Petrol or diesel generator?

[sam pig]

Dear All,

 

I am in the process of pricing up generators for use as a stand-by power source on our 57ft Piper boat.

 

From what i can make out from the sites i have looked at, the petrol options come in at a generally cheaper price than the diesel models.

 

I am looking at approx 2.5KV output and see myself being drawn towards the Marksman range as there are some good deals on e-bay (around £270.00 delivered).

 

Does anyone have experience of having owned both petrol and diesel models and what are the advantages / disadvantages?

 

Obviously diesel is cheaper (at the moment), but i would get the impression that diesel units would be considerably noisier.

 

Any advice would be welcomed

 

Thanks

 

JP

[sam pig]

Also, furhter to the above, i am looking for a reliable but competitively priced battery charger to run off the generator and charge the domestic battereies. I see Victron do a good range but anecdotal information is always welcome.

 

Thanks

 

JP

[WJM]

Check your insurance - they might not allow petrol on board.

 

In the same vein, check your own opinion - I would never have petrol on board regardless of insurance - while others are perfectly happy with it.

[Denis R]

I've a conventional 2.5kW Briggs & Stratton petrol for battery charging through a Victron inverter charger - not one of those 'hush-power' type things. This is not a quiet generator! I suspect that it's at least as noisy as a diesel. In addition its sine wave is very dirty - to the point where I had to re-program the Victron unit using VE Configure in order to get it to accept the input. When the generator is running under light load (as the batteries approach fully charged) the Briggs's speed regulation is not that good and the Victron unit makes all sorts of fussy buzzing and moaning as it tries to control the mess coming in. My Candy Aqua 1000T won't run off the generator mains input - it completely bamboozles the washer's speed control. If I knew then what I know now (i.e. when the boat was built), I'd have had a diesel genny with a 'properly' conditioned AC waveform - but would have spent a fortune more than the £290 of the Briggs of course.

[blackrose]

I am also in the market for a new generator. I'm seriously thinking about a inboard diesel push button start/stop job that takes it's fuel from the boat's main tank (or auxillary built in tank), and uses the boat's skin tank as its cooling system. Obviously these are much more expensive and there are installation costs on top.

 

Whatever you decide, bear in mind that it's the waveform of the AC produced by the generator that will decide whether it will run your battery charger, not just the kw output of the generator.

[sam pig]

And that is exactly why i came on here as i knew all you people would know a shed load more about this than my good self.

 

Thanks for the advice and keep it coming......

 

I hope this is not a stupid question.....what "waveform of the AC", should i be looking for?

 

I am good with some boat stuff but electrics and "wiggly amps" is an area that baffles me. I am learning v quickly though!

 

Cheers

 

JP

[John Orentas]

How often have we had topics almost identical to this one. This is a classic example of 'Added Value' marketing.

 

First you design a battery charger that is so- some would say sophisticated, I would say sniffy that it will not function without a perfect sine wave input, then you sell the person an absurdly complex and over the top generator to power it. At the end of the day the bloke only wanted to charge a few batteries and he ends up paying thousands of pounds more than is necessary.

 

These very clever generators have their place and are invaluable for some tasks, but battery charging is not one of them, essentially a battery charger is a simple device, little more than a transformer and a rectifier, I bought my last one for about a tenner from Halfords, all that is required is a scaled up version of one of those. Couple that to an agricultural quality generator and that is all that is needed.

 

In a few hours people will be telling us that to squeeze the last few electrons into your batteries in two hours instead of a relaxed five hours you will need all this stuff with temperature monitoring to keep everything tottering away from the brink of disaster. Are you really in that much of a hurry and if you can't take that last 10% of charge why not just buy an extra battery.

 

Things have got so bad that you probably can't buy this simple equipment anymore, an entire industry of back street, fly by night electronics engineers have appeared in the past twenty years and are threatening to take over the world.

Edited January 19, 2007 by John Orentas

[blackrose]

And if that didn't help....

 

Many 3 or 4 stage marine battery chargers need a pure or semi sine wave AC input.

 

What this basically means is they need "clean electricity". The graphic of a pure waveform looks like a smooth wave going up and down. http://en.wikipedia.org/wiki/Waveform

 

If you're buying a generator ask about the AC waveform produced - you may also need a pure sine wave to run other sensitive equipment like washing machines, microwaves & computers.

 

(It's true I don't know exactly what I am talking about here - just what I have learned from others and just trying to help. I'm sure there are many people who can correct me if any of this is wrong.)

Edited January 19, 2007 by blackrose

[Sir Nibble]

The sine wave will be clean, this is inherent in the physics of an alternator, unless you have REALLY scrappy regulation. I would suggest that the inportant thing is frequency, and for that you need precise speed control on the engine, preferably electrinic rather than centrifugal. £££££££

[carlt]

These very clever generators have their place and are invaluable for some tasks, but battery charging is not one of them, essentially a battery charger is a simple device, little more than a transformer and a rectifier, I bought my last one for about a tenner from Halfords, all that is required is a scaled up version of one of those. Couple that to an agricultural quality generator and that is all that is needed.

 

Four stroke B&Q performance power genny 1kva- £79, Argos 'diesel engine' battery charger(x2)-£19.99, Surge protector extension lead-£10 or thereabouts, is my usual set up, for charging batteries that is. It keeps 2 banks of 4 110ah batteries topped up when the solar panels aren't working. The surge lead has never tripped btw but it is better to be safe than sorry.

 

I do have other, more sophisticated gennies for running tools, electrickery etc, but to keep the boats afloat and the fridge and telly running, the charging set-up works just fine.

[blackrose]

... essentially a battery charger is a simple device, little more than a transformer and a rectifier, I bought my last one for about a tenner from Halfords, all that is required is a scaled up version of one of those. Couple that to an agricultural quality generator and that is all that is needed.

 

Things have got so bad that you probably can't buy this simple equipment anymore...

 

I think Halfords still sell plenty of cheap automotive battery chargers if that's really what you want to use on your boat.

 

Also, furhter to the above, i am looking for a reliable but competitively priced battery charger to run off the generator and charge the domestic battereies. I see Victron do a good range but anecdotal information is always welcome.

 

Thanks

 

JP

 

Victron are supposed to be good, Sterling's Pro-Digital range are very comptitively priced. I have one which stays on all the time as I am on mains at my mooring. It's a great bit of kit - I just leave it on and all I ever need to do is check the water in the batteries once every couple of months. You can't do that with most automotive chargers.

[sam pig]

wibble......tilt...

 

black rose, thanks for that info, and the rest of you "in the know".

 

I suppose the question i should have asked is "can anyone reccomend a good diesel generator and battery charger combination coming in around the 300 quid bracket"

 

As i say, i am leaning towards this model as there are a load of them on e-bay for what seem to be a good price to me..

 

http://www.buyagenerator.co.uk/eBay-Listin...+Generator.html

 

The top one on the page.

 

Battery charger wise, i am still a bit overwhelmed by the market. I landed on my feet with the inverter we purchased off e-bay but i think it was luck as much as anything. anyone reccomend a good, reliable well priced option?

 

I will not hold it against you if it fails to work out....

 

cheers

 

jp

 

 

 

Blackrose,

 

I like the look of the Sterling pro digital range and feel that would be a good option.

 

Cheers

 

JP

[chris w]

essentially a battery charger is a simple device, little more than a transformer and a rectifier, I bought my last one for about a tenner from Halfords, all that is required is a scaled up version of one of those. Couple that to an agricultural quality generator and that is all that is needed.

 

 

Before anyone has another go at me for jumping down John's throat (see other topics!!), John's statement above is factually and technically not correct. For sure, one can buy a "battery charger" for a tenner that is little more than a transformer and a rectifier. However, to believe this is all you need for good battery maintenance is totally wrong and will end up costing you money and probably much inconvenience when your battery systems let you down at the worst moment.

 

The simple battery chargers will NOT charge your batteries properly, will give you less usable capacity and will shorten the life of the battery due to factors such as sulphation which these kind of chargers will not remove. They will also give you around 25%-30% less charge into the battery than a "proper" charger. For automotive starter battery use, where the battery is never run down, has a few AH taken out of it for starting etc the simple battery chargers are fine. But for domestic boat batteries they are absolutely the wrong beast because domestic boat batteries suffer deep discharges, and many of them, during their life.

 

"Multi-stage" chargers such as those offered by Mastervolt, Victron and Sterling are definitely not just a transformer and rectifier. They are highly sophisticated pieces of kit running under complex software control. That's why they cost more than a tenner! Sure, they'll be "specsmanship" between the various companies but all of these companies sell very elaborate state-of-the-art chargers.

 

To appreciate this though needs a deep understanding of battery technology - the physics and the chemistry which, although outwardly simple is actually highly intricate and mathematical. Victron click on "Energy Unlimited" have a long, detailed and superb article on battery physics etc. Just seeing the level of complex detail, even if one doesn't fully understand the technical bits, will convey the idea that battery charging is a complex science.

 

The reason that I have belaboured this point is that the incorrect charging regime for your batteries will cause you big issues and problems. Don't use a cheap charger - it's false economy.

 

Chris

Edited January 19, 2007 by chris w

[carlt]

wibble......tilt...

 

black rose, thanks for that info, and the rest of you "in the know".

 

I suppose the question i should have asked is "can anyone reccomend a good diesel generator and battery charger combination coming in around the 300 quid bracket"

 

As i say, i am leaning towards this model as there are a load of them on e-bay for what seem to be a good price to me..

 

http://www.buyagenerator.co.uk/eBay-Listin...+Generator.html

 

The top one on the page.

 

Battery charger wise, i am still a bit overwhelmed by the market. I landed on my feet with the inverter we purchased off e-bay but i think it was luck as much as anything. anyone reccomend a good, reliable well priced option?

 

I will not hold it against you if it fails to work out....

 

cheers

 

jp

Blackrose,

 

I like the look of the Sterling pro digital range and feel that would be a good option.

 

Cheers

 

JP

I bought a Nixon super silent 6k diesel generator for around £700 (chinese yanmar copy), it bent a valve after 13 months. It now runs fine with the yanmar engine I fitted to it.

 

I bought a marksman 1k petrol genny for £100, it arrived with a 3 month rtb warranty. It siezed solid after 5 months.

 

I would say you wouldn't get a decent diesel genny for £300, new, and you're looking at an air-cooled lister or petter for that price second hand (budget extra for ear defenders).

 

If you're looking at fitting a top of the range charger with all the trimmings then don't economise on the genny. If my cheap B&Q one chucks a wobbly and fries the charger, then I've wasted £20, If your chinese diesel does the same to a sterling pro digital, then you're going to be more upset than me.

 

 

The reason that I have belaboured this point is that the incorrect charging regime for your batteries will cause you big issues and problems. Don't use a cheap charger - it's false economy.

 

Chris

 

Agree entirely chris but the same goes for cheap generators. My battery management is pretty much covered by solar panels so a posh charger run for a couple of hours a week is a false economy. If I was to rely more on a 240v charger then I would buy the best I can find and link that to a generator of known build quality.

[Moley]

Before anyone has another go at me for jumping down John's throat (see other topics!!), John's statement above is factually and technically not correct.

 

I'm keeping out of this, if he wants to argue his case, let him get on with it.

 

The simple battery chargers will NOT charge your batteries properly, will give you less usable capacity and will shorten the life of the battery due to factors such as sulphation which these kind of chargers will not remove. They will also give you around 25%-30% less charge into the battery than a "proper" charger. For automotive starter battery use, where the battery is never run down, has a few AH taken out of it for starting etc the simple battery chargers are fine. But for domestic boat batteries they are absolutely the wrong beast because domestic boat batteries suffer deep discharges, and many of them, during their life.

 

But that seems like good information, written in a manner which those like myself (who seem to have a mental block when it comes to automotive lectrix) can understand, and I thank you for that, and will check out the Victron site when I've got a little more time.

 

That's it, I've dug myself enough holes for one week, I'm adjourning to the bar and keeping my head down.

 

Can I get you a beer Chris?

[anhar]

It's a great bit of kit - I just leave it on and all I ever need to do is check the water in the batteries once every couple of months. You can't do that with most automotive chargers.

Hello Mike

 

I don't know about "most" automotive chargers but there are quite a lot of automatic models out there that can be left on cars indefinitely. For example on my motorcycles I have a model called an Optimate. Most bikers will be familiar with this make of charger which can be left on for as long as you want, months on end, maybe even years. In the past I've had one on a bike for about six months without interruption. These chargers have a multi stage charging pattern and can't overcharge the battery. In fact they are perfect for prolonging battery life by keeping it fully charged, plus ensuring that it is always at full power for starting. My bikes are plugged in every time they go in the garage.

 

I don't know why anybody today would buy the kind of cheapo charger that John mentions. They're still available but not being automatic they can't be left on indefinitely and so can cause problems. I've still got one in the garage dating from a very long time ago but I would never use it on the bikes or car or a boat except in an emergency. Why ask for trouble when automatic chargers are available? They're dearer but well worth it in my view.

 

Incidentally modern cars and bikes no longer have wet batteries requiring topping up, they're all maintenance free these days.

 

regards

Steve

[chris w]

Incidentally modern cars and bikes no longer have wet batteries requiring topping up, they're all maintenance free these days.

For boats Steve, there are some very cogent arguments as to why wet lead-acid batteries are still the best despite their not being prima-facie "maintenance-free". They will take far more abuse and are more tolerant in general of poor charging regimes particularly over-charging which can very quickly destroy a sealed battery.

 

To be fair, if one followed the same regime with wet batteries as that recommended for sealed "maintenance-free" batteries, the wet batteries would also be maintenace-free. It's the ability to push the envelope and withstand some abuse coupled with lower prices that makes wet batteries still so attractive on boats.

 

Chris

[blackrose]

Hello Mike

 

I don't know about "most" automotive chargers but there are quite a lot of automatic models out there that can be left on cars indefinitely. For example on my motorcycles I have a model called an Optimate. Most bikers will be familiar with this make of charger which can be left on for as long as you want, months on end, maybe even years. In the past I've had one on a bike for about six months without interruption. These chargers have a multi stage charging pattern and can't overcharge the battery. In fact they are perfect for prolonging battery life by keeping it fully charged, plus ensuring that it is always at full power for starting. My bikes are plugged in every time they go in the garage.

 

I don't know why anybody today would buy the kind of cheapo charger that John mentions. They're still available but not being automatic they can't be left on indefinitely and so can cause problems. I've still got one in the garage dating from a very long time ago but I would never use it on the bikes or car or a boat except in an emergency. Why ask for trouble when automatic chargers are available? They're dearer but well worth it in my view.

 

Incidentally modern cars and bikes no longer have wet batteries requiring topping up, they're all maintenance free these days.

 

regards

Steve

 

Hi Steve, I didn't know about those particular car chargers, but I don't quite undrstand why they would be used. I ride a Honda 400 which like most other bikes & cars has an alternator which charges as I ride. Unless it's left for months on end why would you need a constant auxillary charger for a car or bike?

 

As i say, i am leaning towards this model as there are a load of them on e-bay for what seem to be a good price to me..

 

http://www.buyagenerator.co.uk/eBay-Listin...+Generator.html

 

I don't know about those generators. It's cheap enough for what it is, but one thing's for sure - it will be a noisy bastard!

[NB Alnwick]

Things have got so bad that you probably can't buy this simple equipment anymore, an entire industry of back street, fly by night electronics engineers have appeared in the past twenty years and are threatening to take over the world.

 

Where have you been? They took the world over some time ago - just look at Micro-s**t . . .

[anhar]

Hi Steve, I didn't know about those particular car chargers, but I don't quite undrstand why they would be used. I ride a Honda 400 which like most other bikes & cars has an alternator which charges as I ride. Unless it's left for months on end why would you need a constant auxillary charger for a car or bike?...

Precisely for those vehicles that are left unattended for long periods. My bikes are sometimes left like that for example. Bikes have much smaller batteries than cars so if the bike is not used they will discharge much quicker than a car in a similar situation. Also there is frequently some kind of current drain like an alarm which speeds up discharge, especially on a bike with its smaller battery, when it can easily run flat in a few weeks if not kept charged.

[NB Alnwick]

The so-called portable diesel gennies that I have seen (I even bought one off ebay but quickly sold it again) are noisy and very, very heavy. Certainly far too heavy for a near 60 year old such as I to handle.

In the end I went for a SIP T1000 Petrol - available on eBay for around £85 delivered. Link to similar item on eBay.

 

We keep the petrol in an ex military steel jerry-can in a ventilated locker in the bows and only run the generator (to charge the batteries) on the stern deck - still a fire or explosion risk but no risk of a hernia or perforated eardrums - and it is light, easy to start, cheap, economical etc.

Edited January 19, 2007 by NB Alnwick

[anhar]

For boats Steve, there are some very cogent arguments as to why wet lead-acid batteries are still the best despite their not being prima-facie "maintenance-free". They will take far more abuse and are more tolerant in general of poor charging regimes particularly over-charging which can very quickly destroy a sealed battery.

 

To be fair, if one followed the same regime with wet batteries as that recommended for sealed "maintenance-free" batteries, the wet batteries would also be maintenace-free. It's the ability to push the envelope and withstand some abuse coupled with lower prices that makes wet batteries still so attractive on boats.

 

Chris

Hi Chris

 

Yes I'm aware of the view that MF batteries are considered unsuitable for boats by some. Initially I was convinced that on my new boat I'd have MF only, having gotten used to them on cars and bikes where they are a boon. I figured that if they worked as well as they do on vehicles then why not on a narrowboat? It made no sense to me to ask for additional chores if the technology exists to avoid ithem. However that was when I was new to boating, not long ago.

 

I suspected that wet batteries were favoured not because they were superior or cheaper but because there are a lot of people around who are suspicious of anything new and just love to fiddle with maintenance, it's part of their boating pleasure. I've seen a lot of that kind of thinking in the biking fraternity. Not for me though, I just wanna cruise with minimum fiddling about. Not that MF is that new of course, as you'll know much better than me, they have been fitted for some years as original equipment on vehicles. But for traditional boaters, I guess anything less than about a century old is "new".

 

However I've since become more attuned to the wet battery view after reading a lot about it and hearing views similar to those you express. Consequently my new boat in build will have them. It appears that because boat batteries are run down much more and more often than a vehicle battery ever would be, then wets as you say can take this sort of beating better than MF. Pity because I derive no pleasure from messing about with the batteries, something I thought I'd seen the back of years ago on bikes and cars. I'd rather pay more for MF and no messing but not if they are inferior of course.

 

regards

Steve

[NB Alnwick]

Precisely for those vehicles that are left unattended for long periods. My bikes are sometimes left like that for example. Bikes have much smaller batteries than cars so if the bike is not used they will discharge much quicker than a car in a similar situation. Also there is frequently some kind of current drain like an alarm which speeds up discharge, especially on a bike with its smaller battery, when it can easily run flat in a few weeks if not kept charged.

 

I don't really understand this our 1967 MGB GT has been left unattended since we bought the boat in September 2005 - just checked it and there was more than enough power in the batteries (2 X 6v) to start it up! How can a vehicle use electricity when you are not using it?

[stuart]

How can a vehicle use electricity when you are not using it?

 

It cannot!

 

However, all batteries reduce their available charge when left long enough. Even dry-batteries come with "best before" dates on them.

 

It may take many years for the charge to go completely though and environmental issues will prolong/reduce the effect.

[chris w]

Actually, all lead-acid batteries self-discharge. Wet lead-acid (from memory) are about 4% a month. IIRC (without checking) sealed lead-acid are about half of this figure. This is due to tiny internal "short-circuits" between cells that result from small bits of the plates dropping off due to the stress of charging and discharging.

 

On a car of course, batteries will discharge due to an immobiliser and/or a clock for example. This may only amount to about 50mA total but that will discharge a 40AH car battery to half capacity in about 2 weeks.

 

Chris