The Accidental Smallholder Forum

Smallholding => Equipment => Topic started by: Womble on December 15, 2018, 09:56:25 am

Title: Using a petrol generator to power a laptop?
Post by: Womble on December 15, 2018, 09:56:25 am
Hi folks, Rupert the Bear's unwanted deliveries thread has reminded me that I keep putting off buying a petrol generator, and I *really* need to get that sorted before winter. Oh well, too late!  :)

What we would need to power during a prolonged power cut is:
We already have a couple of cheap and nasty generators, but one is now broken, and although the other one works in summer, it won't ever start in cold or damp conditions, so I want to upgrade to something hopefully more reliable, like this Honda EM2300 (https://www.kelvinpowertools.com/honda-em2300-2.3kw-petrol-generator-c-117-p-10104).

My question is, is a generator like that ok for the laptop, or do I need to fork out for a sine wave inverter generator (https://hsstoolshop.co.uk/honda-eu22i-20-kw-quiet-running-suitcase-inverter-generator-petrol-8364-p.asp?) at more than twice the price  :o ?

On one hand, the basic generator seems like it should be ok since the laptop has its own transformer to convert to DC voltage anyway, and I guess I could get a surge protected extension cable too. On the other hand, the accepted wisdom seems to be that sine wave generators are required for anything electronic. Can anyone knowledgeable advise?  :thumbsup:
Title: Re: Using a petrol generator to power a laptop?
Post by: pgkevet on December 15, 2018, 12:18:09 pm
Well I ain't knowledgable but have a little experience. I started with a larger suitcase jobbie 2.2KW but the fancy sine wave inverter whatever couldn't cope with the start-up back EMF from the borehole pump (which an old fashioned honda frame genny borrowed with less power coped with nicely). Anyway V couldn't cope with carting the thing or starting it albeit it wasn't that heavy or hard to pull. I sold it on ebay and bought a wolf 7KW electric start on wheels for much the same money. When we have used it then computers work fine.. I guess their power supplies now have smoothing built in. How you choose to transfer the power is up to you.. you could plug into the main circuit (after switching off the fuse board) but I just run a pair of extension reels and one sub reel from genny.. gets me to borehole pump, kitchen fridge/freezer. kettle and a second one to the router and PC.
At the mo the genny is u/d .. but that's down to a carb issue which I;m sure is due to modern biofuel additions likely dissolving stuff. I had to change the main fuel line last year when the plastic of that got eaten away. It's on my TUIT list to take carb apart and clean with the expensive option of new carb if that doesn't work.
Title: Re: Using a petrol generator to power a laptop?
Post by: Womble on December 15, 2018, 03:33:17 pm
That's interesting - thanks!


I don't think our loads will be all that great TBH. If the power is out, we don't expect to continue as normal and run the washing machine for instance, so I don't think we need a whacking great thing.


I did vaguely think through the issue of carb maintenance, and the thought crossed my mind that maybe we should get an LPG model. Yes, it's £200 more, but my simple head says that it also ought to be immune from all the maintenance issues that seldom used generators tend to suffer from, like perished o-rings, stale petrol etc. We always have plenty of LPG cylinders here since we cook with it. Petrol, less so. So, if this is to be something I hopefully keep for many decades, is it worth the extra?


Of course the other half of me says that blowing over a grand on a generator is a brilliant way to ensure we never have a power cut ever again.....
Title: Re: Using a petrol generator to power a laptop?
Post by: Glencairn on December 15, 2018, 06:44:50 pm
Maybe ask Pete?

https://petepowerblog.wordpress.com/
Title: Re: Using a petrol generator to power a laptop?
Post by: pgkevet on December 15, 2018, 08:22:51 pm
You're not talking a grand for the one I bought...https://www.ebay.co.uk/itm/Petrol-Generator-6500-watts-with-Wheels-8-75kva-15HP-110v-230v-Portable-4-Stroke/372440236513?hash=item56b72b01e1:rk:4:pf:0 (https://www.ebay.co.uk/itm/Petrol-Generator-6500-watts-with-Wheels-8-75kva-15HP-110v-230v-Portable-4-Stroke/372440236513?hash=item56b72b01e1:rk:4:pf:0)They also do a  smaller cheaper one that's still on wheels albeit pull starthttps://www.ebay.co.uk/itm/Petrol-Generator-3200w-4kva-6-5HP-230v-Heavy-Duty-Portable-Wolf-Power/372527893247?epid=27026851730&hash=item56bc648aff:g:mlIAAOSw175cDoZR:rk:3:pf:1&frcectupt=true (https://www.ebay.co.uk/itm/Petrol-Generator-3200w-4kva-6-5HP-230v-Heavy-Duty-Portable-Wolf-Power/372527893247?epid=27026851730&hash=item56bc648aff:g:mlIAAOSw175cDoZR:rk:3:pf:1&frcectupt=true)
Title: Re: Using a petrol generator to power a laptop?
Post by: mab on December 15, 2018, 09:18:10 pm
most computer power supplies are quite tolerant of supply variations - sine wave or modified sine inverters (a lot of the smaller ups's (uninterruptible power supplies) are modified sine wave)- and some will happily run off d.c. as long as the voltage is within the psu's tolerance. Also with a laptop, it can tolerate a 'brownout' - like when the big freezer cuts in - as it simply keeps running off the battery until the power supply comes back up.
My laptop has a universal power power supply (100 - 240v) and I regularly run it directly off my hydro-electric generator (80v 22Hz a.c. up to 150v 34Hz depending on water flow) and it's perfectly happy - even when it's down to 80v.
The only caution i'd put in is overvoltage - most universal powersupplies should handle anything up to sustained 264v (240 + 10%), and anything sold in the UK should be guaranteed up to 253v (230 + 10%), although I have found Apple macbook PSU's are a little sensitive to overvoltage - I had one let out the magic smoke at 255v (ironically when running from the grid). But that's probably down to apples tendancy to push their tech to the limits to keep it compact and stylish.

As for your freezers - the generator should be able to run all three, as long as the aren't all trying to start simultaneously.
Title: Re: Using a petrol generator to power a laptop?
Post by: Rupert the bear on December 16, 2018, 11:15:55 am
Well I ain't knowledgable but have a little experience. How you choose to transfer the power is up to you.. [size=114pt]you could plug into the main circuit (after switching off the fuse board) [/size]

but I just run a pair of extension reels and one sub reel from genny.. gets me to borehole pump, kitchen fridge/freezer. kettle and a second one to the router and PC.

No NO and thrice NO  If you want to to use the house circuits , you must use a properly installed and tested changeover switch, this has a threefold purpose, 1, prevents your 2kw genny attempting to bravely power the national grid , 2 stops you breaking the Law. and 3, and most importantly;  Prevents the line workers getting the unexpected shocks or even possibility of death.
Even if you do use a change over switch it is always good practice to inform the power company's control room, at the time of the outage.