Need some electrical help!

[wedocq]

A few years back, with the help of the forum and a lot of help from Tony (Ulua), I installed the "add a battery" system from Blue Sea. Its the ACR with a battery switch that has OFF, Batt 1, and COMBINE. Because of the extensive help I received, I am confident that the system was installed correctly. So, I am going to jump right into the symptoms (which are very strange and puzzling!) and let you all throw out some theories for me to start testing.  :hoboy:

My Setup.
Dual deep cycle batteries. One for the house, one for starting. I have a fuse panel in the rear that runs the downriggers, wash down pump, and bait tank pump. I have a second fuse panel up front that runs everything else.

Symptoms.
When I put the switch on Battery 1, the motor would not turn over. I had to turn it to COMBINE. It would start on COMBINE, but if I moved it back to BATT 1, the motor would die.  I tested the battery, and it was fine. I looked at the 75 amp MRBF (Marine Rated Battery Fuse) on top, and it's BLOWN! In my mind, to blow a 75 amp battery fuse, you either have to have catastrophic failure somewhere, OR that battery terminal accidently got grounded somehow. 

So anyway, I decided to do a quick test (I am sure this was a perfectly safe thing to do ). I put the battery switch to BATT 1. I removed the MRBF, and I touched it briefly to the POSITIVE terminal to see if I was going to get any spark. Nothing. I then fully connected it to the positive terminal (minus the blown MRBF) and checked for power to boat. NOTHING.

So now I am thinking it's the Blue Sea battery switch.

So what do you think happened? Did a battery terminal somehow get grounded (by a careless tool or something) and fry the MRBF and battery switch all in one shot? Did the battery switch go bad and fry the MRBF? Is there maybe another culprit that I am missing? Thanks for any input you have!

-Shawn 

[dbhazjack]

Hmmm, could be so many things. Switch, Engine onboard circuits, ACR, battery, ignition, etc.

Since the biggest recent change has been the new outboard, I would think it wise to go over everything electrically involved in that install.

The starting circuit should not be protected with a MRBF. Since you are drawing several times 75 amps every time you start the motor.  The MRBF's should just be protecting the ACR if I'm not mistaken.

Good luck, keep us posted.


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[dbhazjack]

Also, you could D/C the ACR and switch, and wire the motor directly to your starting battery. If that works, add back the ACR. If that works add back the switch. So basically isolate and test each component. Hope that makes sense. Others will say it better [emoji120]


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[wedocq]

Thanks! I think I am going to pull the battery switch out and check the continuity when in "batt 1" and work out from there.

[Diablo]

We had a similar problem is Neah Bay with the big boat motors. Scary, for a time we did not have a motor to get home on.
Here is what's I think happened. Your start battery voltage was low which will cause the starter to draw more current. That extra current caused the start battery fuse to blow. I wouldn't stop using that fuse but have spares on board and maybe move up to a little larger fuse for your bigger motor.
Now why wasn't the start battery charged? If the only way you can check your battery voltage is with a spark test, maybe you should invest in a multimeter.
I don't know of a good reason to combine the battery's. If one battery is dead why would you want to attach it to your good battery and risk discharging it? A better battery switch would be; off, batt 1, batt 2, combine.
Your charging connections from you main motor should charge your start battery first then the ACR should close and chlarge your house battery. As for your home charging system a onboard dual battery charger would be best.
Have I spent enough of your money?  :biggrin:

[wedocq]

Now why wasn't the start battery charged?

The battery was charged. I was suspecting some type of catastrophic failure caused the fuse to blow. If I was correct, when I touched the cable directly to the positive without the MRBF, I figured I might have gotten some sparks.

[wedocq]

A better battery switch would be; off, batt 1, batt 2, combine.

I dunno. This is what was recommended to me. I have always left it on "Batt 1", and both batteries would stay charged by the ACR.

[dbhazjack]

Shawn, according to the attached Blue Sea ACR wiring diagram a blown MRBF should not affect starting circuit. It only protects the ACR. Not sure about your wiring scheme, but if the MRBF at 75amps is in the starting circuit it will blow. If not you will have to determine why it blew? Something is not right.

[wedocq]

I filed away my diagram for safe keeping. Trust me, it's so safe, no one is going to find it...ugh  But I can say with certainty, we followed the recommended way to do it, and I posted it on here for comment before doing it. I need to find that, and verify I didn't change anything when I installed the new motor.
-Shawn

[dbhazjack]

I think this is it. Unfortunately the links to your diagrams are broken
http://www.arimaowners.com/index.php?topic=6556.0

[Hydroman]

Shawn,
What load is services by the 75 amp fuse?

Jim

[wedocq]

Ok, I found this:


At Rick's suggesting, I went down from 100 amp to 75. Where is says in small letters coming from the safety hub 6a, 8a etc, that should say 6 awg.

[dbhazjack]

Looks good to me. Are you using an old Perko switch or one on the dual circuit Blue Sea switches that take advantage of the ACR?

[wedocq]

  The Blue Sea switch. I am in the process of tearing down some things and testing. Its so beautiful right now. I should be halibut fishing! safety first...

[Hydroman]

Shawn,

Shorting out either battery would definitely blow the fuse.  Can't imagined a failure in the ACR.

Jim

[wedocq]

Ok, the battery cables to the new motor were correct. What's confusing me is the motor would run in the "combined", but not in the "on" position.

[Hydroman]

I would go  thru the wiring with a fine tooth comb on the battery circuit that the engine won't run on.

Are your lug prompted or soldered? You could have a high resistance at one of the connections.
Jim

[Diablo]

Now why wasn't the start battery charged?

The battery was charged. I was suspecting some type of catastrophic failure caused the fuse to blow. If I was correct, when I touched the cable directly to the positive without the MRBF, I figured I might have gotten some sparks.

Getting a battery to spark is not an indication you have sufficient voltage for normal start current. As voltage goes down, current goes up.

[Diablo]

Ok, the battery cables to the new motor were correct. What's confusing me is the motor would run in the "combined", but not in the "on" position.

With the switch in the on position house loads are connected to the house battery and the motor starter would be connected the start battery. The motor would not start off the start battery because the fuse was blown. The motor would start with the battery's combined. When you combined the battery's, with the blown fuse on the start battery, all you did is use the house battery alone with good voltage to start the motor.

In your drawing you have a 100amp MRBF. You said above you blew a 75amp fuse. Should you have used a different fuse?

[wedocq]

I am suspecting the Blue Sea switch. I am getting resistance between the terminals on the back of the switch when it is in the "ON" position. I am getting no resistance when it is in the "COMBINE" position. Which coincidently coincides with when the motor would run, and when it wouldn't.

My question is, how much resistance is too much resistance? I had it on the lowest setting and it was giving me anywhere from 175 down to 30 (ohms?). As soon as I switched it to combine, ZERO reading.
-Shawn   

[wedocq]

Getting a battery to spark is not an indication you have sufficient voltage for normal start current. As voltage goes down, current goes up.

Yes, I understand that. This was a quick redneck field test to see if I had major issues going on. 

[Diablo]

I am suspecting the Blue Sea switch. I am getting resistance between the terminals on the back of the switch when it is in the "ON" position. I am getting no resistance when it is in the "COMBINE" position. Which coincidently coincides with when the motor would run, and when it wouldn't.

My question is, how much resistance is too much resistance? I had it on the lowest setting and it was giving me anywhere from 175 down to 30 (ohms?). As soon as I switched it to combine, ZERO reading.
-Shawn

I hope you weren't reading resistance with voltage, batteries connected. You check resistance on a dead circuit. You could damage your meter on live circuits.. If you did not measured on a dead circuit the readings are meaningless.
It hard to say what resistance would be normal. Depends on what is "on" and that could very. No resistance would be a problem, that would indicate a dead short. But I don't know exactly what you are measuring.

The switch that dbhazjack posted is what I have and I believe what you have.

Did you try to start the motor and the starter tried to start it but didn't, then it wouldn't even engage the starter on the next attempt?

[Hydroman]

Shawn

An resistance at all across the contacts signs of a bad contact.  Your ohm meter show read the same across the contacts as the meter reads with the leads connected to one another.

If you you have any resistance at all, as the current starts to flow you will start getting a voltage drop across the contacts.

Jim

[wedocq]

I am suspecting the Blue Sea switch. I am getting resistance between the terminals on the back of the switch when it is in the "ON" position. I am getting no resistance when it is in the "COMBINE" position. Which coincidently coincides with when the motor would run, and when it wouldn't.

My question is, how much resistance is too much resistance? I had it on the lowest setting and it was giving me anywhere from 175 down to 30 (ohms?). As soon as I switched it to combine, ZERO reading.
-Shawn

I hope you weren't reading resistance with voltage, batteries connected. You check resistance on a dead circuit.

Did you try to start the motor and the starter tried to start it but didn't, then it wouldn't even engage the starter on the next attempt?

I completely pulled the battery switch from the boat, so no voltage. The switch can go to "ON" and "COMBINE". In "ON", I was getting nothing, nada, zilch. No power to anything. When I put the switch to "COMBINE", everything worked like it should.
-Shawn

[DevMah]

Hmmm, could be so many things. Switch, Engine onboard circuits, ACR, battery, ignition, etc.

Since the biggest recent change has been the new outboard, I would think it wise to go over everything electrically involved in that install.

The starting circuit should not be protected with a MRBF. Since you are drawing several times 75 amps every time you start the motor.  The MRBF's should just be protecting the ACR if I'm not mistaken.

Good luck, keep us posted.

I will correct you on this my starting system is protected with two MRBF 100A fuse from both batteries going to the engine. A second Set of MRBF are protecting my ACR.
IMO
I have not seen many bad blue sea battery switches....

How did you check you battery #1 ? Do you have a battery load test rheostat? Checking the open circuit voltage gives you no indication that a battery is good... it has to be load tested.

I think that your #1 battery is dead...possibly shorted out... or bad connections...that would explain why you engine shuts off when you switch back to it from the combine position to batt 1.

The ACR fuse probably blew when your ACR tried to combine or you some how created a short to B-.
Low voltage will cause higher current.
It's possible that the ACR was combined while you cranked over engine while in position 1 of your switch and the start current was going through th ACR circuit. This is why ACR is equipped with a start disconnect option.

Easy test swap your batteries and see if the same thing occurs.
Dev

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