Here's what I have, please help me fill in the blanks

[leosantamana]

Okay, here's my second post. To recap the goal:
I want to tinker. I will be having some 12 volt landscape lights (maybe 100 watts worth) which will come on at dark automatically. I do not expect this system to save me money, as I know what I already have into it, I could power my lights for a thousand years....

I live in Georgia, and have good full sun for about 1/2 the day to place my panels.

I picked up 3 Goal Zero Boulder 90's last week. They are rated at 90 watts each, 18-22 volts. I have the splitters that will bring them into a single positive and negative output (So, if i were in blazing sun, I would get 270 watts output, I know, probably more like 200 watts).
I ordered the following, and expect to have them tomorrow:
SolarEpic 40A MPPT Solar Charge Controller 100V input Tracer A Series 4210A With Display
The SolarEpic MT-50 Remote Meter LCD Display to go with it.

This leaves me with buying a battery setup for it. As mentioned about, the total load will be less than 100 watts @12 volts, running about 8 hours per night.

A couple of questions for the solar experts:
1. Would a 100ah battery be about right, too small, too big?
2. Would you go with more, if so, how would you wire together?
3. Can I simply run my 12 volt landscape wire directly off the battery (perhaps with an inline fuse in case wire gets broken/chewed in the circuit)
4. What else should I consider for this setup?

Any thoughts (please be gentle) would be appreciated!

Thanks in advance

[Suprasoup]

100Watts x 8hrs =800Wh

800Wh x 1.5 fudge factor= 1200Wh

Solar Array Sizing

1200Wh/sun hrs. (Georgia gets 3.7 in December. )

1200Wh/3.7 = 324W Array

Battery Sizing

Daily Wh x 5 =

800Wh x 5 = 4000Wh

4000Wh/12V = 333Ah Battery

1. 100Ah battery would be way too small.

2. 2 x 6v L16 sized batteries would do nicely. Wire the batteries in series.


Have fun tinkering

[jflorey2]

A couple of questions for the solar experts:
1. Would a 100ah battery be about right, too small, too big?
2. Would you go with more, if so, how would you wire together?
3. Can I simply run my 12 volt landscape wire directly off the battery (perhaps with an inline fuse in case wire gets broken/chewed in the circuit)
4. What else should I consider for this setup?

Well, first question - what is your goal? To play, with money being no object? In that case, you'd want between about 100 and 210 amp hours to match the solar. Two T105's would _probably_ work. However, you should really be designing for a minimum of 3 days runtime. So 128 amp hours a night gives you about 400 amp-hours - which means you have to add more solar. With 400 amp hours at 12V you should really move up to 24V, which would be 4 T105's in series. That would require between 500 and 800 watts of solar.

You can use 12V wire. Be sure to fuse the wire appropriately. You will probably be using the load terminal on your charge controller, and that will limit the available current more than 12 gauge wire will. Fuse for the lower of the two ratings.

[leosantamana]

Is the MPPT Charge controller I bought a decent unit? Is 40amp controller enough?

[leosantamana]

100Watts x 8hrs =800Wh

800Wh x 1.5 fudge factor= 1200Wh

Solar Array Sizing

1200Wh/sun hrs. (Georgia gets 3.7 in December. )

1200Wh/3.7 = 324W Array

Battery Sizing

Daily Wh x 5 =

800Wh x 5 = 4000Wh

4000Wh/12V = 333Ah Battery

1. 100Ah battery would be way too small.

2. 2 x 6v L16 sized batteries would do nicely. Wire the batteries in series.


Have fun tinkering

Suprasoup - pardon the ignorance... still learning here.
I am trying to follow the math...
Why a 1.5 "Fudge factor"?
If my solar array is 90(watts)x3=270 watts per hour, right (@100% perfect, so let's cut that to 200 watts per hour) x 4(hours)=800.
Why "Daily Wh x 5"? Is the "5" the number of days? If so, are you assuming I need 5 days of storage? If so, why 5 and not 3? This assumption increases reserve need by almost 50%.
Which 6v L16 batteries would you suggest? They will be in average outdoor temps in Georgia, so never too cold.

[Mike90250]

....
Which 6v L16 batteries would you suggest? They will be in average outdoor temps in Georgia, so never too cold.

And i've seen broken water pipes with "ice" flowing out the door of a garage, in Georgia.

[jflorey2]

Is the MPPT Charge controller I bought a decent unit? Is 40amp controller enough?

At 12V it's marginal. At 24V it would work fine.

[leosantamana]

At 12V it's marginal. At 24V it would work fine.

When I was deciding on the type of controller, I decided on MPPT, since, from what I read, they are far superior. When I was looking at specs, I saw that (on other web sites) were 4 solar panels (x100 watts each) suggested a 30amp controller, so I figured this had plenty of room to grow. I didn't see many with a lot higher amperage ratings.

Better suggestions?

[jflorey2]

Better suggestions?

The Tristar TS-MPPT-60 is an excellent controller, as are the Outback 60 amp controllers and the Midnite Solar Classics. They are pricey; you get what you pay for. You can get them used for $300 or so.

[Sunking]

When I was deciding on the type of controller, I decided on MPPT, since, from what I read, they are far superior. When I was looking at specs, I saw that (on other web sites) were 4 solar panels (x100 watts each) suggested a 30amp controller, so I figured this had plenty of room to grow. I didn't see many with a lot higher amperage ratings.

They go up to 100 amps. At 30 ampos you are limited to:

360 watts @ 12 volt battery
720 watts @ 24 volt battery
1440 watts @ 48 volt battery.

This is going to get real expensive real fast. You do fully understand anything you take off-grid is going to cost you 5 to 10 times more vs just buying it from the POCO? So ask yourself why you want a huge rate increase because that is exactly what you are asking for.

[leosantamana]

They go up to 100 amps. At 30 ampos you are limited to:

360 watts @ 12 volt battery
720 watts @ 24 volt battery
1440 watts @ 48 volt battery.

This is going to get real expensive real fast. You do fully understand anything you take off-grid is going to cost you 5 to 10 times more vs just buying it from the POCO? So ask yourself why you want a huge rate increase because that is exactly what you are asking for.

Agreed. I think everyone on here (or most) are doing it to save money. They mostly probably like to tinker/design stuff or be prepared for if/when POCO isn't available (either storms or worse).
So, I am going into this with my eyes wide open. I could go on a vaca for $2,000 and have a 5 day experience, or I could "tinker" with same $ and have a lifelong experience.

[leosantamana]

Thoughts on this battery to finish this setup: Renogy Deep Cycle Pure Gel Battery 12V 200Ah

https://www.amazon.com/Renogy-RNG-BA...8W/ref=sr_1_10

[Sunking]

Gel batteries are not suitable for solar. They are for alarm and egress lighting lighting applications.

[leosantamana]

Ooops, sorry, I copied wrong one. Here's what I am considering:

Start with one of them, add a second if/when I see 100ah is not adequate. 12V 100AH BATTERY FOR SOLAR WIND DEEP CYCLE VRLA 12V 24V 48V - Mighty Max

https://www.amazon.com/dp/B00S2MDZFK/ref=dp_cerb_2

Thoughts?

[Suprasoup]

For your first set of batteries stick with Flooded Lead acid. They cost less and are more forgiving of user error. AGM batteries cost more than Flooded and dont last as long.