battery switch in the "Combine Batteries" position, you will bypass this solenoid. Just remember to place the battery switch to "1" when you are not running the engine, and to place it in the "Combine Batteries" before you start the engine. Switch may be labeled, 1, 2, Both, Off.

[Kmucka]

It is a common 12 volt solenoid. Yes, you should be able to get one at a auto parts store. If it is hot, that means the internal contacts are worn/pitted/dirty causing resistance, and if it is either not working, or there is a bad connection in it, you would only be reading battery voltage, therefore, not charging. Replace it, and while your at it, listen to dpfreeze and fix those fuses. Just move one wire from each to the other side. Two risks of fire in one picture is not good!:-)

[MarkJ]

Succcccesssss!!!!!!

OK,

Fuses are redundant. They go into a bigger fuse box that must be newer.

I bought a new solenoid from AutoPro for $45 and when installed started charging as soon as the engine came on. Doing 14.1 or.2 volts where before the best we ever had was 13.6 and normally only 13.3

The solenoid is hot, but not as burning hot as before. Can have my finger on it for 5 seconds no worries.

When I get the budget and the Marine Electrician (next month?) I will get him to give it all a good rogering....

When taking the old solenoid off the bolts into the unit can out a fair but and are flopping around. The new unit instructions say: "When making the connection to the terminal the lower nut must be held in pace when tightening the fixing nut. Failure to comply will void Warrantee”

The old one was bolted using the lower nuts... so maybe there was te problem?

I don't know, but I hope it was because I wopuld like ths to be a long standing resolution to the problem

Thanks so much for everyones help. Your help has really saved me a lot of money. The Marine Electricians here charge $98 per hour and who knows how long it would have taken to solve.. of what other parts would have been deemed necessary(!).

So thanks everyone, I will try to repay with advice in areas where I may know something - or at least in witty repartee!


Mark