# 12 0r 24 volt



## jjh81 (Aug 17, 2010)

ok ran into a problem today was looking to pick up some solar stuff and was asked if I wanted 12 or 24 volts. Ive done some more research and see that it looks like the 24 volt inverter would be more expensive. I would also need 2 charge controllers on 12 volt instead of 1 but are there any benefits for one over the other and are there any savings?


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## TnAndy (Sep 15, 2005)

Less expensive on wire ( you cut the size in half by doubling voltage ), same on fusing.


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## 12vman (Feb 17, 2004)

The choice will depend on your goals. If you plan to use a lot of A.C. items, 24 volts makes more sense. If you plan to operate things directly from your battery, 12 volts is a more friendly voltage to work with.

I chose 12 volts because of the selection of items on the market. There isn't a lot of 24 volt things to provide common creature comforts unless you invert to 120 V.A.C. Many common items like stereos and small TV's operate at 12 volts or less and can be converted to operate directly from the battery without the need to invert. 12 volts can be inverted and as you see, the inverters can be cheaper. 

As TnAndy says, wiring will be cheaper @ 24 volts but it's just part of the investment of the initial system. Some savings will be seen at battery replacement time.

Each system has its pros and cons. It will depend on how you plan to use the energy.


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## mightybooboo (Feb 10, 2004)

Also you can get charge controllers that will take 12/24/36/or 48 in,and put out 12/24/36/or 48 volts,also other configs available.You pick in and out rates,tho output must be equal or less to input volts.With wire size savings that may be what you want?

IE,you could have 24 or 48 volts in,and pick 12 volts out

Cool thing is you can go 12 volt without inverter and be all 12 volt like 12voltman or you can do small system 12 volt like me with a 120 volt inverter or you can go all out,grid connected with backup like TNAndy.

Gotta love that versatility and price options,eh?


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## adamtheha (Mar 14, 2007)

I like 24 volt, most of the new DC appliances will accept 12 or 24 volt, and most charge controllers can be changed as well. You will spend more on charge controllers at 12 volts, because 60 amps at 12 volts is about 700 watts, but at 24 volts, it's 1400~. End result=more panels running off same charge controller. If you run those $600 outback charge controllers, that's a lot of savings.


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## jjh81 (Aug 17, 2010)

dang I'm so confused now I thought I had a handle on this but now I'm lost


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## TnAndy (Sep 15, 2005)

Why don't you describe what you are trying to accomplish ?


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## 12vman (Feb 17, 2004)

jjh81 said:


> dang I'm so confused now I thought I had a handle on this but now I'm lost


LOL.. Don't feel lonesome. We've all been there at one time or another with this stuff.

It works backwards from what you think. You need to set a goal for what you plan to use the energy for and design a system to fit that goal.


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## jjh81 (Aug 17, 2010)

OK all I'm controlling is some lights a computer a TV and a DVD player maybe a ham radio and charging a cellphone


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## 12vman (Feb 17, 2004)

HeHe.. Now it gets fun.. 

_some lights_.. How many? What kind? Wattages?

_a computer_.. Laptop? PC? Size/Type of Monitor?

_a TV_.. Type? Size?

_a DVD player_.. Wattage?

_maybe a ham radio_.. Wattage? Length of Usage?

_charging a cellphone_.. Not a big load but it is one..

Every load needs to be studied and considered by how much they use and how long you're going to use them in a 24 hour period. Once you come to a good estimate, add about 20% to that figure and then figure what it will take to support these loads with a system. It might sound like a lot of work and a bit scarey but that's what it takes..


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## Jay27 (Jan 11, 2010)

You can manipulate the output voltage by changing how you connect your panels - series or parallel


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## roachhill (Jul 8, 2009)

Unless you have a big screen or need long power runs it sounds like a simple 12 Volt system would serve your purpose. Anything else would unnecessarily complicate things for a small system. All of the items you mentioned can be purchased in 12volt DC versions at affordable prices. (other than the Ham radio I don't know anything about them). That's how most of my cabin is set up with 12 volt power and car accessories and you can always keep a few small inverters around to plug in for point of use 110 AC power. I do have a larger inverter wired in directly to power my water pump and for the occasional power tool but for the most part it's a 12 volt DC system.


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## mightybooboo (Feb 10, 2004)

Just my thoughts roachill,if its a small system and future plan isnt large expansion 12volt is the answer IMO.


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## jimsmith (Sep 24, 2010)

roachhill said:


> Unless you have a big screen or need long power runs it sounds like a simple 12 Volt system would serve your purpose. Anything else would unnecessarily complicate things for a small system. All of the items you mentioned can be purchased in 12volt DC versions at affordable prices. (other than the Ham radio I don't know anything about them). That's how most of my cabin is set up with 12 volt power and car accessories and you can always keep a few small inverters around to plug in for point of use 110 AC power. I do have a larger inverter wired in directly to power my water pump and for the occasional power tool but for the most part it's a 12 volt DC system.


I was wondering about your water pumping setup.What size is your inverter and is it pure sine? Also, how many horsepower is your pump? I would eventually like to build a home with at least some solar power but water pumping is one the hardest things to figure out.DC pumps from what I have read, are high maintenance and don't last very long, and some say generators aren't a good long term solution on AC.What is your opinion on all this? I figure if you ain't got water you ain't got nothing as the saying goes.


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## 12vman (Feb 17, 2004)

If you already have an existing, working well, attack it as a seperate issue from everything else. If it has a working pump, use it. Trying to figure out a way to get water to ground level with another type of pump will be more expensive than buying a generator to operate a pump that is already in place. Once the water is at ground level, it's easy to pressure it up using low voltage D.C. pumps.

For the cost of trying to support a pump with solar or whatever could be used to construct a way to store water at ground level. (In-Ground cistern, Above Ground water storage tank, ect.)

The investment of a generator has dual purpose. It can be used to get water to ground level and it can be used as a back up for your house system to charge the battery during the cloudy periods in the winter.

A submersible pump will move a lot of water in a short period at free flow and it won't use a lot of current because it doesn't need to pressure the water up. As long as the generator provides enough power to start the pump, it'll have plenty to operate it at free flow to a storage tank. This means a smaller generator would fit the bill. (~3000 watts) At 8+ gal./min. would fill a tank in a hurry so you won't use a lot of fuel if the well return can keep up with the pump.. 

JMO..


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