Inverter/charger/solar for one dedicated house circuit?

[cujet]

I have 4ea, 190W solar panels, 4ea. 44AH 24v batteries and would like integrate this into a UPS system for one room.

Obviously, inverter/chargers can function like a UPS. And, possibly, solar can be integrated?

I would love to have a system hooked to my family room, to power the TV/Sat/stereo and small chest freezer. My circuit breaker box is in the garage and there is a dedicated breaker for the family room.

Thoughts? Product suggestions?

[DamonHD]

Hi,

It might be helpful to say where you are, eg which US state, from a regulatory and sunshine point of view, and even to say whether you are doing this primarily to attempt to save the planet or your wallet or indeed some other reason(s)!  That may alter the answers substantially.

Rgds

Damon

[cujet]

Oops, sorry for the lack of clarity.

I'm in Jupiter, Florida (S. FL)

The reason for this is simply that I can. I've been experimenting with solar for many years and I enjoy it as a hobby as well as the practical applications. Certainly, running my chest freezer during power outages is a big plus.

I currently have my 65" TV and DirecTV sat receiver on a large UPS, hooked to a single 44AH, 24v battery. It's purpose was initially to prevent the DTV receiver from performing a "reset" every time we had a brief power outage.

But, after the 3 hurricanes, that UPS was a critical item. As generator power was not 24/7. Kept the family content for many weeks.

I'd like to improve on this a bit by making it a proper installation with quality equipment.

[dnix71]

cujet I live in Sunrise. Which hurricanes would those be? Francis, Wilma, Jeannie and which other? I have my solar setup for exactly the same reason. Gensets just don't work well in an urban setting, unless you have a large battery bank that you top it up with. After Wilma we couldn't get fuel so that wouldn't have worked either.

Going direct 12v is simpler. All my apartment lighting is 12vdc. My fridge is a 12vdc. 40 quart Engel, but a well insulated chest freezer might work better if you have a family. I have piped gas for cooking and hot water. That has never failed. If you buy an apartment sized portable washer you can easily run that from an inverter. I have a 600 watt sine inverter hard wired inside my van, so I could go mobile if I had to.

I have DSL on copper wire. That didn't fail even after Wilma. My dsl box runs from 12vdc and my laptop charger will run from 12vdc or a small inverter. I have a small 12v battery powered tv, box fan and battery powered radio. Electricity wasn't restored until 4 weeks after Wilma at my apartment, so I ate elsewhere if I could and just kept it simple. My batteries are inside (not recommended here) but it works fine for me. The panels are right outside on the ground where I can get them inside quickly if a storm is coming.

I have avoided trying any building wiring mods - not legal and not necessary. You can't make money from off-grid home solar, it's about quality of life after the SHTF.

[Bruce S]

Great place Jupiter! there used to be hog dog stand "ladies" back in the early 90s when I went there for factory training at was is now GE Medical.
One major thing you will need to do before beginning this challenge: Get the ratings for ALL the devices you want to put on the UPS.
The Freezer when it starts will take up 10x the running current when the compressor starts.
Are your batteries true deep cycle 24V batteries or hybrids? This will also figure into how much draw you want to have before you start to shut this off to conserve battery power.
Are your panels also 24V rated? this will be a factor as well. IF 12V you'll need to wire them up 2-series with two parallel sets. IF 24V then you're ahead in the game.
Either way you're panels will give a max of 960W at 12Vdc that's ~63A at 24Vdc that's ~40A . Batteries 44Ah at 24Vdc will give you ~ 176Ah total which if they are Lead acid based batteries should only be used down to ~88Ah before you get into the danger of ruining the batteries.
AT 960 it will only take ~ 2 hours to begin cooking your batteries, unless you have some type of controller.
One way to save on wire is to have the inverter/UPS as near to the batteries as possible and output the 120Vac using extension cords, as AC can travel further with less line loss than DC, until you get up into the 72Vdc range.
As dnix71 posted there are items you can probably run direct instead of going through wall warts that'll also save you that little bit extra savings.
Hope some of this helps
Bruce S

[cujet]

The battery situation is fluid. I generally get used "Concorde" brand aircraft batteries. Sometimes only 1 year old. They are AGM batteries, but seem to work well enough in my 48V golf cart and the cycling they experience there.

So, I am not limited to 4 batteries. That's simply the current crop of healthy batteries on hand.

The chest freezer is a common 5 cubic foot unit, which as you know draws very little. Well less than a KWH per day (the Kill-a-Watt was showing 600w/h daily) Start up loads are around 250W. No problem for any quality inverter.

Inverter brands? Models?

[OperaHouse]

That is about what I have to run a chest fridge.  I use a dedicated HF 2000W MSW inverter that is turned on only when it is called for.  I use a couple old car batteries just for the startup current which is about 90A @ 12V.  The system sleeps at night and thermal mass carries it through the night.  A relay connected to the solar panel could switch the fridge back to grid power for a start.  I like multiple dedicated inverters, but that is just me.  You don't want the freezer to stop just because someone watches too much TV.

[cujet]

That is about what I have to run a chest fridge.  I use a dedicated HF 2000W MSW inverter that is turned on only when it is called for.  I use a couple old car batteries just for the startup current which is about 90A @ 12V.  The system sleeps at night and thermal mass carries it through the night.  A relay connected to the solar panel could switch the fridge back to grid power for a start.  I like multiple dedicated inverters, but that is just me.  You don't want the freezer to stop just because someone watches too much TV.

Well, if the electric companies power is on, everything can be used without an issue. It's only when "off grid" that I want this capability. Even then, generator power can be used to run things at times.

[cujet]

I'm having a bit of a time finding a viable inverter. I'm sure someone here knows what hardware will work.

Here are the particulars.

1) One circuit only, 115V
2) It's on a 15A breaker
3) Must be 24V or 48V as the free batteries are 24V
4) Electrical company power will be used when on grid
5) Would like the ability to "tie in" my 4 solar panels. But this is not 100% necessary. I can always "hack" them in when necessary.

[peter altas]

Hi cujet,

Have a look at Victron Multi Plus inverter/chargers.

I have 2x Victron Multi Plus 24/3000/70 (system voltage/inverter output in VA/charger output in A) setup as two seperate circuits. These work perfectly as a UPS with grid and/or generator connection and the charge cycle can be programmed to maintain your batteries for peak performance.
On grid failure, the transfer is so fast everything stays on just like a UPS should.
These would probably be far bigger than you would need. 3kVA happily runs our house which has a 450L fridge and a 700L chest freezer, plus a davey household pressure water pump and a front-load washing machine.

For solar regulation I use 3x Outback Power Flexmaxx MPPT controllers. These are great in that they can downscale PV voltages (ie. your panels wired up as 120VDC can be converted to charge 12/24/36/48/60 volt batteries). They have lots of programming fine-tuning options which are nice.

All are very simple to use and setup and will work flawlessly in your application.

[peter altas]

I'm having a bit of a time finding a viable inverter. I'm sure someone here knows what hardware will work.

Here are the particulars.

1) One circuit only, 115V
No probs, Victron make 115 Volt versions
2) It's on a 15A breaker
The 3000 model has a 16A max input/transfer circuit and can output 3000VA continuous, 6000VA surge
3) Must be 24V or 48V as the free batteries are 24V
12/24/48 models available
4) Electrical company power will be used when on grid
Wired with mains into input protected by 16A breaker, load wired to output, load will be supplied by mains power THROUGH the inverter and the inverter will also use grid power to keep the batteries fully charged with a 4 stage programmable charge cycle.
When the grid fails it instantly reverts to inverter UPS function and begins drawing from the batteries.  When grid power returns it supplies load again from grid and recharges the batteries.
5) Would like the ability to "tie in" my 4 solar panels. But this is not 100% necessary. I can always "hack" them in when necessary.
The solar panels get wired directly to the batteries via a charge controller. They don't go through the inverter. This is effectively a seperate circuit and can be added at a later time.

If you have any questions about the Victron setup or suitability to your application please message me or email peteraltas/at/gmail.com

[cujet]

Thank you very much. I was unaware of this unit. I'll learn about it.

[XeonPony]

most inverter chargers function that way, xantrax is the best imo, and they have good industry backing behind them.

[peter altas]

Agreed that Xantrex is also a quality brand.

It's often overlooked, but please look into service and warranty repair centers near you for whatever you look at buying.
Being in Australia, I couldn't get Xantrex serviced/repaired here at the time (might be different now) and Victron repair is on the other side of the country, with parts coming from The Netherlands. It may be something you overlook now but will be valuable later in its life. My choice was limited because at the time, there weren't many options of grid/generator interactive inverters that worked this way. Victron was the only one at the time that did this that I knew of. Now there seem to be quite a few built in Australia that have copied this functionality.

What I have found with Victron is that if something fails (I recently had an issue with mine outside of warranty which I think was my fault in overloading it too often) they only hold spares for about 3 years. If parts aren't available they offer a brand new unit at a greatly reduced price (about 1/4 - 1/3 of new) with a full new warranty.

You won't have problems with either brand.

[fabricator]

Nothing to add here, but I've seen that cujet handle somewhere out on the intrawebs.

[Mary B]

I put an outlet on one of these, an extension cord for grid power and a cord to the inverter for off grid. Flip inverter on and it switches in 30 seconds to off grid. http://www.ebay.com/itm/POWERMAX-PMTS-30-30-AMP-AUTOMATIC-TRANSFER-SWITCH-NEW-/220771405700?pt=LH_DefaultDomain_0&hash=item3367004f84