small genny + bat + inverter?

[Troppo]

Does this have any advantages in regard to electricity on boats:

Use a smaller generator to charge the batteries and use a bigger inverter for the occasional use of bigger 240 volt equipment. I'll explain, but I'm not sure if I am being clear so please persevere:

A Honda or Yamaha generator 1 kw (rated .9) genny weighs about 13 kg, a 2 kw (rated 1.6) one 21 kgs.

My electric drill is 1,000 watts, vacuum cleaner 1,800 watts. So, to run them I would need a 2 kw one, the bigger one. However, I don't run that equipment for long.

As an alternative - and this is what I would like your opinion on - when I need to use the bigger equipment I could run the smaller generator output through a good-sized 240 volt charger into my batteries and have a 2 kw inverter supply the required juice. So long as I don't use the tools for hours then I shouldn't drain the battery.

The benefit, as I see it, is that I dont' carry around the extra capacity generator for the few times I need it. Passing a 13 kg genny up and down to the dinghy is much more do-able than a 21 kg one. : )

What do ya reckon? What's the pros and cons?

[Phillip]

Afternoon All,

I've just done an adit of all my electrical useage and have LED or removed high consuming items!

I will be using a 100w solar panel. On those days when I use the autohelm [the largest consumer] I will run the engine for about an hour which I usually do when entering and leaving a anchorage/marina.

I will also charge the batteries [2x 150ah + starter] at any 240V power source I can find.

Period, all done, no need for extra petrol engines etc etc etc.........

[Swift]

Troppo

There's nothing wrong with this approach but the appliances you already have may be a problem. Unfortunately a 2000 w inverter may not run a 2000w vacuum. This is because inductive loads (any electrical appliances with a motor) have high initial inrush voltages - up to 3 times the rated wattage. However even though the 1000 w drill is also an inductive load it should work fine straight off the 1000w genny. The reason for this is that as drills are speed controlled they have low initial current draw and also rarely draw full power except with really large drill bits. You could always buy an even bigger inverter than 2000w but maybe it's cheaper to get a smaller vacum?

Phillip.
Wow! 2X 150 amp batteries in addition to the starter battery is serious reserve power. Now an additional 100 w panel, I like your approach!

[surrealbass]

Hi Troppo, this is certainly valid as a way to go, the things that Philip points out are totally valid- you need to know the starting current of appliances as well as the operating current, also depends on type of equipment but you have to be careful of the inverters waveform too true sine wave being the ideal but expensive and unnecessary for some equipment. This is how Joylee is being set up as she is to be stink free when she sets sail again with 8.5kW electric power- apart from the gen only being for extended sojourns if required. Mine is a truckload more complex in design but I was an EFI car specialist in a previous life and this sort of silliness is good fun to me one word of advice though, bear in mind that when you hit that power sw on the inverter or crank up the genny you have a rather serious potential for disaster if proper safe design and practice is not followed!!! the ability to sleep with your hand in the bilge in case she develops a leak and starts to sink will make it a SHOCKING discovery!!!! Not sure what the 240v regs are in NSW but even if you may be able to bypass inspection due to portable equipment, it is certainly not the system to "suck it and see" so have a talk to a friendly sparky and make sure you keep all outlets above heeled waterline, protect installation from inadvertent splashing etc. Keeping the whole lot running to power the laptop nav through one of your infamous bar crossings may be a tad risky- you get the idea. I have had a couple of massive boots back in the less regulated days and may be a little "wary" but I may not have survived any of them so best not to ever have one!!