DIY solar system (need help)

[ph2003]

hi all~

im very new into this(solar system).
my current per month usage is 300-400kwh.

i have some question:
- will a 1500watt panels will support my usage?
- how many batteries i need?
- i read the low volt + higher AH battery will give more watts is that real? so a 6v 160ah battery is better than 12v 160ah?
- this Solar Cells stat 8A/4.2W output per cell, so a panels of 72 cell give 500+watts? and i only need 3 of it for a 1500watt PV?
- do i need a mppt controller at all? i live in asia, we have the sun for the whole years
- will the panel overheat if i diy with woods/molting with glue and gells, i dont wana make fire off it ?

thanks for any input!

[inetdog]

- i read the low volt + higher AH battery will give more watts is that real? so a 6v 160ah battery is better than 12v 160ah?
thanks for any input!

A 6 volt 320ah battery and a 12 volt 160ah battery will store the same amount of energy. But if you have to put together multiple batteries to get the energy storage you need, it will be better to use large lower voltage batteries in series than higher voltage batteries in parallel.

Example: If you need 320 ah at 24 volts to drive a 24 volt inverter to supply the amount of power you need, you will need 4 of the above batteries to do the job.
Better to put four of the 6 volt batteries in series than to put two strings of two 12 volt batteries each in parallel.

For the overall system, higher power, higher energy storage systems will work better with higher inverter and battery bank voltages and can use smaller wire and smaller current-output charge controllers.

[Sunking]

my current per month usage is 300-400kwh.

OK that is going to be a huge battery system. It means you use 13 Kwh per day. The battery alone is going to cost $16,000, weighs around 3800 pounds, and will need replaced every 3 to 5 years.

i have some question:
Q1 - will a 1500watt panels will support my usage?
Q2 - how many batteries i need?
Q3 - i read the low volt + higher AH battery will give more watts is that real? so a 6v 160ah battery is better than 12v 160ah?
Q4- this Solar Cells stat 8A/4.2W output per cell, so a panels of 72 cell give 500+watts? and i only need 3 of it for a 1500watt PV?
Q5 - do i need a mppt controller at all? i live in asia, we have the sun for the whole years
Q6 - will the panel overheat if i diy with woods/molting with glue and gells, i dont wana make fire off it ?

A1. No way to answer question without knowing your location. If you live in say Tuscon Az around 4000 watts. If you live in Seattle WS around 16,000 watts. You tell us....
A2. Based on 13 Kwh per day will require a 48 volt 1350 AH or 60 volt 1100 AH battery. Due to the extreme size you will be forced to use 2 or 4 volt cells like this one. You will need 12 of them for a 48 volt system, or 15 of them for a 60 volt system. No way this can be done with at 12, 24, or 36 volts.
A3. For this monster sized of a system you will be using 2 or 4 volt batteries.
A4. Like I said you are going to need 4000 to 16,000 watts of solar panels. 1500 watts is not even a down payment.
A5. You will be using 80 amp MPPT charge controllers, possible up to 4 of them depending on your location. 1 in Tuscon, 4 of them in Seattle at $800 each unit.
A6. I don't care. I just want your money. For a system this large you are looking at $40,000 or more. All depends on location.

As you can see right now, your hopes and dreams are shattered and this will not be happening.

[ph2003]

thanks inetdog and Sunking.

its very well explained, i though using solar will be less expensive in long terms.... but now it doesnt looks like it
guess ill pay my bill haha

thanks you very much!

[Sunking]

thanks inetdog and Sunking.

its very well explained, i though using solar will be less expensive in long terms.... but now it doesnt looks like it

You are welcome. Unfortunately a battery system has no payback ever. It means paying many multiples more for electricity the rest of your life. Something the government and supporters do not want you to know.

[bonaire]

In what way does the government "hide" the costs of off-grid systems? I've just never heard of this conspiracy.

Now installer companies - they *will* hide the ongoing costs of off grid by not saying that batteries may need to be replaced every few years. They will also up-sell fake electric rate increases that are "forthcoming" and "SREC sales" and all sorts of incentives that just aren't there. That's where the conspiracy really is. Regulations should be put in place to at least make the installer sales process fully describe to the potential customer the actual facts of buying into the systems.

I do have to wonder where folks get the idea that "solar is cheaper than electric grid of today". I feel it must come from the "big price increase" news that comes out of places like Southern California with it's crazy tier structure. And we know it's because of the crazy CA state government not allowing new power plant installations. Self-imposed headaches.

[Sunking]

In what way does the government "hide" the costs of off-grid systems?

Have you ever heard anything from government with respect to off-grid solar?

[ph2003]

oh well, theres so many "hidden" things we dont know.

i think i should build a small solar setup just around 50kwh?

how much PV and batteries do i need?

thanks!~

[bonaire]

If I read this right, you want a Solar off-grid system to supply 50 kWh per day?

Given you should plan to only take the top 20% of the battery charge down per day, you need batteries for 250 kWh total storage.

Open your bank account - that would be an enormous system and cost over $100,000 USD.

[Naptown]

If I read this right, you want a Solar off-grid system to supply 50 kWh per day?

Given you should plan to only take the top 20% of the battery charge down per day, you need batteries for 250 kWh total storage.

Open your bank account - that would be an enormous system and cost over $100,000 USD.

I think he meant 50 KWH in a month

[bonaire]

I went to the OP post on top and it sounds more like he may want something in between. Was asking if 1500W array will support 300-400kWh per month. So, perhaps that is 10-15kWh per day needing storage for 5x that or roughly 50-75kWh of storage in total to handle multiple days of clouds. If sunny "every day" as the OP says, then perhaps the formula changes for that. And, it also sounds like he wants to build modules by hand rather than buying factory made ones.

May be best just to go 1500W grid-tied (or up-size it using monies that would have gone to batteries). If the idea is to cut utility costs, grid-tied is the best way to go. Try to go larger if you can as the total output from 1500W per year would be only 2500-3000kWh in a sunny climate and that is only part of your total (3600 kWh or so if 300/month).

[ph2003]

thanks for the replies~

now i only think of supporting 50kwh per month.
just using for light bulbs or fan to cutdown the cost.

im still gathering info for now before i went to some factory
u know they never gave u the right info haha :P

grid tied require to mod the original on grid system ( thats something i dont wana do, because im renting ppl house haha)


thanks again!

[Sunking]

now i only think of supporting 50kwh per month.
just using for light bulbs or fan to cutdown the cost.

Sadly that will not happen. You will be paying more for electricity even if the panels are free. With a 1500 watt panel setup you will be required to operate at 24 volt battery that requires a $800 charge controller and a $3000 battery that you have to replace every 3 to 5 years.

So if you look at battery cost only in 5 years will supply roughly 3650 Kwh or $400 worth of electricity if bought from the POCO. The battery will cost you $3000 for 5 years. Which is greater than the other? $400 or $3000?

It really comes down to two gas stations siting side by side on a street corner. One station called Elephant sells gas for $3/gallon. The other called Jack A$$ sells it for $30/gallon. Which gas station do you fill up at?

[ph2003]

wow... thanks!
really? i cant believes solar system is still so expensive.

i think i better plan on how to lower my usage instead of using solar energy

[russ]

wow... thanks!
really? i cant believes solar system is still so expensive.

i think i better plan on how to lower my usage instead of using solar energy

Actually you should be looking at solar thermal water or air - either can do what you want far more cost effectively and are good DIY projects.