battery backup solar systems -- how they work

[nomoreremakes]

Solar systems should all be connected to the grid??? Isn't getting off the grid the point of getting solar power?

[zlozlozlo]

@nomoreremakes the point of solar power is to create a kind of 'smart grid' - an intelligent, decentralized grid with many small independet sources. The grid could be modelled after the internet. Ever seen the entire internet go down? No? That's because the internet is highly dencetralized and every connection is doubled over many times. In fact it was originally designed to survive an all-out nuclear war.

[zlozlozlo]

@nomoreremakes this approach would eliminate the massive blackouts and brownouts, cause if the 'big source' failed, the millions of 'small sources' could sustain the grid at least for a while, before the main source is restored. The more important point yet is that they would take signifficant load off the centralized power sources - like coal and nuclear power plants - which would eventually enable us to replace them with renewables as well.

[ruzz3ii]

Clearly an electric vehicle is needed to make this system cost effective. $300-$500 savings on gasoline makes the payback period on this reasonable.

So how would one use the vehicle batteries as a power source for the grid?

[giantquesadilla]

People need to understand that grid-tieing is good. I see these solar powered EV chargers with battery packs coming out. What a horrible product.

Does your battery backup system disconnect your house from the grid when the power goes out (so anyone working on it doesn't get electrocuted)?

[pgm98387]

What are your thoughts on getting rid of all the charge controllers, put a battery load dump set at 13.5V off the battery bank, connecting the dump into a grid tied inverter?.

[WulfBand]

@pgm98387 And or simply put a voltage regulator on the batteries just like in the old days on cars before computers. They only used an alternator and a voltage regulator that is set from the supplier at 13.5 volts ? I would think that that would work.

[pgm98387]

@WulfBand

So just put blocking diodes in the combiner box from ea. seperate panel?

[valhala56]

This is why solar is going to be a failure. Cost is one issue. I have been thinking about installing solar DIY on my house, but I got a feeling not only would I screw up the installation but I probaly could end up burning my house down.

It's too bad they don't make and sell simple Kits for people to install.

[OBXSOLWIND]

I am confused. I thought that xantrex just got into the hybrid inverters with the XW series if you have an older hybrid inverter I would love to know the full model number. If you figured out a way to modify a standered inverter to run hybrid with island protection I would love to here how you did that.

CHEERS OBX NC

[lpgas1]

i understand what you mean doug!

[d3adp001]

I am sorry but your explaination is not very clear at all. I know what your system is doing, but thats because I am a master electrician, and electrical contractor, and I understand solar installations.

Maybe start at the panels and explain each component till the system ends with the grid. You kinda jumped around after talking three times about the PPT of the outback.

[d3adp001]

Answer this for the world. what model is the inverter? what do it do in "normal" status, what does it do in grid off status. How does it control power back into the grid, or does it. Is it a charger inverter, or do the batteries rely on the charge controller only for their source of power.

Just looking in from the outside.

[liveoilfree]

@d3adp001 The model doesn't matter much; it's a Xantrex 5448, but the principle is the same. Sorry if it's unclear, this is designed for the non-engineer, the general public.

The charge-controller merely stops the batteries from over-charing, in the rare case that the grid goes down for a protracted period of time.

The battery backup inverter just puts power in and out, unless the grid goes down. Then it goes to the battery (or to a generator if the batteries are weak).

[d3adp001]

I tried

[WulfBand]

@d3adp001 So theoretically if he turned off his master at the main to the house this system would also kick in ?

I'm working on a system but it's not solar, it's wind generated and my goal is to isolate my house from the grid and only use the grid when my system goes down.

[d3adp001]

yes turning the main off would effectively similate a power outage, and turn on the backup, so in your ap it would do what you want it to. Just remember that when you turn the gird back on the charger/inverter would also be charging the batteries, not a bad thing but it does consume power from the grid, just FYI to keep in mind.