Weird sudden loss of 12V DC.

[Cadence]

Originally Posted by tkeithlu

It was a learning experience yesterday. We were going into Apalachee Bay on the Florida panhandle, headed for home. Everything was fine, and I was being lazy and not marking our position on the paper chart. The house batteries were sitting at 13.4V, so the charging circuit off the engine was just fine.

First, the autopilot reported low voltage. WTF?! Then over about five minutes we lost all DC electrical power. Zero. No instruments and no autopilot, including no compass given a steel boat that does not like magnetic compasses.

I was surprised at how much we had to adjust to using a paper chart and Mark I eyeball. A general but not specific knowledge of where we were was not reassuring or adequate. We make it home OK, but got well off course once in very familiar water. My confidence took a beating.

Examination showed that a single ordinary Perko rotary switch in the DC circuit had failed, leaving us with only the back-up battery behind the panel to cover all DC needs. The house batteries were fully charged, but isolated, and the five minute course of failures was the backup battery going to zero.

So, our next move is a compass app on my cell phone, and perhaps a completely isolated power source for the nav computer with OpenCPN. My summary feeling is that even with our attention to having paper chart backup, it is easy to get dependent on the electronics and out of practice doing it the old fashioned way.

I’ve pontificated on the forum about keeping at least some instruments separate from a glass cockpit, because a monitor or CPU can go PIFF, but I didn’t think about loosing the source of electricity beyond having the backup battery to use to call for help if the house batteries flooded with seawater. The switch from the house bank to the single backup battery went unnoticed, because the voltmeter still said 13.4V as the backup battery was drained.

A hand held GPS and paper is a great backup.

[captmikem]

Instead of carrying all this extra (electrical) gear, just carry a set of good jumper cables and a cheap Volt Ohm Meter (about 5 bucks at Harbor Freight). These should be standard equipment on any vessel.

What happened to you is the equivalent saying you lost all your fuel even though your fuel gauge showed full, because you had a fuel filter clog).

The electricity was there, you just did not know how to get it.

Become a master of your boat, not a passenger.

M

[captlloyd]

Originally Posted by captmikem

Instead of carrying all this extra (electrical) gear, just carry a set of good jumper cables and a cheap Volt Ohm Meter (about 5 bucks at Harbor Freight). These should be standard equipment on any vessel.

What happened to you is the equivalent saying you lost all your fuel even though your fuel gauge showed full, because you had a fuel filter clog).

The electricity was there, you just did not know how to get it.

Become a master of your boat, not a passenger.

M

You beat me to the post !

[sailingabe41ds]

I have a handheld gps/plotter always charging. I do not know how to use it, but I will figure it out if the necessity arises and if I can remember where I stored the manual.

Abe

[goboatingnow]

Originally Posted by wingssail

I think often about this scenario (battery switch or other failure which cuts off the DC system including the main DC distribution panel hence all the instruments) and potentially engine starting supply since they all go through the battery switch.

I am comforted by the knowledge that my laptop running OpenCPN has an internal battery which will keep the computer going for several hours. I also have a GPS puck which runs off of USB so the laptop's battery will run the GPS. At least we will have an active charting system showing our position and track.

Portable VHF Radio is also battery powered so we will have that for several hours.

One problem I won't have is unnoticed automatic devices which switch battery power around. We do not have any battery combiners, ACR's, DC-DC chargers or other electronic devices in charge of stuff I can (and would rather) do myself. We don't even have an audible low voltage alarm. If we were on deck and under sail or power the first indication would be failure of the instrument displays which seem to be pretty intolerant of low voltage. This would trigger immediate investigation.

My recommendations for all people navigating on a vessel with important electronics is:

• Make sure you have redundant battery powered devices which can continue if the ship's DC is lost.
• Avoid automated electronic switching devices which can take you out of the loop on important power decisions.

An extreme example:
I toured a new yacht with the latest electronic and electrical systems. I observed that this vessel, with 6 24 volt Lithium batteries each containing eight cells, had at least 6 BMS and ostensibly 48 temperature and HVC, LVC, and other sensors, plus a significantly complex and important Electrical Management system (with its own BMS) to manage the very large 48 volt alternator and the battery banks, and a complex display and control device (similar to a phone). They also had four NPPT solar controllers (one for each solar array) all managed by BlueTooth to a laptop app, and 10,000 watts of inverter plus DC-DC converts, plus a "normal" 12v system and battery bank connected to the other engine. And of course battery switches and the full array of electronics.

It was all totally impressive and the capabilities astonished me.

However the complete manifest of electronic devices was shocking to someone who has spent 40 years keeping a "simple" boat's electronics all functioning. One concerning aspect is that the monitoring system does not have the same granularity as the level of electronics has. If the system shuts down, how do you know which part, or which of the 48 or so little electronic devices has fried its little brain?

The one thing you'll know when you granddaughter comes to you and says, "My phone won't charge" is that something has gone horribly wrong. I guess at that point you pull over and call a tow truck.

Maybe I am a Luddite, and maybe today's electronics will never fail, but I doubt it.

The answer is simple either you understand it or you have someone on the payroll that does or you shouldn’t own it.

[billgewater]

So what warranties are given on the electronics with new boats? Does it vary from company to company, boat to boat? Is there any legislation in any country regarding the warranties? This forum may be the just right place to spread the information and experiences of new buyers. Some exposure just may lead to better warranties or better quality electronics.

[Mirage35]

I can relate. On our usual little trip this spring moving from winter storage to summer marina:
- GPS on the chartplotter stopped working;
- iPad battery was getting low;
- charging cable for the iPad had a failure.

So we went to Plan "D" and pulled out the paper charts, because even if it's familiar waters there are some tricky bits. All of it is close to land so no compass navigation required, which is nice because the local magnetic anomalies make a compass pretty useless anyway.

My lesson learned: Don't just think about plan "B", think about "C" and "D" as well.

[SeanPatrick]

Originally Posted by captmikem

What happened to you is the equivalent saying you lost all your fuel even though your fuel gauge showed full, because you had a fuel filter clog).

The electricity was there, you just did not know how to get it.

Become a master of your boat, not a passenger.

M

And what happens when the electricity is not there and they have not kept their chart work skills sharp?

[hpeer]

FWIW

2 steel boats

Sat in the cockpit, on anchor, St Martin lagoon, nothing on and watched the compass do a 180 swing. Did something similar once coming out of a Florida inlet. Compensate THAT. Why? Not a clue, but happened more than once. Awe inspiring but not confidence building. Very annoying.

Phone compass is effected just as badly as any other compass. Worthless.

Phone GPS works just fine. Phone GPS will provide heading if you are moving. Which app to use depends on a bunch of things. I use AquaMap (stateside) and iNavex (elsewhere.) Will now have 2 cell phones for redundancy.

I have a largish cell phone external battery, a couple actually, that will run the phone for white a long time.

I also have jumper cables and do not use a combiner switch, systems totally separate except for common charging sources.

Good luck, glad all worked out OK.

[waterman46]

Originally Posted by LittleWing77

Isn't a compass-swing and adjustment for deviation related to the onboard electrics?

If Keith suddenly lost all of the onboard electrics, his compass headings would have immediately been impacted by the loss of electricity because compass deviation would have been set with the electrics working.

LittleWing77

Probably very little effect due to current. The magnetic field of wires is quite small at the levels of current found in any devices you'd usually have near the steering compass. The compass at the steering station, on a sailboat anyway, is usually much higher and meters away from any major DC current drawing devices like watermakers, reefers, battery chargers and HF radios. There can be a lot of deviation due to other devices nearby, but that deviation is caused by the metals in those devices, not the current they draw.

I checked my compass with the nearby radar and chart plotter both on and off and could see no difference. On the other hand, I had to compromise a bit when I added the 12" chartplotter since just holding it where I really wanted it, without connecting the wiring yet, made the compass deviate more than 4 deg.

[waterman46]

The compass will work fine so total DC power failure worse effect is we'd have to manually steer. Now that would be royal pain. Outside of any channels or bays, we are 100% on autopilot unless manuevering for some reason.

Nav is simple: if you are in cell phone range just bring up your nav app on the phone. If you know you will be going out of cellular data range then you should have installed a stand-alone nav app. Keep your phone and tablet batteries charged! You should be able to get 24 hours on a charge, that gives a lot of time to figure out and bypass the problem.

[Frankly]

Replace the old Perko with a Blue Sea. Fits the same foot print and a better switch IMO.


Frankly

[wingssail]

Originally Posted by goboatingnow

The answer is simple either you understand it or you have someone on the payroll that does or you shouldn’t own it.

Sorry goboatingnow, even if you do understand it (and I am sure that I do, as well as anybody would) it will be damn hard to diagnose and resolve (diagnose, mostly).

Then, impossible to have someone on the payroll as you sail across oceans or in remote places. Even only slightly remote places, you cannot have an electrical engineer on board, and resolving issues by phone with photos won't be easy either.

As for "you shouldn't own it"...I'm afraid that is going to apply to a lot of people who discover over time that the wonderful electronic magic which controls everything on their boats just isn't going to be 100% reliable,no more any any boat electronics.

You know, I've got a simple boat, with maybe 5 electronic pieces in the electric system, and I'm pretty much on top of it all, carry spares and diagnostic equipment, etc, and I have issues every year. I solve them, but it is often hard and it takes time. This guy I described has dozens of electronic pieces and no diagnostic equipment other then the items themselves, and little technical knowledge. And he is typical. I'm not wrong about the future of these vessels, they will be broken down in foreign ports inthe future.

[tkeithlu]

Thank you for a bunch of good advice. Regarding the various "Know your boat" posts, I built the boat and designed the electrical system. The switch in question cuts off the house bank, and has not been used since construction was underway - I've had no reason to isolate the house bank.

I'm very much a fan of redundancy, and there actually are three tracking GPS's among the instruments (Open CPN, backup GPS, and AIS), all of which, of course, failed. The paper chart is right beside me and (usually) gets half hour locations marked.

Again, thank you for all the good advice.

[John Williams]

Exactly the same thing happened to us sailing down the east coast of New South Wales in the middle of a dark night. We survived with iPad and Navionics and our two iPhones with Navionics and paper charts. But ours was just suddenly nothing. No lights! No backup battery to slowly go flat. Somehow I got things going again - did not now how, and it was not until quite some time later in Hobart, Tasmania that it happened again and we found the culprit. Faulty isolation switch. About as easy a fix as you can imagine.