Monday, 13 September 2010

Diesel Generator.

Well the weekend soon came and went! I did very little towards all the jobs I was planning to do. So maybe this next weekend will let me catch up.

We lit the stove for the first time last weekend and the boat was soon very hot and it was very difficult to control the heat. It seems that the door seal - is not doing its job and to much air is entering the fire. The fire is in run-away mode of operation. I had a quick peruse on eBay and found a replacement door seal which I have fitted. So this weekend we will test the fire again.

We also managed to find a Zanussi compact washing machine on eBay and we picked it up on Thursday night after we finished work. So it looks like fitting the washer will be high on the jobs-to-do-list. As my carpentry/joinery skills are somewhat limited we will be engaging the services of a more competent chippie person.

I have been looking at those small portable 3kva generators (Diesel and Petrol) on eBay. We want one for use with the compact washing machine that we are going to add to the boat. I am thinking of adding a separate supply feed from the generator just to the washer. The idea being to set up the generator on the tow path whilst the weeks washing is done.

In common with most boats we have a mains hook-up on-board Rosie. This is fine for most uses when we are at the marina. If our plans to do some cruising in the winter months are to come true we need to look at a back-up system for providing some additional power.

So, I have been having thoughts about adding a second source of power. The reasons behind making this change are two fold. The first option could be to add a third alternator to the engine to provide mains voltage for running an onboard washing machine and any other high current appliance when we are off the mains. However, I have almost discounted this as a viable option, due to the extensive engineering work required and to the cost.

The second option is to add a diesel electrical generator that can supply mains power. I could use a (cheaper) petrol generator. However, I am a bit wary of petrol generators because of the need to store petrol somewhere on board. Diesel is already stored on board and because of its nature is a much safer option than petrol. That's not to say that petrol generation is a bad option - there are millions of petrol powered cars on our roads. However, we would not store petrol indoors in our homes to use in our cars for obvious safety reasons. So we would not store it aboard for the same reasons.

The third none electrical option that I also want to look at, at some point in the future is changing the Alde gas fired central heating system (that uses far to much LPG gas for my liking). I would like to change to something that runs on diesel like an Eberspatcher. This could then be utilised by adding a second built in diesel tank co-located in the engine room. I would like to do this in such a way that it minimises any cutting and welding of the boat structure. However, before I go this route I will watch what happens to the cost of red diesel over the next few months.

From what I have been able to find elsewhere on the net, it would seem that there are two forms of the portable generator – One is done as direct AC and using a single pole from a three phase alternator, speed is pretty well fixed at around 1500 rpm to create a 50hz output. However, the waveform is not a pure sine-wave and can cause problems for electronically controlled devices. This could include the control electronics in a washing machine.

The second form is not engine speed dependant and uses a single phase alternator rated between 100 and 120 volts AC output, which is then converted to DC. The waveform and output voltage conversion back to 230v AC are done through an electronic control panel. However, the waveform is a much better approximation to the correct waveform. The engine speed can vary quite a bit. However, at the lower engine speeds current output (Amperes) is somewhat limited. So when an extra electrical load is demanded the engine will speed up to generate the additional requirement.

Size matters!

Contrary to popular belief size does matter when selecting a generator. Both physically so it can be stored and manhandled easily, as well as its power provision capability. So I need to look at exactly what it is that we want the generator to do. Which is to provide sufficient power to run a washing machine when we are off the mains hook-up. (2.5/4 Kva).

Portable generators can also be used to supplement what's available from our battery pack via the on-board Victron inverter/charger. The generator can be used to provide an additional back-up charging system for the boats batteries.


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