Invertors. 150watts? 1000 watts?

CodStewart

CodStewart

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Power Inverter

Converts 12v DC batteries to 230v AC . For use in most cars, caravans, boats & lorries. Overload and short circuit protection. 150w & 300w includes cigarette lighter plug. Crocodile clips supplied with 500w.
Code Price Inc VAT Qty
58864 150w


to 1000w available.

Ahoy,
Sorry to bother you with my naivety again but what kind of invertor is most useful for a boat.
They appear to range from 150w to 1000.

Which would you choose?

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It depends what you want to power. You will need one which is just a little bigger than the total power you will want to use. But beware to distinguish between the power available contiuously and what may be the maximum available in short bursts.

Remember inverters are less than 100% efficient so with an output of 1000watts the power consumption will be in well excess of that, which at 12 volts will be more than 83amps so you will need some seriously large batteries and some heavy wiring

Remember that unless specified to produce a sine wave output they may not be suitable for powering electronic equipment
 
What would an average cruising boat go for? Will want to occasionally use a blender/computer and that's it.
Just very, very average.
=which wattage shall I go for?
 
Try to see the instructions before buying.

I have a 600 watt model (can't remember the manufacturer) but there is a warning that using with inductive loads, i.e. anything useful that contains a motor, may damage the invertor. Don't think it is a proper sine wave, so its only use is to run light bulbs!
 
Look at the power requirement of the blender and the computer and add them together if you are likely to need to use both at the same time, otherwise take the power of the larger, and then chose the inverter that will give that power contiuously. It's the computer that is likely to dislike a non sinewave supply even the elctronic speed control of the blender may object.
 
After trying 2 or 3 of the 'cheapo' type, available from Maplins etc, we went for a Sterling 600Watt model.

The cheap ones simply don't do what's printed on can! I opened one of them to find the most awfull terminal connections i've ever seen. We got through 3 in 2 years! The Sterling model has more than proved itself for us, but no doubt any of the main brand marine models are the same.
 
a 1 kw inverter, working with 80% efficency is using around 100A. A modern sinus inverter is capable to doubble that for several minutes. In my opinion, this is too much stress on batteries and chargers in a AWB. If you have several 100's of AH installed, no problem. But if you have the average 2 battery (2 x 100 ah) setup, the stress to this system may be to much in the long run.

Peter
 
A PC will usually require about 75w or less but a blender could use 500w plus depending upon the model. For a PC I suggest you use one of the small cigarette lighter DC-DC converters which are more efficient than going DC-AC-DC when you use an inverter with the standard AC power pack of a PC. Most of these DC-DC converters (available from Maplins in UK but since you are in Japan there are plenty of supply opportunities). Reflect well on what you need to power on board. Do you REALLY want a blender? The problems of managing your 12v DC supply and keeping it well charged can bring these matters into focus quickly. It is not just the initial cost of an inverter. As others have pointed out the current required to run them is significant. I say keep it simple. I have lived aboard for 5 yrs and the most powerful inverter I have is 300w which is not often used, my 150w unit is the most used and is quite efficient but of course it can't run a blender or a hairdryer.

Ray
 
This months' Sailing Today (March) has a less than positive review of a Sterling Inverter. The factsheet delivered with it was wrong (out of date) and after the fuse blowing several times when trying to plug a piece of equipment in, the whole inverter packed in...
 
I have a cheap 300W (600W peak - or so it says) inverter that worked so far with everything I tried. Mobile phone chargers, TV, Laptop even an old 340W B&D drill. Only when the drill needs full power the inverter stops but after off-on it resumes.

I guess I've been very lucky so far...
 
I found that if you use a small inverter for say TVs, Laptops, ect they are fine. When you start looking at larger invertors for power tools, 12v microwaves ect they are to much of a drain on the batteries so you are not really acheiving anything. For that sort of power you would be better with a small silent running Generator.
 
Absolutely. That's why I didn't opt for the larger ones although they were equally cheap. I wouldn't like to drain windlass' power from the batteries for a long period.

I forgot to mention that even while working with the drill I always keep the engine running. 30 Amperes are already quite a drain and a stress to the batteries.
 
Aside from the possibility of using a hand operated drill, believe it or not you can buy a hand operated blender too (google 'vortex blender')... if of course, a blender is something that you require. Just means if your batteries fail, you can still make holes and daquiris, at least until all the ice melts.
 
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