Need recomendations for grid tied with batteries solar system

[tecnico]

Hello would like your recomendations / suggestions for new solar system at house that would be able to meet a max of 5 kwh daily. Besides that some data about the most power hungry equipment are the following : fridge consumes 155 watts when compresor is on , needs to be on 24/7 ; washing machine consumes aprox 500 watts is wash and aprox 1300 in spin will be used 1 day a week , will only be washing during the day to dry afterwards in the sun : ) and only 1 load of clothes , electric shower head is the most consumes aprox 2400 watts continious and would be used for aprox 15 min daily and would be used 2 times ( 2 persons ) only during the day also.
the idea to use this 2 power vampires during the day only are to try to configure a system that would power them only from solar panels and not use the batteries to make them last longer and have them available to use at night, and based on that during the night only things beside the fridge on would be some 6 watts led lights in the rooms for reading and maybe watch tv that consumes aprox 70 watts and other miscelaneous like fish tank aquarium filter uses 4 watts and maybe ocasional nebulizer that consumes 7 watts.

so as you can see the consume of watts - electricity, is practictly small .

so i would like to know if based on that would you think 4 mono cristaline panels at 315 watts each ( we have aprox 5.5 hrs of usefull sun for solar here in PR ) :1,732.5 watts per panel = 6,930 total watts , would be enough to cover the demand during the day and at the same time charge the batteries ? or maybe its to much and maybe only 2 panels = 3,465 total watts would be enough to cover day time use ?

and regarding bateries based on that small evening consume would 4 batteries at 106 ah , like the Outback Energycell 106 NC cover the necesity ?

and also what Economic and good MPPT solar controler ,charger and inverter would you recomend me for this configuration?

just as a note take in account maybe 2 to 3 cloudy days : / when giving me your suggestions / advice for this systems , as always after storms weather is cloudy and rainy : ( .


So will be waiting your coments, thanks in advanced


P.S. , the title of topic says : Need recomendations for grid tied with batteries solar system, because im using the grid as basic source of elctricity , this solar system would be in case of blackouts and when electricity is off line due to faults in the energy system that sometimes afect.

[bcroe]

Get a generator for backup, solar is a lousy backup. Batteries of the size you would need, would be quite
expensive, require constant maintenance, and regular replacement. Energy for a day (time) is in watt hours
or kilowatt hours, not watts. Bruce Roe

[tecnico]

Get a generator for backup, solar is a lousy backup. Batteries of the size you would need, would be quite
expensive, require constant maintenance, and regular replacement. Energy for a day (time) is in watt hours
or kilowatt hours, not watts. Bruce Roe

hello the fact is that in the recent storm event to get a galon of gas would involve making a line or around 50 or more cars and around 3 hours aprox , if you got it because some times after making the line and near the gas pump they told one , that gas was over , tank empty and you had to leave without gas : ( , and regarding the batteries i was considering the sealed ones that dont need maintanence or refiling them , and as fot the generator the problem is the fumes from the gasoline generator and the system is for a ederly person : /

[tecnico]

just to make clear , in the event there is no electricty from the grid and only would have the batteries and solar , the batteries would only be used to cover the use of the fridge and some lights , and miscelanous, when the cloudy days are gone would use again the shower and washing machine

[Mike90250]

.... electric shower head is the most consumes aprox 2400 watts continious and would be used for aprox 15 min daily and would be used 2 times ( 2 persons ) only during the day also......

So, this is a deal breaker. You have to have a big honking inverter and big honking batteries to power this load, even mid day. Why ? Because PV panels cannot supply surge power, and to create a 2400W AC signal, it has to come from batteries. The solar may be making part of it back up, but you HAVE to assume the batteries will supply the load.

Is there no way propane can be used for this, with a tankless water heater - even a camping model. It would save a lot of $$ from building up a huge PV system to handle this one load.

2400W @ 24V is 100A coming out of the batteries for 15 minutes, or at 48V, only 50A !! (more like 60A because of losses and such)

[bcroe]

Even if you have batteries, you will need a generator to maintain them. With a grid, ditch the batteries and just
use the generator. Don't wait till after the storm, buy the fuel beforehand. For a serious gen, run on your natural
gas or use diesel.

Dropping the washing machine, TV, and 2400W shower is going a long way toward practical. An RV fridge that
runs on 12VDC or 120VAC might just do it. good luck, Bruce Roe

[J.P.M.]

You can have anything you want. The question is cost and practicality. You are unaware of the limitations of solar, how inappropriate it is to heat water with resistance electricity and the practical aspects and limitations of using batteries to meet loads better supplied by non electrical sources of energy.

As long as you have really deep pockets and don't mind a lot of time and extra $$ on maint., as well as a lot of reality checking and spending a lot more time learning what you're getting into before you spend dime one on equipment, you'll be fine.

[jflorey2]

so as you can see the consume of watts - electricity, is practictly small .

That's not a small draw. That's actually a huge draw for a solar power system.

I'll echo the others here. Get a propane generator and keep a few canisters on hand. For the shower, get a propane instantaneous heater. For refrig, fill the refrig with water bottles and then run the gen a few hours a day to keep the fridge cold.

If you want solar, then get a grid tied solar power system that makes sense for your electrical needs while the grid is there. You can get systems that feed back to the grid most of the time, and provide backup power when the grid goes out. (Enough to run a TV, charge cellphone, run a laptop etc at least while the sun is out.)

If you want batteries, get a small battery system with an inverter/charger and maintain it either with the grid or the generator. This will allow you to decrease generator run times and save propane. Use it to power SMALL loads (like the TV.)

[citabria]

Full time off-grid system here...I concur with the previous posters, that you may want to consider a propane fueled generator for you back up needs.

[SunEagle]

Full time off-grid system here...I concur with the previous posters, that you may want to consider a propane fueled generator for you back up needs.

I agree that if you need a long term emergency power system a propane fueled generator is the way to go.

On the flip side any type of fossil fuel (propane, gasoline, diesel) may be hard to come by during or after a major event so you have to decide how much you can store on hand if the lights go out or minimize your emergency electrical loads to only the necessities.

What someone should not do is rely on a solar/battery system to provide backup power for heavy loads like water heating or air conditioning. The up front and maintenance cost of a large battery system will easily be more then a large fossil fuel storage tank and gen set.