Too good to be true inverter?

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Avocet

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I'm progressing slowly with my plans to build an inverter generator for when our electrickery goes off periodically. It won't see much use, (couple of times a year maybe), so I can't justify cashing out on a "shop" one. (Besides, where's the fun in that?)!

I currently have an 8 horse Honda engine and now have a 180 Amp Passat alternator and some bar stock that will eventually become pulleys. I do need to source the expensive bit though - the inverter.

Has anyone had any experience of (or comments on) these?

http://www.ebay.co.uk/itm/like/1907...1=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0

2kW constant, 4kW peak, pure sinewave...

...seems awfully cheap!
 
the vendor seems to have been around for a while and to have sold a good number of units, with 100% feedback.



What do they mean by 'soft start' ?
 
Dunno. I was wondering that too. I could see how something that DRAWS power could be "soft start" but not something hat supplies it?
 
Avocet said:
Dunno. I was wondering that too. I could see how something that DRAWS power could be "soft start" but not something hat supplies it?
Click to expand...

I think "soft start" inverters reduce the power supplied initially to induction loads, so as to prevent the inverter automatically shutting down.
 
Avocet said:
I'm progressing slowly with my plans to build an inverter generator for when our electrickery goes off periodically. It won't see much use, (couple of times a year maybe), so I can't justify cashing out on a "shop" one. (Besides, where's the fun in that?)!

I currently have an 8 horse Honda engine and now have a 180 Amp Passat alternator and some bar stock that will eventually become pulleys. I do need to source the expensive bit though - the inverter.

Has anyone had any experience of (or comments on) these?

http://www.ebay.co.uk/itm/like/1907...1=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0

2kW constant, 4kW peak, pure sinewave...

...seems awfully cheap!
Click to expand...
Has anyone tried squirting more volts in to the exciter to make it produce more volts doing away with the need for an invertor?
S
 
Yes, I wasn't thinking of running it at 2kW. I'd have thought constant load would be about half of that, with the odd spike. Last winter we lost power for about 36 hours - which wasn't funny! That was exceptional though. This would be powering two fridges and a freezer, the central heating boiler and a few lights. If the output is clean enough, maybe the router and computers. The Honda engine is 8 hp, so if we do find we're using it more than I think we will, I could always fit a second alternator.
 
The supply cables pictured are not going to cope with ~180 - 200 amps 2,000 W will require for too long. They look like 16mm2. Continuous rated cables for the rating would need to be at least 35mm2, and ideally 50mm2, and any length of cable run will cause considerable losses.

I would simply use a 240v 2 kVA genny and transform down to 12 vdc as reqd, rather than invert up. 2 kVA will easily cope with your stated requirement of about 1 kW

12 vdc was never intended to run powerful 240vac appliances and at best it will only work for a few minutes IMHO.
 
superheat6k said:
The supply cables pictured are not going to cope with ~180 - 200 amps 2,000 W will require for too long. They look like 16mm2. Continuous rated cables for the rating would need to be at least 35mm2, and ideally 50mm2, and any length of cable run will cause considerable losses.

I would simply use a 240v 2 kVA genny and transform down to 12 vdc as reqd, rather than invert up. 2 kVA will easily cope with your stated requirement of about 1 kW

12 vdc was never intended to run powerful 240vac appliances and at best it will only work for a few minutes IMHO.
Click to expand...

Confused by this, perhaps I didn't understand OP correctly.

1) "use a 240v 2 kVA genny and transform down to 12 vdc"
I thought that OP wanted 240v AC for his house and that would make transforming a 240v output to 12V DC pointless.

2) "12 vdc was never intended to run powerful 240vac"
I thought that Honda EU20i generator produced 12V internally and fed this to an inverter to get 240v

Correct about cables though and I'd hope anyone buying the inverter would replace the ones supplied. I was interested to see that it has 7 parallel fuses giving a rating of less than 3kW so 4kW peak must be for a very short duration (no surprise).
 
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The OP proposal should be OK however any power claims should be reduced in practice by a huge margin. But then it is unlikely the fridges will be running so much and it is the heating boiler that really needs power.
Re Honda EU20i it is unlikely that they generate at 12v DC to feed the inverter. Much more likely /efficient to generate at about 350 volts DC which can then be converted more eficiently by switching to 250vac. ie a 12v inverter will convert the 12vDc to 350vDC in a switch mode converter before converting that to AC. Of course I may be wrong.
Hence there might be much wisdom in buying an AC generator built as such from the bgiuning with no batteries involved.
Then set up a simple 12vDC LED lighting system for home. good luck olewill
 
Mistroma said:
I was interested to see that it has 7 parallel fuses giving a rating of less than 3kW so 4kW peak must be for a very short duration (no surprise).
Click to expand...
That's interesting, thanks! I hadn't spotted that. It's exactly the sort of insight I was hoping for. It does suggest that it is "only just" up to meeting it's claimed figures. (As do the battery cables, although I have some heavier cable anyway, so that won't be a problem). I guess there has to be a reason why inverters with similar claimed outputs from the likes of Victron or Waeco are 4 times the price!

The only thing I don't understand is how 3kW of fuses can handle 4kW of power? Is it just because they won't get hot enough to blow? If so, surely that's only a fraction of a second?
 
William_H said:
The OP proposal should be OK however any power claims should be reduced in practice by a huge margin. But then it is unlikely the fridges will be running so much and it is the heating boiler that really needs power.
Re Honda EU20i it is unlikely that they generate at 12v DC to feed the inverter. Much more likely /efficient to generate at about 350 volts DC which can then be converted more eficiently by switching to 250vac. ie a 12v inverter will convert the 12vDc to 350vDC in a switch mode converter before converting that to AC. Of course I may be wrong.
Hence there might be much wisdom in buying an AC generator built as such from the bgiuning with no batteries involved.
Then set up a simple 12vDC LED lighting system for home. good luck olewill
Click to expand...
Fair comment, but for the amount of time it's going to get used, I don't really care how inefficient it is. I can't really justify spending £2k on a "proper" generator for the amount of time I anticipate using it. I already had a lot of the bits, so this setup is only likely to cost me about £300 - 350 plus a bit of time. Looking round, I wouldn't have got much of a second-hand generator for that. The boiler is oil-fired. It has a pressure pump for the oil, a circulating pump for the water, and a fa to blow air into the combustion chamber. I think it pulls less than 500W when running. I borrowed a nice Honda "suitcase" inverter genny from someone last time we had a power cut and the engine note barely changed when the boiler fired-up. That was only rated at 1800W.
 
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