How quiet are silent generators?

[RainbowsParticipant @rainbows]

As a christmas present to myself I am about to get a new generator. My current one is a clarke 94dB machine. The one I am looking at claims to be 58dB.

http://www.ebay.co.uk/itm/Wolf-800w-2-6HP-4-Stroke-Petrol-Inverter-Suitcase-Portable-Generator-240v-12v/282728691547?epid=1447476469&hash=item41d3f1775b:g:RKsAAOSwVlVZ6H-8

Looking at a decibel example chart I would be taking it from a ear damaging level to the sound of a conversation. Physical smallness and portability will also be nice to have.

Before I drop £200 though can I check if anyone can comment on the quality? Any issues? As quiet as advertised? So on? I have some old wolf tools and know them to be pretty damn good, of course that says nothing for the ones made under new ownership.

[RainbowsParticipant @rainbows]

[JasonBModerator @jasonb]

Is 7-800w going to be enough to run your workshop?

[RainbowsParticipant @rainbows]

Just about I think. My lathe is 550w. My mill has a 1.5kw motor (it was the only motor to hand) sitting on it but I dont think the rest of the machine can keep up to it, its more built for 0.75kw. Im going to stick an amp meter of the vfd remote control box so I can be sure not to cut too hard. Add 50w of lighting on top of anything else. I guess it limits further expansion into industrial grade lathes but that might not be a bad thing

[steamdaveParticipant @steamdave]

I've considered getting an emergency generator for when power cuts occur. Originally I looked at the 'suitcase' types, but they are quite expensive for their modest output.

My present consideration is similar to eBay 272527775595. Not quite as quiet as the Wolf model but a more useful output (for me) and the fact that it will be used outside (but stored under cover) negates the noise reduction.

Dave
The Emerald Isle

[Clive FosterParticipant @clivefoster55965]

Rainbows

With generator noise level specifications its important to verify what generator output it refers to. Many of the small suitcase style specify the noise at a zero power output, idle, mode with the engine turning slowly on closed throttle. Start drawing power and the noise ramps up seriously. Running flat out is noisy and thirsty. We reckoned about 2/3 rds output was the sweet spot on trials work.

My back up is an old water-cooled Honda EX5500 which, in their day, were reckoned to be the quietest out there. Maybe 64 dB at full output. It came from a film equipment hire specialist who mostly only supplied Hondas considering all the other makes to be too loud for indiscriminate use on film sets et al. They reckoned the newer Honda EU series "super quiet" models to be a bit of a backwards step noise wise as being little louder than the EX model. After demoing the one I'd just bought to prove it actually was good they promptly started the later one up to prove it. A bit louder but still reasonably OK to run inside a building. As i recall it specs for that were 58 dB idle, 65 dB full power.

I reckon anything louder than my Honda will be a nuisance. However the film hire people were fairly sanguine about supplying the compact diesel powered ones as not being too intrusive for catering and similar use well away from sound areas. Not complimentary about build standards and reliability tho' regardless of the name on the box. Allegedly "all the same" and "throw away are a year" quality. But a hire outfit has to be able to rely on supplying stuff that "just works" every time.

Clive.

[pgk pgkParticipant @pgkpgk17461]

Out here in rural wales we get the ocassional power cut. Whenthat happens we lose even water from our borehole pump. It happened early on here when local builder happend to have left his ancient frame based honda 2kW genny and that powered things nicely. So I bought a fancy inverter 2.5kW suitcase genny (can't remember the brand) to have as a handy standby. The problem with the fancy modern thing was that it's internal cutouts couldn't cope with the start-up draw of the borehole pump, it was actually a very heavy luggable thing and my wife couldn't get the hang of pull-starting it even if she could lift it from storage. I sold it and for not much more bought a 7kW Wolf genny on wheels with electric start. Parked outside it makes very little noise with a more efficient silencer system, obviously has no start-up current problems..can run the borehole, fridge&freezers, downstairs lights, internet/PC's and even boil the kettle. As you will gather if you have storage space then better to have spare capacity and more than enough power than minimums.

[OldironParticipant @oldiron]

To be honest I would have thought a 800w genie would be way underpowered to run your lathe plus the lights plus the coolant pump you will add plus the USB charger etc etc. 800w will be the max output for only a very short time. A lot of these cheapy type gennies only have a 50/60% duty cycle. It would be likely to stall a bit when you lathe starts up from cold. I have a 2kw Honda propane powered set and even that will sound a bit bogged down running a couple of good industrial tools. ie, chop saw & a mag drill. It will run my 180amp stick welder but that's the limit. I would think you need to be in the 2kw to 3 kw range as a minimum to be comfortable. The other thing to consider is that the VFD may not even like to run on a gen set. They usually want a nice clean supply and a good earth. Maybe a check with the VFD manufacturer before you take the plunge would be a good idea. Also consider hiring a gen set for a couple of days to get an idea how things will run. Its not that expensive for the hire.

regards

[not done it yetParticipant @notdoneityet]

From a thread by the same poster, about 6 months ago:

“I do have a petrol generator in there (2.8kw?) which matches my planned needs (2kw?) for small 1ph workshop machines but the noise it makes is pretty bad. Would also be nice to have 6kw-ish for a big welder I have.”

I am wondering what has changed since then. I can’t envisage a small suitcase genny of 800W (per JB) being of much use at all. Likely only 700W for rated running. Might not even start a freezer compressor motor (160W) let alone a one horse, especially if it has start windings.

 

Edited By not done it yet on 25/12/2017 21:31:36

[colin wilkinsonParticipant @colinwilkinson75381]

I have a Kipor 1000w for use with a motor home and wish I had bought the 2000w model. I found the 1000w will cut out if the microwave is used on anything over half power. No chance with hair dryer etc. Noise levels are not bad but most campsites ban them after 11pm as they certainly are not "quiet". Also make sure the one you buy is sine wave as there are some cases of blown circuits after using a cheap generator that was designed to run floodlights on building sites etc. Lots of posts on motor home forums on generators, almost as many as arguments on which oil to use on motorcycle forums and don't even start on ethanol in unleaded petrol! Colin

[Danny M2ZParticipant @dannym2z]

This one works quite well, it depends on how you load it up but it's nice and quiet and not to greedy on fuel **LINK**

You should be able to find one closer to home. I use one for when a storm takes out the power though never tried the microwave on it, it runs a few portable lights and the pc ok though.

Isolate it from the mains and run required devices through extension cords as one does not want a repair person hanging off the power lines being zapped by your generator. So be aware of safe practices when running a generator at home.

I don't even think of going to the workshop with no power, other priorities!

* Danny M *

[Steve Skelton 1Participant @steveskelton1]

Rainbows,

I was in the same position as you but required it for use on a small boat in crowded anchorages – hence the need for it to be silent.

I carried out a lot of research and came back to the same make of generator each time – Honda suitcase units (in your case I would recommend the Honda EU20i). They are very reliable and probably the quietest on the market, without going to an exotic MOD spec or water cooled unit.

I have been using it for a year and can confirm that they are silent – we run it on deck and it is not at all intrusive to us or others in the anchorage. We run it about 15 feet away from where we sit and read books, hold quiet conversations and even eat meals. The only downside, we find is we sometimes smell exhaust fumes when the wind is in certain directions compared to the tidal current.

They are expensive (about £2K new) but can be had for about a quarter of that second hand.

There are other clones about but we wary, they are not as reliable and getting spares, should you need them, can be difficult.

Have a great New Year

Steve

[Russ BParticipant @russb]

The Honda EU10i, EU20i and EU30i were always astounding quiet in the pits and paddock area – but your not going to pick one of those up anytime soon for a few hundred quid! (1kw, 2kw and 3kw respectively)

You could walk past an EU30i onload with a set of tyre warmers on and not even realise it was on. They’ve got enough power to run the warmers and the microwave at the same time, but not warmers and the kettle.

The inverter regulates the engine rpm, so when output is low, the engine rpm drops, unlike a traditional vacuum controlled genny. The inverter corrects the frequncy and the fancier the inverter, the higher/lower range the generator can operate at. An expensive Honda might be 5% more efficient, that’s 5% less load on the engine.

[RainbowsParticipant @rainbows]

Ok thinking of

https://www.ebay.co.uk/itm/DIGITAL-PETROL-GENERATOR-SILENT-SUITCASE-2-KVA-2-year-uk-warranty-last-few-reduc/312032248026?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

Puts it up to 2000/2200peak power for those motor inrush surges. Quotes the same noise as a Honda though Im sure there could be some difference in real life.

Reason for the reduced power estimate was that I gave up on the welder and had a more realistic idea of how much the mill would take.

[peak4Participant @peak4]

I can't comment on the actual generator as I've never used one, but it's about the same level of noise as my Honda NX650 which is quite unobtrusive to most people.

I do like the idea of a solid state clean output that claims to be suitable for PCs etc. though I'd be inclined to ask both the inverter and generator makers before committing.

When I first bought my Honda genny, years ago, I checked it under varying loads, including unloaded, and it seemed pretty stable. A friend borrowed it and as well as using it for a light in the evening, also used it for battery charging some 2 way radios, ready for the following days Landrover event.

All was fine, except the following afternoon when the light wasn't plugged in; the current dropped, as one might expect, but the voltage rose to something appreciable over 300v when very lightly loaded; exit one radio charger.

Fortunately repairing such things was his profession, so no major harm done. Everything was eventually fine, when we gave the genny a proper service, and set it up exactly according to the manual.

[not done it yetParticipant @notdoneityet]

I looked at the spec on that auction. The details do not add up. Says 2.2HP engine, for a start, qotes 122kW and 3.7A (at 230V?).

Do makecsure you know what you are actually getting. May still not start a lathe motor.

[Clive FosterParticipant @clivefoster55965]

Rainbows

Interesting generator in that E-Bay link. Second feedback guy says its noisy. Unsurprising as its knock off of a Honda look-alike knock-off. Personally nothing I'd touch with a barge, let alone the pole, as spares'n service items are likely to be problematical. 58 dB will be zero output idle noise at, probably, the alternative 10 metres measurement distance often used for the big factory/industrial emergency power genesets rather than the 7 metres normally applicable to baby ones.

A more reputable Honda look-alike knock off is the Hyundai (badged not made) HY2000Si. Claims 64 dBA at full load which is more like it but, to my ears, Hyundai use bigger dBAs than Honda. No distance specified so probably 10 metres nominal not the proper 7. At full output the Hyundai motor runs at 5,500 rpm so no wonder its pretty loud. I'd be unsurprised to discover that the cheapie runs even faster. For example car alternators deliver their rated current at 6,000 rpm yet are mechanically safe to 10,000 or more. 200 + amp types can be found quite easily so that means up to 3 (spec sheet!) KW is readily obtained from cheap, off the shelf, standard technology. Inverter needs DC input and doesn't care how fast the generator is turning so long as it has enough amps in to support the amps out demanded.

Old technology, direct AC, generators usually run around 3.500 rpm which helps keep noise down at high output. Especially with water-cooled motors as per the old Hondas. High speed motor and air cooling means serious work if its to be quiet.

Bottom line is 60 dBA at 7 m means you can talk normally if standing close together but the genset can clearly be heard underneath. 65 dBA and you are shouting.

In some ways the Euro LWA noise specification is more reliable for relative ratings as thats really for hand held / operator close by tools and equipment. Pretty much noise level when you are standing next to it rather than the usual out in the middle of a (small) field situation. On LWA figures even the quiet Hondas are loud.

Clive.

Edited By Clive Foster on 27/12/2017 15:01:55

[Steve Skelton 1Participant @steveskelton1]

I would be cautious if you plan to get one of these – there is an on-line report that they are very noisy. I would check that spares are, and will be, readily available.

I got the price for the 2kW EU20l Honda wrong – they are well under £1K and if you can source a good second hand one at half that price you may find in the long run that it is more economical, reliable and maintainable (regarding parts).

I do know that people who have bought low cost Honda clones have regretted it and then went to a Honda suitcase unit.

[RainbowsParticipant @rainbows]

Sent em an ask about the power and they corrected it to 5HP, guess thats a good deed for the day. My current generator set is 94dB, so in that regard its hard to get worse in terms of noise.

I will give it a bit of time in case a used Honda appears near me. I see some nice refurbished ones on ebay but they are only 1000w for £300 as opposed to my 2000w for £300 at the moment

[JohnFParticipant @johnf59703]

Rainbows, I too would be cautious of these–there does not appear to be a brand name ? Some years ago i purchased a Kipor Honda 10i knock off, it ran ok but was noisier than the Honda and it soon became clear it would not last the course so sold it on and bought a Honda — no regrets except I should have bought the 20i

As far as power out put is concerned you do need to asses what you are intending to drive with it, my 10i is fine for most power tools, lights and at one time caravan etc but you also need to consider startup load which is normally considerably higher than the motor for normal run/load.

Personally I would buy a known brand and you will not regret Honda.

[jimmy bParticipant @jimmyb]

Posted by jimmy b on 28/12/2017 06:43:14:

Posted by not done it yet on 27/12/2017 14:17:13:

I looked at the spec on that auction. The details do not add up. Says 2.2HP engine, for a start, qotes 122kW and 3.7A (at 230V?).

Do makecsure you know what you are actually getting. May still not start a lathe motor.

122KW?

[Ady1Participant @ady1]

Add 50w of lighting

Go LED on the lighting for starters, 5W a bulb for decent lights

[MikeParticipant @mike89748]

Forgive the ramblings of someone who doesn't really understand electricity, but my workshop is powered by a generator. In my case noise isn't that important because the location is close to the shore and not close to houses, and the worst noise is deflected seawards by baffles. Started off with a 2.5kw generator, not realising that although none of my electric motors were very big, I hadn't allowed for the starting current which, in some cases, put the lights out and all but stalled the generator. Now electricity is provided by a 5.5kw Honda-powered Pramac, which does the job perfectly. I'm a great fan of Honda industrial engines – 100 per cent reliable – touch wood!

[Clive HartlandParticipant @clivehartland94829]

All the conversations so far have been about generators with minimal output used to drive high input requirements. Firstly double or triple the generator output with reference to the load requirements otherwise it will get HOT !.. A 1.5 Kva will hardly drive an electric lawnmower of 1200 W capacity.

A 3.5 Kva generator would just about run a 1 Hp lathe motor, it is the load under power that matters.

An emergency lighting generator at 1.5Kwa will run a TV and a couple of lights OK.

[Ian S CParticipant @iansc]

One of the nicest little units I'v had anything to do with is a 3Kw Robin diesel, made by Subaru, pull start, instructions say pull quietly over two compresions, if more than two pulls required to start, read instructions. Very quiet, can't remember the Db, but it was used aboard my brother in law's first boat. In his second boat, a 16 metre power cat he had a 6Kw diesel generator unit, but I don't know much about that one, I know the first one(bought second hand on line) for that boat was basicly a spare anchor, and before heading off shore it got replaced with a new one.

Ian S C

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