Solar Power and Transformers Versus Batteries

[deaun99]

Hello,

I am not an electrician and I know very little about electricity, but I had an electrician tell me that I should avoid the conventional off the grid thinking as it pertains to batteries.

He explained that solar can be linked (?) to a transformer that will house (?) the energy and work more effectively then how the battery setup with inverters normally work.

Does anyone have any experience working with transformers and solar combined? Before I began putting my energy into researching transformers etc. I would like to know if anyone has any knowledge regarding this type of setup?

[kscherzi]

The main idea with physical home solar is to use the sun to offset some of your electricity consumption. Most electricity suppliers bill bases upon tiers. The initial tiers of power are cheap and additional tiers of power become progressively more expensive. Home solar is intended to keep you from needing to purchase the more expensive tiers.

An off the grid solution for a house is pretty extreme and very expensive. This is almost never done.

An RV solar setup however is off the grid. Living off the electrical power of two 12 volt batteries is an exercise in minimalism.

[lewster]

Originally Posted by deaun99

Hello,

I am not an electrician and I know very little about electricity, but I had an electrician tell me that I should avoid the conventional off the grid thinking as it pertains to batteries.

He explained that solar can be linked (?) to a transformer that will house (?) the energy and work more effectively then how the battery setup with inverters normally work.

Does anyone have any experience working with transformers and solar combined? Before I began putting my energy into researching transformers etc. I would like to know if anyone has any knowledge regarding this type of setup?

In any off-grid solar application, you need a way to store the energy that is collected from a solar array. Transformers do not perform a storage function.....batteries do! While a transformer based system might satisfy your power needs while the sun is out, what happens when there is no sun........ as in cloudy days or at night? Further, without the buffer that a battery bank provides, any interruption in the collection of the sun's rays (think partly cloudy day) would create havoc with the energy conversion process. I would suggest that your 'electrician' get a bit more of a thorough solar education before making recommendations pertaining to solar charging and energy storage systems.

Newer energy storage technologies like lithium iron phosphate batteries and high efficiency power inverters can and will provide sufficient energy to operate just about anything you desire. It then becomes a matter of how much energy you need and how deep your pockets are...........

[idroba]

Your electrician is out to lunch on RV solar. There is no way to store solar power for use later in an RV other than batteries of some kind. Certainly no power is stored in a transformer.

At the current state of the art you can use ordinary low cost flooded cell lead acid batteries, or higher cost sealed AGM batteries.

If you have very deep pockets and want to be on the cutting edge of RV solar and battery technology the lithium iron phosphate battery is now developing.

But you will need batteries of some kind.

[deaun99]

Originally Posted by lewster

In any off-grid solar application, you need a way to store the energy that is collected from a solar array. Transformers do not perform a storage function.....batteries do! While a transformer based system might satisfy your power needs while the sun is out, what happens when there is no sun........ as in cloudy days or at night? Further, without the buffer that a battery bank provides, any interruption in the collection of the sun's rays (think partly cloudy day) would create havoc with the energy conversion process. I would suggest that your 'electrician' get a bit more of a thorough solar education before making recommendations pertaining to solar charging and energy storage systems.

Newer energy storage technologies like lithium iron phosphate batteries and high efficiency power inverters can and will provide sufficient energy to operate just about anything you desire. It then becomes a matter of how much energy you need and how deep your pockets are...........

Thanks for sharing this info. So the transformer with or without batteries does not add or make a more efficient power/off the grid system? Just curious as I am really trying to learn how this process works and what would provide the most power, at the cheapest cost in the most efficient manner. Also, not having to replace parts and do heavy maintenance on the system ($$$) is very important. Your wisdom and experience is greatly appreciated.

[deaun99]

Thank you for taking the time to share. I wasn't quite sure if what he was saying was practical or not and that is why I asked.

[deaun99]

Originally Posted by idroba

Your electrician is out to lunch on RV solar. There is no way to store solar power for use later in an RV other than batteries of some kind. Certainly no power is stored in a transformer.

At the current state of the art you can use ordinary low cost flooded cell lead acid batteries, or higher cost sealed AGM batteries.

If you have very deep pockets and want to be on the cutting edge of RV solar and battery technology the lithium iron phosphate battery is now developing.

But you will need batteries of some kind.

It then seems that the only draw back of a transformer is the inability to store power. If that is the case then wouldn't it be of benefit to use the transformer to produce power all the while using the batteries to store it? I am sure I am probably missing something here.

[Al and Missy]

A transformer does not generate power; it only converts one voltage of AC to another. Some converters have a transformer that converts the 120 volt shore power to 12 volts as a part of the process of providing 12 volts for lights, refrigerator, furnace, and other 12 volt appliances. The only things that generate power for the trailer are a generator, solar, and shore power.

I'm not aware of any application of a transformer (only) in an airstream, unless it is to use a trailer that is set up for 220 volt European power on 120 volt US power.

Al

[Gnorts]

Originally Posted by deaun99

It then seems that the only draw back of a transformer is the inability to store power. If that is the case then wouldn't it be of benefit to use the transformer to produce power all the while using the batteries to store it? I am sure I am probably missing something here.

You have been done a disservice by your "electrician." Don't ask him any more questions. You will not get usable answers. And remove the term "transformer" from your worthwhile efforts to understand RV electrical systems, charging systems, etc. Just forget you ever heard the word. It just doesn't apply in any direct way to anything you're trying to accomplish.

Can anyone recommend a good electrical reference book for new RV owners? One that cuts through the fog of misinformation and explains things in terms that are easy to understand for someone with no experience in this area? I could recommend several books, but I fear they would be too complicated.

[jbxx]

Transformer= AC
Solar=DC

[Gnorts]

OK, here's a great reference. Perhaps not for the casual reader, but it covers pretty much everything. It's a bit dated now, but the basics don't change.

Living on Twelve Volts With Ample Power: David Smead, Ruth Ishihara: 9780945415022: Amazon.com: Books

[markdoane]

Here is another:The 12volt Side of Life (Part 1)

[Kota]

Might have been some miscommunication. Home solar systems generally provide power directly to the house and or grid through an inverter system which incorporates transformers. There is no energy storage. Energy from the grid is used when your solar panels are not producing enough power for your demands.

Storage is available by batteries to those wishing to live off the grid. Very expensive!

In a RV the whole idea is to be able to function unplugged. Power from the solar charges your storage batteries with direct current with an efficient charging circuit. You either use the battery power directly for lighting and equipment that runs on 12 volts DC like your water pump, vent fans... You can run an inverter off the battery (s) to power 120 volt AC devices like electronics. TVs, stereos, phone chargers... AC units like ovens, cook tops... are generally beyond the capacity of an inverter and your battery storage.

I'd give the electrician the benefit of the doubt. Or he might be a complete idiot that shouldn't even be allowed to change the batteries in a flashlight.