Small Cabin

# Posted: 14 Jun 2025 08:25pm
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travellerw
Have been using solar for 15 years, just missed the bit about 12 volt and amperage requiring so much more wire.
I don't profess to know it all so this is why I have had Signature Solar do it and I will see then.

# Posted: 15 Jun 2025 08:58am
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Ime that 'bit' is commonly missed....
I dont remember it being particularly emphasized in the 'planning materials'. And to me the marketing and pamphlets for inverters are far too casual about the load inputs. Often any supplied cables are iffy to totally inadequate to the capabilities. By that I mean the cable quality, gauge and terminal crimping.
There is no downside to going a gauge up over what a chart says for the length of run you have (well, ok, it will cost a little more).
So, will you be able to refurb your system now and maybe get it up and running better soon?

travellerw
Member

# Posted: 15 Jun 2025 12:42pm - Edited by: travellerw
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Quoting: groingo

Have been using solar for 15 years, just missed the bit about 12 volt and amperage requiring so much more wire.
I don't profess to know it all so this is why I have had Signature Solar do it and I will see then.

Wait..... You have been using solar for 15 years, yet you don't understand watts, amps and voltage? Frankly I find that insanely scary. How you haven't caught something on fire yet is beyond me! Fire might be the best outcome, killing yourself is a real possibility.

If you really want to learn, there are some great people here that can help. However, based on your comments about just using a generator makes me think you don't (or maybe are trolling). Learning how to install and use solar properly is not something simple. If you want to just plug stuff in and have it work, then solar is not for you unless you use a professional to do it for you.

P.S. Charging electric cars is not a "standard" use case and would require advanced knowledge.

# Posted: 17 Jun 2025 06:42pm
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travellerw
I guess I like living life on the edge, a lot of things have changed in that 15 years, LFP batteries especially.
The guys at Renogy were a big help initially and a lot of the information online especially Will Prowse helped alot when LFP's came around but the car charging info is mainly focused on charging from a generator which is easy, but solar typically requires a lot bigger system that is impractical for most.
For now have been talking with Signature Solar about their server rack battery systems that should do the job but winter is a big if so, the best bang for the buck is what I have wich is a hybrid system, solar for the house and grid power or generator if needed for the EV's or just dump the EV's and use my 93 metro and say F the whole EV self charge thing.
Genetically I have radio technicians on one side of the family and electricians on the other side but I somehow didn't get the gene so I just learn by doing and I am still here to talk about it!

# Posted: 18 Jun 2025 10:35am
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Imo and e it would be a good idea to get a modest system up and running (for a good while, not just a short time) Very Well before venturing into a 'server rack' size system.
Im sure that any number of solar outfits will be happy to have you spend as much money as to can, or cant, afford

# Posted: 18 Jun 2025 05:05pm - Edited by: MtnDon
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IMO, and it is just my opinion, if one has an EV and they want to charge it at home they probably should have grid toied solar. A large enough array to generate the amount of energy required for the home and the EV use, AND the system should be grid tied. That means no on-site storage batteries needed at all, unless one desires to have some available backup storage to keep the fridge, furnace and a few lights going if/when the grid goes down.

That allows an EV to be charged day or night, sunshine or clouds. The monthly meter fee is very cheap rental for using the grid as a battery. YMMV, especially if your grid is liable to be disrupted frequently. I can not recall the last time our grid went down and it was only for a few hours.

I would not want to charge an EV directly off solar as daytime is when I am more likely to want to be using the vehicle rather than charging it. But that is me, and people's pattern of use varies.

In any event if one is doing anything with solar, having battery storage and using an inverter for AC power IMO, they must have a thorough understanding of the relationship between Volts, Amps, and Watts. With 12 volts DC and 120 VAC it should be very simple to switch thinking back and forth as the difference is a factor of multiplying or dividing by 10, plus an allowance for efficiency of conversion.

I would think that after 15 years, one should have a system that is fully understood, with no surprises. Some of the hardware, as well as the NEC, has had big changes but the underlying electrical theory remains the same.

We closed on a 2021 Rav4 Prime Tuesday. There are a couple of minor details being looked after before we pick it up. It is everything we wanted, even the color was onour preferred list (Ruby Pearl). We have some surplus grid-tie solar capacity. Time will tell if it might be worth it to expand capacity. Its EV range should cover our everyday use around town. Best of both (electric and gasoline) worlds, IMO.

travellerw
Member

# Posted: 18 Jun 2025 07:30pm
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I'm going to disagree that EV charging requires a bigger system then is practical. It just requires proper design.

The thing about design. Its all math. You NEED to understand the math!

As an example, you keep saying batteries, but batteries are only a part of equation. Here is some food for thought. The server batteries you mentioned are 4800Wh. The smallest battery in a Tesla car is 78000Wh (yes seventy eight thousand). If you wanted a system that can continue to charge your car through the night you would likely need a battery bank 1/2 the size of your car battery. Then a GIANT system that could charge that bank, plus the car during the day!

A smarter solution is a smaller battery pack that acts as a buffer, then a medium sized solar array (15KW or so). This would allow charging during the day when its sunny %100 off the panels. The bank would just provide a buffer for clouds or shade. You use the software in the car (or the charger) to stop the charging outside sunny hours.

Anyway... I would suggest that you maybe stop talking to companies that want to sell you stuff, and instead talk with a knowledgeable installer. Any knowledgeable installer could easily design a on-grid or off-grid system that could charge a car. I promise it will be worth the money you pay that person.

I'm also confused as to why you are doing this? If you are trying to drive for "free" off solar, then this is a fools errand. You will be long dead before it becomes "free" if you are comparing it to a Geo metro! Especially with the way you are trying to build it.

# Posted: 19 Jun 2025 02:11pm
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The EV charging system should be simple which is to "rob peter to pay paul" so you charge your battery bank (which should be at least twice the KWH size you need to carry through poor solar days) and there in lies another rub, come winter we have not only shorter days but a lot of rainy dark days. Bottom line it can be done but the complexity and cost makes no financial sense and finding a competant trustworthy Solar Electrician is very tough round here in Washington.
Don, I am doing much the same as you, if I didn't already have my 93 Geo Metro (52 m.p.g.) I would strongly consider a Prius Prime hybrid.
By the way, we goback a bit, I remember when your system got taken out by that lightning strike!

# Posted: 19 Jun 2025 03:44pm
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Think if I had grid I use it to charge my EV(s) and have a setup to run my house off a car in an outage.
If I had a hybrid that would recharge itself most of the time Id likely be using it as my bat-bank with maybe a small solar system to mess with on the side.

# Posted: 19 Jun 2025 08:19pm - Edited by: groingo
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gcrank12, Your close.
I recently just replaced and upgraded my solar from 600 watts to 800 with 4 200 watt 20 BB panels new charge controller and 4 12 volt LFP 100 AH batteries and a 2000 watt PSW inverter. The EV's are charged with grid power only and the house is pure solar.
I use four individual batteries for redundancy rather than one big battery. Water well is operated using generator for drinking water only used only a few minutes a week.

# Posted: 19 Jun 2025 08:50pm - Edited by: MtnDon
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Quoting: groingo

I remember when your system got taken out by that lightning strike!

July 2014. That was quite the blast. A lot of equipment lost.

FYI, after that, the cabin and system received a newly thought-out lightning protection system. After the new protection system was installed I know that we have been hit again, but maybe not as directly, as there have been no further signs of lightning burns. However, I have had to replace two Midnite Solar surge protectors. For those who are not familiar with them, they had blue LEDs that light up when the unit is able to send a strike to ground. Each strike deteriorates the MOV's a bit. When the surge protector MOVs are all used up the LEDs do not illuminate. Those Midnite Solar devices work!! They were not available when I put the original system together. The older Delta protection devices were not nearly as good. They were blown apart.

So, we have the same inverter that we installed after that. The CC was replaced though when we changed to a 24 volt LFP battery as the replacement CC was very good but had one fault that made use with LFP a potential problem.

The cabin system could be used to recharge something like the Rav4 Prime, but even that would be a long charge time. A pure EV with its much larger capacity battery would not be advisable. No sweat at home with the grid-tie.

# Posted: 19 Jun 2025 09:02pm
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Quoting: gcrank1

If I had a hybrid that would recharge itself most of the time Id likely be using it as my bat-bank

The Rav4 Prime has a 1500 watt inverter to provide 120 VAC power. It draws off the 12 volt vehicle battery. That is replenished by the main battery when the vehicle is placed in "ready mode". The main battery is 355 volts (I think) and for higher wattage there may be a way to tap directly into that. I have no plans to do that.

# Posted: 19 Jun 2025 09:07pm - Edited by: MtnDon
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Some of the lightning protection stuff

FishHog
Member

# Posted: 21 Jun 2025 07:27am
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Quoting: MtnDon

Some of the lightning protection stuff

Something I've been considering for years. We aren't prone to lightening strikes and haven't had any in 12 years at the cottage, but still concerns me. Every time I search about a solution I end up more confused and do nothing. Maybe a new thread about your system would be of interest to people. I'd appreciate it if you have the time and interest to share.

# Posted: 21 Jun 2025 08:55am
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Quoting: FishHog

Maybe a new thread about your system would be of interest to people. I'd appreciate it if you have the time and interest to share.

I'll see what I can do. I did not take many pictures but I can write.

# Posted: 21 Jun 2025 09:12am
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Yes you can! I always look forward to your well thought out and expressed commentary