Total 12V power loss for a second or two

[BrianSmith]

In the middle of an all-day cruise, suddenly the XM Sirius radio goes off, as does all of the electronics (chart plotters, radar, autopilot, etc.). Comes back on in a few seconds. I had to reboot all the electronics to get them up again, but no damage done (everything worked fine the rest of the day, anyway).

What could make the 12V system "brown out" like that? This has never happened before in 2 1/2 years owning the boat. The XM radio isn't even on the same circuit breaker as the electronics, so I'm pretty sure it was a whole-system issue.

 

[MYTraveler]

Something -- inverter, pump or other high amperage DC equipment, or even a loose wire creating a dead short, imposed a high load for a short time, dropping the voltage to below the minimum required for the operation of your various equipment.

 

[RT Firefly]

Greetings,
Mr. BS. Check your grounds, first and foremost. Even though you lost power on what you think are separate circuits, and they may well be, they may share a common ground. Could also be as Mr. MY suggested. Problem with electrical gremlins is there are potentially many sources of failure.

 

[High Wire]

A high amp DC motor like a macerator type head being flushed. I could watch the FB chartplotter volts drop 2 volts then keep going. The whole system dropping right down to the lead battery posts. Digging into that found my alternator regulator shot and 8D AGMs toasted.

 

[Lepke]

In a previous pickup, a garage installed a new positive cable and didn't route it correctly. It rubbed on the frame until the insulation was gone. Then it would short out the 12v for a second. Took crawling and wiggling wires to find the fault.

 

[Alaskan Sea-Duction]

Agree with RT. Also check all your battery connections for loose terminals....

 

[BrianSmith]

Thanks, all, for the input. Nothing is new, nothing has changed, in months, but I'll check every major electrical connection I can, especially all the ground busses. A lesser version of it happened again today (on our way to Provo in Turks and Caicos, by the way!), with one of the MFD's shutting down, but nothing else. Gremlins!

 

[Alaskan Sea-Duction]

Please let us know what you find out..

 

[kchace]

In the middle of an all-day cruise, suddenly the XM Sirius radio goes off, as does all of the electronics (chart plotters, radar, autopilot, etc.). Comes back on in a few seconds. I had to reboot all the electronics to get them up again, but no damage done (everything worked fine the rest of the day, anyway).

What could make the 12V system "brown out" like that? This has never happened before in 2 1/2 years owning the boat. The XM radio isn't even on the same circuit breaker as the electronics, so I'm pretty sure it was a whole-system issue.

2 things I can think of that could cause this type of problem. First, somebody "switched" a battery switch.

Second, a major piece of positive cable came into contact with a ground source - bounced or bumped against it. The "couple of seconds" would be the time required for electronics to come back up to the point you could see they were restarting.

Definitely something very scary that if it happened to me I would be scouring the wiring to try and find.

Ken

 

[wkearney99]

Definitely something very scary that if it happened to me I would be scouring the wiring to try and find.

I'll second this concern. You really do not want power being randomly interrupted. It's not good for various electrical bits, nor is it good for keeping clean underwear if it goes out during tricky conditions (like docking).

 

[boatpoker]

2 weeks after 9/11 all our electronics took a dump off Manhattan, A few weeks later all our electronics took a dump through Hampton Roads then same thing happened around the Kings Bay nuc sub station in Georgia. A month later all our electronics took a dump near the naval air station up close to Jacksonville.
Couple of months later, heading south from Dry Tortugas enroute to Havana same thing happened after sighting an AWAC ..... seeing a pattern yet ?

 

[Cigatoo]

2 weeks after 9/11 all our electronics took a dump off Manhattan, A few weeks later all our electronics took a dump through Hampton Roads then same thing happened around the Kings Bay nuc sub station in Georgia. A month later all our electronics took a dump near the naval air station up close to Jacksonville.
Couple of months later, heading south from Dry Tortugas enroute to Havana same thing happened after sighting an AWAC ..... seeing a pattern yet ?

Heard of that happening near the Navel War College in Narragansett Bay after 9/11. Was lots of Navel Security in that area for a year or two after. Fully armed and not bashful. They didn’t seem to understand that I was “one of the good guys” when going over to have a look.

However I think that the OP should start with checking all ground connections very closely. Starting with the battery and starter and working methodically forward.

 

[FF]

Looking at grounds is good advice , however ALL DC loads will generate some tiny heat at connections. This creates space at the connection for resistance to grow.

The simplest solution , when cleaning terminal ends is to install a copper star washer.

Copper , not brass or iron brass or copper plated.

These work well in commercial buses and trucks for decades , and are a one time low cost (but high labor) fix to many electric glitches.

 

[diver dave]

2 weeks after 9/11 all our electronics took a dump off Manhattan, A few weeks later all our electronics took a dump through Hampton Roads then same thing happened around the Kings Bay nuc sub station in Georgia. A month later all our electronics took a dump near the naval air station up close to Jacksonville.
Couple of months later, heading south from Dry Tortugas enroute to Havana same thing happened after sighting an AWAC ..... seeing a pattern yet ?

If you want to play around the military, you might find lots of quirky behaviour from your electronics. You see, their stuff could be rated for 90V/m RF fields; yours maybe 3V/m. And, that's only if it carries a CE mark.
Even with that, I am aware of no non-kinetic weapons that will take out raw 12V from a large battery.

 

[Roamer Blue]

Jumping to conclusions?


All we know is that the electronics "turn off" and then "turn back on".


What conditions or triggers will do that?


Power source interrupt? low or high voltage? overload of inputs? "this device must accept interference fed it"?



I like the military angle, our electronics can easily be used for terrorist purposes, you can be sure there's ways to counter that...


I'm a lazy trouble shooter. Shooting in the dark, rattling all the cabling, how will you know it really was "fixed"?


a quick search, data log the voltage to rule out some trouble?
https://www.dataloggerinc.com/product/el-usb-3-usb-voltage-data-logger/


There will be tons of others available at different price points.


Pretty cheap compared to yard shop rates...?

 

[Cigatoo]

“The simplest solution , when cleaning terminal ends is to install a copper star washer.”

Sounds like a great idea. Be worth having an assortment on hand. Have a source for those?

 

[Roamer Blue]

Grainger is one place for plain copper washers


https://www.grainger.com/category/washers/fasteners/ecatalog/N-8obZ1z0nmq7

 

[diver dave]

Far easier to get "pure" copper flat sealing washers than toothed lockwashers.
Sil Bronze is around 90% Cu, and are easily available with teeth. 99% Cu with teeth, is pretty darn exotic.

 

[Alaskan Sea-Duction]

So BS, what was the outcome?

 

[BrianSmith]

So BS, what was the outcome?

Well.... nothing, so far.

This happened when we were on one of our three legs from San Salvador (Bahamas) to Provo (Turks and Caicos), and we didn't see another vessel, or even jets overhead, most of that journey. So I think we can rule out military interference.

Our battery switches are in the ER, behind some plastic storage bins. Fran never goes in the ER underway, so no one jiggled a battery switch.

There are two of us on the boat, and Fran was dumping the black water tank and cleaning the heads when it happened the first time, and was possibly using the head the second time. I did, fairly recently, rewire the forward head to shorten the cable run. (It was experiencing a 2V drop when flushed before, now, with bigger, shorter, wiring, it's about 0.2V.) The black water tank valve and pump switch are operated by a big lever in a cupboard under the sink. We've both noticed that the pump switch hasn't been 100% reliable lately, so that's going to be my first thing to seriously investigate, followed by the new forward head wiring.

But as we are now in Turks and Caicos, and it's absolutely gorgeous here, and we've had to assist not one, not two, but three different sailboats that have stopped here on their way to the Virgin Islands in the 10 days we've been here... my own problems have been put on the back burner. But not forgotten, I assure you!

I promise to report back after my investigation.

 

[MikeM]

A similar thing happened to us. All of our 12V instruments lost power for a few seconds. In our case, it was everything on our pilothouse house panel, which is really a sub panel powered from the main panel. The breaker on the main panel was going bad. I replaced the breaker and all was well.

 

[BrianSmith]

A similar thing happened to us. All of our 12V instruments lost power for a few seconds. In our case, it was everything on our pilothouse house panel, which is really a sub panel powered from the main panel. The breaker on the main panel was going bad. I replaced the breaker and all was well.

Since I recently solved an 18-month old problem by replacing a breaker, I guess I should have thought of that! The only thing that makes me think it's not that is the AM/FM/Sirius XM radio - it doesn't go through the "Electronics" breaker, but it also blipped off.

I may get around to checking some things today. I will post results, if I find anything.

 

[Wxx3]

Agree with RT. Also check all your battery connections for loose terminals....

This has happened to me more than once in a car. Check connections from battery outwards. Most likely a ground connection is loose.