>>902833
Well, context is everything with these systems.
Where would you like to use it?

400W should cover as you've said, piddly crap.
TV should work, laptops. Smaller things in general.

>>902835
I guess my reall question is what would I reasonably power off an ac plug car battery, simply to reduce load on my power bill every month.

I am just fiddling around with solar power without go full blown roof panels.

Realistically, I'd probably just use it as a power cube footstool in the living room, for putting my feet on and charging the laptop/cellphone.

Would this be an overkill setup? Or would downgrading to lawn tractor batteries make it more cost effective per functionality.

And, befor I check google, how do you calculate charging/discharging times for batteries?

>>902836
>investing in non-grid tied solar
>merely to reduce the power bill

You really need to calculate your Return On Investment first

40/40 keks

>>902836
>simply to reduce load on my power bill every month
Don't bother.

>>902833
Just doing some basic car battery math.

Supposing the car battery has 24mah, it would take 24 hours to discharge at 1 amp, and with the inverter topping out at 3 amps, it would take 8 hours to drain the battery.

Now, assuming the solar panel you get is optimally 25 watts at 1amp, it would take 24 hours to recharge said battery. But you won't get optimal power, and due to resistance and other shit, let's just double that to be safe to 48 hours.

Now, if you live at the equator, you'll get maybe 12 hours good light per day, meaning it'll take 4 days (96 hours) to charge a battery that'll discharge in 6.

Anybody want to call out my estimate math?

>>902850
I'll back that up

I have a similar set up in a remote cabin in Canada. It has two higher end solar panels charging 2 deep cycle batteries. It powers a small inverter to charge phones and laptops, a large inverter to power a water pump, and 12 volt led strips.

In the middle of the summer there is daylight over half the day so about 12 hours of useful sun. That is enough power to; charge a few phones, run the leds when it's dark and you're not asleep (maybe 2 hours a day), and pump water for 10 minutes. As soon as you have more then one day in a row of no sun the batteries can't keep up, there is less then 12 volts so the inverters don't work. Also when it's not summer there isn't enough daylight to run the system at all.

The whole setup cost about $500 Canadian and I bought the panels used. Every other year we have to replace a battery because, they're cheap batteries (maybe lack of maintenance, shit happens). After all that, I basically can't run any appliances for more then a few minutes a day, in ideal sun conditions. It sure beats having no power at all, but it expensive for "free" energy.

>>902877
Got some more hard info? How much power are the panels each, how much capacity have the two batteries, etc.
I need a similar set up for my own cabin in the woods.


All I know is you want a MPPT (Maximum Power Point Tracker) if you want any usable life out of your batteries.

>>902886
http://www.canadiantire.ca/en/pdp/nautilus-group-24-starting-deep-cycle-battery-0102499p.html
that's the batteries

http://www.princessauto.com/en/detail/18w-solar-panel-with-7a-charge-controller/A-p8416646e
I started with this panel and charge controller with a single battery. The charge controller was faulty and over charged the battery which then exploded (for real, acid everywhere). I replaced the charge controller with a better one and eventually added a second battery

I used to use a small 12 volt pump for pumping water into the cabin but burned out one pump and decided to go with a 120 volt ac pump.

http://www.princessauto.com/en/detail/1-2-hp-shallow-well-jet-pump/A-p5770077e
There's the water pump but I had to add an inverter to power it.

http://www.canadiantire.ca/en/pdp/motomaster-eliminator-3000w-power-outlet-inverter-1999930p.html
That's the large inverter. We only turn it on when we need to pump water. The small inverter is just a 75 watt one that plugs into a cigarette lighter socket and is always on.

After adding the new inverter and pump it wasn't long until I started looking for a new panel. I found two used ones for sale on kijiji. I don't have the stats on them or even the brand but I recall them having a built in charge controller and costing over $1000 each new. I payed $200 for both of them as the power a solar panel produces does get less and less the older the panels get. The night I got them home I hooked up my multi-meter and they were producing 11.5 volts just from my kitchen light.

The next thing I would add to the system is more batteries. I know on a really sunny days the two batteries are charged just after noon and any sun after that is wasted.

>>903168
luckily for me not deleting any emails ever, I found out that the solar panels are 2.3 amps each. I also bought them 5 years ago next week.

>>903168
That was the exact battery I was considering for my setup.

But I did further research and found that even on sale, the canadian tire panels are overpriced.

Now I just have to decide how much I want to drop on this system without being able to reasonably calculate the savings.

I consume 500kwh in summwe, 1000 in winer (extreme points on the range.) And to simplify math, thats 90-150$ a month.

I could drop 1000$ on a solar array that OPTIMALLY produces 2.25kw per day.


If kw=kwh/hours,

kw=750(average usage)/30.5(average length of month)* 24 hours

kw=750/732= 1.024 kw

If I understand my estimate math, my house if consuming 1kw of power per hour.

So, assuming that the solar panels are operating at 50% capacity, I am removing 1kwh of power per day from my bill, or 30.5 kwh on average.

Doing a comparison where

90$/500kwh = x$/30kwh

500kwhx= 2700kwh$
/500kwh
=5.4$ savings per month.

if the system cost 1000$/5$, it would take 200 months to pay for itself, or 200/12= 16 years.

I sure hope I did that math wrong.

>>903181
no the estimate seems right. even worse, the times when you use the most power are the times the system produces the least. To off set that, you need to add even more panels. This is the big problem with solar, unless you have no grid hookup and the cost to do so is outrageous (think remote cabin), the cost of the solar system will never pay off because as soon as you're close, you will need to start replacing components.

>>902833
>What could I expect to run off pic related?
>run off
>off

whatever you want depending on what the supply is