Electrical Issues

[Blackacre]

I'm looking for some guidance on a recent electrical failure I experience while sailing. With the engine off, I heard a slight pop. When I went below to investigate I noticed the entire panel lost all power. At the time, I was running the usual electronics, refrigerator, autopilot Radio, VHF, etc... My initial concern was that the engine wouldn't start however it started without hesitation.

The boat is equipped with two battery banks each with two Group 27 deep cycle batteries. There is a battery charger connected to each bank and the refrigerator connected to one bank. The battery cables are connected to a dual bank battery switch wherein one bank appears to join with the main bilge pump auxiliary power. Output from the switch goes directly to the starter with a second line going to the main breaker in the panel.

Initial Troubleshooting:

- Starting from the batteries I tested each connection for voltage. The Batteries the battery switch and the main breaker all show 13.4V (+/-). Once the main breaker is turned on the volts drop considerably. The main breaker indicator light is very dim and turns off if you turn on any other accessory.


Questions:

- All four (4) batteries share the same engine ground and are connected in series and joined with the battery charger and refrigerator grounds. Is this a problem or should I add a ground block for all the battery banks and direct connect accessories to share.

- The alternator connects into the wiring harness which does not directly connect to the batteries or battery switch. According to the schematics this seems to be correct. How does the alternator connect to the batteries for charging and is this configuration correct?

- How best should I rule out the alternator as a potential short circuit?

- Is it possible I damaged the battery switch and do I need to upgrade the capacity since I added additional batteries?



Any additional information would be appreciated. thanks in advance.

 

[ramblinrod]

Completely impossible to troubleshoot from afar.

Pop and power generally indicates a breaker or fuse. Pop, power loss, and smoke generally indicates arced connection or burnt wire.

Adding batteries does not necessitate increasing ampacity of circuits, increasing loads does.

My recommendation is to hire a qualified marine technician WITH a recognized electrical certification; not some guy who has done some electrical work, and his boat hasn't burned to the waterline (yet).

DC battery power is nothing to fool with. While it won't electrocute you if you accidentally touch it, (unless it goes through an inverter), a single deep cycle battery contains enough energy to burn your boat to the waterline, and consequently several others around you, if wired incorrectly.

A friend who did not heed my advice to remove jewellery before working around a battery, is now heeling from second degree burns to both hands; one where his metal watch was, and then the other hand, attempting to remove a very hot watch.

Ramblin' Rod

 

[Blackacre]

Thanks for the advice. I don't expect someone online to accurately determine the problem but hopefully I will get some guidance and learn from others experiences. I first want to try and tackle this project myself.

I don't mind buying and installing a new main breaker but I can't find a supplier for the AirPax used on my Hunter H34. Does anyone know if another brand will fit?

 

[Stu Jackson]

Sure, it's just a standard breaker.

But do yourself a favor, draw a wiring diagram or two or many as you go. You don't need to be fancy at first, pencil & paper will do (you could use the computer if you're good at it already, but draw the diagrams by hand first).

This will give you not only a picture of what you have as you go, but will be great records for the future.

You also have to understand WHY the fuse popped. Or else you stand the chance of popping the new one.

Good luck.

 

[Blackacre]

Thanks for the advice. I'll pick up a new breaker today. Any idea what the original AMP size would be. I haven't really added load much since new.

I have this wiring diagram found on the side. I believe it's from the owners manual. I'll take your advice and use it as a template to build on to.

How could I verify the alternator is not shorting out the circuit?

 

[Bill Roosa]

turning on the CB results in a large voltage drop.....!!!!!! you have a short somewhere. Turn off all the secondary breakers and turn on the main. Does the voltage drop still occur? If so your problem is in the main CB itself. If not then turn on each secondary CB in turn and see what happens. the one with the problem circuit will show the same voltage drop.

 

[Blackacre]

Thanks. I'll install a new main breaker today and then do as you suggested. I'll report the results here.

 

[Blackacre]

Thanks for all the help everyone. I located the problem. Is everyone's bets in....

It was the main power wire running from the battery switch to the circuit breaker panel. It runs from the battery switch through the engine compartment underneath the floor and back up to the panel underneath the navigation table. on my boat it runs alongside the main ground which follows the same path and terminates on the engine block. It also runs alongside brown cable for the auxiliary power use for the bilge pump and a Romax style marine cable for the AC power on the starboard side of the boat. These four wires run underneath the center of the boat inside of a flexible conduit. Apparently One of the previous owners ran a new power cable but did not use tinned marine grade wire. As a result I've spent several hours trying to troubleshoot this issue. Thank you to everybody for their advice. Hopefully somebody can avoid this in the future by reading this post.

Here is the procedure I used to determine the problem.

– Using a continuity tester I confirmed the ground connection from panel to engine. I've been repeated the process for the powerline and I did not get a signal.
– Confirmed battery switch both banks greater than 13V
– I then check the voltage of the powerline which terminates at the breaker panel and the voltage was far less around 9V.
– before I ran out to the store to buy a new power line I ran a temporary line from the battery switch to the breaker panel. To my enjoyment the panel lit up. I' then tested all the other breakers

 

[Johnb]

"AIRPAX™ brand products are now produced under Sensata Technologies, Power Protection Division. Sensata Technologies has acquired Airpax Corporation"

Even though you have solved your problem, for future reference you should be able to find a part number on the breakers and at least the current rating of each breaker. I re furbished my electrical panel and was able to get exact replacements for all the AC breakers and a couple of the DC breakers.

 

[Blackacre]

Thanks for the reference. I just used a blue sea brand from West Marine for convenience. Also if you're interested, awhile back I also posted where you could buy the indicator lights.

Does anyone know what the recommended gauge wire should be used for the panel. Should it be insulated also.

 

[Blackacre]

I replaced the old 12 AWG copper wire with 15 feet of red 8 AWG tinned marine grade wire. The previous owner neglected to use the proper wiring when he installed new wiring a few years ago. The problem was fixed but it was a lot of trouble figuring out what needed to be replaced. As I said initially, I was getting voltage to the main breaker on the panel but it was not consistent nor was it the same voltage I seen on the batteries. I went to the store and bought an inexpensive continuity tester and I was not getting a signal through the main power line. This tool proved to be better at diagnosing the problem. I then confirmed my suspicion by running a temporary power line.

It was very tempting to jump to conclusions and think that I had a short or some other part had broken. Once again the lesson is start with the basics and eliminate the easy stuff first.

Attached are pictures of the main power line that was removed.

Fishing the new line under the floor was not easy. I ended up tying a string to one of the good lines and pulling it through since the power line was broken. I then tied the good line and the new power line to the string and pulled everything back though.

 

[jlp0217]

That's why there is supposed to be a fuse within 8 inches of the battery. You are very lucky that wire decided to act like a fuse and not a heater. Could have started an electrical fire and burned your boat to the water line. I would pull all the other wires from that conduit and check them both for integrity and appropriatness, for safety's sake.