“10 golf cart batteries”
How long do those batteries last I wonder before they go flat and you have to buy new ones to replace? IOW a recurring cost, and disposal of the old ones? Not tryin’ to be snarky, just wondering about some of the outlying details.
“That all being said, properly maintained battery packs in fleet carts tend to last about 4-6 years while private owners tend to get about 6-10 years out of their battery packs.”
http://www.islegolfcars.com/blog/item/how-long-do-batteries-last
That site is talking about batteries being used in actual carts, not with solar panels, but I imagine the maximum lifetime won’t exceed 10 years either way.
Here is reality aka physics:
From the EIA, the average US house consumes 30 KwHrs per day. That’s average, including the central air con days of summer. The lowest state for consumption is Hawaii, at 16.6 KwHrs/day and most was Louisiana at 42 KwHrs/day. This is mostly air con but for hawaii, close to the equator, lighting.
So if you have an avg house you need 30 KwHrs in a day.
The Tesla house battery (Powerwall) silliness is 10 KwHrs. That’s 8 hrs of power. Got a snowstorm that has power out for a week? This thing is worthless.
10 Golf Cart batteries? A Trojan T105 golf cart battery has 205 amp hours. A watt is an amp X a volt, and these are 6 volt batteries. So that’s 1.2 KwHrs and you want 10 of them so that’s 12 KwHrs. About 9 hrs of power for your house if there’s an outtage.
If you get a snowstorm, your solar panels will be covered, so you get nothing from them and all you have is 9 hrs of power for your house.
For $15,000 you can get a 10 Kwatt solar array (not including labor). On sunny days, with air con off, it will power your house. If aircon is on, your instantaneous power reqmt is way above the 30 KwHrs needed for the whole day, and your demand will overwhelm the panels, and draw on the batteries. If you have some cloudy days that are hot, like most of the southern US, you won’t be getting much from the panels and will drain the batteries pretty fast.
So, the $15K plus labor really only serves you for a very narrow number of days in the year, provided you live in a mild climate area. If you’re in Hawaii, it probably can work. If you’re in Minnesota, your furnace blower is on a LOT. If you’re in Arizona, your air con will eat those panels up.
You are NOT off the grid with these. There are going to be days you need the grid, and whenever something breaks you need the grid to not just give you power, but to give you spare parts.
It’s all mostly a scam, for most locales.
My oldest Trojans still in use were manufactured in 2005. They test at about 80% of new capacity. I keep them in a small array separate from the newer batteries. I recondition all the batteries frequently.
Batteries and the panels are expendable. Lead acid batteries are very sensitive to cycling outside of a limited voltage range. Panels degrade over time.
He has 12 6v golf cart batteries rated at a lifespan of 10 years, and he uses a trickle charger to keep them charged, and also a device called a battery desulfator which extends the life of the battery to 30 years. (I have to take his word, I understand the concept, but have never had experience with them)
I like the way this guy did it, he designed the system with redundancy, and even has a faraday cage around his charge controllers (in the event of an EMP).
It isn't super pretty, but looks very functional, well thought out, and under $5000.
(If you are interested, here is the youtube link: DIY Solar Panel System)
I keep a couple of golf cart batteries charged up for short term emergency hurricane lighting of my home, using an inverter and LED bulbs. Those batteries last a max of five years in my experience.