New To Solar Panels, Need Help

[ArcticWolf_11]

Hi all sorry if this is in the wrong section. But I am thinking of buying 16 250w solar panels and i'm wondering how to hook them up to a 500Ah 12v battery bank to generate power for my new home and my computer equipment because the power they use cost me a decent amount on electricity. Also how fast will 4kw take to charge a 500Ah battery bank? Thanks

[SunEagle]

Well first thing is that 4000watts is too much for a 12volt battery bank. Even one of the largest charge controllers rated at 80amps can only use 1000 watts for a 12volt battery.

For a 500Ah 12volt system you need about 50 to 60 amps of charging which comes to about 700 watt of solar panels but depending on where you live you might need more wattage.

Last thing I will say. Depending on where you live and what your cost is for electricity the cost to generate the same amount of kWh from a solar / battery system could be 5 to 10 times what it costs to purchase the same amount of kWh from your electric utility.

Now if you just installed a 4000 watt grid tie system without batteries, you should be able to get a pack in a number of years.

[Mike90250]

A 500ah 12V battery bank is just wrong. Sort of like hooking a dual axle travel trailer to a VW bug. It will work, but you get a surprise.
read the Stickie Posts here https://www.solarpaneltalk.com/forum...-panel-systems
about sizing and calculating the size of system you need. Just randomly starting with a bunch of panels and batteries, will not get good results.

[ArcticWolf_11]

Ah thanks! So would it be possible to get 4 250w panels and use them to run my computers which take 975-1000w according to the power meter and how many Ah would I need to run them through the night? Also thinking about making my own panels with this kit http://www.ebay.com/itm/1KW-WHOLE-3x...bs8xQDXbj5AeiA

[Sunking]

Would be the dumbest thing you ever did and could bankrupt you. It would burn your house down which might teach you a lesson.

Anything you take off grid is going to cost you 5 to 10 more than the electric company charges you for the rest of your life.

So please explain to us why you want to pay 500 to 1000% more for electricity? Please tell us, we really want to know.

[SunEagle]

Ah thanks! So would it be possible to get 4 250w panels and use them to run my computers which take 975-1000w according to the power meter and how many Ah would I need to run them through the night? Also thinking about making my own panels with this kit http://www.ebay.com/itm/1KW-WHOLE-3x...bs8xQDXbj5AeiA

Hard to tell what you need in panel wattage without really knowing what your computers use (watt hours) per day.

Does your power meter say 975 -1000 watts or watt hours? If it is watts then 4 of those 250w panels will not be enough and 500Ah of battery is also not enough.

Based on today's prices of < $1/watt for a complete manufactured solar panel you really can't save any money building your own with individual cells. Back when a panel cost ~ $4/watt if might have been worth it but not now.

[ArcticWolf_11]

Hard to tell what you need in panel wattage without really knowing what your computers use (watt hours) per day.

Does your power meter say 975 -1000 watts or watt hours? If it is watts then 4 of those 250w panels will not be enough and 500Ah of battery is also not enough.

Based on today's prices of < $1/watt for a complete manufactured solar panel you really can't save any money building your own with individual cells. Back when a panel cost ~ $4/watt if might have been worth it but not now.

The server's I use are all under full load every hour of every day, in the neighborhood of 975 ish watts with more servers being installed in the future, Buying that 1KW kit would probably cost me $50 - $100 in materials to build the frame for 4 panels.

[SunEagle]

The server's I use are all under full load every hour of every day, in the neighborhood of 975 ish watts with more servers being installed in the future, Buying that 1KW kit would probably cost me $50 - $100 in materials to build the frame for 4 panels.

Ok. If your load is 1000 watts that is running 24 hours a day you will need a battery system that is sized for 96kWh which even at 48volt is 2000Ah. The solar array needed to keep that battery charged is in the neighborhood of 10KW.

Sorry to say but that 1KW kit will not be anywhere big enough for your needs.

[ArcticWolf_11]

Ok. If your load is 1000 watts that is running 24 hours a day you will need a battery system that is sized for 96kWh which even at 48volt is 2000Ah. The solar array needed to keep that battery charged is in the neighborhood of 10KW.

Sorry to say but that 1KW kit will not be anywhere big enough for your needs.

Okay then, well that idea is probably going out the window... How much would you take it would cost anyways for that and what if it was only for the day to help power it? Thanks

[ButchDeal]

it will not save you any money to be on battery. If you did a grid tie you could save some money but a battery solution is just going to cost more.

[ArcticWolf_11]

Oh, Is there a way to skip the batteries and then just use the power from the panels to help power it while being on the grid?

[SunEagle]

Okay then, well that idea is probably going out the window... How much would you take it would cost anyways for that and what if it was only for the day to help power it? Thanks

The best way to get solar pv to reduce your electric bill is to go with a grid tie system. As Butch mentioned anytime you add in batteries you will end up spending more per kWh then if you just purchased it from your POCO.

A grid tie system usually requires a contract with your POCO to get it connected and working.

Do not try to just put up some panels and use a cheap and illegal plug in grid tie inverter. That will get you in trouble with your POCO and someone may get hurt if that illegal inverter catches fire which they have been known to happen.

For a base cost estimate for an off grid system. The price has been between $2500 to $3000 per kWh. So for a load like yours it would be probably close at least $100,000 or more depending on any environmental concerns due to the very large battery system.

[ButchDeal]

The best way to get solar pv to reduce your electric bill is to go with a grid tie system. As Butch mentioned anytime you add in batteries you will end up spending more per kWh then if you just purchased it from your POCO.

A grid tie system usually requires a contract with your POCO to get it connected and working.

Do not try to just put up some panels and use a cheap and illegal plug in grid tie inverter. That will get you in trouble with your POCO and someone may get hurt if that illegal inverter catches fire which they have been known to happen.

Don't let that discurage you. You can still do DIY on grid tie just get a permit and interconnect.

[SunEagle]

Don't let that discurage you. You can still do DIY on grid tie just get a permit and interconnect.

I agree that if possible a DIY grid tie system is the OP's lowest cost option.

[ArcticWolf_11]

Okay, thanks. The batteries will only cost me $120 each for 100AH 12v, is it worth it then? Also I live in Arizona where the sun is pretty much always shining. So say I want to run the setup for 12 hours at night, so 1000AH, $1200 for the batteries and I use a 4000w array in case of bad weather, does this sound right?

[ButchDeal]

HA so you think you can get a 1000AH 48V battery for $1200, thats funny.
I have a no name brand 48V 200Ah that cost me $1200 and I built battery cabinet, vent, and wiring all my self.
Just forget batteries. and you do not have 12 hours of sun either.

[SunEagle]

Okay, thanks. The batteries will only cost me $120 each for 100AH 12v, is it worth it then? Also I live in Arizona where the sun is pretty much always shining. So say I want to run the setup for 12 hours at night, so 1000AH, $1200 for the batteries and I use a 4000w array in case of bad weather, does this sound right?

Short answer. NO.

First off forget about building a 12volt battery system. At the watt hours your load is using you need a 48volt system.

Second, if you need a 1000Ah battery system you wire 1000Ah batteries in series not 100Ah batteries in parallel. (check out the 2v 1000Ah Trojan type).

Third, it really doesn't matter how much sun you think you get, the solar panels will not produce anything close to their nameplate wattage except for the amount of solar insolation each day. That can range from 3 to 6 hours depending on where you live.

Look. If you are so focused on building an off grid system to run your computers then go ahead it is your money. Just don't say some of us didn't warn you that your path is going to cost you a lot of money and still not get you the power output you so desire.

[Sunking]

Okay then, well that idea is probably going out the window... How much would you take it would cost anyways for that and what if it was only for the day to help power it? Thanks

Which part of this statement are you having problems with:

"Whatever you take off-grid is going to cost you 5 to 10 times more than buying the power for the rest of your life"?

The battery required to supply you 1 Kw round the clock weighs 7000 pounds, requires a reinforced floor with spill prevention, EPA permits with cradle to grave paperwork, and yearly inspections. That battery will cost you $23,000 today without shipping, handling, labor, and a ton of material cost. It will cost you even more in 4 to 6 years when the batteries need replaced. If you had just bought that power from the Power Company only cost you $2000 to $5000 in that same time period. That means you lost 19,000 to $22,000 of income wasting it on batteries and ignorance.


What part of money talking do you not understand? Your money is talking, listen to it. Money knows two words. Good Bye or Hello. Your money is saying Good Bye to you, it is not welcomed in your pockets and looking for some place to go where it is treated with respect.

So hire me, I will gladly take your money away from you and give it a good home to grow up in.