inverter for a solar power system [CLOSED]

[bubba931]

My brother installed a 12V solar system in his cabin and attempted to add an inverter for 110V to run the submersible well pump. It draws around 1800W.  He had been running the pump with a 2200W gas generator.  The inverter that was installed was a 3000W modified sine wave.  When the pump kicked in the inverter committed suicide and it was an ugly sight.  He called the place where he bought it and they told him that the inverter outlets were not tied together and that he could only expect 1500W from each outlet and that is why it fried itself.  They suggested an Aims inverter because the outlets are tied together.  Is this a fact?  The inverter was installed following the manual so it nothing he did wrong.  We would appreciate any input.  Thanks people...  

2 weeks with no response from original poster for clarification. Just plaibn rude. [CLOSED] No sense wasting more of your time, folks.

[dnix71]

It sounds like he connected both outlets together left-left right-right ground-ground.

That really doesn't make sense. But that means the inverter isn't really 3000 watts, it's 2 inverters in one and each half is only 1500 watts.

You are going to have a difficult time starting a motor that pulls 1800 watts when running. Especially on a 12 volt system. That's enough amps to start an 8 cylinder engine. The start load on a motor may be more than 3 times the run current.

Are you sure it's an 1800 watt motor? You say it will run from a 2200watt generator.

The inverter here with 1800 watt continuous output pulls 180 amps max.

http://www.newmarpower.com/Inverter_Chargers/Inverter_Chargers.html

One with a little extra capacity pulls 250 amps max. That's a scary amperage at 12 volts for more than a few seconds.

Their 24volt only pulls 110 amps to put out 2200 amps continuous. How long does this pump need to run? Can you fill a large tank and then gravity draw, or does it have to cycle on and off every time you turn the faucet?

How deep is the well? Do you really need that kind of power? Can you get by with a smaller pump? That's a 2.5 HP pump. I only use 1.5 HP to pump from a canal and irrigate a duplex lot with one zone (front and back all going at once.)

[RUFUS]

I'm resisting the urge

Tom W.Please step in here

                       Rufus

[TomW]

RUFUS;

Uh, I don't follow you?

I see a typo where dnix probably meant watts but said amps?

I may be slow today?

On the inverter topic, thats an insane amount of continuous draw on a 12 volt system and would need an awesome source feeding it from solar plus an equally awesome storage capacity and cables of 1/2" copper rod.

Tom

[TheCasualTraveler]

     The problem is they don't make inverters for entire solar systems. Maybe one or two planets at most.

[zap]

: )

[SteveCH]

Man, that is some pump. And he did not buy a 3000 w/ inverter, as has been suggested already. I've never heard of an inverter being sold/rated like that. Methinks shenanigans at the point of sale.

In any case, the start surge for that motor is very high, and whatever inverter he uses must be rated for that [and the rate will be significantly higher than the "advertised" wattage/amperage, however it's said]. The owner manual for the inverter will tell you in the spec's. The spec's for the pump will tell you what the start surge is. So you should be looking at those numbers before buying another inverter.

Far as I know, the modified sine wave type of inverter should work fine. I mean, rather than buying a pure sine wave inverter. At least, our modified sine wave inverter runs our Grunfos pump just fine. However, I went with a soft-start model to avoid the surge problem. I am not an expert on either pumps or inverters outside of the ones we have here, so don't assume my info' is perfect for your situation.

[kurt]

fixed it so you jokesters wouldn't hurt yourselves trying to contain yourselves.... but you would be amazed how many times i have seen people say solar system in reference to a solar power system it is almost as common as interchanging watts for both watts and watt hours interchangeably......  

[dnix71]

Yeah, I see the typo now. Should be '2200 watts continuous'. There is no editing here. The forum software doesn't support it.

[FuddyDuddy]

I haven't been on this forum vey long, and I notice that those that have been are quite rude to the newcomers. I think I'll pull my sub to this group.

This knid of response isn't helpful to anyone and I really don't want to be a part of it.

Please go ahead and beat me up all you want. Maybe you'll get it out of your system and treat the next person better...

Feed up with the BS I see from the older persons, although not all. Some are actually helpful. Isn't that nice ??

[Bruce S]

FuddyDuddy;

 At the point of maybe sounding like the rude people you're refering to :/

They were just making a funny or at least trying to be .

No harm was ment by RUFUS or anyone else.

Why the slam ?

We knew it was a typo plain and simple.

others were merely joking around maybe not so easy to tell on flat pages. Otherwise the ADMINS would've removed or done something.

I can't seem to understand your position here. Best I can see is that on your posts people have been civil.

Plus, you here, committed what you're complaining about, you hijacked this post.

The guy had a problem with a 3000 watt inverter and other are helping. Sure others piped in about the typo but not in a mean way.

Having a bad morning are we?

relax the weekend is near.

Bruce S

 

[Bruce S]

bubbda931;

  The inverter should've shut down with an over load like that, I would take it back and demand refund.

I have a 3000 watter that is rated for 1500 watt continous and it's shut itself down when hit with an over large surge and it's just a cheapy Harbour Freight unit.

From reading your post I believe the unit is flawed , sounds like a "duh" I know .

If the 2200w gas unit ran it then certainly a 3000 watt unit can too.

Is the gas unit a 12Vdc type as well?

Bruce S

 

[RUFUS]

You nailed it Buddy

              Rufus

[wpowokal]

bubba931, step right back to the beginning, a submersable pump will draw varying amounts of current on starting. First check out the pump specifications, look for locked rotor amps, that is the current it will draw the instant the power is supplied.

Now gas generators have far better ability to start loads than inverters, given an overload that the pump in question would present it will dig it's heals in, the voltage will drop and ultimatly it will start (you stated that it did).

Cheep inverters have inherantly bad surge capabilities, usually less than 100% overload. Now a 1.8Kw pump will draw on start up 3-5 times run current(Kw), so to reliably start a 1.8 Kw motor you would need a 5.4-9 Kw surge capacity without soft start capability.

In my experience there is no way a 3Kw inverter, even one with 300% overload will start that pump because the overload is for a very few seconds, and submersable pumps can take 5 seconds to start on a good supply. Gas generators do not have these time restraints, as long as their thermal overload if fitted, does not activate.

I have glossed over the deep theory at this stage just to give you some idea of the problem, happy to expand if you desire.

allan down under

[tomtmook]

Gotta add my two cents.  

I recently backed up my water pump with a battery bank and inverter.  It's come in handy several times since I installed it in January.  Pulled my butt out of the sling during a graduation party with many guests.  

I've got a 3/4 Hp 220 volt Jet pump that pulls water from a shallow well.  Before I designed the backup, I measured a surge of around 20 amps for under 1/4 second.  I'll venture a guess that the deeper the well, the longer the surge.  This because there's more water to get moving for a longer distance.  After the pump gets running it draws only about 6 amps and takes about 40 seconds to fill my tank.  

Bubba931, you may have a 1 Hp pump that draws that much power.  Although with a pump that size, I'd rather run it at 220 volts to lower the wire ohms losses.  

I chose a pair of Xantrex DR1524's for the system.  I needed the pair for the 220 volts.  My battery bank is four 92 AH AGM's in a series parallel arrangement to get 24 volts.  I figure that covers me, most of the outages we see are under 4 or 5 hours.  

Before the battery backup my 3000 watt generator held its own against the pump load, but it really slowed it down at startup.  

I've looked around for an inverter/charger that's cheaper than the Xantrex pair.  I've had no luck and that's a pity, I've know several people who'd love to have it but can't afford the price tag.  

Good luck with it.

[Vince]

That's what I did with my relative's well.

Begin with a 220v submersible pump. It cuts the start-up load in half.

Then a matching pair of inverters.

The rest is fairly straightforward.

[Clifford]

Wow, that sounds like a pretty power hungry pump.

How many GPM are you pumping?  How frequently does it cut in?

Perhaps you could consider a cistern system with a smaller pump.

Also, make sure you don't have any water leaks...

I've been using "modified sine" for about 2 years now.  I have 2 inverters.  Small, 600 Watt for my computer, and "small things".

I plug in my "Bad Boy" inverter for running my power tools.  I've even welded using inverter power.

Sometimes my computer power supply will hum.  Otherwise, I have no problems running drills, saws, welder, grinders, etc on modified sine.  Well, the welder was maxing out my capacity.

If you browse E-Bay, you will find several 5000 Watt Load / 10,000 Watt peak inverters, as well as a few other high power inverters (3000/6000, 3500/7000, 4000/8000, 5000/10000, 6000/12000).

Prices for the imported high power modified sine inverters are less than $500.  Search for "inverter", then sort by descending price.

I'm not too impressed with some of the Chinese workmanship.  Mine should be 12V in, 120V out.  However, I think it is about 1V off...  so, if I feed 12V in, it cuts out due to low voltage, especially if I have voltage drop due to significant load.  It runs fine off of a 14V system.

I also have a 5000W 110/220V transformer, also snagged from E-Bay.  I did re-wire all the electrical connections on the transformer recently.  I was amazed at how cheaply it was constructed (lots of thin wire inside)...  now I don't want to see the inside of my inverter.

http://cgi.ebay.com/5000W-Voltage-Converter-Step-Up-Down-Transformer_W0QQitemZ360079269900QQihZ023QQ
categoryZ50588QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

Anyway, I use 220V power from the inverter+transformer for my table saw and welder.

I'd encourage caution if you choose to wire multiple inverters together as recommended above.  Make sure they support that configuration.  I think you are better off purchasing a native 110V (60HZ) or 220V (probably 50HZ) inverter.  Running at 50HZ should be fine for most applications, except for some electrical/mechanical clocks.

[TomW]

After 9 days with no response to multiple clarification requests, I would pronounce this thread a waste of time unless he actually responds soon.

Just a common issue I see repeated here on Fieldlines. Ask a question then fail to reply to questions from folks trying to help. Seems rude? Maybe its me.

Tom