cost per watt of solar panels graph

Battery technology using less expensive materials are in the works. Unfortunately at least at present you get what you pay for in the controllers though new models from Morningstar just came out.

JiminDenver wrote:
Now if we could get the price of the better controllers, batteries and inverters down, we could afford a nice big solar system.

I do not understand the controller market. Locally, we have Can Tire now with their PWM, $21, 8.5a 127w controller that was going for the same price two years ago, but was then a 7a 105w model.

This is competitive with the eBay ones for convenience of having it right now instead of waiting a month for the mailman to deliver it.

Meanwhile, they still sell their next up in size, 30a PWM controller for near $100 which is totally outrageous, when you can get a 30 amper on eBay for $35.

The usual suspect MPPT controllers that are claimed to be made in USA are hugely expensive but most of that seems to be so you can hook your laptop to them. I always thought the idea was to hook a solar panel to them!!!

For sure do the math on having two or more smaller amp controllers on the same battery bank instead of one big expensive controller. Prices do not go up linearly with amp sizes!

You can split up your array into smaller arrays each with its own controller. Don't forget that option!

We still have a long way to go here for RVers, while all this plays out.

That graph is a good diagram for "race to the bottom"

Too bad improvements in quantum efficiency of the panels is only a few points better now than it was in the 70s. So much focus on making them cheap, very little focus on making them better.

I've seen the hi bred batteries on craigslist and even if I knew how to use them, I'd have some reservations as to why they were available.

A accident that totaled the car would have put heavy stress on the plates, etc. of the battery. That can't be good.

They could degrade to the point they need replacing and still be usable to us but how long before that degrading increases and rapidly too.

Perhaps the best scenario is that the dealership replaces the batteries before they degrade but it is time to do so as part of a schedule. Either that or the "it's a good idea" scam so they can make some extra money. Those batteries could be in great shape.

With a 3000 lb CCC, 660 lb is no big deal for us, where to put them is.

Hi Almot,

Yes there is a limited life span. The battery is considered "done" when it can't hold 80% of OEM values. But 80% of 24kwh is still a little over 19 kwh. That's the equivalent of having a little over 14 lead acid batteries.

Unless an RV is being purpose built, those 14 batteries would "eat up" all the carrying capacity of the unit whereas the LI would weigh about 660 lbs. (still not light--but way better than lead acid)

Used batteries, probably. In hybrid and electric cars this is a problem, battery costs half of the car price and has a limited lifespan. Don't count on cheap new batteries, though. As consumption in India and China increased, prices of raw materials skyrocketed. There aren't going to be less people in the world in future.

Hi Jim,

Just wait for the used electric car batteries to come "on line".

Now if we could get the price of the better controllers, batteries and inverters down, we could afford a nice big solar system.