Need Some Assistance Trying to Design a Very Small Solar Panel Setup

[ga-hvac-tech]

yeah, really clueless about the battery decision ... was thinking standard lead acid golf cart batteries then watching videos about the actual amperage produced is not very appealing ... then you have the maintenance on them, guess you are suppose to check the electrolytes in the solution once a month or so and then occasionally equalize them ( charge them with no load at a high rate to drive chemicals off of the plates and back into the solution, or something like that ), so still have no idea what to do about batteries ..... I am really liking these 1860 battery packs though, just no sure I would want a bunch of them in the basement, but supposedly it can be done safely .....

Do you mean 18650 battery packs???

Little known fact: the lowly 18650 battery... that we see in LiIon LED flashlights...
Most elec cars have literally thousands of them... in 'packs'...

There is a newer version, called a 26650... size is about half again larger volume, with almost 2x the 'power density'...
LiIon is a good battery... as long as you do not 'flash drain' or 'flash charge' them... and do not take them down below 20-25%... if it were me... below 35%.

Back on the golf cart batteries...
This is why folks have a BIG bank of batteries...
So you will drain them slowly, rather than quickly... and of course lots of reserve.

That thing: draining them slowly, and charging them slowly...
Is IMO the key to keeping batteries in good shape.

[hvacskills]

do your self a favor. Get a transfer switch 6 circuit for what you want to power. Hook this up. This can run off generator or inverter. ( problem with the gen you bought its 120v only. A 240 gen will serve you best)

https://www.electricgeneratorsdirect...SD/p95053.html

But there is only one 120v transfer switch I am aware of. Only gives 4 circuits.

https://www.electricgeneratorsdirect...14A/p1109.html

You can then run 4 circuits off your gen..

Now the solar on the cheap.. This is how I run my RV off the grid.

You need charge controller.. And you want MPPT not a PWN.

This is a good cheap unit. I have it

https://www.amazon.com/EPEVER-Contro...gateway&sr=8-3

You want to get 4 golf cart batterys. Hook two in series and the pair in parallel making 24 volts. This lets you use smaller wiring.

go to sams club or batterys and bulbs and get the 6 volt duracells 225 amp hours.

https://www.batteriesplus.com/productdetails/sligc115

Then you need 24 volt inverter.

Krieger 24V 2000 Watt Power Inverter

https://www.dcacpowerinverters.com/product/mr2000/

https://www.kriegermfg.com/product/mr2000/

Then two residential panels hooked in series.

At least 280 watts each. like this..

https://www.ebay.com/itm/LG-Solar-Panel-295-Watt-60-Cell-Mono-crystalline-New/283379510095?hash=item41fabc2b4f:g:Q2cAAOSwrhNcZH5 u:rk:3f:0

thats a start

thank you for the time and effort you put into your response, I checked out the links and will check them out again and give your suggestions thought ....

how long have you had your set up and how long before you had a somewhat thorough understanding of how all of this works ? it does not seem complicated once you get an understanding

[hvacskills]

Do you mean 18650 battery packs???

Little known fact: the lowly 18650 battery... that we see in LiIon LED flashlights...
Most elec cars have literally thousands of them... in 'packs'...

There is a newer version, called a 26650... size is about half again larger volume, with almost 2x the 'power density'...
LiIon is a good battery... as long as you do not 'flash drain' or 'flash charge' them... and do not take them down below 20-25%... if it were me... below 35%.

Back on the golf cart batteries...
This is why folks have a BIG bank of batteries...
So you will drain them slowly, rather than quickly... and of course lots of reserve.

That thing: draining them slowly, and charging them slowly...
Is IMO the key to keeping batteries in good shape.

that is what I am starting to pick up on, large quantity and slow discharge rates, think they have controls that can monitor discharge rates

not sure why they go 18650, was watching something somewhere and supposedly the next step in batteries is nano technology where each small individual area of the battery is charged, or something like that, so maybe 18650s work better in packs, no idea

I am still having a hard time understanding the Ah, discharge rates, charging rate, ect... , once I do that then I will be able to size what is needed, sometimes certain things take longer to sink in and this is one of them, just watching and learning from videos ...

thanks for your input it has been helpful ...

[Lawrosa]

thank you for the time and effort you put into your response, I checked out the links and will check them out again and give your suggestions some thought ....

how long have you had your set up and how long before you had a somewhat thorough understanding of how all of this works? it does not seem complicated once you get an understanding

I have been camping with solar for some time..

I camp without hookups. I plug the camper into the inverter. The inverter runs off my dual batterys. And the solar charges the batterys..

You can essentially do the same for the home..

Im 12v inverter 1100 watt as thats all I need to run coffee pot and microwave when needed when camping. Run the tv's and charge stuff. all through the outlets.

This my old controller. Sorry about the mumbling..This will give you an idea..

https://www.youtube.com/watch?v=fD5cpclHjqA&t=14s

[ga-hvac-tech]

AS I understand it... the answer to your question about little 18650 batteries in large quantities... is in one word:

HEAT

LiIon batteries produce heat when they discharge and charge...
If they make too much heat... internal damage happens to the chemical structure of the components of the battery... think of it kinda like pitting that happens when something rusts and the rust is washed away.
When enough pitting happens... the battery is capable of 'run-away heat'... which leads to battery fires.

Lots and lots and lots of little lowly 18650 batteries... have lots of space to dissipate heat...

AS I understand it... the struggle to develop the 26650 battery, was to maintain the ability to dissipate heat under loads and charging rates of elec cars.

Another little known fact: Take an 18650 battery... and cut it open...
You will find a little disc like circuit board in one or the other end...
That board does one thing... regulates the rate of draw down and charge... so the battery does not overheat.

I still like the golf cart batteries... just get lots of them... and arrange for ventilation.

The post a few up... with the 295W panels... and running a 24V battery system (4x 6V batteries in series; with multiple sets of these groups in parallel)... would make for the most effective arrangement IMO.

Most of those 295-300W panels that produce ~30-35V... are 3 ft x 5 ft.
IMO 4x those panels... or ~ +/-1200W out of the panels... into, say,
8x 6V golf cart batteries: divided into 2 groups of 4 in series... then these 2 groups in parallel...
Would give you LOTS of reserve power without a heavy discharge rate.
Now later, you could add more group(s) of 4x 6V batteries to the parallel group... just connect them.
And if you wanted... add another panel or so.
Might want to plan ahead... and get a large enough charge controller... or a controller that can be 'piggy-backed' with additional controllers...

Another little known fact about 'wet lead acid' batteries (automotive batteries)...
Give them a S L O W charge... and they will build up depth of available power!
Flash charge them... and they will develop chemical issues deep inside.

[hvacskills]

I have been camping with solar for some time..

I camp without hookups. I plug the camper into the inverter. The inverter runs off my dual batterys. And the solar charges the batterys..

You can essentially do the same for the home..

Im 12v inverter 1100 watt as thats all I need to run coffee pot and microwave when needed when camping. Run the tv's and charge stuff. all through the outlets.

This my old controller. Sorry about the mumbling..This will give you an idea..

https://www.youtube.com/watch?v=fD5cpclHjqA&t=14s

sounds like a cool little set up you have, bet it is pretty cool to go camping and be off the grid yet still have some electricity, sounds as if that was a good investment ... you run the Duracell batteries ?

[hvacskills]

AS I understand it... the answer to your question about little 18650 batteries in large quantities... is in one word:

HEAT

LiIon batteries produce heat when they discharge and charge...
If they make too much heat... internal damage happens to the chemical structure of the components of the battery... think of it kinda like pitting that happens when something rusts and the rust is washed away.
When enough pitting happens... the battery is capable of 'run-away heat'... which leads to battery fires.

Lots and lots and lots of little lowly 18650 batteries... have lots of space to dissipate heat...

AS I understand it... the struggle to develop the 26650 battery, was to maintain the ability to dissipate heat under loads and charging rates of elec cars.

Another little known fact: Take an 18650 battery... and cut it open...
You will find a little disc like circuit board in one or the other end...
That board does one thing... regulates the rate of draw down and charge... so the battery does not overheat.

I still like the golf cart batteries... just get lots of them... and arrange for ventilation.

The post a few up... with the 295W panels... and running a 24V battery system (4x 6V batteries in series; with multiple sets of these groups in parallel)... would make for the most effective arrangement IMO.

Most of those 295-300W panels that produce ~30-35V... are 3 ft x 5 ft.
IMO 4x those panels... or ~ +/-1200W out of the panels... into, say,
8x 6V golf cart batteries: divided into 2 groups of 4 in series... then these 2 groups in parallel...
Would give you LOTS of reserve power without a heavy discharge rate.
Now later, you could add more group(s) of 4x 6V batteries to the parallel group... just connect them.
And if you wanted... add another panel or so.
Might want to plan ahead... and get a large enough charge controller... or a controller that can be 'piggy-backed' with additional controllers...

Another little known fact about 'wet lead acid' batteries (automotive batteries)...
Give them a S L O W charge... and they will build up depth of available power!
Flash charge them... and they will develop chemical issues deep inside.

how do you know so much about all of this, batteries ( lithium, wet lead acid ), discharge rate, ect ?

[hvacskills]

Do you mean 18650 battery packs???

There is a newer version, called a 26650... size is about half again larger volume, with almost 2x the 'power density'...
LiIon is a good battery... as long as you do not 'flash drain' or 'flash charge' them... and do not take them down below 20-25%... if it were me... below 35%.

I am searched but I did not see 26650 batteries sold in bulk, but I see the 18650 sold in bulk ( 100 )

https://www.ebay.com/itm/Lot-Bulk-Pa...Z04A:rk:1:pf:0

you did not seem to be against the 18650 battery packs, been watching youtube videos and it appear to be somewhat common, except some people are using the battery packs for large ' flash drain ' items, but that would concern me having lithiums in the house, but what if I did not use them for large ' flash drain ' items, just basic items like lighting, computer, modem, router ....


here is a thought, taking a little bit of advise from everyone .....

what if I split the system up in two ?

system one - TV, modem, router, printer, lighting, or other small wattage items that are not ' flash drain '

2 - 300 watt solar panels

40 amp control charger ( 600 / 24 = 25 amps )

1 - Kreiger 1100 watt inverter

https://www.dcacpowerinverters.com/product/mr1100/

several 18650 battery packs that I make myself, with a BMS ( battery management system, that will shut off the battery pack for low / high voltage, excessive current draw, and even monitor the different banks for differing voltage ), I could build these easy, time consuming but easy


system two - refrigerator, washing machine, coffee maker, dishwasher ... obviously I could not use them all at once

2 - 300 watt panels

40 amp control charger ( 600 / 24 = 25 amps )

2 - 200 Ah Renogy deep cycle batteries, they are sealed, no maintenance .... I do like the idea of saving money on the acid batteries, but if I could spend a few hundred more and not worry about maintenance or ventilating them I would prefer that, if it was a camper I would go with the gulf cart or Duracell probably

https://www.amazon.com/Renogy-100Ah-...s%2C210&sr=8-3

1 - Krieger 2000 watt inverter

https://www.dcacpowerinverters.com/product/mr2000/

only problem is these inverters are not full sign wave inverters so I am not sure


I could also supplement each system with a 24 volt battery charger for periods of time when there is low solar output from the solar panels, I would just have to figure out a way to wire / control them

https://www.ebay.com/itm/110-120v-AC...S!-1:rk:2:pf:0


of course I would still have my small back up generator if the grid went down


it was your idea of having a controller that could be piggy backed, and the other dudes idea of just 2 - 265 watt panels made me look at everything differently ...... also having redundancy would be good, plus I think I could get a lot of years out of the lithium battery packs running them this way and probably several good years out of the deep cycle batteries, and that is a big concern

I think something like this would accomplish what I am looking to accomplish, I ran the numbers ( finally caught on ) and it appears those batteries will run the refrigerator and washing machine ( there will be a serious drain on them, but still not less than 50 % ), and that is HUGE, can do without a dryer if need be but not a washing machine

obviously still need to give further thought and refine everything

[ga-hvac-tech]

I am searched but I did not see 26650 batteries sold in bulk, but I see the 18650 sold in bulk ( 100 )

https://www.ebay.com/itm/Lot-Bulk-Pa...Z04A:rk:1:pf:0

you did not seem to be against the 18650 battery packs, been watching youtube videos and it appear to be somewhat common, except some people are using the battery packs for large ' flash drain ' items, but that would concern me having lithiums in the house, but what if I did not use them for large ' flash drain ' items, just basic items like lighting, computer, modem, router ....


here is a thought, taking a little bit of advise from everyone .....

what if I split the system up in two ?

system one - TV, modem, router, printer, lighting, or other small wattage items that are not ' flash drain '

2 - 300 watt solar panels

40 amp control charger ( 600 / 24 = 25 amps )

1 - Kreiger 1100 watt inverter

https://www.dcacpowerinverters.com/product/mr1100/

several 18650 battery packs that I make myself, with a BMS ( battery management system, that will shut off the battery pack for low / high voltage, excessive current draw, and even monitor the different banks for differing voltage ), I could build these easy, time consuming but easy


system two - refrigerator, washing machine, coffee maker, dishwasher ... obviously I could not use them all at once

2 - 300 watt panels

40 amp control charger ( 600 / 24 = 25 amps )

2 - 200 Ah Renogy deep cycle batteries, they are sealed, no maintenance .... I do like the idea of saving money on the acid batteries, but if I could spend a few hundred more and not worry about maintenance or ventilating them I would prefer that, if it was a camper I would go with the gulf cart or Duracell probably

https://www.amazon.com/Renogy-100Ah-...s%2C210&sr=8-3

1 - Krieger 2000 watt inverter

https://www.dcacpowerinverters.com/product/mr2000/

only problem is these inverters are not full sign wave inverters so I am not sure


I could also supplement each system with a 24 volt battery charger for periods of time when there is low solar output from the solar panels, I would just have to figure out a way to wire / control them

https://www.ebay.com/itm/110-120v-AC...S!-1:rk:2:pf:0


of course I would still have my small back up generator if the grid went down


it was your idea of having a controller that could be piggy backed, and the other dudes idea of just 2 - 265 watt panels made me look at everything differently ...... also having redundancy would be good, plus I think I could get a lot of years out of the lithium battery packs running them this way and probably several good years out of the deep cycle batteries, and that is a big concern

I think something like this would accomplish what I am looking to accomplish, I ran the numbers ( finally caught on ) and it appears those batteries will run the refrigerator and washing machine ( there will be a serious drain on them, but still not less than 50 % ), and that is HUGE, can do without a dryer if need be but not a washing machine

obviously still need to give further thought and refine everything

That is an interesting idea...
2x systems...

The one with the pack of 18650's would be slow drain... so minimal damage to the LiIon batteries...
And the one that was higher drain... would be on cheaper batteries, which you could gang up as necessary to have adequate reserve. Now if you 'manage' the load on the second system; only run one thing at a time... which would be easy other than the fridge... you may need to figure out something there...
You may be onto something!

Suggestion... measure the roof and determine how many panels you can put up there...
I have this gut feeling... you are gonna expand the system later... grin!

And just a thought: If you can get it permitted and approved... and get 30% of the cost back in tax credits... I would definitely look at that... free $$$ is free $$$...

And selling juice back to the power co during the day when you are out running calls...
Well that cannot be a bad thing... grin!

[hvacskills]

That is an interesting idea...
2x systems...

The one with the pack of 18650's would be slow drain... so minimal damage to the LiIon batteries...
And the one that was higher drain... would be on cheaper batteries, which you could gang up as necessary to have adequate reserve. Now if you 'manage' the load on the second system; only run one thing at a time... which would be easy other than the fridge... you may need to figure out something there...
You may be onto something!

Suggestion... measure the roof and determine how many panels you can put up there...
I have this gut feeling... you are gonna expand the system later... grin!

And just a thought: If you can get it permitted and approved... and get 30% of the cost back in tax credits... I would definitely look at that... free $$$ is free $$$...

And selling juice back to the power co during the day when you are out running calls...
Well that cannot be a bad thing... grin!

yep, glad you approve ..... just took everyones suggestions and combined them together ....

still figuring it all out but I think I have pretty much decided to go with the two systems ... for the 18650 battery packs thinking of building them in multiple packs ( 7 batteries in series 3.5 v x 7 = 24.5 v ), then those 7 batteries paralleled 8 times ( 3,400 Mah x 7 = 23.8 amps ), that would allow me to easily swap out a bad pack in the future, and since each pack is 24 volts I would just be down the amperage until the pack was replaced, not down 1 or 3 other batteries ...... building the packs will be time consuming, and not dirt cheap, figure I can build and add the to them system as I complete them, was thinking of using smaller pre-made packs, lithium iron phosphate are supposed to be really safe, used in hybrid buses or something


https://www.amazon.com/Discharge-Lit...r=8-4-fkmrnull


problem is these pre-made packs may not be available 5 years from now in the same voltage / amperage, but 18650 s will be, so I will easily be able to repair or replace a pack .... but still need to research all of this and see if it can be done ... thinking as an extra safety measure, in addition to the BMS, to install an inline fuse to prevent something from being operated on the battery pack system that should not be ......

I need to go on the roof in the early morning, this time of year, and see where the Sun will be falling on the solar panels because the flat roof I want to install the panels on sits a few feet lower than the peak, so I will need to figure out the height off the roof to ensure the panels can be fully illuminated when the Sun is low in the horizon, I will measure everything while I am up there

thinking of ordering some of the equipment soon

thanks, you have really been a good help

[DavidDeBord]

hvacskills,

I Personally Believe for many reasons that You will get Your Best Professional,as well as Intelligent, Data,about this Solar Setup,from Poodle, BBeerme, & BNM.

Wrap Yer arms around what they tell You, & Cherish it like the Gospel.

[BNME8EZ]

I went into my panel box that I set up to run the solar off of last night. I put my 902 ampmeter on it. I had 1 amp on the soffit lights (24 LED can lights) with the dimmer as low as it would go and just under 2 amps with the dimmers turned up. It makes me wonder if the lighting load I have is worth the cost of the solar.

[hvacskills]

I went into my panel box that I set up to run the solar off of last night. I put my 902 ampmeter on it. I had 1 amp on the soffit lights (24 LED can lights) with the dimmer as low as it would go and just under 2 amps with the dimmers turned up. It makes me wonder if the lighting load I have is worth the cost of the solar.

well, you can always go with plan B ...

probably not much of a payback, but maybe if you add your outdoor lighting and your flag pole, if the concern was also for back up lighting might be worth some checking into, plus the 30 % tax credit ... I can run a few numbers and give you an idea what size you are looking at, became somewhat knowledgeable the last few days, do you know how much the outdoor lighting is, and an estimated wattage on your flag pole lighting ?

[ga-hvac-tech]

I am not sure if this applies to the thread...

However...

One of the things I am doing at my place...
Is changing all the outdoor 'motion lights' from the old fashioned ones that used light bulbs...
To sealed LED varieties.
The ones I got use 15-20 watts each, and produce the same light as the old ones that had 75W old fashioned bulbs.

Along the way... I am wiring all the outdoor motion lights to a central point...
Reasons...
*I can turn them ALL on at once if I want to initiate a significant point to folks not invited to my place...
*They can be run from a back-up power supply.

At 20 watts each... if I had, lets say... 10 of of them around the house... that would be 200 watts current draw (in reality, most of them are 15 watt, however thought I would use the worst case scenario). At 120V, 200 Watts is 1.67 amps... Wonder how long a pair of auto batteries would last through a 24V power supply providing 1.67 amps...

The other thing on this set up... is the 16 camera security system, which literally includes facial recognition...
All the 16 cameras are 'POE' operation... along with the 'NVR' (a DVR arrangement designed specifically for security stuff... it literally has 8 TB of storage).

This arrangement uses another 250 watts total... so the worst case scenario would be 3.75 amps/hr... again... wonder how long 2x auto batteries would last???
And I can use the generator during the day to build them back up!

SOOO (scenario)...
Power goes out... I hear something in my yard...
HUGE amount of light comes on... and the video is copying everything that happens!

Yeah... an old f*art with his toys...

Grin!

[hvacskills]

I am not sure if this applies to the thread...

However...

One of the things I am doing at my place...
Is changing all the outdoor 'motion lights' from the old fashioned ones that used light bulbs...
To sealed LED varieties.
The ones I got use 15-20 watts each, and produce the same light as the old ones that had 75W old fashioned bulbs.

Along the way... I am wiring all the outdoor motion lights to a central point...
Reasons...
*I can turn them ALL on at once if I want to initiate a significant point to folks not invited to my place...
*They can be run from a back-up power supply.

At 20 watts each... if I had, lets say... 10 of of them around the house... that would be 200 watts current draw (in reality, most of them are 15 watt, however thought I would use the worst case scenario). At 120V, 200 Watts is 1.67 amps... Wonder how long a pair of auto batteries would last through a 24V power supply providing 1.67 amps...

The other thing on this set up... is the 16 camera security system, which literally includes facial recognition...
All the 16 cameras are 'POE' operation... along with the 'NVR' (a DVR arrangement designed specifically for security stuff... it literally has 8 TB of storage).

This arrangement uses another 250 watts total... so the worst case scenario would be 3.75 amps/hr... again... wonder how long 2x auto batteries would last???
And I can use the generator during the day to build them back up!

SOOO (scenario)...
Power goes out... I hear something in my yard...
HUGE amount of light comes on... and the video is copying everything that happens!

Yeah... an old f*art with his toys...

Grin!

I will re read your post and try to plug in a few numbers ... my stumbling block figuring everything out was how to calculate the watts being used and battery storage .....

my understanding is it works pretty much like this

look at a battery as a total amount of stored energy in watts

a 12 volt 100 amp battery stores a total of 1,200 watts, this stored wattage will be lower when discharging the battery at a high rate, and will also be lower in colder temperatures, but assuming you are discharging at a steady rate, which you would be with a normal amount of lighting and your battery was inside the battery can store 1,200 watts ........ however, you can only deplete a battery so much, some batteries have a 75 % depletion ( lithium ), some 50 % depletion ( still researching all of this and batteries ) ..... so say you have a battery that has a stored amount of 1,200 watts, with a recommended 50 % depletion, that 12 volt 100 amp battery can deliver 600 watts ( 1,200 x 50 % ) from start to finish before it needs to be recharged

so with in your situation, with just your 24 indoor can lights, drawing 2 amps ( 2 x 120 = 240 watts ), this 12 volt 100 amp battery would last you 2.5 hours ( 600 stored watts / 240 watts = 2.5 hours )


that is my understanding .... once you get your mind around that it starts to make more sense

if this is wrong anyone feel free to jump in and correct me

[ga-hvac-tech]

I will re read your post and try to plug in a few numbers ... my stumbling block figuring everything out was how to calculate the watts being used and battery storage .....

my understanding is it works pretty much like this

look at a battery as a total amount of stored energy in watts

a 12 volt 100 amp battery stores a total of 1,200 watts, this stored wattage will be lower when discharging the battery at a high rate, and will also be lower in colder temperatures, but assuming you are discharging at a steady rate, which you would be with a normal amount of lighting and your battery was inside the battery can store 1,200 watts ........ however, you can only deplete a battery so much, some batteries have a 75 % depletion ( lithium ), some 50 % depletion ( still researching all of this and batteries ) ..... so say you have a battery that has a stored amount of 1,200 watts, with a recommended 50 % depletion, that 12 volt 100 amp battery can deliver 600 watts ( 1,200 x 50 % ) from start to finish before it needs to be recharged

so with in your situation, with just your 24 indoor can lights, drawing 2 amps ( 240 watts / hour ), this 12 volt 100 amp battery would last you 2.5 hours ( 600 stored watts / 240 watts = 2.5 hours )

that is my understanding .... once you get your mind around that it starts to make more sense

if this is wrong anyone feel free to jump in and correct me

Hmmm...

The part underlined and in bold... I am not sure about that either...
Does the battery have that much power available???

If you find more information on this... can you post it???

THX

GA

[BNME8EZ]

Well that's kinda what I was thinking. Now I carried it out a little further so someone correct me if I did the math in my head wrong but if I leave the outside lights for 10 hours a night average @ $.105 / kWh it will only cost me a quarter a day, or $7.50/month. Seems like I would have to add a lot more to the solar to make it worth while. Now there actually are more lights that are wired into the panel for solar but we only use lights in the room we are in so not a lot of demand there. I do want to do a flag light so that will add and I have a gazebo that I want to build and put strings of light on which will add, then there is the out building with lights and ceiling fans that if I put the fans on it would add quite a bit of load but it seems like they are only 2 amps each max. I see my biggest gain in the hot water. Being able to keep the out building above 40 in the winter will be great as well as what gets added to the house plus domestic hot water.

[hvacskills]

Hmmm...

The part underlined and in bold... I am not sure about that either...
Does the battery have that much power available???

If you find more information on this... can you post it???

THX

GA

I believe batteries are rated in amps per hour ..... so a 12 volt 100 amp battery ( 1,200 watts ) can deliver 1,200 watts for one hour ... as far as where I picked that up ? one of the 50 or so youtube videos I watched, but I will see if I can provide you a link ... I did start tagging the more informative ones ....

watch this one ......

https://www.youtube.com/watch?v=cxkV...ndex=15&t=221s

[hvacskills]

clarification for post 75


my understanding is it works pretty much like this

look at a battery as a total amount of stored energy in watts per hour

a 12 volt 100 amp battery stores a total of 1,200 watts per hour, this stored wattage will be lower when discharging the battery at a high rate, and will also be lower in colder temperatures, but assuming you are discharging at a steady rate, which you would be with a normal amount of lighting and your battery was inside the battery can store 1,200 watts per hour ........ however, you can only deplete a battery so much, some batteries have a 75 % depletion ( lithium ), some 50 % depletion ( still researching all of this and batteries ) ..... so say you have a battery that has a stored amount of 1,200 watts per hour, with a recommended 50 % depletion, that 12 volt 100 amp battery can deliver 600 watts ( 1,200 x 50 % ) per hour from start to finish before it needs to be recharged

so with in your situation, with just your 24 indoor can lights, drawing 2 amps ( 2 x 120 = 240 watts ), this 12 volt 100 amp battery would last you 2.5 hours ( 600 stored watts per hour / 240 watts = 2.5 hours )


it is the per hour part that gives the understanding

[DavidDeBord]

Well that's kinda what I was thinking. Now I carried it out a little further so someone correct me if I did the math in my head wrong but if I leave the outside lights for 10 hours a night average @ $.105 / kWh it will only cost me a quarter a day, or $7.50/month. Seems like I would have to add a lot more to the solar to make it worth while. Now there actually are more lights that are wired into the panel for solar but we only use lights in the room we are in so not a lot of demand there. I do want to do a flag light so that will add and I have a gazebo that I want to build and put strings of light on which will add, then there is the out building with lights and ceiling fans that if I put the fans on it would add quite a bit of load but it seems like they are only 2 amps each max. I see my biggest gain in the hot water. Being able to keep the out building above 40 in the winter will be great as well as what gets added to the house plus domestic hot water.