Back up power system I threw together a few years ago, got me through many grid outages.

[G.W. Mad Scientist]

I built this power system over 2 years ago from lots of leftover stuff I had laying around decided to get creative I had been using a 2,000 w modified sine wave freedom inverter but it smoked my smoke detectors of all the crazy things and my pilotless ignition on the stove did not like it either so I decided to go pure sine wave instead of a high end modified sine wave I was able to pick up a 12v 3000w Sata Dimensions utility type sine wave inverter off eBay for $300 it has a extremely high surge capability can start a 1 1/2 hp motor I tied that together with a trace 220 Step up Transformer to run my well used a stat power/trace type battery bank charger even added a boost capacitor to help the starting capability. Use 10 car batteries an old shelf I had in the garage even added in Anderson connectors and made me a set of extension cables with clamps that I could throw out the office window and run it off my CNG truck I actually powered the house one time for over 3 weeks when the grid went down in an ice storm the system worked incredibly well and it's been an excellent backup system for me, everything included I only have about $1,000 in it I added a 240 outlet and made myself an emergency suitcase cable box with all the necessary cables to backfeed to my breaker box and a direct cable to plug my well in which was originally hardwired I created a plug-in outlet for it that allowed me to plug my pressure tank control into this system, has worked pretty darn good for the cost sorry for the lack of punctuation it's late I'm tired I'm talk texting this postthought I would throw something on to get started on the Forum I didn't really know a lot about these Sata Dimension inverters until I got this one and it turned out to be a very Stout little inverter this is made for utility trucks and made to Run induction Motors. At one point I was going to wire it through the house to the breaker box ended up not doing it decided to save my cables for something else Although it doesn't have solar going to it ? it's an excellent backup power system soon to be replaced by one tenfold in size ??

 

[Bud Martin]

You are using NEMA 5-20R (120V 20A) for 240V outlet instead of NEMA 6-20R (250V 20A)?
You got good deal on that Sensata dimensions 3000W inverter.

NEMA 6-20R duplex.

 

[G.W. Mad Scientist]

Yes I know it's unorthodox but I had a 30 amp 100 ft 125 volt cord I hated to cut the end off so I did that and created a short adapter cord you can see it in that suitcase it allows me to go from that to the 240 well plug..

 

[G.W. Mad Scientist]

Yes I know it's unorthodox but I had a 30 amp 100 ft 125 volt cord I hated to cut the end off so I did that and created a short adapter cord you can see it in that suitcase it allows me to go from that to the 240 well plug..

 

[G.W. Mad Scientist]

I was wondering how long it would take someone to catch that good hi there bud in actuality almost everything was scrounged from my shop the only thing I actually bought two years ago was the inverter the well plug and Outlet and one end of that adapter cord I think I might have spent $400 at the time when I put it together I figured that price based off of all the equipment that I've had laying around in the shop most of that stuff is 10 plus years old to me, did later clearly label the outlet and I'm the only one that uses it so it should be all right it's proven itself through countless hours of use.

 

[wattmatters]

Nice work on pulling together the system. So good to have power during long outages.

I put my own together but using a more conventional path.

and made myself an emergency suitcase cable box with all the necessary cables to backfeed to my breaker box

Is the system isolated from the grid when you do this, e.g. with a break before make transfer switch?

It's very important there is zero chance of energising any grid power lines during outages.

 

[G.W. Mad Scientist]

Thanks wattsmatter, Yes of course the the incoming grid power to the breaker box is killed via 200 amp main breaker all 240 loads are turned off, before this system is ever used. The well is powered directly from the transformer, I also install a bridged 240 breaker which then feeds the other half of the breaker box while in the temporary backup power mode. The new system I'm designing will have a new cover panel for the breaker box which won't allow you to have the mains and the back up power on at the same time makes it idiot proof I have a replacement panel that has a built-in interlock that will be installed when I upgrade to the full blown solar and new backup system.

 

[wattmatters]

Nice work.

at the same time makes it idiot proof

Someone once told me never to underestimate the ingenuity of idiots.

For a while I had a process which required shutting off a breaker or two before cutting over to backup. But I did not like the potential for human error, so I made changes to ensure it could not accidentally happen. In my case it wasn't for preventing back feed to grid but other things (e.g. accidentally supplying my 3-phase GT inverter with single phase backup supply).

 

[G.W. Mad Scientist]

Nice work.


Someone once told me never to underestimate the ingenuity of idiots.

For a while I had a process which required shutting off a breaker or two before cutting over to backup. But I did not like the potential for human error, so I made changes to ensure it could not accidentally happen. In my case it wasn't for preventing back feed to grid but other things (e.g. accidentally supplying my 3-phase GT inverter with single phase backup supply).

Yes people can definitely be ding dongs I lol I live by myself so the chances error are very slim, my new system design it is impossible to turn any two things on at the same time there will be three transfer switches in the new system one at the breaker box to switch from grid tie to the power room in the power room it can be either generator or inverter and inside the inverter module it can be inverter one or inverter 2 I have backup for the backup for the backup LOL the new system is going to be ridiculously redundant. Originally inside the power module for the xantrex inverters it had a transfer switch for either generator or grid or the inverter I decided to change that slightly and it's now inverter 1 or inverter 2 if the grid goes down and I'm will be on the back up inverter 1. if it fails I will go to the inverter 2 if it fails I go to the propane generator if that fails I go back to my SATA Dimension 12 volt system.... I'll be asking lots of questions I have so many... been working in the power room for the last 90 days installing all this equipment I've acquired.

 

[wattmatters]

Yeah, I have the one off-grid inverter for backup and a generator to back that up. Generator can either charge batteries or power home directly if the off-grid inverter is down for some reason.

I'm now permanently running the home via the off-grid system and use automations to manage the switching between using grid power or using battery.

 

[G.W. Mad Scientist]

Yeah, I have the one off-grid inverter for backup and a generator to back that up. Generator can either charge batteries or power home directly if the off-grid inverter is down for some reason.

I'm now permanently running the home via the off-grid system and use automations to manage the switching between using grid power or using battery.

That sounds really nice being able to be completely off grid. Sounds exciting and scary at the same time. I imagine I will stay on the grid but reduce my bill to zero is the goal other than the monthly $15 fee for being connected I have a lot of equipment to install 15 KW of solar and the fronius inverter and another 10Kw of solar that will go to a victron mppt 450/200 and charge the batteries in the power room and feed the two Xantrex sw5548 inverters, I'm going to install a actual generator transfer panel that would normally be used for generator only circuits from the house but I'm going to wire it between the grid tie inverter and the off grid inverter so while on the grid instead of being all off grid or all on grid I can at will switch 2 240 loads and 6 120 loads between on grid or off grid while I'm on grid allowing me to experiment with being off grid while still on the grid I have a feeling it's going to take me all summer to get this accomplished I started in the power room about 90 days ago and this is how far I've gotten keep in mind this is a closet and 3 months ago there was nothing in there that was as of a few weeks ago in this pic

 

[wattmatters]

That sounds really nice being able to be completely off grid. Sounds exciting and scary at the same time.

No, not off-grid at all. That's not happening.

I have an off-grid system which, when the system option is chosen, can pass grid power straight though.

I also have a grid-tied PV system.

So in the daytime I pass "grid" power (which is really being supplied by my grid-tied PV) through the off-grid system to power loads. Then at night the off-grid system switches over to power the home from the battery (which was charged by the PV during the day).

Some loads are grid side only - all the high power stuff (ducted AC, oven, water heater etc). Water heater is powered in the daytime with smart PV diverter, so it draws nothing from the grid. Aircon uses grid-tied PV in the day but will draw from grid at night, same for oven/stove. But most of the rest of the place is powered via the off-grid system, including my mancave and a second dwelling.

For grid outages the off-grid system has a battery reserve (I keep a 20 kWh sealed lead acid bank in reserve for outages) plus whatever the 10 kWh of LiFePO4 battery used for regular daily cycling has left and a small PV array to keep things running, and if solar conditions are poor and the outage long then the generator can provide supplemental battery charging capacity.

 

[G.W. Mad Scientist]

No, not off-grid at all. That's not happening.

I have an off-grid system which, when the system option is chosen, can pass grid power straight though.

I also have a grid-tied PV system.

So in the daytime I pass "grid" power (which is really being supplied by my grid-tied PV) through the off-grid system to power loads. Then at night the off-grid system switches over to power the home from the battery (which was charged by the PV during the day).

Some loads are grid side only - all the high power stuff (ducted AC, oven, water heater etc). Water heater is powered in the daytime with smart PV diverter, so it draws nothing from the grid. Aircon uses grid-tied PV in the day but will draw from grid at night, same for oven/stove. But most of the rest of the place is powered via the off-grid system, including my mancave and a second dwelling.

For grid outages the off-grid system has a battery reserve (I keep a 20 kWh sealed lead acid bank in reserve for outages) plus whatever the 10 kWh of LiFePO4 battery used for regular daily cycling has left and a small PV array to keep things running, and if solar conditions are poor and the outage long then the generator can provide supplemental battery charging capacity.

I see that sounds like a really nice, I like the way you've got that ran that sounds a great system, I'm very impressed. I'm curious how many watts of solar do you have? I'm pretty much thinking that my house is so efficient I'm hoping that I'll be able to sell so much to the grid during the day that even using it at night I'll still end up with a zero bill if I'm able to pump enough into the grid during the day I'm pretty sure I'm going to end up with a zero bill it won't matter if I use any of the backup 10 KW but I'll be offsetting if I need to by transferring more to it during the day because the batteries will hardly get used they'll be probably literally in float most of the time. I'm going install a frontious Primo 12.5 KW grid tie inverter with 15kw of panels(60) and the power room will be supplied by 10 KW of panels(40) I actually have 110 panels I'm going to put 100 in service and I'll have spares in case something happens to some of them, so the grid tie system will be automated tied to a fronius smart meter and it will sell to the grid what I use the backup system is going to be old school as far as the inverters are and transfer switches are concerned however I'm going to use modern victron charge equipment with Bluetooth and internet monitoring capability I have the victron 500 amp smartshunt the victron 520 Global monitoring unit already up and running I still need to install the RS 450 / 200 mppt unit, and build the solar racks and get busy installing panels I've already bought the panels bought all the 2-in schedule 40 piping and a lot of the unirack I'm going to need I've already got a spot cleared front of my house I cleared out about half an acre of trees so I'm in the beginning stages of this. The build is going to take a while it's been a decade in the making but I'm ramping it up to get this knocked out by the end of summer I hope. The big goal become energy independent have my house paid off in four and a half years retire in 8 years and be able to live with virtually no expenses.

 

[wattmatters]

I'm curious how many watts of solar do you have?

See here:

Backup down under

Greetings from down under. I live in a home near the small town of Bellingen, in northern NSW, Australia. Glorious country: That's our home at left centre, and obscured by the tree and slightly off the left of the image is a secondary dwelling where my Mum lives. 12 acres, behind our home (to...

diysolarforum.com

I'm pretty much thinking that my house is so efficient

This is important. Ours has terribly poor thermal performance and is a work in progress. I've worked hard to reduce our consumption but still have much more to do.

I'm going install a frontious Primo 12.5 KW grid tie inverter with 15kw of panels(60)

We have a 3-phase Fronius Symo 10 kW grid tied inverter.

You might also be interested in reading the journey @live4soccer7 has been on with his system, with 3 x 15 kW Fronius Primo inverters:

Finally, the start of my 25kw Ground Mount grid-tie system

Ok. I have been wanting to do this for years now since I have moved into my current location which I will be until I physically can't be here anymore. I have some things planned. Location: Spokane, WA 99022 (Eastern WA) I am still deciding on a source for panels and exactly which panel I would...

diysolarforum.com

 

[G.W. Mad Scientist]

That is incredible what you have done with that building and what a beautiful property you have! Not many Americans are using the fronius but after my research I'm sold on them plus if you have an issue they're a snap to change, we have very similar circumstances I live on 15 Acres I have a big shop which is my second shop as my first one burned down in the wildfires 10 years ago as well and as with you my mum lives on the property in my mobile home. I used to live in before I built my house. My mum is actually from England I'm half English my dad was in the Air Force and that's how they met. Thanks for the info on the other threads I'm going to read them. I'm curious did you commission your own inverter when you got ready to put the inverter into service? Here's a few pics of my place looking down at the house from the shop looking up from the house at the shop. I just finally put concrete in front of the shop it's so nice to a have well gravelef driveway and slab it's ongoing process. If you look at that slab to the left that's where my old building used to be before it burned down. See the snow on the ground I cleared out a half acre of trees that's where the 4 solar arrays will be put up. You can actually see my mom walking up the sidewalk from the house going home LOL a little peek inside my shop you have to excuse all the cars and mess I'm a mechanic by trade and I flip cars to supplement paying for all this stuff.

 

[wattmatters]

Not many Americans are using the fronius

Rules over there make pure grid tied string inverters less common, tend to see more microinverter and optimiser style sets ups like Enphase and Solaredge.

The modern Fronius models are very well built robust hardware.

as with you my mum lives on the property in my mobile home

Sadly my mum passed away in January. She had a great three years here though.

I'm curious did you commission your own inverter when you got ready to put the inverter into service?

Nothing grid-tied here is DIY.

It was installed by professional local solar PV installation company. Here it's a very well serviced and competitive industry, you put out a request for quotes and can get many companies to bid for your business. Almost one in every three homes in Australia has a grid-tied rooftop PV system. Much cheaper to install here than in the US. You can get rooftop PV installed by professionals for between US$0.5-1.0 / watt.

My little off-grid system (which has grown since I first put it in) was DIY, with the exception of the AC side as none of that can be DIY, all must be licensed electrician. Even the DC side is a bit of a grey area for DIY but keep stuff to code and it helps. My sparky is helpful with it when needed.

it's ongoing process

It never stops. I have my days when it can be a bit overwhelming.

 

[G.W. Mad Scientist]

Sorry to hear about mum. That price is incredibly cheap I think I paid about 30% to 50% of retail for most of the equipment I did get a few items for about 80% and that would be the new victron equipment. I'm still going to be at US $30k for 25kw of solar. That does however include fronius grid tie inverter and the double inverter. As well as the 20.5 KW watt hour lithium battery backup system and a 10 KW propane generator. I guess when it comes time to Commission my inverter I'll be doing a lot of research I think I have about 90% of this total system figured out.