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

[K7ABE]

blah, blah, blah,,,

in your first post you said to crunch my 216wh daily usage numbers with a $10 battery and I'll get power at 1¢ per kwh... but there is no $10 battery that will sustain the usage,,,? the OP is looking for facts,,, not unicorns.

I offered options withincluding real numbers to someone wanting to come into solar small on a tight budget. There are many options including thin film at 34 cents of watt, new panels UL listed.
Abe

[Sunking]

Compare the life cycle charge between Interstate golf cart batteries, Trojan batteries, And rolls-royce batteries. The ratings look close at first but the golf cart batteries are rated at 20% discharge, The Trojans are rated at 50 percent discharge, And the rolls-royce at 80% discharge. If you treat a better batteries like the cheap batteries they will last 15 or 20 years. If you treat the cheap batteries like the better batteries they only last 1 or 2 years. The manufacturers numbers are deceptive at first look.
Abe

Not in your wildest dream Raymond. All the mentioned battery manufacture cycle life chart follow the same cycle life curve. There is a direct relationship between DOD and cycle life. The real answer is the battery warranty. Trojan RE line is 24/60 exact same as Rolls 4000 Series. That means a 5 year battery period. Abuse them by more than 20% in hot conditions you will get much less.

Trojan Cycle Life Chart

[Sunking]

I offered options withincluding real numbers to someone wanting to come into solar small on a tight budget. There are many options including thin film at 34 cents of watt, new panels UL listed.
Abe

And those thin films will be in the garbage in 5 years or less. You are in the wrong place to BS. To many pros here on this form and we can spot amateurs in a heartbeat. Unfortunately amateurs know quite a bit more than you.

[Mike90250]

Passive House (heating and cooling) is a fairly common idea now. start your research here

http://www.passivehouse.us/bulletinBoard/viewtopic.php?f=5&t=21

As for battery ranking. I'd suggest your first set be a "sacrifical learning set". Costco or Wally world deep cycle batteries. 6V|200ah if you can get them. Design your bank on paper, get the batteries, and see if your paper guesses (recharging, loads) match up with your real life usage. Then use the data you gather to design the 2nd bank, and use the best batteries you can get locally, why pay huge shipping fees. And maybe in 2 years (500 cycles) there will be a new battery on the market.

[K7ABE]

I can only assume you mean FLA for cycle applications like RE. Batteries are made to do different things. So for a FLA RE applications.

1. Rolls 5000 Series, followed by the 4500 and 4000 series. The 5000 series will get you 5 to 7 years service if kept cool, shallow cycled, and TLC. 4500 series a 4 to 5 year, and 4000 around 3 to 4 years
2. Trojan Industrial Line is a solid 4 to 5 year battery at moderate price levels.
3. Trojan RE series a good 3 to 4 year battery
4. Trojan standard deep cycle 2 to 3 year battery
Anything from Wally World or a box store a 1 to 2 year battery

There are some other very good manufactures out there like Deka, C&D, Enersys but those are high end utility models for special purposes.

Sure et (sp) batteries are good, the numbers sound like there are out of a book with minimal number of batteries to meet system requirements. If not abused both Rolls and Trojan lives or longer. And I would consider the rolls 5000 series to be 10 to 20 year batteries depending on how well they are taken care of and making sure you have enough of them to rarely drop below 75 percent charge. For that kind of investment that would pay to check Consumer Reports and customer feedback get some real numbers from real people.
Abe

[PhillyTitan]

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.

I offered options withincluding real numbers to someone wanting to come into solar small on a tight budget. There are many options including thin film at 34 cents of watt, new panels UL listed.
Abe

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.

[K7ABE]

Passive House (heating and cooling) is a fairly common idea now. start your research here

http://www.passivehouse.us/bulletinBoard/viewtopic.php?f=5&t=21

As for battery ranking. I'd suggest your first set be a "sacrifical learning set". Costco or Wally world deep cycle batteries. 6V|200ah if you can get them. Design your bank on paper, get the batteries, and see if your paper guesses (recharging, loads) match up with your real life usage. Then use the data you gather to design the 2nd bank, and use the best batteries you can get locally, why pay huge shipping fees. And maybe in 2 years (500 cycles) there will be a new battery on the market.

I like Mike's advice. The price of lithium iron has dropped nearly half in last couple years and new technology is coming along all the time.
Abe

[PhillyTitan]

Passive House (heating and cooling) is a fairly common idea now. start your research here

http://www.passivehouse.us/bulletinBoard/viewtopic.php?f=5&t=21

As for battery ranking. I'd suggest your first set be a "sacrifical learning set". Costco or Wally world deep cycle batteries. 6V|200ah if you can get them. Design your bank on paper, get the batteries, and see if your paper guesses (recharging, loads) match up with your real life usage. Then use the data you gather to design the 2nd bank, and use the best batteries you can get locally, why pay huge shipping fees. And maybe in 2 years (500 cycles) there will be a new battery on the market.

I will look into the passive house thing, but my hopes for that aren't high considering the weather where I live.
And that's a nugatory on the battery thing. That is the one component that I don't want to experiment with. Thus I'd like some more input on the battery.

[Sunking]

If not abused both Rolls and Trojan lives or longer. And I would consider the rolls 5000 series to be 10 to 20 year batteries depending on how well they are taken care

Not even remotely possible. You might get 10 years out of a 5000 series is shallow cycled to no more than 20% each day. If discharging to 80% just a few years as Rolls Charts indicate. Batteries will not outlive the warranty. A Rolls 5000 is 36/120, but you better have detailed monthly records past 3 years to get any pro-rating rebate.

[Shockah]

The price you are quoting is for FLA. AGM cost twice as much as FLA and last half as long. So in effect AGM is 400% higher than your quote.

No, my 76¢ /kwh is based on an AGM battery, 12V 105ah @ $300.
That was also based on 5 years... (wishful thinking).

If you ran the numbers you would find cheap batteries cost are higher. A cheap Wally World Box Store battery will cost you roughly $100/Kwh of storage and you are looking at 1 to 2 years. A good 5 to 7 year battery cost $220/Kwh. When you run the numbers a cheap battery cost $100 / 146 Kwh = $.68 Kwh, vs $220 / 511 = $.43 Kwh

Truth.

Not so sure that is true. On the Islands you cannot buy batteries as cheap as you can on the mainland. For example a Rolls 6CS25PS cost $1220 in the lower 48 drop shipped. Is suspect it is considerable higher in Hawaii like everything else cost there.

Yes, but with the competitive battery market, there are distributors willing to work with me on pricing and shipping costs, which make it close to purchasing in the upper-48. I just haven't had the need for a bulk purchase to take advantage of those offers.

With Hawaii heat and humidity you might be able to squeeze 5 years out of it if you are lucky. Heat kills batteries. At 90 degrees F will cut cycle life 50%.

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.

[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.

Yes and a good high efficiency 24V refrigerator is about $2500. I use a lower cost, less efficient refrigerator and extra solar panel to cover that. Early I was advised to build the biggest system possible within my means, all with one charge controller & 1 and inverter. I found using smaller systems with interchangeable components works better for me, if a charge controller goes out I have one on the shelf. This also allows many other flexibilities within the systems. The batteries are the only part of my system that are individualized for specific task. The most important information to share about solar may be energy conservation, I don't remember seeing that here yet.
Abe

[Mike90250]

...And that's a nugatory on the battery thing. That is the one component that I don't want to experiment with. Thus I'd like some more input on the battery.

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.

[russ]

The most important information to share about solar may be energy conservation, I don't remember seeing that here yet.
Abe

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

[PhillyTitan]

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.

The experiments have already begun. I've already purchased solar lights for the shed and front porch. Flood lights will be replaced by a $50 system.... I have already decided to run the small appliances and interior lights and whatnot on a smaller, separate 12V solar system. And I'll do some experimenting with it, but I've already learned enough to know that the longevity for it is indeed possible.

The energy hog is what I'm hoping to find a solution for. If one can't be found then I may not even start building.

[Sunking]

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.

That is a much deeper subject, but I will try to KISS it. (Keep It Simple Stupid)

Lead acid batteries fall into two groups of Flooded Lead Acid (FLA) and Valve Regulated Lead Acid (VRLA) In those two groups of FLA and VRLA are three sub categories of Starting Lighting & Ignition (SLI) Hybrid which are marketing names for Golf Cart, Floor Machine, RV, Marine, and Leisure.. Last in line are Deep Cycle batteries which is what you want.

SLI batteries are designed to crank engines and be recharged very quickly. They are made with very thin spongy plates to increase surface area which lowers internal resistance. That low resistance is what is needed to provide very high current required for starting engines, and then be recharged very quickly. If pressed into cycle service will fail only after a few cycles. Those thin plates will sulfate and dissolve quickly when deeply discharged and charge slowly. Bottom line do not use SLI batteries for cycle service. You can spot a SLI battery real fast if you see a spec called CCA or cold cranking amps. They will not have a Amp Hour Rating, only CCA.

Hybrid batteries are a cross between SLI and Deep Cycle batteries trying to be the best of both worlds but fall short in either applications. They have thicker plates than SLI batteries so they can be cycled and last longer than SLI, but not as thick and heavy of a plate as true Deep Cycle. They do have a place in RE applications. They can provide higher discharge and charge rates than deep cycle batteries because they have more but thinner plates than deep cycle. Thinner plates mean more surface area and lower resistance. So they can be used in places where you have to use high charge/discharge rates in excess of C/8 up to about 1C in some types like AGM. The trade off is cycle life is sacrificed. Another use for hybrid batteries is their various marketing names like Golf Cart, Floor Machine, RV, Marine Deep Cycle. A dead give away is they wil have a Spec called RC = Reserve Capacity meaning how many minute the battery can deliver 25 amps. MCA or Marine Cranking Amps, along with Amp Hours. They are available in both FLA and AGM models

Deep Cycle batteries are the long lasting types and they are not created equal. True Deep Cycle batteries have fewer but much heavier thicker plates thant can be cycled many times. The thicker plates reduce resistance and limits charge and discharge current to about C/8 where C = the battery 20 hour amp hour rating. So if you have a 100 AH battery they can only supply around 12 to 13 amps without significant voltage drop. But those thick heavy plates last a long time. Th eonly spec you will see published on a True Deep Cycle battery is AMP Hours usuall the 20 hour discharge rate. High end batteries will publish Amp Hours at 100 down to 1 hour discharge rates. A Deep Cycle Battery will never have a CCA, MCA or RC spec. Only Amp Hours.

Need some more discussion on FLA and VRLA. FLA is just what you think, a flooded battery that you have to add water too. They are the least expensive and last the longest period. In the VRLA family are Absorbed Glass Mat (AGM), and Gel Electrolyte. No need to discuss Gel batteries as they are not good candidates for RE applications. Gels are used for emergency standby applications and that is it so no more discussion. AGM are excellent batteries sort of. By design they have very low internal resistance and the plates can be made of pure lead which contributes to low resistance and small spaces. They can be charged/discharged at very high rates which has usefulness in RE applications. IMO they are niche application batteries. For example planes and mobile applications where spillage cannot be tolerated. Extreme cold of arctic and ant-arctic of 50 below zero, remote locations, or where very high charge and discharge rates are required. Th ereason they are niche application is cost. For a given capacity they cost twice as much as FLA and only last half as long. So in the end they cost 400% more than FLA and you had better have justification to spend that extra.