Cheapo Generators

[pandroid]

There was some discussion recently on the unsuitability of cheapo generators (circa £150) for battery charging, due the fact that their frequency was unstable enough to damage (or at least confuse) the posh 3 stage chargers we all have. (I've got a Mastervolt)

I've tried searching for the stuff, but the search system seems pants this morning, so can anyone give me a definitive answer, or do I have to buy one of the (expensive) Honda ones. (Which means I probably wont...)

 

[pvb]

Alternative forum search method...

The forum search facility doesn't work very well (understatement!). But you can search for threads using Google. Just put site:www.ybw.com as the first word in the Google search box. It will then only return matches from the YBW site.

 

[Colvic Watson]

Re: Alternative forum search method...

Makro was the place mentioned in the earlier posts. £50 I think!

 

[philmarks]

Re: Alternative forum search method...

Yep, 850 watt £49.95 (plus VAT)

 

[supermalc]

Re: Alternative forum search method...

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=58148&item=3862943042&rd=1

What's wrong with one of these....charger built in.

 

[geoffatstanpit]

Re: Alternative forum search method...

Or a cheapo charger? My 1950s Gamages 15/6d job doesn't seem to be too fussy.

Geoff

 

[Anonymous]

[ QUOTE ]
There was some discussion recently on the unsuitability of cheapo generators (circa £150) for battery charging, due the fact that their frequency was unstable enough to damage (or at least confuse) the posh 3 stage chargers we all have. (I've got a Mastervolt)

[/ QUOTE ]You would have to ask Mastervolt but it is worth asking because my guess is that it will be fine over a very wide range of input voltages and frequencies. After all, yachts expect to visit third world countries and harbours at the end of distribution lines where the supply is terrible. Furthermore, it is a requirement these days that battery chargers have a power factor very close to unity and this requires some conditioning at the input side so I suspect - but I am guessing - it will be fine. Try asking Mastervolt themselves.

 

[redhot]

I bought a Generator from Makro.
The one I bought was 2.6Kva and runs my 50A charger well.

The problem with a 850w £50 charger is it won't run a 50A charger.

I have been told that a 50A charger draws about a Kilowatt, and I would be tempted to agree with this theory.

I am looking at investing in some solar panels to negate the need for a generator to charge, but thats a whole new subject. I told SWMBO that rather than spend £1000 on a quiet 2KW generator, we might be better of half filling the roof with solar panels.

I am looking at Shell Solar Shell Solar

 

[cliff]

Re: Alternative forum search method...

[ QUOTE ]
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=58148&item=3862943042&rd=1

What's wrong with one of these....charger built in.

[/ QUOTE ]


£107.85 is the problem - damn expensive compared to Costo's offering of similiar machine for £44.99+vat.

----------

 

[Koeketiene]

eBay

It's the same one I bought in Makro for £42.99 + VAT only last week.

Just goes to show - just because it's on eBay, it does not mean it's a good deal.

Have been looking for Sealskinz gloves on eBay - usual Buy Now proce £27.99. They're £24.99 from Nauticalia

 

[supermalc]

Re: Alternative forum search method...

No URL to check price etc. so I couldn't see if it had a charger or not. If not 850watts would only run a low amp charger. (someone else can tell you the amps, I can't be bothered with the maths)

 

[gorb]

Re: Alternative forum search method...

The problem with cheapo gensets is not the frequency - it will be 50Hz or damn near - but the wave shape. Instead of a nice sine wave, which is what you will get from the mains, the cheaper ones will have nasty waveshape closer to a square wave. This can cause problems for modern lightweight chargers. Sadly the problems may not show up straight away but may lead to overheating iof the expensive charger and a more gradual failure.

I believe the danger is not so great if a genset is used well below its max capacity. So for a 50A charger, this converts (no losses) to 50x14 volts = 700watts. Assume 75% conversion efficiency = 933watts. Call this 1Kw for safety. So to significantly underrun a genset feeding a 50A charger you would need something like a 1.5Kw genset.

OK?

 

[terryw]

If it will only be used to charge your batteries then why not buy a cheapo car battery charger, plug it into the cheapo genny, and connect directly to the battery terminals. I also suspect that it will charge faster.

 

[Thresher]

Re: eBay

Let us know how you got on with it. I bought one from Makro last year, I had a lot of problems getting it started and then the pull cord starter mechanism started jamming after about only 20 hours use. It's been in the garage ever since.

 

[Guest]

Re: eBay

Many times all sorts go for more than they can be found at shops .... think its the excitement of bidding .... plus the thought that eBay has to be cheaper !

I watch often GPS sets go for daft prices .... old 8ch and even discontinued newer 12ch sets ..... when I say daft - I mean daft low AND high prices.

 

[pandroid]

Well thanks to everybody who replied, although only two people actually answered the question. The rest just waffled on about buying a different charger (and no I dont want a cheapo car charger to fry my batteries, thats why I bought a posh one!)

I spoke the Mastervolt bloke at the boat show. His answer was - it depends. He said that the charger was pretty immune to frequency and phase oscillations, but could be subject to voltage spikes. Some of the cheap generators can spike up to 300 volts, and their chargers dont like much more than 260 volts up 'em Mr Mainwaring.

So its back to the solar cells for me. They are quieter anyway.

P.S. Did anyone see the chargers on the Hallberg-Rassy at the show? Its their MDs boat and every cupboard you opened had a set of switchgear like Sizewell B. For some reason he's got loads of batteries and no gen set. Hmmm.

 

[Anonymous]

[ QUOTE ]
I spoke the Mastervolt bloke at the boat show. His answer was - it depends. He said that the charger was pretty immune to frequency and phase oscillations, but could be subject to voltage spikes. Some of the cheap generators can spike up to 300 volts, and their chargers dont like much more than 260 volts up 'em Mr Mainwaring.

[/ QUOTE ]I'm surprised that it would be as low as 260V peak. I would imagine that it is good for 300V max continuous. I spent a good 10 mins talking to a very technical chap on the Mastervolt stand who knew the product I had inside out, but there were also semi-technical people on the stand who I'd spoken to first.... Furthermore, I don't think that the cheapo generators will cause spikes of anything like that. I think you would be best advised to phone Mastervolt and be sure to speak to an engineer - they do have excellent engineers who could answer all these questions for you.

[ QUOTE ]
So its back to the solar cells for me. They are quieter anyway.

[/ QUOTE ]I've just bought two 180W solar panels to complement the 6kVA generator, so I agree! However, a generator does allow you to cook, heat and run air conditioning.

Did you see the fuel cell on the Plastimo stand? Now that really IS interesting!

 

[Guest]

Also surprised ....

OK - I'm not an electrician .... but when I did AC theory etc. at college - I seem to remember that 220 / 240V was the mean of the wave ..... and that highest could approach 300V .... but of course it was years ago when I did it - so could be wrong ...

 

[Anonymous]

Re: Also surprised ....

Yes, it's root 2 times the rms voltage so a 230V rms mains supply has a peak voltage of 325V with respect to neutral but that isn't the value that (should) concern us here. I've dug out my data and my Mastervolt, the 12/80-2, is rated to accept input (rms) voltage of 230V -10% +15% i.e. 207Vrms to 265Vrms and a frequency of 50-60Hz +/- 5 Hz (sic). I'd be very surprised if that was the Absolute Maximum rating for very short periods but it is possible and one should ask Mastervolt. In any case I doubt if the cheap generator would supply 265V rms for any length of time. If I wanted to use a cheap generator I would certainly dig a bit deeper however the Honda portables are so quiet and compact.....