How to connect battery bank to appliances?

[Kenbat]

Hi, it may sound like a stupid question, but nobody seems to talk about this much. So, for a non-grid tied inverter system, how do you get the power from the inverter to multiple appliances around the house? I know most inverters have a couple of plug sockets, but what if I want to power 6 different appliances in several rooms in my house? I'd be interested to know what the options are.
Cheers!
Darren

 

[DarkRaven]

Well, you could run extension cords all the way. But basically this is not how it's supposed to work. There is no solution because it shouldn't be a problem in the first place. That's what grid tie inverters are for while the non grid tie inverters are meant to be used locally.

I mean, you could install a second set of power lines that are fed by the inverter so you'd have normal grid powered sockets and inverter powered sockets but it's hardly worth the effort.

 

[jesusangel]

I think the best way is you or your electrician do some cabling and install some automatic or manual transfer switch so you can select the input for you whole house from grid or from your inverter or with more work you can set individually for every circuit so you can have oven and high power appliances connected to grid and light or low power appliances to the inverter.

 

[Redpacket]

your electrician do some cabling

This.
Basically you get the house wired for normal mains with a switchboard incl circuit breakers & leakage breakers.
Like jesusangel said if you do have grid mains present you would have a change-over switch too.
A few items you can get away with extension cords but sounds like you're further along than that

Depending on your setup, you might also have some DC circuits, eg for lights.

 

[Kenbat]

Hi Thanks for your replies. I'm at battery harvesting phase at the moment. I've got 2 options in mind at the moment. My first option was to power a fridge and freezer, and maybe some phone charging etc, keep it fairly small and simple. My latest idea is to power the cinema room that I converted from my tandem garage. This room is directly adjacent to where i would mount the battery packs, and therefore I could run cabling direct to this room and mount new sockets. I'm still doing the calcs, but I think i'm looking at 7s 100p.

 

[DarkRaven]

Running the cinema would be fairly easy then. For the fridge and freezer you could use a microinverter, if their are legal in your country. That would be a very simple, quick and also cheap solution. Small stuff like phone charging can be done close to the battery, maybe even straight from DC. It's probably not worth it to run AC lines for that. If it's inconvenient you could make a small battery that you can take with you into the house and charge it once a week or so from your battery.

 

[Kenbat]

Running the cinema would be fairly easy then. For the fridge and freezer you could use a microinverter, if their are legal in your country. That would be a very simple, quick and also cheap solution. Small stuff like phone charging can be done close to the battery, maybe even straight from DC. It's probably not worth it to run AC lines for that. If it's inconvenient you could make a small battery that you can take with you into the house and charge it once a week or so from your battery.

cool, thanks. early days yet but I'm trying to get my head around it all so i know what I'm doing. just about processed my first 100 batteries!

 

[ChrisD5710]

Just for info, micro inverters will not work. You need at least a 1 KW inverter in order for the fridge compressor to start.

Just run an extension cord to Your fridge and freezer, but keep it clear of all mains connections. Otherwise you may run into problems with Your utility company.

Here in Denmark all equipment connected to the Mains (Public Utility Grid) must be approved, and that goes for batteries as well. (Read, no home made batteries can be connected to the mains)

My solar equipment is totally isolated from the mains. This means that when I run out of solar power, I will manually have to move the fridge plug from the solar extension cord to the normal mains socket. This has not been necessary just Yet

 

[DarkRaven]

Just for info, micro inverters will not work. You need at least a 1 KW inverter in order for the fridge compressor to start.

That's massively over-simplified combined with a misunderstanding.

First, this might be true for some cases, like huge and/or old units, but not in general. In other words, no, you're wrong, as it is often the case if you're trying to over-simplify something. You don't need at least (!!) 1kW.
And second, you probably don't know much about microinverters? Even if you need 1kW why should that be a problem so that microinverters will not work? There are models in this power range available. Or just use several.But because of the way they work you don't need a 1kW inverter to run a 1kW load. They are grid tied and the remaining power comes from the grid.

The only thing you can't do with them is going off grid because they turn off without a grid connection. But for supplying your base load they are perfect. But sadly they aren't legal everywhere yet.

 

[Geek]

I think the best way is you or your electrician do some cabling and install some automatic or manual transfer switch so you can select the input for you whole house from grid or from your inverter or with more work you can set individually for every circuit so you can have oven and high power appliances connected to grid and light or low power appliances to the inverter.

That would be the most effective way to go. You would probably opt to keep the heavy draw appliances off the inverter. Heating uses a lot of power, so unless you have a really large system, its best to leave those on the grid.

By having a transfer switch you can use your existing cables and power points. Most houses even have more than one circuit.

You may even want to look at a solution like the Victron Multi Grid. It basically does not back feed the grid, but rater forward grid power when the inverter can't keep up, or the battery goes flat.

 

[jesusangel]

I think the best way is you or your electrician do some cabling and install some automatic or manual transfer switch so you can select the input for you whole house from grid or from your inverter or with more work you can set individually for every circuit so you can have oven and high power appliances connected to grid and light or low power appliances to the inverter.

That would be the most effective way to go. You would probably opt to keep the heavy draw appliances off the inverter. Heating uses a lot of power, so unless you have a really large system, its best to leave those on the grid.

By having a transfer switch you can use your existing cables and power points. Most houses even have more than one circuit.

You may even want to look at a solution like the Victron Multi Grid. It basically does not back feed the grid, but rater forward grid power when the inverter can't keep up, or the battery goes flat.

I reread my post and I think I correctly express myself. With some cabling I mean some cabling fron main panel to aditional panel where you installtransfers switch, for the whole houseif you have a large inverter/batteries to feed that amount power or individuals transfer switches for evey circuit, so with a less large system you keep heavy draw appliances connected to the grid and you use inverter to feed light circuits and low draw appliances.

Didn't I said that in my last post? Of couse some cabling doesn't means duplicate the whole installation for the house or some circuits just few centimeters if you can add a secondary panel, or install a transfer swicthes.

I have a MPP Solarhybrid inverter of 4kW, and have only one transfer switch for security reasons, I have the inverter in offgrid mode with backup, so I can be using 2000Wfrom the panels and 1000W from the grid when the oven is ON, or at night mix from the battery and the grid if I set a maximun current drawn for thebattery, the same that makes the Victron Multi Grid.

 

[Crimp Daddy]

+1 on the have your electrician do some cabling work.

The gorilla way to do it is switch the mains breaker off and back-feed your own panel though an available outlet but it's not the right way or even something you should really consider doing. Primary because is there is no protections against accidentally back-feeding the grid which is dangerous and illegal.

I am getting a manual transfer switched / Generator Interlock Kit which is probably the most inexpensive way to do it mechanically. Only one can be on at a time, either the breakers mains, or the dedicated circuit used to feed the panel. Its how many lower budget emergency generators are connected for homes, but instead of a gen, you use an inverter.




You can then have a dedicated higher amperage plug installed on the breaker that controlled by the interlock kit. Either near the panel which is common for a gas generator or near wherever your inverter / battery room is.

This is probably the least expensive way to do it right, but there are much better and more elegant solutions using automatic transfer switches or even higher end multi-input inverters like the Victron Quattro which can accept battery, grid, generator, and can do load and input management automatically. I like these systems because you can program it be to grid priority which uses like the battery more like a UPS or battery to use as much battery before drawing from the grid. It can also use a generator to make up for any high amperage loads like an oven if your battery bank cant handleit. With something like this, power just keep working. You probably would noteven know you had an outage because its all automatic.

https://www.victronenergy.com/inverters-chargers/quattro

 

[Cherry67]

- snip (Read, no home made batteries can be connected to the mains)

And i thought, german burocrats wheree the "best...."