Small cabin in Alaska, smaller system using Yeti 1250 as the heart

[alaskan84]

Hello, as the topic states I have a small cabin on an island in Alaska and want to play with a small solar system. We have line power and I am in the works of getting an automatic generator installed to take care of the times high winds or something else takes out a pole/line for a few days. I have had a yeti 1250 for years now and have used it on and off when we have lost power. This project is purely for fun and I have no expectation of actually being able to run anything beyond stuff that I can plug into the yeti. Now I have quite a bit of solar gear already and more panels that I could likely use with the yeti, but that is what i am here asking you all for advice. Obviously here in Alaska we are not going to get alot of sun, and definitely more shaded days so the more panels I can potentially utilize without overloading the built in mppt controller the better.

I have:

2 150W HGST panels
-Open Circuit Voltage 22.7v
-Short Circuit Current 8.09a
-Optimum Operating Voltage 19.1v
-Optimum Operating Current 7.89a

9 100W Renogy panels
-Open Circuit Voltage 21.5v
-Short Circuit Current 6.4a
-Optimum Operating Voltage 17.1V
-Optimum Operating Current 6.1a

Yeti 1250 charging capability ( this was direct from GZ Support)
-Charging Port (input, 8mm) 16-48V, up to 10A (160W max)
-Power Pole Charging Port (input) 16-48V, up to 20A (320W max)
Total Max Input 320W


Now i have some y branch parallel connectors and in theory this is how I thought things could be connected, please forgive me if I seem to be missing some core solar knowledge with my understanding here.

The two 150 watt panels could be connected in series which would keep the amperage at 7.89 but bring the voltage to just under 40v. These two panels would be safe to connect to the 8mm input charging port since its under 10A and within the voltage range.

The 100 watt panels could be connected by 4 in a parallel connection which would bring the amperage to 24A and keep the voltage the same at 17V.

That is where i begin to get a bit confused on the limits...Can I actually only utilize 3 of the 100 watt renogy panels due to the 24A of 4 in parallel, or is the amperage irrelevant and I can actually hook up all 9 panels in parallel?

Thanks for any insight/advice you can provide!

I have photos of the panels and everything else if that is helpful..including a photo of my beach cabin for views.

 

[snoobler]

Amperage is mostly irrelevant. I don't know that I'd go 9 in parallel, but but you'll be limited to 10A regardless.

When you put panels in series, you need to consider their Voc when looking at limits UNLESS the device states operating voltage. I would avoid putting panels in series since their Voc would be very close to the limit, and you likely need about 15-20% margin due to cold weather voltage spikes.

https://www.goalzero.com/media/files/yeti-1250-user-guide-16-799e.pdf

I would put each the lower one at 1X 150 and 3X100W all in parallel for starters. On the higher one, 1X 150 and 6X100W all in parallel.

The goal here is to provide about 2X possible current in hopes of being able to hit and maintain the maximum permitted for as long as possible.

Nice looking cabin.

 

[ghostwriter66]

Hello, as the topic states I have a small cabin on an island in Alaska and want to play with a small solar system. We have line power and I am in the works of getting an automatic generator installed to take care of the times high winds or something else takes out a pole/line for a few days. I have had a yeti 1250 for years now and have used it on and off when we have lost power. This project is purely for fun and I have no expectation of actually being able to run anything beyond stuff that I can plug into the yeti. Now I have quite a bit of solar gear already and more panels that I could likely use with the yeti, but that is what i am here asking you all for advice. Obviously here in Alaska we are not going to get alot of sun, and definitely more shaded days so the more panels I can potentially utilize without overloading the built in mppt controller the better.

I have:

2 150W HGST panels
-Open Circuit Voltage 22.7v
-Short Circuit Current 8.09a
-Optimum Operating Voltage 19.1v
-Optimum Operating Current 7.89a

9 100W Renogy panels
-Open Circuit Voltage 21.5v
-Short Circuit Current 6.4a
-Optimum Operating Voltage 17.1V
-Optimum Operating Current 6.1a

Yeti 1250 charging capability ( this was direct from GZ Support)
-Charging Port (input, 8mm) 16-48V, up to 10A (160W max)
-Power Pole Charging Port (input) 16-48V, up to 20A (320W max)
Total Max Input 320W


Now i have some y branch parallel connectors and in theory this is how I thought things could be connected, please forgive me if I seem to be missing some core solar knowledge with my understanding here.

The two 150 watt panels could be connected in series which would keep the amperage at 7.89 but bring the voltage to just under 40v. These two panels would be safe to connect to the 8mm input charging port since its under 10A and within the voltage range.

The 100 watt panels could be connected by 4 in a parallel connection which would bring the amperage to 24A and keep the voltage the same at 17V.

That is where i begin to get a bit confused on the limits...Can I actually only utilize 3 of the 100 watt renogy panels due to the 24A of 4 in parallel, or is the amperage irrelevant and I can actually hook up all 9 panels in parallel?

Thanks for any insight/advice you can provide!

I have photos of the panels and everything else if that is helpful..including a photo of my beach cabin for views.View attachment 24477

WOW - I would love it if they would transfer me there next .... anyway - I am surprised that you are looking at SOLAR and not wind ... with the amount of sun you get and the overcast days -- I think that you are looking at very little ROI ... but wind on the other hand ....

 

[alaskan84]

Thanks for the replys!

So if amperage is mostly irrelevant, then is it not a concern to harm the built in MPPT controller of the yeti by going over its amp rating? It's only the higher voltage that would potentially damage the controller?

It sounds like Parallel is the way to go, which is good since thats the only connectors I have at the moment. Although if i can fully utilize all of my panels without risking the controller in the yeti then I will need to order a few more adapters.

I'm actually on Kodiak Island which is now running on 100% renewable energy. We have a few large turbines on a mountain just next to our city and we 200% get more wind than sun! Solar just seems easier for plug and play at this point plus I have had the yeti for awhile...but your right on the wind comments...another project down the road!

Kodiak Island 100% renewable energy

Here are a couple photos from over the 4th of july this year, we do get some good sun

 

[snoobler]

In general, current doesn't matter. The MPPT SHOULD just pull as much current as it can. Most behave this way, so I'm assuming the Yeti is the same.

"cabin" - seems like a modest word for that dwelling.

 

[alaskan84]

Thanks again for your response snoobler. You are confirming what I have read as far as how the controller should behave. I might just try another email to GZ support to confirm that said built in controller will not have issues.

Yes, "cabin" is a bit of a stretch although its just been a carry over term. My family has had these two beach lots for many many years and for the longest time there was just a small A frame cabin with power and an oil drip stove. Now I have had my own 2 bedroom/2 bath "cabin" on the beach for about 6 years and my parents are just finishing their own 2 bedroom cabin next door on the second lot.

Edit...we are also not on city water/plumbing out here, so I have a septic tank for sewer and currently have about 3000 gallons of water from rain catch in a cistern for my cabin. When my parent's "cabin" and my shop are finished I will have about 9000 gallons of water stored between us all