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Forum Index : Solar : Inverter help please
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| curiosity Newbie  Joined: 04/12/2011 Location: AustraliaPosts: 31 |
Dare I say it, I've been looking on ebay and found a "*SALE* 4000W 8000W 48V solar pure sine wave inverter charger 50A LCD 220V" around $1000. I'm hoping that someone has used one or these and could elaborate on their quality. Here is a user manual http://www.mppsolar.com/manual/PIP-HC%20user%20manual.pdf It looks like a nice unit for what we will eventually use (power wise) Our farm house is not permanently resided at.We have a generator but at some appliance "switch on" times it struggles so we thought stage1 would smooth the power fluctuation problems. It is better for wind generation rather than solar but for monetary reasons we must progress in stages.I'll explain a bit more.. stage1 I plan to use 1x200w solar panel and 4x12v 120ah batteries for the moment. We also have a 4.8kva generator that is used at large power usage times (wired directly to house) and may be used via the inverter to top up batteries. stage2 The battery bank will be increased and a 1.5kw wind generator will be added. The wind generator will go to the battery bank via it's own charge/dump load controller, so the battery bank will power the house via the same inverter that the solar panel is connected to. I welcome thoughts and ideas. What do you think of my crazy plans? |
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| VK4AYQ Guru  Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Curiosity My friend has a bigger version of this unit on 48 volts and works well. You would need more panels at least 4 to be useful more is better Wind turbine is a good top up but not a reliable power base unless you live in the roaring forties, better use it as a extra instead of main and put your money into a few more panels. Bigger battery bank would be require if you want to be serious at least 500 amp hours @ 48 volts. All the nest Bob Foolin Around |
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Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301 |
Hi Curiosity, I noticed it's a pure sine wave inverter which can be a plus.It will run most things unlike the modified wave which some devices don't like or won't work on.Cheers Rastus see Rastus graduate advise generously |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
A quote from the manual "Fig. 3 shows a Series-ParaIlel connection consisting of five 12V,100AH batteries to form a 48V, 500AH battery bank. I guess they lost something in the translation but that make 5 x 12 = 60 at least it was when I went to school, I can just imagine someone who has little knowledge of such things following the manual. From the specifications.... Output volts + or - 20%! so set for 230V nominal it may output anything from 184 -276 volts. Operating temp.... 0-40C probably enough but house in a well ventilated area. Allan "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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| curiosity Newbie Joined: 04/12/2011 Location: AustraliaPosts: 31 |
Thanks very much for your input. This sounds very encouraging for the quality By the "roaring forties" do you mean wind speed or time wise? The area is always windy with good speeds for generation. Allot of the time it is cold. Until recently we use such things as kerosene lanterns, an esky and a copper for bath water. Now we have all the mod cons  Fridge,hot water and stove are all gas. We even have a brand new, second hand wood heater (the no fan type). TV is non existent due to no reception... Hmm guess we live in the roaring 40's any way you look at it
We use very little power when there. It would consist of 2-3 light globes (energy saving fluros) for 6hrs max and a water pump (1.2kw) for 30 min all over 2 days. The system then has months to rejuvenate. Stage 2 would be a decent battery bank as you say |
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| curiosity Newbie Joined: 04/12/2011 Location: AustraliaPosts: 31 |
Well picked up 
I haven't read the manual closely and missed that one. I'd say if you were using 12v 100ah batteries to make 48v 500ah, it would be closer to 20 batteries wouldn't it.
The seller does however seem to be helpful with support type questions with several forms of contact 0-40C.We may need to put some extra fans or use cool room panels to make the shed at that rate. |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
Justin, As cheep inverters go it may well be a good unit but as one who relies on my inverter I prefer Australian made for Australian conditions, having said that as it is for occasional use even I may lean towards a cheep unit, your call. 20 batteries yes but only 4 per bank, not 5 as our Chinglish friends suggest in their instructions. Allan "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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| curiosity Newbie Joined: 04/12/2011 Location: AustraliaPosts: 31 |
Allan, Unfortunately the cheap option is our only one as money just would not allow otherwise. I doubt even the ausie version is all ausie made parts inside anyway. Yeah I had realized 5 banks in parallel of 4 batteries in series. I wouldn't have wired them 4 banks of 5 even if the instruction told me to  |
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| curiosity Newbie Joined: 04/12/2011 Location: AustraliaPosts: 31 |
I guess I would need a small dump load controller for my set up and was hoping to make that myself. Would anyone have a circuit diagram for something like this? |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
http://www.thebackshed.com/windmill/articles/TL084-Controlle r.asp "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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| curiosity Newbie Joined: 04/12/2011 Location: AustraliaPosts: 31 |
Thank you very much Allen. It looks very simple but is there any way to make it 48v? Maybe changing the resistor,capacitors and relay or would this not be possible? I realize you can just hook it up to 12v (one battery) but wouldn't that be harder on that battery? |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
Justin the voltage regulator has a max. input voltage of 35V, I don't know who the author of that project is maybe Glenn can chime in and help with that. If you can find one that has an max. V of 65-70.. For a simple solution I would build the 24V version and put it across 2 batteries, it's current draw would be negligible, the relay will be the only item that sees 48V. I have seen starter motor coils used as heavy duty relays. Allan "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yeah you would need to add a pre-regulator to drop the 48V down to something like 20 volts. There was a circuit published here in the forum recently for a regulator using a mosfet, not sure where. And you would need to change R1 to suit. Unfortunately I dont have the time for the next week to help out with this, I need to comeplete a 12 week cource in 5 days, so a little on the busy side. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
found this post...same problem Allan "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yeah thats it, the pre reglator, a nice simple circuit. I havn't tested that circuit, but it look OK. You would need a heatsink on the MOSFET if you intend to supply any more than say 100mA. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| curiosity Newbie Joined: 04/12/2011 Location: AustraliaPosts: 31 |
Excellent guys. That should get me out of trouble (or into some )
This forum is an excellent wealth of knowledge. |
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| curiosity Newbie Joined: 04/12/2011 Location: AustraliaPosts: 31 |
A few days have passed and there has been an unfortunate discovery that may halt my plans totally  In the manual of the inverter that i chosen, it says if a generator is to be used as AC power, it must be a sine wave type. My 4.8kva is a square wave type so that brings me to another question..
Is there any way to convert a square wave generator output into a sine wave? |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
A 4.8KW square wave generator???????????? We are talking about a petrol/diesel powered generator aren't we? It may not be a perfect sine wave but a sine wave it is, I suppose someone could make a square wave unit but it would require some fancy machining and winding to achieve it in a rotating machine. In OZ Gen-tech is considered the best sine wave from a portable generator, maybe you need to tell us about this square wave generator. I imagine a bloody big box sitting on your work bench with a selector knob marked sine/square/triangle and two huge brass studs for connection to your latest experiment. Allan "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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| curiosity Newbie Joined: 04/12/2011 Location: AustraliaPosts: 31 |
Oh. maybe it is a sine wave then. We assume it isn't. It's one of those petrol honda motor type similar to but not exactly the same as. It is 400km away atm so I cant check. We have had a problem that it burnt out a pump so we assumed that may have been the problem see here or that it's power is not regulated well enough. Either volts or hz Rastus is my older brother We have planned to do away with the generator eventually but can not atm |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
Justin the pump that burnt out did it have a "Presscontrol" on it and was it that unit that burnt out or was it the motor windings? Presscontrol's are good but having a very crude way of developing the low voltage for the control board they are prone to letting the magic smoke escape under high voltage. Portable generators that have capacitor excitation need the correct size capacitor that is within tolerance, if the capacitance is too high then the no load volts will be high, note: motor speed/frequency also affects this. I don't believe you have as big a problem as you think, if in fact there is a problem. Building up a plug in voltage and frequency board for portable generators is a good investment, instrument are cheep from China and a suitable box can be sourced from on line electrical wholesalers in OZ for a good price. Allan "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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