Fact or fiction: running with the chartplotter off to save electricity

[Nicholson58]

Originally Posted by Pete7

I take it then you don't want AIS information, or is there another way you get AIS information.



That's about 10A for us.

Watchmate 850 stand alone AIS. About 8 watts. Who cares!

That said, we have instruments on under way. LCD 8” Simrad NSE-8. We cruise the Caribbean with shoals, reefs, currents etc. two depth sounders, 985 watts solar, 740 AH LiFePo at 26 volts. Autopilot- 6 amps max but less for well trimmed sails. I would never fly blind here. The plotter is invaluable for keeping to course with wind and current changes.

Modern electronics and lighting are so more efficient that they are barely concerning. Fridge, freezer, watermaker are the big consumers.

Running a 58 foot, 40 ton boat aground is simply not an option.

[flightlead404]

Originally Posted by Jammer

I'm a year or two away from a major electronics refit.


As recently as 2010, books and articles on preparing a boat for cruising emphasized the importance of being able to shut down the chartplotter to save electricity during extended passages. The guidance was to have a separate wind instrument, depth sensor, and autopilot controller so that these functions could still be performed with the chartplotter shut down.


I am wondering whether that advice still makes sense.


I find that I am not comfortable running without radar and, as a result, I have the chartplotter on anyway.

A much bigger consumer of power is an electrically powered auto-pilot.

[s/v Jedi]

Originally Posted by flightlead404

A much bigger consumer of power is an electrically powered auto-pilot.

All autopilots are electrically powered.

[Cheyne]

We have had our plotter on for the past couple of months here in the Bahamas. Since we are on a mooring ball right now and not using the Anchor alarm I turned it off for two days to see if I could see a difference. My DC usage is almost the same. We have a Raymarine Axiom Pro 12.

[Seacod]

""The days of "electrical stuff is scary and we should have as little as possible on board" are behind us at this point, I think.[/QUOTE]"


Well.... Hubris pays a high price on the water

and is only true till the water Gods test you and your boat during a thoroughly wet snotty day/night/week etc and finally inveigle a path to short out some item in your gear. Happens all the time in the real world and assuming you have maintained your vessel impeccably (all boaters do of course) it will still happen, usually without warning...at a critical moment. Which is why backups for hand radios, gps's, batteries and every other thing that can break have to be on any boat wishing to be able to respond effectively. Otherwise

[s/v Jedi]

I think that when I switch my B&G Vulcan to standby, it’s still fully operational just disables the screen.

[pbiJim]

I used to have a little chart plotter on a fishing kayak that I used out in the ocean. It ran off of a little battery that weighed a few pounds. That little battery would last for days. The little chart plotter drew almost nothing. Some of the modern gear is pretty efficient. You need to check what you have & how much YOUR chart plotter draws.

Now things like autopilots are a different story. Depending on what actuator you have, how tight the dead band is set, & what the weather is doing, they can draw A LOT of power. You can draw down 100 amp hours or more out of a battery bank in an hour in some cases.

As for what equipment you need to have on, that will depend on what boat you have, how you are registered, and where you are going. In the event of a collision, having watch equipment shut off can earn you extra percentage points of liability. I've seen a big swing in liability for a boat that had radar installed but shut off during a collision. If you are not going to actually use the radar, you may be better off not having it on the boat at all.

As for secondary systems, I'm a big fan of having redundancy in all navigation & safety systems. Things do fail. I lost both a chart plotter & an anemometer while helping to run a sailboat race a few weeks ago. Fortunately, I had plan B on board in both cases. During a delivery a few years ago, the boat suffered a total 12vdc system failure that put the chart plotter off line and my hand held GPS came out of the bag with corroded batteries in it. That just left Navionics on an I-phone to get us past the coral heads going into Rodriguez key at dusk. I was not feeling good about that. We did some visual dodging.

[Jim Cate]

Now things like autopilots are a different story. Depending on what actuator you have, how tight the dead band is set, & what the weather is doing, they can draw A LOT of power. You can draw down 100 amp hours or more out of a battery bank in an hour in some cases.

Ummm... you sure about those numbers? To consume 100 ampere-hours in one hour means that the AVERAGE current drawn by the a/p is 100 amperes for the entire hour. I don't believe that there are any recreational a/p actuators that could do that, no matter what the conditions!

Hyperbole is ok in arguments, but ya gotta be somewhere in the ball park to maintain believability.

Jim

[wholybee]

Originally Posted by s/v Jedi

I think that when I switch my B&G Vulcan to standby, it’s still fully operational just disables the screen.

My Raymarine instruments are the same. I have analog transducers connected to the instruments, which make the data available on NMEA2000. Even when turned off, the instruments still read the transducers and output the data on NMEA2000. Only the LCD screen is turned off.

Not sure about chartplotters, but assume it would be the same, for a quick power on cycle instead of needing to wait for it to boot the OS.

[Tupaia]

Originally Posted by Pete7

I take it then you don't want AIS information, or is there another way you get AIS information.

There was but not any more Vesper Marine produced a WM850 and WM650 that sat in standby until a target popped up when it would light up the screen and sound an alarm. Brilliant solution offshore especially at night when instruments were dark. Alas, my unit has finally died. Replacement or repair not possible since Garmin bought them out and replaced it with their massively expensive, overly complicated and wholly unreliable Cortex system. There is little point in running a chart plotter 1000NM from land it is just a distraction.

[charliepsycho]

We have enough solar to keep up with everything running at sea, but not at night! So on long passages we end up with about a 30%-40% deficit every day depending on how hard the Autopilot works.

At anchor we typically have all the instruments switched off (inc NMEA2000) except the Watchmate XB-8000 AIS with GPS which provides an anchor alarm and wifi connectivity, this is our minimum draw situation, consumption is about 20% battery overnight (Fridges, fans, phone chargers etc) which we can make up with Solar during the day.

Interestingly we have experimented with running on just the Watchmate during the day, using an iPad as a chartplotter (Timezero as it links to everything we have) but we still have to have the NMEA2000 network on to run the Autopilot, but all the instrument heads and chartplotters off. Pretty much we can get back to 100% just on solar if its a nice day. The problem comes if you need to start the chartplotter, it can take a good 30 seconds to get up to being usable! Sooner or later we will get a Hydrovane, then we won't need the NMEA at all for blue water passages.

I am growing very tired of stupidly expensive chartplotters which are obsolete in a couple of years and MFD instrument heads that cost $500 when all they really display is wind or depth once you get bored of the clever stuff (Oh and you can't really switch them off!) I suspect someone will release some cheap Raspberry Pi based header displays soon and given how good iPad chartplotters are I'm getting hard pressed to see the point of a dedicated device now. iPads take seconds to boot use very little power indeed now.

[rslifkin]

Originally Posted by s/v Jedi

I think that when I switch my B&G Vulcan to standby, it’s still fully operational just disables the screen.

On the Navico plotters I've used the internal depth sounder also stops pinging when in standby. I'm not sure if they all do this or if it's only under certain conditions though.

[pbiJim]

Originally Posted by Jim Cate

Ummm... you sure about those numbers? To consume 100 ampere-hours in one hour means that the AVERAGE current drawn by the a/p is 100 amperes for the entire hour. I don't believe that there are any recreational a/p actuators that could do that, no matter what the conditions!

Hyperbole is ok in arguments, but ya gotta be somewhere in the ball park to maintain believability.

Jim

Good catch. I was distracted when I was writing that. I didn't reread before posting. I had been changing the wording but didn't finish the change. Originally it said that you can draw down a 100ah bank in under an hour.

To be more clear, I have seen a 100ah group 27 battery go from indicating full to cut off in just under an hour in tough conditions with an auto pilot working hard. Looking back, maybe the battery wasn't new & maybe it had some diminished capacity. Also, maybe the 50% usable reality for lead acid batteries may have been in play. My empirical inaccuracies aside, I stand by the statement that autopilots can draw a lot when they work hard. Especially the ones with big linear actuators on the quadrant or the ones with hydraulic pumps. If you hear the thing running close to non-stop, keep an eye on your bank voltage. You may get an unpleasant surprise. I have had to shut autopilots off in the wee hours of the morning many times due to low bank voltage.

[pbiJim]

Originally Posted by s/v Jedi

All autopilots are electrically powered.

That makes the assumption that one does not consider a wind vane to be a form of autopilot -

https://www.youtube.com/watch?v=W8FyWojjgC8

https://www.youtube.com/watch?v=X81wSVDXf9c

I understand that the two are different. An autopilot steers to a defined position. A vane steers to an angle off the wind direction. Wind shifts cause a vane to steer in a different direction. Autopilots, not so much.

[pbiJim]

Originally Posted by charliepsycho

... I suspect someone will release some cheap Raspberry Pi based header displays soon and given how good iPad chartplotters are I'm getting hard pressed to see the point of a dedicated device now. iPads take seconds to boot use very little power indeed now.

My only issue with using an I-pad for boat navigation, is that I don't consider them to be a properly salt-resistant, shock-resistant, marine-grade device.