Off Grid desert nest

[scrubjaysnest]

In our area rated Voc of 80V or less will be fine on a 100V controller, but at 14.4V, 2S may be a little more efficient if you don't have long PV wire runs.

The 100/20 will limit output to 20A regardless of panel configuration. You simply don't want to exceed the PV input current limit and Voc published in the datasheet.

1 thing I'm considering is set the battery bank up as 24 volt. Means buying a different inverter and dc to dc converter for a few 12V items like the water pump.
Move the 12V inverter to the RV for the microwave.
Voc for the new panels is 21.8, round it to 22 and 3 panels is 66 volts in series.
The older 12 volt panels have Voc around 20 volts. And the 2 240 watt Trina panels are about 37 for Voc so a 24 volt bank may be a better choice.
Some will say just goto 48 and be done. That's what White Mountain Solar is suggesting.

 

[sunshine_eggo]

5 deg F in showlow this morning so far. It will be similar at the desert nest.

My weather station is currently reading. 3.4°F with a low of 2.7°F logged at midnight.

Brrr....

1 thing I'm considering is set the battery bank up as 24 volt. Means buying a different inverter and dc to dc converter for a few 12V items like the water pump.
Move the 12V inverter to the RV for the microwave.
Voc for the new panels is 21.8, round it to 22 and 3 panels is 66 volts in series.
The older 12 volt panels have Voc around 20 volts. And the 2 240 watt Trina panels are about 37 for Voc so a 24 volt bank may be a better choice.
Some will say just goto 48 and be done. That's what White Mountain Solar is suggesting.

I'll be blunt. 48V pays off in the end. It completely removes barriers to expansion and maximizes your MPPT yield, though you need to select a 48V capable unit.

My neighbor has a 24V system originally specced out in the 90s, and it's been carried forward. With 4kW solar, he needs 2X 80A controllers. I only have 2kW mounted, but my single 100A can handle the installed plus the 3kW I have planned for mounting. Furthermore, as his demands have increased, he had to add a dedicated 24V/6kW inverter for his well pump, so it's something of a cobbled together setup. Works fine, but 48V would have expanded his options.

 

[scrubjaysnest]

That is the nice thing about the Victron 100/20 click and grunt, it's now 24 or 48 vdc.
Yesterday's snow ❄ pic

 

[sunshine_eggo]

That is the nice thing about the Victron 100/20 click and grunt, it's now 24 or 48 vdc.
Yesterday's snow ❄ pic

Ah... I forgot you had the 100/20. That's a unique one. IIRC, none of the other 100V units support 48V.

 

[sunshine_eggo]

Waiting for some heat before I can charge my batteries!!!!



At 0°C, the system will use PV to power the loads. At 5°C it will charge. I can manually turn on/off a 1500W space heater in the container, but it doesn't do much since the container is uninsulated. Once it's at least 0°C, the PV can power the heater, and it seems to get me to charging temperature about 30 minutes faster than the sun heating the container can.

 

[scrubjaysnest]

And here in FL the entire grid is down county wide. River flood warning, tornado warning, coastal flood watch, severe weather warning, and light rain. Wind gusts to 48 mph with possible 70 mph and 1/4 inch hail. Poor solar day!

 

[scrubjaysnest]

Worked on getting the new shunt to work with negative bus bar. Used 1 inch square copper shim so bus bar clears smart shunt electronics housing.

Leaning towards Sungold power for a basic 4kW inverter, most likely 24 volt input

 

[sunshine_eggo]

Worked on getting the new shunt to work with negative bus bar. Used 1 inch square copper shim so bus bar clears smart shunt electronics housing.

Leaning towards Sungold power for a basic 4kW inverter, most likely 24 volt input

IMHO 48V FTW. It doesn't cost much more, and you only need half the MPPT output to get the same PV power.

 

[scrubjaysnest]

At 48 volt it does allow for more pv, I just have to keep in mind I'm running 12AWG wire to the cc's. Don't really require more then 4kW.

 

[scrubjaysnest]

Haven't pulled the trigger yet but the Sungold Power 6kW 48 volt split phase inverter is $10 more then 24 volt. https://www.amazon.com/SUNGOLDPOWER...00CBAUZAM/ref=cm_cr_arp_d_product_top?ie=UTF8
And today's snow pic.

 

[sunshine_eggo]

Only downside to that inverter is its massive idle burn. It's about 120W. My neighbor has the 24V version of that we installed for his well pump.

It's made by Sigineer:

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About $500 difference, but this price is uncommonly good. They say 48V is available, but it's not selectable.

Looks like the snow stuck to my camera...

 

[scrubjaysnest]

For us idle current isn't an issue as the inverter will be off most of the time.
Found the 48 volt version here..https://energetechsolar.com/6kw-apc-inverter
That appears to be their main site. Now to figure shipping $.
Thanks for the link.

More snow coming from what the weather guessers are saying.

Did some figuring and at the full inverter output the current battery bank will last about 1 hour and 12 minutes. My thinking on the 6kW is we only need 4kW max so at 2/3 power the inverter isn't working as hard. Maybe it will last longer.

Watts247 has a pair of 3048's on sale for about the same price.
Seem to be a lot of clearance sales. Reducing inventory for tax season or new models?

 

[sunshine_eggo]

For us idle current isn't an issue as the inverter will be off most of the time.

You'll be turning it on and off manually?

Found the 48 volt version here..https://energetechsolar.com/6kw-apc-inverter
That appears to be their main site. Now to figure shipping $.
Thanks for the link.

yeah. They're the same company.

The 6kW shipped for about $110 via UPS a couple years ago.

More snow coming from what the weather guessers are saying.

Yep! This is the Weather Underground forecast for my weatherstation.

Did some figuring and at the full inverter output the current battery bank will last about 1 hour and 12 minutes. My thinking on the 6kW is we only need 4kW max so at 2/3 power the inverter isn't working as hard. Maybe it will last longer.

Peak inverter efficiency is around 30% of rated - so 1800W will be your sweet spot. That's about 1 RV A/C unit and some backgroudn loads.

Watts247 has a pair of 3048's on sale for about the same price.
Seem to be a lot of clearance sales. Reducing inventory for tax season or new models?

Maybe!

 

[scrubjaysnest]

About right on the A/C then the specs say 1360 VA or we can ignore VA and call it watts. No other loads for the inverter at present. All goes out the window if my bride decides rustic no longer suits.

 

[Bop]

They definitely look like rebranded Sigineers, a pretty good company and have a good reputation in Australia (in fact my own charge controllers and the 12kw inverter (which is currently sitting unused in the shed) are all Sigineer units- this is my 'retirement home' and I wanted the 'best' in terms of what had the best reliability for the best price (one advantage of being 'in the game' for the last 40 years lol- you get to know what is good, and what 'likes to brag but is a poor choice' lol


Snow- uggh- no thanks- I seen snow twice- and that was twice too often lol- its 6AM here and a chilly 21C, today's a nice cool top of 32C- nice as we have had tops over 40C for the last month...
21C is 'long sleeve flanny or a light jacket and tracksuit pants' territory for me lol- thats 70F atm for the yanks with a cool daytime top of 90F... better than the 104F we have been having...

Out west one town had a top of 52C (125F) a couple of weeks ago...

 

[sunshine_eggo]

They definitely look like rebranded Sigineers, a pretty good company and have a good reputation in Australia (in fact my own charge controllers and the 12kw inverter (which is currently sitting unused in the shed) are all Sigineer units- this is my 'retirement home' and I wanted the 'best' in terms of what had the best reliability for the best price (one advantage of being 'in the game' for the last 40 years lol- you get to know what is good, and what 'likes to brag but is a poor choice' lol

They 1000% are. When working with my neighbor on resolving technical issues, a Sigineer engineer "Franklin" contacted me to answer questions ECPC couldn't.

 

[Bop]

About right on the A/C then the specs say 1360 VA or we can ignore VA and call it watts. No other loads for the inverter at present. All goes out the window if my bride decides rustic no longer suits.

Not quite- as it is an A/C ie motor, it likely is quite an inductive load- and will be more watts needed than just 'W=VA': that only applies to resistive loads with a power factor of 1...
Motors power factor can vary quite a bit, but most are around 0.7-0.8- assuming it is a power factor around 0.8, that makes it around 1640W actual...

 

[Bop]

They 1000% are. When working with my neighbor on resolving technical issues, a Sigineer engineer "Franklin" contacted me to answer questions ECPC couldn't.

LOL- so you have met him too (well met as in online)
Franklin Chu- we have chatted via email many times

 

[scrubjaysnest]

Not quite- as it is an A/C ie motor, it likely is quite an inductive load- and will be more watts needed than just 'W=VA': that only applies to resistive loads with a power factor of 1...
Motors power factor can vary quite a bit, but most are around 0.7-0.8- assuming it is a power factor around 0.8, that makes it around 1640W actual...

That was a bit of tongue in cheek. Having worked in electronics and the power industry all my life I know the difference. Here on the board the thinking is VA=Watts. That's why I remind folks about Victron inverters. We can easily forget a 3000VA Victron is 2400 Watts. Saw one vendor today and the inverter was showing as 3000VA = 3000 Watts in the add.

 

[Bop]

All too common (especially in the cheap end of the market)- I have seen cheap inverters (and cheap generators) using VA with a quoted power factor of 0.5!!! makes a 'small' inverter look better when it has 'bigger numbers' on it LOL
And catchs far too many people out who think 'VA = Watts'...