Solar Power Push

[Mike J]

21 hours ago, jimeve said:

Have you looked at "LIfePO4" batteries, they last 4 x more than Lithium batteries.

 

Thanks for pointing that out Jim.  Yes I have and that is the battery type we will buy unless something better, price and performance, comes along.   Expensive but last far longer and less danger of overheating and fire than lithium ion.   Was not able to find a chart to show price history on LifePO4 but I would suspect they will not be getting any cheaper unless the price of lithium would drop.

Edited January 3, 2023 by Mike J

[Mike J]

17 hours ago, hk blues said:

And yet again I'm left scratching my head at the Math!

At a monthly bill of 3k I'd bet the majority of that comes at night when the 2 x A/Cs kick in and the TVs and lights go on etc - we don't use/need them during the day so at the very best we'd save 1k a month (the daytime usage) so assuming a capital outlay of 100K we'd take 8+ years to make our money back - pretty much as I calculated 5 years back.  I've taken a broadbrush approach but it won't be a million miles out.

My conclusion is that unless my daytime usage was much higher we'd not recover our outlay in anything like 3 years. Of course, I could then decide to use the A/Cs all day but it's not something we need and I'd also lose out on the FIT.  

Unless I'm missing something.

 

The ROI is longer if the majority of your power use takes place at night.   That being said, the numbers posted by @fillipino_wannabe  are realistic if you have an optimum location for the panels.   The numbers have changed a lot in the past five years.   

[Patryk]

On 1/2/2023 at 6:15 AM, Mike J said:

We had planned on putting in a 5 to 7 KW off grid system in 2023 but the expenses from the typhoon last year will delay that for at least a  year.  I have crunched the numbers and for us the payback looks like it would be between 4 and 5 years.   Currently planning on having battery backup for brownouts and night use.  The price of electricity here is high and the cost of labor to install a system is relatively low.  This, combined with the reduction in cost of solar panels, means the ROI (return on investment) is much shorter here than in many other countries.  I did a quick google and it suggest the ROI on solar panels in the USA for example is 10 years as opposed to the 4 to 5 ROI here.  

4/5 years for ROI, but did you consider a change of batteries? Let's say you will discharge them every night, and their lifespan is charged in cycles, do you think they will even survive 5 years? Maybe something worth considering is a wind turbine for a night? 

Due to the high cost of batteries, people think of any way around it. Some build DIY power packs from 18650 batteries  ( some even from used batteries which makes it really cheap and even shorter lifespan/ totally unexpected). It is pretty much the same as car batteries or tesla powerwall. The issue here may be to get quality batteries to start with.  

I also heard about the guy who bought a massive amount of used truck batteries ( like 10x of what he wanted to use), but I didn't followed it how it goes.

[Mike J]

26 minutes ago, Patryk said:

4/5 years for ROI, but did you consider a change of batteries? Let's say you will discharge them every night, and their lifespan is charged in cycles, do you think they will even survive 5 years? Maybe something worth considering is a wind turbine for a night? 

Good point and yes I did consider that.  Current battery tech for lithium iron phosphate batteries allow 5000 cycles discharge of 80% capacity, and up to 10K 80% cycles under "optimum" conditions.   That puts the low end of the estimate at 13+ years if discharged to 80% on a nightly basis, and 20 years would not seem unreasonable.   So they are expensive but last a good long time.  At my age they that first set could very well last "a lifetime".    I would not invest a huge amount for batteries as we typically only use fans at night, so our demand is quite low.

Edited January 4, 2023 by Mike J

[Guy F.]

4 hours ago, Patryk said:

I also heard about the guy who bought a massive amount of used truck batteries ( like 10x of what he wanted to use), but I didn't followed it how it goes.

I know a guy who made his own electric car with a bunch of 12v batteries connected in series. The result was a truly impressive fire which left a deep hole in the street. The fire crew said it got to be 1,200 degrees Fahrenheit in the hole.