stupid inverter question

[(unknown)]

Big power inverters are expensive but you can usually find used ones around 2000 watt fairly cheap. my question is can you feed one circuit from 2 or more inverters,possibly with some big blocking diodes to keep them from back feeding each other. Or should I just stop being so cheap and buy a big inverter

[willib]

Not a stupid question.

I dont recall it being asked before.

i'm not sure how you would get the outputs to sync up though.

If it is a start up problem that you are having , like a large motor ,

hmm what if you took two UPS's , both plugged into the same inverter output?

It is a nutty idea for sure , but they both would sync up in theory , mind you.

i'm not sure if i would actually try it though.

but the two UPS's could supply enough start up power combined to handle a larger load than either one on its own could.

I'm not sure why they wouldn't sync up though , thats their job after all.

lets see what others think of the idea.

[Norm]

 IMHO bad idea....why take a chance on ruining a

couple of inverters on the say so of anyone even

if they were right?...might work but in the long

run....just buy a bigger inverter that was meant

for the job....has a warranty....thoughts of fire

etc. when you try experiments .

The only thing about a question is that it isn't

stupid unless you're looking for a stupid

answer....like mine

[kurt]

you cannot stack two inverters together to share a load (that is what you are talking about is called unless they are specifically designed to do so and then usually the same brand and model so that they work together and usually you have to buy a stacking cable that links both inverters together so that basically both inverters run off the same Hz clock perfectly in sink with each other.

just trying to hook two ordinary cheap inverters together would make for an interesting show if you do it make sure you do it outside away from all flammable materials. because they will be out of phase with each other when you turn the second one on the magic smoke is coming out of one or both of the inverters most likely quite impressively.

[Opera House]

Even ebay has cheap stackable inverters, but even these tend to be more than regular ones.  I love the HF 2000/4000W inverters that I get for $20.  Sure they need to be repaired, but it is usually a simple problem.  I remove the fans and create a 3/4 inch air space with the bottom plate for natural cooling.  That saves about 0.4Awhich is a lot at low loads. I just hate fans, always an indication of bad design. Sometimes I pull out a couple fuses to make it a 400 or 1,000W inverter.  Anything below a 200/4000W inverter is just unreliable.   Then I dedicate an inverter for every purpose.  It does complicate the wiring which is the reason most people go for big inverters.  

[wooferhound]

Do not hook the outputs of inverters together unless they are specifically made to sync together. In the USA a 12ga house circuit is only good for 2400 watts anyway so 2000-2500 watts is about all it can handle.

So just add more inverters to the battery and wire them to separate circuits.  

[Tritium]

Grid tie inverters would be the exception to what has been stated so far since they are line syncing by design.

Thurmond

[DamonHD]

...but might need a 'lead' inverter to sync to.

Rgds

Damon

[tanner0441]

Hi

One comment you mentioned was using diodes to prevent back feeding, inverters are AC out beit sine or queasy (QUASY) so diodes are only going to stop one half of the cycle. If the inverters are 180 degrees out of phase when you switch them on that could double your voltage which could toast whatever you have plugged into them, as well as the inverters themselves.

If you have just won the lottery you could try it I supose, but I would sort it with seperate circuits or the big inverter...

Brian.

[(unknown)]

I kind of figured there would be a problem getting two inverters to sync up,I guess I'll save up for a big inverter. Being a firefighter I would look pretty stupid if my home brew electricity burned my garage down.

Thanks

 Matt

[ghurd]

There is a good chance I am reading too much into this and your past posts.

How much inverter do you really need?

Your rather limited charging capacity implies a rather limited amount of WH/D (meaning there is not a lot of power available).

Might be better off with a smaller inverter running lighter loads for more hours?

The smaller inverter will be more efficient than a large inverter with smaller loads.

It would not be a stretch to say a huge inverter doing nothing but being On, takes more battery power than a small inverter powering a small LCD TV.

If your intention is refrigeration or a sump pump when the grid is down, then the whole perspective is changed.

A large pump can draw enough surge current to drop the battery voltage of a small(ish) battery down below the inverter's low voltage shut down, resulting in cycling that can ruin the motor.

Bigger is not necessarily better.

G-

[(unknown)]

true I don't generate much power and don't have many batteries. I am still experimenting but my goal is to be able to run my work shop off grid with the ability to feed the house during a power outage,When I get more solar and build a better wind generator I will expand the battery bank accordingly. the biggest cost other than the batteries is a good inverter,a 2000 watt inverter will run all my lights, circulator pump on the wood boiler and small power tools at the same time but won't start large motors like a table saw,I know even with a huge wind gen and lots of batteries big machines will drain them fast so I built a back up gas  DC generator that I am trying to run on wood gas but that's a whole different subject. If I ever do generate enough power to meet this lofty goal I was hoping to find an alternative to a $2000 inverter and put the money into more batteries but it looks like I will need a big expensive inverter. Of course I'm not going out to buy one tomorrow,at this point I still need lots of other stuff first. I just want to get some idea of what I will need over the next few years. Or am I jumping in way over my head??

[Opera House]

"with the ability to feed the house during a power outage"

This can present a problem with most inverters.  By code the house neutral will be grounded and this is incompatible with common inverters where both the hot and neutral are floating.  Wiring the neutral and ground together will short out the inverter or make the battery deadly to touch. I have worked on some inverters where the ground pin is left floating!   There are inverters designed to work into house wiring, but these are much more expensive.  Check details closely before you buy.

[(unknown)]

http://www.magnumenergy.com/MS-AEseries.htm

dont know how to copy and paste on this forum but this is the 240 volt inverter I used on a midnite solar epanel that the gfci breakers are grounded.you can read up on the web link.