Diesel Generator Question

[DDabs]

Pretty simple noob question... how much gas does a generator go through? How long do you usually leave it on? For example, if you're anchoring in the islands and want to run A/C, does it run all night, or do you usually just run it for an hour or so?

[Pblais]

A diesel generator burns diesel fule not gas The size of the engine will determine the the rate of fuel consumption. To run A/C all night means you will run the generator all night even if it will cycle when not under load. For the most part when anchored out the boat hull will take on the temperature of the water so with warm water you will need A/C longer. You may find running a bit in the early evening allows it to cool enough to then open ports and take advantage of breezes. On days of lower humidity you may not feel the need to run it at all.

To recharge your batteries you may find a few hours daily is enough.

[DDabs]

Pblais, let's assume this is a 6-8kw generator. Do people usually run the A/C all night? Is the main purpose of having a generator on board to solely run the A/C? If the boat is outfitted with solar panels and a wind generator, the only purpose of the generator would be to run the TV or A/C... correct?

[Hudson Force]

We now have 3,400+ hours on our 7KW diesel generator. We most often run our generator for a couple hous in the morning or evening, but do not run it thoughout the night. Our typical need is for cooking, entertainment and cooling with the AC's for a terrm. The generator is capable of being used to operate the AC's over night, but we tend to favor the fresh air and quiet. We also cruise north for the summer.

[Pblais]

I think CaptForce is most when it comes to using a generator. I know trawler friends that use household appliances and so the generator helps reduce the use of the inverter since those use AC power. When they anchor out a lot they need the generator to charge up the batteries. Some trawlers like to anchor out often too. If you run a generator during high energy loads you'll find your batteries are easier to fully charge. If you stay anchored in one spot you can just run the smaller generator engine instead of the main engine and often get better fuel efficiency since both burn fuel to make electricity. They both make noise but perhaps a generator would be less noise and less heat.

The most energy demand on most cruising boats is the fridge! They consume more power than anything else on most boats. More than everything else on our boat. Our A/C needs shore power. We have solar too and it stretches how long we can go before running the engine. I had a wind gen on the last boat but I find I choose not to anchor where the wind is blowing strong. They can make a lot of power under way but most have a noise factor. These days solar panels add a pretty good boost and are silent with costs coming down. Eliminating the use of power is the first step and maximizing solar should be the second step. More power use just adds more work for the crew (me). You need to understand how much power you need and how you use it and when you use it to get a grip on making all your energy production balance out every couple days.

Solar and wind cost a lot but the trade off is you get more peace and quiet. If that isn't a goal they are a waste of money as a generator is cheaper. At night we all want peace and quiet and a generator is neither.

[djmarchand]

The previous posts gave a good profile of different cruisers use of the generator. Actual fuel consumption of a 5 KW unit will vary from 1/4 to 3/4 gallon per hour depending on loading.

David

[skipmac]

Originally Posted by djmarchand

The previous posts gave a good profile of different cruisers use of the generator. Actual fuel consumption of a 5 KW unit will vary from 1/4 to 3/4 gallon per hour depending on loading.

David

Quite correct. Ones cruising style will determine the amount of generator time and can vary a lot depending on what's wanted by the cruiser.

For me 90% of the time a generator would be for backup and occasional battery charging. But on those hot, still, muggy nights when the bugs get bad I would close the hatches and crank up the AC. Sometimes it's good to run the AC for an hour or so when cooking dinner and to cool the boat off after a hot day. Then shut down when the sun goes down and it cools off.