Solar powered AC air conditioning, a bummer or a challenge?

[Sunking]

Although that is the rule, I personally know of 2 exceptions on Oahu where the off-grid batteries are 7 years and still going...
and one of those is a bank of 7x 35ah AGM batteries in parallel on a bus bar. Had me swallowing my words when I critiqued his system.

I am going to stick my neck out with an educated guess or bet. I bet those installations are at altitude?

[Shockah]

I am going to stick my neck out with an educated guess or bet. I bet those installations are at altitude?

Both are within 2 miles of shore line.

The 7x35ah AGM is on the east coast of the island. I believe his cycles are less than 20%, but it is used nightly, as he lives in an off-grid shack.
He acquired the batteries new, in 2006, from the vendor who was maintaining the emergency call boxes.
( That is a story in itself. )

The other is on the west coast of Oahu, the hotter side. It is an off-grid home that uses 2 FLA former fork-lift batteries.

[inetdog]

The article makes it clear that the used batteries in question were in cycle rather than float service and so can be presumed to have been designed for cycle rather than UPS use.
That is not the case for most battery banks for communication facilities where the primary power sources are grid and generator. Some cell facilities do use off-grid solar power, in which case they would also use deep cycle rather than UPS batteries.
The people who got those batteries cheap (less than salvage value?) were quite fortunate.

[Mike90250]

for a small off-grid air conditioner, you need to look a what are called "Mini-Split" systems, some even have a vari-speed compressor and fans which will greatly reduce your power needs. But they are not cheap.

[Shockah]

The article makes it clear that the used batteries in question were in cycle rather than float service and so can be presumed to have been designed for cycle rather than UPS use.
That is not the case for most battery banks for communication facilities where the primary power sources are grid and generator. Some cell facilities do use off-grid solar power, in which case they would also use deep cycle rather than UPS batteries.
The people who got those batteries cheap (less than salvage value?) were quite fortunate.

Yah,,, I inquired about the purchasing 276 batteries which were removed.
I got a "we'll look into it" from the DOT, but never any follow up.
Obviously some insider pulled of a good heist.

Then I later came across this guy who bought 7 "NEW" @ $20 each from the maintenance contractor...

[PhillyTitan]

for a small off-grid air conditioner, you need to look a what are called "Mini-Split" systems, some even have a vari-speed compressor and fans which will greatly reduce your power needs. But they are not cheap.

Yep. A mini split is not viable. When I looked into those last year, I seem to remember astronomical charges for installation.

[Sunking]

That is not the case for most battery banks for communication facilities where the primary power sources are grid and generator.

Not the case for any of them. Stationary Batteries for Telco are designed like a starting battery and discharged at C/4 and higher. They are used for emergency stand by only which is rare. When commercial power goes out, the generator starts and takes over within minutes. If the genny fails to start the site will crash in an hour or less from over heating even if it is -40 below zero outside. Built thousand of telephone office and cell site plants. Press those batteries into cycle service and you wil only get a couple hundred of cycles out of them

Some cell facilities do use off-grid solar power, in which case they would also use deep cycle

Yep built a few hundred of them. Most usually have 10 day reserve capacity and over sized panels plus generator. However they do not use batteries I speak of here on the forum. They are industrial grade. Not so sure if salvaged or replaced batteries would be a good idea as they will have already had 10 years of cycle service on them, or failed in service. They are only warranted for 10 years.

Here is a nasty secret folks should know. Utility batteries are large and require EPA permits to trace then from Cradle to Grave. It cost utilities a lot of money to remove them, store, and dispose of them. To make up from some of those losses, and more importantly relieve them of the EPA liability and fines, is they find a sucker to buy them. Once you sign those papers, it i snow your problem and liability. If there is a spill, fire, or accident with them, you wil be held responsible. Dump them illegally, they will trace them back to you and hold you accountable for the clean up and heavy fines plus any criminal charges locals will hit you with. .

[billvon]

Yep. A mini split is not viable. When I looked into those last year, I seem to remember astronomical charges for installation.

So do it yourself. If you can drill holes and pull coolant lines/wiring you can install one. Once you have it connected call an A/C guy and for $99 he will purge the lines and charge it.

[PhillyTitan]

So do it yourself. If you can drill holes and pull coolant lines/wiring you can install one. Once you have it connected call an A/C guy and for $99 he will purge the lines and charge it.

Eh, I'm sure I could do it, but for a permanently installed, expensive unit (which I'm desperately trying to avoid), stuff should be left to professionals. I believe caution should be exercised when installing permenent air conditioning units without a permit and a HVAC certified installer.

I will revisit this if a cheaper solution can't be found, but that would mean admitting failure first.

[billvon]

Eh, I'm sure I could do it, but for a permanently installed, expensive unit (which I'm desperately trying to avoid), stuff should be left to professionals.

Well, so should solar. But it sounded like you wanted to try this on your own. Good rule of thumb - it is ALWAYS, ALWAYS cheaper to cut loads first (most efficient A/C, more insulation, LED lights etc) than keep the inefficient loads and add more solar/batteries. So if you are really aiming to reduce power usage, spending your effort on installing the mini-split will pay better dividends than installing battery backed solar.

I will revisit this if a cheaper solution can't be found, but that would mean admitting failure first.

Admitting failure? Sounds like it would be a win to me.

[K7ABE]

Hey Sunking, I really mean types of batteries not brands. I really have no knowledge at all about the subject, only that AGM is supposedly very good and low on maintenance.




Abe I've said this before, but I don't mind saying one more time. It's the individual components that I'd like to keep down in cost. For instance, a 24VDC 12,000 BTU air conditioner would be at least $1700.00 (<-- the only one I found with a price tag on it). Or a solar array professionally installed for $10k. A few batteries for a couple hundred each is not an extreme cost. The first question on this thread was is it viable to have a sustainable working system that won't break the bank when one of the individual components fail.

I found the batteries to be the most expensive part of my system. For a small remote cabin or RV application with no washer and dryer no AC 1000 or 2000 amps at 12V is minimal. With the lowest cost batteries this is still two to five thousand dollars, every three to five years. Grid tie systems including everything except mounts and installation Are between $1 and $2 per watt. Off grid systems that include batteries are considerably more even though the inverters cost less.

Many hundreds of professionally installed solar panels Near Palm Springs and desert palms were recently picked up and thrown around in the wind. They were sold for the scrap aluminum frames. I choose to make my own mounts and mount my own. Mounts I use in mild Oregon weather are much different than the mounts I use in hurricane alley East Texas. Solar trackers are a consideration in Oregon but have proven to be unsuccessful in Texas.
Abe

[K7ABE]

Read a small amount on the site and you will see that conservation is pushed very much.

Thank You Russ. I have bogged myself down in introductions for two days. I'll try to look around some more.

[K7ABE]

Not the case for any of them. Stationary Batteries for Telco are designed like a starting battery and discharged at C/4 and higher. They are used for emergency stand by only which is rare. When commercial power goes out, the generator starts and takes over within minutes. If the genny fails to start the site will crash in an hour or less from over heating even if it is -40 below zero outside. Built thousand of telephone office and cell site plants. Press those batteries into cycle service and you wil only get a couple hundred of cycles out of them



Yep built a few hundred of them. Most usually have 10 day reserve capacity and over sized panels plus generator. However they do not use batteries I speak of here on the forum. They are industrial grade. Not so sure if salvaged or replaced batteries would be a good idea as they will have already had 10 years of cycle service on them, or failed in service. They are only warranted for 10 years.

Here is a nasty secret folks should know. Utility batteries are large and require EPA permits to trace then from Cradle to Grave. It cost utilities a lot of money to remove them, store, and dispose of them. To make up from some of those losses, and more importantly relieve them of the EPA liability and fines, is they find a sucker to buy them. Once you sign those papers, it i snow your problem and liability. If there is a spill, fire, or accident with them, you wil be held responsible. Dump them illegally, they will trace them back to you and hold you accountable for the clean up and heavy fines plus any criminal charges locals will hit you with. .

My experience is different. Many of the date codes on cell tower pulls were less than 2 years old. And EPA has certainly changed the playing field for recycle batteries. What is the cradle the manufacturing factory the wholesale distributor? And is the grave when the company signs off that they are dead and turns them over for recycling. I am aware of date codes on batteries but I have never seen a serial number on one (including the 230A 12V 8 D batteries). Do large industrial batteries have serial numbers or is the cradle to grave thing just a bureaucratic process that ends when the last T is crossed in last I is dotted. Is this a commercial realm where the authority stems from the Universe Commercial Code and ends with the private sector. My home in Oregon is in an incorporated area, my home and Texas is in an unincorporated area. Here in Oregon there is a viable used market for submarine batteries and forklift batteries. Maybe government surplus auctions are violating EPA rules.
Abe

[PhillyTitan]

I will reiterate

Geez. I feel like I'm repeating things so I'll repeat my goals expectations from the beginning and I'll even give $ figures this time.

Budget
Inexpensive but capable solar array <$1000
Inexpensive but capable inverter and charge controller<$300
Inexpensive battery bank <$1000 (I can bend more on this for the right thing)
660 watt 120VAC air conditioner

My expectations to prove this model sustainable:
-This system would work just the air conditioner in a well-insulated 25x11' off-grid home addition.
(The 12v electrical outlets and lights would all be working off a separate, smaller, 12volt system.)
-The air conditioner should run estimated 5-7 hours per day for 150-200 days a year.
-The larger array and battery bank will not be in use the other 6 months of the year.
-Batteries should last for at least a couple years.


I have constantly been told by naysayers in my city and state and people who've expressed no interest in investigating the matter that it's pointless and can't be done without an extreme startup cost and pricey components.

My ONLY goal is to prove first that off-grid Air conditioning is sustainable in the Deep South with only inexpensive components, DIY knowledge, good insulation, and conscientiousness. If it can be done, I can change the thinking around here one person at a time, and perhaps apply the principles into a future home later in life.

If it can't be done, then I can probably still build the home addition with more conventional methods.
I don't have anything against the power company. I am aware the cost of power will be higher than a regular home addition with the new electrical added. I have no interest at this time for grid-tie or conventional methods. I would gladly investigate them only if I admitted defeat first.

I believe this can be done. But I'm not certain. This is the only reason I've joined the forum.

[K7ABE]

Then i would say, just quit now. Any neophyte trying a MAJOR project, is going to make mistakes. YOU open the fridge 3x a day. But the cat gets in there 7x a day and there goes your power budget, along the the primo brand batteries. If you leave the porch light on one night because you were sick and forgot.... Mistakes happen, and you need to design your system to be resilient enough to not die from the first one.

I killed car batteries and Trojan L-series first.