Choosing a new generator

[Butterfly8]

Look interesting, wondering if anyone is actually using one and:

 

- how noisy is it (cannot be silent)

- where would you build it in - looks too big for the engine room?

- could it be wired so it was controlled from inside the boat, or to start automatically if the batteries are low or the power is too much for the invertor

- is it possible it might be incompatible with the invertor? Sure I've read about problems with this

 

Also, if these do work well why would anyone want to spend thousands on a Tavel Pack or another type of generator?

[Chris Pink]

I'm confused by the spec (great price btw)...

 

Now that can't possibly mean that it uses 280 gallons per kW hour... so what DOES it mean?

 

Tony

 

grammes?

 

Look interesting, wondering if anyone is actually using one and:

 

- how noisy is it (cannot be silent)

- where would you build it in - looks too big for the engine room?

- could it be wired so it was controlled from inside the boat, or to start automatically if the batteries are low or the power is too much for the invertor

- is it possible it might be incompatible with the invertor? Sure I've read about problems with this

 

Also, if these do work well why would anyone want to spend thousands on a Tavel Pack or another type of generator?

 

in order, not too bad - there's one along the canal near where I cruise

it lives on his back deck but you could easily (more easily than petrol) build one into an engine room with an exhaust extension

yes, yes, no

no, they are not on together - you will need a(n automatic) transfer switch

because it is another engine when you already own one.

[Timleech]

Look interesting, wondering if anyone is actually using one and:

 

- how noisy is it (cannot be silent)

- where would you build it in - looks too big for the engine room?

- could it be wired so it was controlled from inside the boat, or to start automatically if the batteries are low or the power is too much for the invertor

- is it possible it might be incompatible with the invertor? Sure I've read about problems with this

Also, if these do work well why would anyone want to spend thousands on a Tavel Pack or another type of generator?

 

I'm assuming you mean Travel Power, the main reason for using one, given that they are expensive, is surely space. Room can usually be found for one more or less within the envelope of the existing engine unless perhaps it already has two large alternators fitted.

 

Tim

[Guest]

Biggles has proper deep cycle batts.

 

Tony

I see, thanks. What voltage can deep cycle batts. be safely discharged to?

Cheers.

[Chris Pink]

I see, thanks. What voltage can deep cycle batts. be safely discharged to?

Cheers.

 

Difficult to answer. I would say 11.35V is a bit low. 'safely' is your ambiguous word. Every discharge shortens a battery life, a deeper DOD shortens it more, the economics have been the subject of discussion. Deep cycle batteries go to a higher DOD without severely shortening life. (ie the more 'deep cycle' the battery the more linear the battery life against DOD graph. )

 

But of course the more important factor is whether they are charged back to 100% afterwards, which, in a 1000 hour bank back from 80% DOD, is a long time or a very big charger indeed.

Edited October 6, 2011 by Chris Pink

[WotEver]

Difficult to answer. I would say 11.35V is a bit low. 'safely' is your ambiguous word. Every discharge shortens a battery life, a deeper DOD shortens it more, the economics have been the subject of discussion. Deep cycle batteries go to a higher DOD without severely shortening life. (ie the more 'deep cycle' the battery the more linear the battery life against DOD graph. )

 

But of course the more important factor is whether they are charged back to 100% afterwards, which, in a 1000 hour bank back from 80% DOD, is a long time or a very big charger indeed.

What Chris said

[Guest]

Difficult to answer. I would say 11.35V is a bit low. 'safely' is your ambiguous word. Every discharge shortens a battery life, a deeper DOD shortens it more, the economics have been the subject of discussion. Deep cycle batteries go to a higher DOD without severely shortening life. (ie the more 'deep cycle' the battery the more linear the battery life against DOD graph. )

 

But of course the more important factor is whether they are charged back to 100% afterwards, which, in a 1000 hour bank back from 80% DOD, is a long time or a very big charger indeed.

Thanks. Yes better to never discharge at all! I was just curious how much more they could be discharged than a cheapo.

[WotEver]

I was just curious how much more they could be discharged than a cheapo.

The very good ones are pretty happy to go all the way down to 20% (80% discharged), but you still have to put it all back...

 

Tony

[Nickhlx]

The very good ones are pretty happy to go all the way down to 20% (80% discharged), but you still have to put it all back...

 

Tony

 

I think I saw on the Trojan T-125s a figure for life quoted at DoD of 80% ( i.e 20% left 'till flat) which seemed an impressive number of cycles ....

 

Nick

[Bob18]

To answer Tony's question:

Now that can't possibly mean that it uses 280 gallons per kW hour... so what DOES it mean?

 

Its grams of fuel per kW hour.

 

To get to something more understandable:

First multiply this "magic number" by the number of kW being produced by the generator. This gets the number of grams of fuel used per hour. Since diesel weighs about 850g per litre, or about 3800g per gallon, to get to gallons per hour divide the grams per hour by either 850 to get to litres per hour, or 3800 to get to gallons per hour.

[churchward]

Look interesting, wondering if anyone is actually using one and:

 

- how noisy is it (cannot be silent)

- where would you build it in - looks too big for the engine room?

- could it be wired so it was controlled from inside the boat, or to start automatically if the batteries are low or the power is too much for the invertor

- is it possible it might be incompatible with the invertor? Sure I've read about problems with this

 

Also, if these do work well why would anyone want to spend thousands on a Tavel Pack or another type of generator?

In terms of noise I think it states it is 72DB. Not that loud but indeed not silent. A noise like that would mean (if you were near it) you would have to lean into to hear someone speaking in a normal voice.

 

The Db scale is also one of those measurement scales that is not an analogue progression. ie 70 db is twice as loud as 60db.

 

See the link below for some examples of types of noise at various db levels

 

http://www.industrialnoisecontrol.com/comparative-noise-examples.htm

[Smudge]

Our travel power cost £3500 extra fitted when we bought the boat personaly i wouldnt be without it, its relieable but i did have to have the alternator reconed after 6 years of abuse. It will run a top of the range Hotpiont washer-dryer,dehumidifier and the hoover all at the same time Also making the engine work a bit harder stop the bores from glazing, wouldnt swap it

[Chris Pink]

In terms of noise I think it states it is 72DB. Not that loud but indeed not silent. A noise like that would mean (if you were near it) you would have to lean into to hear someone speaking in a normal voice.

 

The Db scale is also one of those measurement scales that is not an analogue progression. ie 70 db is twice as loud as 60db.

 

See the link below for some examples of types of noise at various db levels

 

http://www.industrialnoisecontrol.com/comparative-noise-examples.htm

 

I think manufacturers db figures are pretty crap when it comes to generators, there is no substitute for hearing one.

 

The noise also varies enormously with load.

[Bob18]

I agree with Chris, the noise from small generators varies greatly with load, most will have a "sweet spot" of load - a load at which they are quiet, and this can be anywhere from no load to full load, depending on the type, how it is mounted, what it is mounted on, what's around it, where the exhaust is pointing, and so on.

Generally if you can mount it on a solid surface, using vibration mounts, then surround it with something to absorb the noise you are on to a winner - oh and a good exhaust silencer helps as well...

 

 

(and make sure all the bits aren't loose - there's nothing like a rattling bracket to really annoy everyone.)

[Butterfly8]

Our travel power cost £3500 extra fitted when we bought the boat personaly i wouldnt be without it, its relieable but i did have to have the alternator reconed after 6 years of abuse. It will run a top of the range Hotpiont washer-dryer,dehumidifier and the hoover all at the same time Also making the engine work a bit harder stop the bores from glazing, wouldnt swap it

 

Thank you for this.