700sf Self Sustaining Power System Advice

[ADKMountainman]

Building a New solar System for a 700sf full time Cabin. Well insulated, Wood stove heated. Would like some opinions on a solar system.
My thought is EG4 6.5kw charge controller, 2,000 watt solar array, LifePO 100ah (2).??? Would this be enough based on info below.

Northern NY
Calculation based on worst of winter and least solar for longest period of time.
The numbers are as follows:
We would use approx. 2500 WH per day
utilizing a 48 V system
allowing for 5 day redundancy


Thanks in advance

 

[sunshine_eggo]

First, the EG4 6.5kW is going to burn close to 100W continuously even if no loads are used.

100W 24/7 is 2.4kWh/day.

The inverter therefore nearly doubles your energy consumption from 2500Wh/day to 4900Wh/day.

The inverter alone will consume your battery capacity in 4 days - this assumes no loads.

At best, you have two days redundancy with 10kWh of battery capacity.

Additionally, 6.5kW unit for 2000W solar and a mere 2.5kWh/day consumption is borderline absurd unless you're looking at it for additional utilization down the road.

 

[Rednecktek]

Do a search for "Blurb" under my user name, that'll get you pointed in the right direction.

First thought is "Do you need that much AC power?" Are you powering a deep well pump or something? If you only need 110v power, look at the 3kw version for less than half the standby power and 2kw worth of array.

 

[ADKMountainman]

First, the EG4 6.5kW is going to burn close to 100W continuously even if no loads are used.

100W 24/7 is 2.4kWh/day.

The inverter therefore nearly doubles your energy consumption from 2500Wh/day to 4900Wh/day.

The inverter alone will consume your battery capacity in 4 days - this assumes no loads.

At best, you have two days redundancy with 10kWh of battery capacity.

Additionally, 6.5kW unit for 2000W solar and a mere 2.5kWh/day consumption is borderline absurd unless you're looking at it for additional utilization down the road.

Didn't realize the 100w consumption for that unit. And it will be mounted inside the cabin and the noise i understand is not good. I plan on building a sound proof vented box for any unit i go with with, with outside air intake for cooling. Thanks for your response it all helps.

 

[ADKMountainman]

Do a search for "Blurb" under my user name, that'll get you pointed in the right direction.

First thought is "Do you need that much AC power?" Are you powering a deep well pump or something? If you only need 110v power, look at the 3kw version for less than half the standby power and 2kw worth of array.

Interior transfer pump from well. All accounted for in the 2500 watt usage per day. We live frugal with low power consumption. 1/2 year refigeration is done with outdoor air reezer and ice cold water siphon copper loop for refigeration. Ill search your Blurb. Thanks for the info.

 

[Steve_S]

I'm an full-time Offgrid Cabineer in the north (Algonquin Park, Ontario Canada).
I run on 120VAC, have fridge/freezer soft-start 120V GrundFos SQ deep well pump (280' deep), Radiant Heating in slab floor (propane fuelled).
My average is 3.5kWh per day (24 hours) which is the same Summer or Winter. I have a 1293AH/33.4kWh LFP Battery Bank that provides me with 9 Days of power from 100%.

At present I have 2080W of Solar (Canadian Solar 260W Panels 4S2P configuration) connected to a Midnite Solar Classic-200 Charge Controller and using a Samlex EVO-4024 Low Frequency Inverter/Charger which outputs 120VAC/4000W and handles up to 12,000W Surge. The Samlex uses 8W Standby or 11W idle as it is 97% Efficient Tier-1 product. Solar Panels are mounted at 45 Degrees for Year Round average generation. The SCC Outputs 79A in full sun. The Samlex Inverter/Charger can do up to 100A Charging from 120V/30 Generator Input, I cap mine to 80A Charge which translates to 120V/23A/2700W and allowing for Passthrough Power.

Next spring I am adding another Midnite Solar Classic-150 Solar Charge Controller connected to 6, 395W QCell Panels in 2S3P to provide an additional 92A Charge Rate for the bank. This will help during winter for charging due to low sun & volumes of snow on panels.


Top Link in my Signature is all about my system, the setup/config & components used etc.
Hope it helps, Good Luck.

 

[ADKMountainman]

I'm an full-time Offgrid Cabineer in the north (Algonquin Park, Ontario Canada).
I run on 120VAC, have fridge/freezer soft-start 120V GrundFos SQ deep well pump (280' deep), Radiant Heating in slab floor (propane fuelled).
My average is 3.5kWh per day (24 hours) which is the same Summer or Winter. I have a 1293AH/33.4kWh LFP Battery Bank that provides me with 9 Days of power from 100%.

At present I have 2080W of Solar (Canadian Solar 260W Panels 4S2P configuration) connected to a Midnite Solar Classic-200 Charge Controller and using a Samlex EVO-4024 Low Frequency Inverter/Charger which outputs 120VAC/4000W and handles up to 12,000W Surge. The Samlex uses 8W Standby or 11W idle as it is 97% Efficient Tier-1 product. Solar Panels are mounted at 45 Degrees for Year Round average generation. The SCC Outputs 79A in full sun. The Samlex Inverter/Charger can do up to 100A Charging from 120V/30 Generator Input, I cap mine to 80A Charge which translates to 120V/23A/2700W and allowing for Passthrough Power.

Next spring I am adding another Midnite Solar Classic-150 Solar Charge Controller connected to 6, 395W QCell Panels in 2S3P to provide an additional 92A Charge Rate for the bank. This will help during winter for charging due to low sun & volumes of snow on panels.


Top Link in my Signature is all about my system, the setup/config & components used etc.
Hope it helps, Good Luck.

Thank you Steve for your reply very helpful! I look over your thread and found allot of useful information. Really appreciate the tips and insight.

 

[PreppenWolf]

I'm using (2) 6500s and I'll confirm you need to build in the solar usage for the units of this type. They are heavy on the idle consumption. That said you would need to just add panels to offset. And panels are cheap compared to everything else.

For such a small system, it would be good to look at other options like Steve_S posted. If this is a stepping stone to future growth, it dcouod make more sense to use the 6500 as it give you a ton of expansion options.

 

[Hedges]

Didn't realize the 100w consumption for that unit. And it will be mounted inside the cabin and the noise i understand is not good. I plan on building a sound proof vented box for any unit i go with with, with outside air intake for cooling. Thanks for your response it all helps.

Tier-1 brands will be 1/4 the standby power, and silent.
SMA Sunny Island, Victron, Outback, Schneider, etc.
You'll pay more for the inverter, get better quality and performance. You'll save on batteries and PV.

Another option is an inverter with standby mode, that checks periodically for loads.
Sunny Island, for instance, is 5.75kW continuous output, 25W consumption no-load, 4W standby.
But cheap inverters offer similar feature.

 

[PreppenWolf]

The Sunny Island is only an inverter though right? And it's $4,700.

All the low standby options are going to be a lot more than adding (10) 350W+ panels and one more server rack battery. The 6500 is currently $1200.

 

[Hedges]

Yes, Sunny Island is battery inverter/charger only. Requires AC or DC coupled PV to make a complete system.
$5700 MSRP, $4700 street price, $2500 new liquidations on eBay (due to DC Solar bankruptcy)

Other brands have varying degrees of functionality included. Some are low frequency, some high frequency.
SolArk is an AIO getting lots of attention today, but not cheap.

Yes, additional PV and battery may be cheaper than the premium for retail tier-one inverters. I favor extra PV in particular, because it is long lasting and particularly cheap. I went with SMA in part due to the extreme bargains I got at the time ($0.25/W for Sunny Island and $0.10/W for Sunny Boy.) Economy brands may be the way to go, can even have a spare unit on the shelf for fewer $$ than top brands. But make sure they meet your motor starting needs.

 

[50ShadesOfDirt]

Is there a backup (generator) plan? If conditions get tough (long period of little to no solar, solar equipment failure, etc.), will you just accept that power might run out?

Of course, a generator option requires consideration of fuel type and availability at your location. If little to no fuel issues, you might consider adding:

- honda eu2xxx inverter-gen, gasoline-based, light-weight, but not smart
- westinghouse open-frame wgen models, propane-based, smart-plug (support for auto-start based on inverter/battery capacity, scheduling)

I'm off-grid, but I also run a propane generator, and any time solar isn't up to snuff (or we go crazy with loads), or a piece of equipment dies, the gen kicks in, and battery bank is recharged. Battery bank, already there for your case, means gen won't need to run full-time.

Honda option (or similar gen's) is useful where propane can't be brought in, kept-full delivery, and such.

We use the second item above (we have 500-gal propane tank on site), and we have ability to schedule start/stop of westinghouse gen (like a generac, but w/o the cost/complexity), which is good for vacation mode. Otherwise, it is in standby-mode, and as we monitor battery reserve, we can remote start the generator if needed.

Hope this helps ...

 

[ADKMountainman]

Is there a backup (generator) plan? If conditions get tough (long period of little to no solar, solar equipment failure, etc.), will you just accept that power might run out?

Of course, a generator option requires consideration of fuel type and availability at your location. If little to no fuel issues, you might consider adding:

- honda eu2xxx inverter-gen, gasoline-based, light-weight, but not smart
- westinghouse open-frame wgen models, propane-based, smart-plug (support for auto-start based on inverter/battery capacity, scheduling)

I'm off-grid, but I also run a propane generator, and any time solar isn't up to snuff (or we go crazy with loads), or a piece of equipment dies, the gen kicks in, and battery bank is recharged. Battery bank, already there for your case, means gen won't need to run full-time.

Honda option (or similar gen's) is useful where propane can't be brought in, kept-full delivery, and such.

We use the second item above (we have 500-gal propane tank on site), and we have ability to schedule start/stop of westinghouse gen (like a generac, but w/o the cost/complexity), which is good for vacation mode. Otherwise, it is in standby-mode, and as we monitor battery reserve, we can remote start the generator if needed.

Hope this helps ...

Yes. Planned on a small generator due to the fact we are in a forest and winter is long. I didn't think propane though with standby mode good idea. Thanks for the insight

 

[12VoltInstalls]

Is there a backup (generator) plan? If conditions get tough (long period of little to no solar, solar equipment failure, etc.), will you just accept that power might run out

And it will in the Adirondacks.

Economy brands may be the way to go, can even have a spare unit on the shelf for fewer $$ than top brands

That is one motive I have operated with. I haven’t had anything die yet, though?
Nicer equipment is less risky but if you buy known dependable performers from the lower shelves you can have spares and still have money leftover.
On the other hand, running some Victron components like SCCs or Midnite stuff gets you top tier; while still more money, often not a life changing cost difference.

 

[Hedges]

Did I mention the dozen Sunny Islands I have, between the ones hanging on the wall operating, and the ones still boxed up and in storage? ?
And the 15 Sunny Boys ... also two TriPower

 

[12VoltInstalls]

^^^ no but we can’t see them through that pile of leaves