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

[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.

[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.

[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.

[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]

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]

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

[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.

[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.

[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

[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]

Ok, so here's a question I'm sure you guys have heard, if you'd be so kind.
Cost and personal feelings aside, rank the types of batteries from best to worst.

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.

[PhillyTitan]

All in all,
it will cost you minimum 60¢ , 76¢, or even more per kwh,
if buying BRAND NEW AGM Battery(ies) that are large enough to cycle only 20%.

You could buy a cheaper/smaller battery and cycle it 50% or 80%...
but the life span is drastically cut.
I don't have a ¢ / kwh on that, because I've never gone that route.

One way to cut your ¢ / kwh is to employ FLA (Flooded Lead Acid) Batteries.
They are about half the price of AGM Batteries.
However, FLA requires maintenance of electrolyte levels.
There is no access to AGM's electrolyte.
Being that FLAs are maintainable, it is possible for them to have a longer life than AGM...
lowering your ¢/ kwh even more.

@ Hawaii's POCO rate of 37¢ to 49¢ per kwh,
it almost makes sen¢e to build an FLA off-grid system for a 5-7 year term...
if you have the time to maintain the batteries and a generator for extended cloudy periods.

Ok, so here's a question I'm sure you guys have heard, if you'd be so kind.
Cost and personal feelings aside, rank the types of batteries from best to worst.

[Sunking]

All in all,
it will cost you minimum 60¢ , 76¢, or even more per kwh,
if buying BRAND NEW AGM Battery(ies) that are large enough to cycle only 20%.

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.

You could buy a cheaper/smaller battery and cycle it 50% or 80%...
but the life span is drastically cut.
I don't have a ¢ / kwh on that, because I've never gone that route.

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

@ Hawaii's POCO rate of 37¢ to 49¢ per kwh,
it almost makes sen¢e to build an FLA off-grid system for a 5-7 year term...
if you have the time to maintain the batteries and a generator for extended cloudy periods.

Not so sure that is true. On th eIslands 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. 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%.

[Shockah]

All in all,
it will cost you minimum 60¢ , 76¢, or even more per kwh,
if buying BRAND NEW AGM Battery(ies) that are large enough to cycle only 20%.

You could buy a cheaper/smaller battery and cycle it 50% or 80%...
but the life span is drastically cut.
I don't have a ¢ / kwh on that, because I've never gone that route.

One way to cut your ¢ / kwh is to employ FLA (Flooded Lead Acid) Batteries.
They are about half the price of AGM Batteries.
However, FLA requires maintenance of electrolyte levels.
There is no access to AGM's electrolyte.
Being that FLAs are maintainable, it is possible for them to have a longer life than AGM...
lowering your ¢/ kwh even more.

@ Hawaii's POCO rate of 37¢ to 49¢ per kwh,
it almost makes sen¢e to build an FLA off-grid system for a 5-7 year term...
if you have the time to maintain the batteries and a generator for extended cloudy periods.

[Sunking]

I'm going to take this one step at a time. Two questions:

1: So our goal is to get the batteries to last 5 years, right? In order to get them to last 5 years, we'd have to run them down by only 20% of full capacity per day. Is this assuming that you ran them down 20% all 365 days a year?

If you use a high quality battery like a Rolls 5000 series and treat them well you will get 5 to 7 years max out of them. Use a medium quality Trojan standard flooded lead acid battery 2 to 4 years. With that said regardless of the manufacture maximum battery life is obtained by shallow cycles of about 20%.

But here is the bottom line. Look at the battery warranty. It will tell you how long it will last with proper care and shallow cycles. For example a Trojan T-105 carries a 24/36 month meaning 2 years free replacement, and after 2 years prorated up to end of 3rd year. That tells you it is a 3 year battery. A Rolls 4000 Series battery caries a 24/60 which tells you it is a 5 year battery.

2: I think I understand the table. Is "cycle" just another term for a single day's discharge and recharge?

Yes that is basically what it means. Just keep in mind no battery will perform to the charts claims. They are not tested in real world application over time. They are preformed in a lab under ideal conditions in controlled enviroment on a accelerated schedule where they can get 4 or more cycles completed in a day.