Long range cruising DC questions

Gunni · Dec 1, 2016

Best bang for your buck? Upgrade your engine alternator to an externally controlled, temp. compensated 150 Amp Balmar. Convert all your toys to 12 vdc and forget the inverter - you don't have the DC capacity to be fooling with an inverter. 2 100 Watt solar panels on your arch or davits would really give you a boost. Beyond that you will need to go to a strict regime where you only run your windlass and that winch when you are under power, and come up with a plan to cycle your refrigeration off part of the day unless the sun is shining bright! Even then you will be listening to the engine every morning...and every night.

Ralph Johnstone · Dec 1, 2016

redunculous said:
Have looked into the alternator upgrade before - will take another look and get serious about it

I'd recommend installing an external alternator regultaor first (if you don't already have one) and then see if you need a larger alternator. This is going to depend on your sailing/motoring regime.

When every saved amp counts, consider LED's throughout the boat.

CloudDiver · Dec 1, 2016

At it's core, your laptop is already a 12V device. That 'brick' that you plug into it and the wall is just a big resistor to turn the 110V down to 12V. All you need is a 12V power supply for the laptop, easy to find on Amazon. If I'm not mistaken, many smaller TVs are also 12V... or at least you can buy one that is set up that way. TV's have gotten MUCH cheaper for low power consumption LED HD. Forget all that 4K crap or giant screens, no place for those monsters on a cruiser.
If you haven't already, convert all your lighting to LED bulbs (including your NAV lights). There are resources online to buy reliable replacement LEB bulbs for just about any style light.
If you add another batter bank of T105's, do your research and find a Trojan distributor in your area (usually someone who mostly deals with Golf Carts, not the Marine industry). For example, here in San Diego I would have to pay around $225 for a T105 at any of the 'marine' suppliers. If I make a 90 minute day trip up to the Santa Ana (Los Angeles area), I can get T105's for $109 each from a gold cart place.
Many people go solar and it is a deep subject... much research is required. For open ocean passages I think wind generators are more bang for your buck, just keep in mind they can be 'noisy', they whine as they spin. Many people find this incredibly annoying when boats are at anchor, but during a windy passage you might not even hear it. The wind generators that the most quality, most bang for your buck as far as watt output, and publish low operating decibels will be pricey. Beware of 'cheap', you get what you pay for.
I think first and foremost go with Gunni's advice, an alternator upgrade is key. Like he said, during an anchoring evolution your engine should be running anyway, and it should still be running when you use the winch to hoist the main. Otherwise, you'll have relatively low amp draw from everything else. You didn't mention how you make hot water or if you have a 120V water-maker or 12V unit... those also effect the times of day and duration you might run the engine.

rgranger · Dec 1, 2016

A second battery bank will still require charging capacity.

Jackdaw · Dec 1, 2016

Hydrogenerator. Its how the pros roll.

http://www.wattandsea.com/en/cruising-hydrogenerator

Terry Cox · Dec 1, 2016

Each year we usually do a two month long range cruise into PNW waters. We like our setup and it works well as we prefer anchoring out as opposed to marina life. The further north you go the less frequent the marinas and more remote the anchorages. I wrote an article awhile back that provides more details here: http://hunter.sailboatowners.com/mods.php?task=article&mid=45&aid=6102&mn=42

rgranger · Dec 1, 2016

Jackdaw said:
Hydrogenerator. Its how the pros roll.

http://www.wattandsea.com/en/cruising-hydrogenerator

Wow... at first I thought "way cool" and then I looked at the price... still way cool but a bit pricey for my tastes.

http://www.southernseasmarine.com.au/watt-and-sea-hydro-generator

I think I could cover the entire surface of my boat with flexible solar panels for half of that price...

dlochner · Dec 1, 2016

To add to the mix of good advice, consider upgrading the battery monitoring system. A Balmar Smart Guage will provide critical State of Charge information and a good amp meter, such as the Victron Battery Montior will provide real time measurement of amps in and out and an amp counter.

If your house battery bank is not wired as one large bank, change the wiring to make it one large bank. The batteries will last longer and you will have more useable amps. (Maine Sail has posted on this issue many times, check his forum and or the Compass Marine site.)

The usual recommendation for sizing an electrical system is to first do an inventory of the electrical devices, their current draw, and the time the devices will be running. In reality anchor windlasses and electric halyard winches, although they draw a lot of current, don't count for much because the engine is usually running while they are being used and they are only being used for a few minutes a day.

Once you have an inventory of your electrical needs, you can look sizing the battery bank. Once the battery bank is sized, the charging system can be developed.

Let's say you use 100 amp-hours a day. A draw of this amount needs a battery bank with a capacity of at least 350 amp-hours. But that is cutting it very thin. 4 GC batteries will provide about 450 Amp-hours, a 100 amp-hour draw down will only bring down the SOC by 25% in a new bank. And would require 100+ amp-hours of charging to bring it back to 100% SOC. This is a real simplified explanation and incorrectly assumes 100% efficiency. Your mileage will definitely vary in the undesired direction.

Going back to the beginning, how many amp-hours do you need a day?
How can the draw be reduced?
How large a battery bank do you need to support those amp-hours?
Now, ask, how do I get those amps back into the battery?

Good Luck,
Dave

CloudDiver · Dec 1, 2016

Here is a more recent article touching on the state of technology for each mode of power generation;
http://www.yachtingworld.com/gear-reviews/wind-water-and-solar-power-65797

Benny17441 · Dec 1, 2016

Consider adding an inboard generator to the boat if it is within your budget. It is cheaper to put hours on the generator rather than on the main engine. As a less expensive option consider packing a portable generator, some of them can run on propane. This may solve many problems, avoid the use of a number of transformers and provide 120V for use in many appliances from lap tops to microwave ovens besides keeping the batteries charged.

jeepbluetj · Dec 1, 2016

Do a power budget (i.e. calculate how many amp-hours you will use per day)
Then figure out how you're going to be able to make more than that per day.

Consider not using the freezer if it's seperate from the fridge.
LEDS for everything (like others said)
Use the windlass and maybe the powered winch with the engine on (most folks would anyway)

I like lots and lots of solar. Wind too, if you're gonna be in a windy place. Running a generator or engine every day would drive me nuts. Doesn't bother some folks though.

For example: I have a 120W panel with a PWM controller on my boat and that's not quite enough to keep up with the fridge (in socal, where it's pretty sunny). I've got 400W with a MPPT controller on my motorhome and that endlessly powers everything including a household fridge off an inverter. My charger gets to float about noon every day in the motorhome.

More batteries give you a bigger "tank" of electricity. But you still need to charge it.

Bill Roosa · Dec 1, 2016

Couple of thoughts:
hydro generators only work when underway. 90% of your time in blue water is at anchor. FWIW
The variables are production, storage and usage(both time and load). They need to be balanced to achieve the workable solution. I built a spreadsheet that lets you play with the time usage of loads, storage capacity and type/size of production. Just ask for it.
Things I learned from playing around with the spreadsheet:
Use electricity as you produce it instead of storing it. Storage incurs about 20% charge/discharge losses in the batteries. i.e. run the reefer during the day and coast at night......use a holding plate unit.
Hang as much stuff off the engine (DC gen, water maker, compressor,hot water heater, AC genset) as possible. Then when you do have to run the engine you can (for example) heat your shower water while you cook your evening meal on the AC range and draw down the holding plates. and make fresh water...... You get the idea.

Stu Jackson · Dec 2, 2016

You're reinventing the wheel.

With a daily draw of 100 or so ah/day, you have a normal draw. Your job is to replace that use with engine, solar, wind, water or rubbing sticks together on the foredeck. Nothing has changed much in the past few years. All have been discussed here and on other boating forums, endlessly.

Energy budget, larger high output alternator with external regulation, solar, generator if you must...

All it means is how long you have to run the recharging sources you have. If you're gonna be motoring a lot, the bigger alternator is a sure winner. If you're gonna be sailing a lot, then solar.

This is not rocket science. Your battery bank is perfect for your use. Windlass on the house bank makes sense, you're gonna be running your engine when that's on anyway, right?

A frequent contributor here on the C310 section, is Jesse, aka Smitty. Read his stuff, he's very good. Here's an example with his link to his blog:

http://forums.sailboatowners.com/index.php?threads/2000-30-mkiii-or-310-help.180919/#post-1318060

Have a great trip.

Rick D · Dec 2, 2016

I'm going to be a contrarian here. I have what you have in terms of power draw and the same battery bank. We moor in Catalina for weeks at a time with no power or water. You will pull 90-110 amps per day. That's turning the frig and freezer down, using minimal lighting if not LED (mine are all LED), running a coffee maker in the AM (saves CNG) about an hour to two of TV for my wife & news, CD player for four hours, and all the rest of the usual stuff. Plus, I have a Freedom 25 inverter/charger. So, OK, before I took other measures, and with fresh batteries, and a Blamar 90 amp alternator and three-stage external regulator, I would run the engine at about 1500 RPM for an hour twice a day to keep up with the demand. Then I got a Honda 2000 generator, and I put it on the aft transom locker lid (Strapped to the pushpit!) and set the maximum draw on the Freedom to 20 watts AC which is all the Honda will tolerate. That would give me about 80 amps DC on bulk charge. So, I would run it about an hour and a half a day. (All this is drawing down no more than 50%)
When sailing overnighters, (races) I typically charge by engine twice a day for about an hour to an hour and a half since the radar, chartplotter and autopilot are all drawing, plus my netbook. Running lights are LED. Also, however, I run both the frig & freezer 24/7 and that is a BIG draw. If you did without the freezer, your draw would be WAY less. It might cost you a wife, however.
When we are on our Catalina mooring, we use a large Solar Shower with an extended hose into the forward head to have warm water for showering rather than running any electrical to heat water.
In subsequent years, I added 266 watts of solar with a combination of 66 watts flexible panels on the bimini top and 200 on rails replacing the aft upper lifelines. Those only go on when we are planning on being somewhere more than five days or so. Basically, that combinations, in the summer, allows me to go two or three days without running the Honda.
So, I would not add to your battery bank. Why? Because it just makes it that much longer to recharge. If you can go longer without charging, it just takes that much longer to recharge. If I had double the battery capacity, I would go (without the solar) two days instead of one, but then I'd have to run the Honda three hours (or the engine three hours twice a day). Why drag all that weight around for occasional need? That's what the guy said when I recommissioned it 17 years ago and he was absolutely right.
Your boat, your call. This is one guy's perspective.

Stu Jackson · Dec 2, 2016

Rick D said:
I'm going to be a contrarian here.

Rick and the OP:

That's NOT contrarian, that's good balanced system design and management.

capta · Dec 2, 2016

Living on the hook full time, the first thing I did was purchase DC power supplies (car chargers) for our computers and a 12 volt TV. Inverters have some loss and use power for the cooling fans. Cigarette lighter USB adapters work well for most other electronic gear.
Solar is wonderful, but obviously a day time source of power. Wind chargers are much less efficient and consistent. Average day (24 hours) down here is about 4 to 6 amps TOTAL in 10 to 15 knots of wind. Now that it's winter and blowing 15 to 25 knots, I'm making about 20 to 25 amps a day, average. Not really all that much considering my solar can make 20 amps an hour with good sun. I can see a fluctuation of several amps in a few seconds with wind charging, while solar is pretty steady over a much longer period.
Almost none of the equipment you listed is drawing power continuously. The head, electric winch, windlass and radar are almost negligible power draws over a 24/7 period. Same with your water pumps and bilge pumps. They only run a few minutes each hour at most. Your nav displays are also pretty low power draws. If your boat is well trimmed and you have a quality autopilot, that shouldn't draw much over 5 or 6 amps an hour.
The fridge is your biggest draw, probably taking between 30 and 60 amps over a 24 hour period, depending on the set up, insulation and how many times you go into it.
Why 3 banks? One for house and one smaller one for starting should be sufficient, IMO. Starter bank should stay fully charged most of the time, leaving all your charging to maintain the house. I run 90 house/10 start on all chargers that allow me to choose.
Remember, no matter how much 'green power' you produce, there are periods where you will produce little or none. In that case you must have the batteries to cover those periods or a generator and electric battery charger to maintain your batteries for as much as 5 days, perhaps longer in some places.
It all boils down to basic math. If you can produce as much power as you consume then your batteries are going to be happy campers. If not, you'll have to learn to conserve energy and prioritize.

Benny17441 · Dec 2, 2016

Minimalism is basically for young people with small boats; I was there once. If you have a boat equipped with fridge, freezer, electric head and other electronics and you are going on an extended cruise, you are going to want to use them all. The most reliable source of power on demand will be a gas, diesel or propane generator. We do two week trips in the Bahamas with a most modest 2 group 27, wet cell battery bank and a Honda 2000 portable generator. The Honda runs our 12K btu A/C at night and also recharges the batteries while during the morning runs our coffee maker and microwave oven and TV and DVD player in the evening. We tie a 5 gallon gasoline can on a board at the stanchions and will likely refill it every 5 days. If you need more range just add another can. Nothing like wanting to use the microwave oven now and not having to wait for a slow source to recharge the batteries so you can drive drive an inverter. These Honda units sell for under $1,000.