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rockies
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# Posted: 30 Jan 2018 08:07pm
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An interesting site with several good articles about energy consumption and the systems needed to run an off grid home..
https://modern-off-grid.com/
I wonder how Creeky would reconfigure his system?
https://modern-off-grid.com/2014/01/02/living-off-grid-daily-energy-use-and-considera tions/
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creeky
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# Posted: 31 Jan 2018 08:48pm
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That's a nice "ye olde solar" set up. Truly a lovely "of its time" build.
His site is interesting in the Solar 101. And the considerations page is useful too.
Now if we were to play "what would that look like today?"
Obviously a better battery. That lead acid is, you know, maintenance heavy, short lived, toxic off gassing and less than 80% efficient; plus its now at the end of its lifespan (with his Tesla pack post I wonder if its been replaced?). So lithium, and more than just the tesla pack, is the upgrade there.
I also found it funny: He put in an 8kw inverter (note: I always tell folks not to oversize their inverters) and then in the next sentence he says 3.8 is the max load he's ever run. Ha! Point made.
So I might suggest a smaller inverter.
With 6.5kw solar panels he throws away a lot of power (as he states). So the solar is oversized. But he does start to heat water with electricity and that's a pretty common realization/adaptation. Plus, now that big inverter starts to make a little more sense. And, with "today" being the focus. His solar may be right sized. What he needs is an electric car to charge. 
Now of course you'd use an air source heat pump for hot water. GREE has some lovely new tech arriving this year. Keep an eye out for it. He has a heat pump for a/c I think I saw?
Even as late as 2016 he's touting "lead" as safe and reliable. While it is neither. So I find that just a tad old school. Lithium is the only choice now. Has been for quite awhile.
But all the above is just updating a really lovely system to today's configuration.
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Steve_S
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# Posted: 1 Feb 2018 06:59am
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Hehehe agree with Creeky and also a good chuckle @ he needs an EV.
I've tried to get details on how much panel, battery etc would be needed to support an EV like a Bolt or Model-3, geez, you'd think it was a nuclear secret and what little info is out there is far from clear or consistent. There is an opportunity there for a smart solar dealer to come up with a couple of "EV Packages / Kits" for 2 or 3 more common models.
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Just
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# Posted: 1 Feb 2018 08:55am
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Question " so I have a small ev scooter 48 v 20 amp hr . lithium plus I have a 1020 watt 72 volt panel set up . presently running a 3 in 48 v. water pump on demand. between the panel and the pump there is a mppt controler no batteries. only runs when the sun shines . the system gets very little use in the summer mostly sits idle. What would I need between the panals and the ev to charge the lithium battery ???naturally the little bike gets mylost of its use in the summer months.
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creeky
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# Posted: 1 Feb 2018 10:44am - Edited by: creeky
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I have a friend/customer who uses 3kw to charge a leaf and run his household in the summer. He has made 18kw in one day. Yowzah!
Neat set up Just. For your scooter just adjust your mppt controller to the specific 48v of the scooter battery. I don't know what that is. It will be in the literature somewhere (or put a voltmeter on your battery when full). And you will be good to go. That voltage should be fine for the pump also. As DC motors usually have quite a wide operating voltage range. (as you undoubtedly know. But for others. Btw. The Victrons with their easy to program voltages would be ideal for this.)
You're right Steve. EV use makes solar so cost effective. The payback when you're replacing gas is like 3-5 years. Plus all the other stuff you get. Doesn't take much. A basic EV charger and a 240 split phase is what my friend uses. 480v direct DC (aka fast charge) ... its available. I wouldn't install it though. That's too freaky even for me.
I would suggest what that fellow has. 6.5kw. Something around there.
Am I allowed to make a bobolinksolar comment? Avert your eyes if not. I have a solar panel deal coming. If anyone wants to install an EV charging system. This would be the time.
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Just
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# Posted: 1 Feb 2018 11:21am
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What would prevent the system from overcharging the battery ? There is no external adjustments on the controller " not even a name†Chinese “
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creeky
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# Posted: 1 Feb 2018 11:34am
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Oh. None then. Maybe you could find a dc/dc converter with adjustable input/output and set the output to the battery voltage.
What is the output on the controller vs the max charge on the battery?
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Just
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# Posted: 1 Feb 2018 12:58pm
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The Box says 300 v max in. 48 v out I would test that before I would believe. !!
I think it would be best if I stayed away from that controller and created a new circuit .I will look for a new controller with adjustable voltage. Can’t spend a lot. It only cost 25 cents to charge it on grid. Maybe 50 times a year!! Thanks for the help.
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creeky
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# Posted: 1 Feb 2018 04:22pm
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48v is the catch. You can get super cheap adjustable mppt for peanuts. But up to 24v.
300v in. Mmmmm. That does sound dicey. Was that 300 w in?
Be easy to check the voltage. Put a voltmeter on it. If its 48 you're good to go.
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