High frequency or low frequency inverter

[Cjm19922]

Hi everyone im new to this site and I hoping someone could help me out I live in the UK and I need a inverter to run some pretty heavy duty tools but only intermittently say 15-30 minutes at a time on a heavy load and would also use it for charging cordless tools I was thinking that 3000w would handle it with out straining the inverter but I'm unsure as to get a high frequency or low frequency inverter and waight is not a issue I'm running a 12v set up as I'm charging the bank of 4x120ah batteries from the vehicle
I'm hopping to spend less than £1000 on the inverter so any help would be appreciated and thanks in advance PS needs to be pure sine wave

 

[Woodentop]

3000W is 3000W whether at mains or 12V. Assuming 100% inverter efficiency (which it won't be) 3000/12 is 250A. Have you considered the size of connections and cable that you would need to handle that much current???

Buy a Honda petrol generator instead.

 

[Cjm19922]

Im over sizing on the inverter and What I'm talking about when I say high frequency or low frequency it is that from what I can gather from other places is that low frequency inverters are better for start up surge im just trying to get a straightforward awnser and I'm not referring to 50hz/60hz I'm referring to the type of transformer that the inverter uses, I'm gonna size cable for 400A and No I don't want a generator it would not be practical for my needs thanks anyway and if anyone could stear me in the direction of a good brand I would be very grateful thanks

 

[ProfJohnL]

Im over sizing on the inverter and What I'm talking about when I say high frequency or low frequency it is that from what I can gather from other places is that low frequency inverters are better for start up surge im just trying to get a straightforward awnser and I'm not referring to 50hz/60hz I'm referring to the type of transformer that the inverter uses, I'm gonna size cable for 400A and No I don't want a generator it would not be practical for my needs thanks anyway and if anyone could stear me in the direction of a good brand I would be very grateful thanks

Its unusual for caravanners to use such a large inverter, as teh main limitation is the caravans ability to carry enough batteries for it to be practical. You may be better looking at teh marine market. For example battery weight is not a major issue, and I am aware there are several systems favoured and approved for use in canal and river boats. These also often contain an inbuilt smart charging system which also looks after the batteries when mains power is available. Most of these marine systems will not use 12Vdc, but 24 36 or even 48V battery systems (most will be 12V batteries but its teh way they are connected to produce 12, 24,36 or 48V) this keeps teh dc power cabling a more manageable size.

If you are looking at pure sine wave conversion, the efficiency of the inverter will only be about 65 to 70% efficient at best, so you may need to consider a bigger battery pack to allow for the system losses. so if you need 3kWh of energy you should be looking for battery with a capacity of about 4kWh.

Try googling
"Marine inverter systems"