An off-grid solar kit has to do everything a utility line does: make power by day, store enough for the night and a cloudy spell, and deliver the 120V or 120/240V your appliances expect. Buying the inverter, battery and panels as one matched kit means the charge voltage, battery communication and string voltage already agree.
The hard part is size: a weekend-cabin kit leaves a family home dark by 9 PM. This guide sorts every complete off-grid kit we have in stock and active on October 26, 2026 by home size, shows the sizing math, and flags the limits that spec sheets bury - 120V-only output, battery current, inverter warranty. Prices are store prices before any promo code; every kit includes an inverter/charger, LiFePO4 batteries and solar panels.
1. Off-grid solar kits compared by home size
| Kit | Best for | Price today | Inverter (surge) | Output | Battery | Solar array | Est. solar per day* |
|---|---|---|---|---|---|---|---|
| Sungold SGKT-3PRO | Weekend cabin, shed office | $2,485 | 3,000 W (6,000 VA), 24V | 120V | 5.12 kWh (2 x 24V 100Ah, self-heating) | 4 x 200 W = 800 W | ~2.4 kWh |
| Sungold SGM-5K5E | Small cabin, first system | $3,145 | 5,000 W (10,000 VA) | 120V | 5.12 kWh (1 x 48V 100Ah) | 6 x 200 W = 1,200 W | ~3.6 kWh |
| Sungold SGR-5KE | Tiny home, full-time cabin | $4,782 | 5,000 W (10,000 VA) | 120V | 10.24 kWh (2 x 48V 100Ah) | 6 x 415 W = 2,490 W | ~7.5 kWh |
| Sungold SGK-8MAX | Small home with a 240V well pump | $6,979 | 8,000 W (16,000 W peak) | 120/240V | 10.24 kWh (4 x 12V 200Ah, self-heating) | 12 x 450 W = 5,400 W | ~16.2 kWh |
| Sungold SGR-10K2M | Mid-size home, sunny site | $9,330 | 2 x 5,000 W (20,000 VA peak) | 120/240V | 20.48 kWh (4 x 48V 100Ah) | 12 x 450 W = 5,400 W | ~16.2 kWh |
| Sungold FR-12K20CP | Typical full-time home | $9,990 | 12,000 W (24,000 W surge) | 120/240V | 20.48 kWh (4 x CoreX 5 Pro) | 16 x 450 W bifacial = 7,200 W | ~21.6 kWh |
| Sungold FR-12K30CP | Larger home, cloudy winters | $13,150 | 12,000 W (24,000 W surge) | 120/240V | 30.72 kWh (6 x CoreX 5 Pro) | 16 x 590 W bifacial = 9,440 W | ~28.3 kWh |
| Sungold SGR-20K32P | Big home, farm, shop | $15,975 | 2 x 10,000 W = 20,000 W | 120/240V | 32.14 kWh (2 x PowerMax outdoor) | 32 x 450 W bifacial = 14,400 W | ~43.2 kWh |
*Our estimate: array kW x 4 sun hours x 0.75 to allow for wiring, inverter, temperature and dust losses. Listings quote 4 sun hours without losses, about a third higher. Your real number depends on your location and season - northern winters can deliver 2-3 sun hours, the desert Southwest 6 or more.
Specs come from the manufacturer data on each product page. All eight kits are Sungold Power because that is where our complete in-stock off-grid kits sit today; if you already own panels, battery-and-inverter cores such as the NEXUS 14.3 kWh + EG4 6000XP ($4,544, 6 kW split-phase) are the alternative.
2. Storage vs daily solar: what each kit can actually support
An off-grid kit is balanced when the array can refill the battery on an ordinary day and the battery can carry you through the night. The chart shows the pattern. The two small kits store more than their panels make in a day - fine for weekends, not for full-time living. The SGK-8MAX is the opposite: a 5.4 kW array on a 10.24 kWh battery refills quickly even on a short December day, which is why it is popular in northern states. The 12 kW and 20 kW kits are balanced for daily cycling, with roughly a day of storage for the energy they produce.
3. How to size an off-grid solar kit
Size four numbers in this order: daily energy, battery, array and inverter. Our Solar Kit Calculator does this from your appliance list and ZIP code; here is the math behind it.
Step 1: daily energy (kWh per day)
List what you run and for how long. Typical off-grid profiles:
- Weekend cabin (lights, small fridge, chargers, water pump): 2-5 kWh per day.
- Tiny home or full-time cabin (fridge, washer, Wi-Fi, some mini split use): 6-10 kWh per day.
- Small home with propane cooking and heat (fridge, freezer, well pump, laundry): 10-18 kWh per day.
- All-electric family home: 20-30 kWh per day or more. The average US home uses roughly 28-30 kWh a day on the grid, according to EIA residential averages - off-grid homes usually trim that with propane appliances and efficient heat pumps.
Step 2: battery (kWh of storage)
Battery kWh = night-time use / 0.9 (LiFePO4 is commonly run to about 90% depth of discharge) x days of autonomy. Example: a small home using 16 kWh a day burns about 9 kWh between sunset and sunrise. 9 / 0.9 = 10 kWh for one night. Add one cloudy day (16 kWh / 0.9 = about 18 kWh) and you are at about 28 kWh - that is the gap between the 20.48 kWh and 30.72 kWh versions of the same 12 kW kit. A generator input lets you buy less battery and run the generator on the third gray day.
Step 3: array (kW of panels)
Array kW = daily kWh / (winter sun hours x 0.75). For the same 16 kWh home at 3 winter sun hours: 16 / (3 x 0.75) = 7.1 kW - the 7.2 kW array in the FR-12K20CP. At 5 sun hours in Arizona the same home needs only 4.3 kW. Size for your worst month, or accept generator hours in December.
Step 4: inverter (continuous watts, surge and voltage)
Add up the loads that can run at the same time, then check starting surge. A 1 HP well pump runs at about 1,000-1,500 W but can draw two to three times that for a moment at start; a 3-ton central air unit runs at about 3,000-3,500 W. If anything on the list is 240V - well pump, dryer, range, central air, EV charger - you need split-phase 120/240V output, which rules out the 120V-only SGKT-3PRO, SGM-5K5E and SGR-5KE.
Step 5: check the battery can feed the inverter
Battery current = inverter watts / 51.2 V / 0.95. A 12 kW inverter at full load pulls about 247 A; the FR-12K20CP's four CoreX 5 Pro modules have 100 A battery management systems each (400 A combined), so the bank is not the bottleneck. The single 5.12 kWh module in the SGM-5K5E is rated 50 A standard and 100 A maximum, so plan continuous loads around 2.5 kW and treat 5 kW as a short-term ceiling until you add a second module. On the SGR-20K32P, the two PowerMax batteries are rated 150 A continuous each (300 A, about 14.5 kW from battery alone) - the full 20 kW is available when the panels are producing, or by adding a third PowerMax. Our 48V server rack battery guide explains this check.
4. Price per kWh: where the value is
Dividing the kit price by the battery kWh it includes is a quick value check (the panels and inverter are in the price too). The 30.72 kWh FR-12K30CP is the best value per kWh at about $428, followed by the SGR-5KE ($467), SGKT-3PRO ($485) and FR-12K20CP ($488). The SGK-8MAX looks expensive by this measure ($682) because a large share of its price is panels - 5.4 kW, more than any kit below the 12 kW class - and the SGM-5K5E ($614) carries the fixed cost of a 5 kW inverter on a single battery module.
For installed budgets, see our whole-home battery backup cost guide. The federal 25D credit ended for home systems paid for after December 31, 2025 (not tax advice).
5. Our picks by home size
Sungold Power FR-12K20CP - 12 kW, 20.48 kWh, 7.2 kW solar - $9,990
The FR-12K20CP is the most affordable way into a true whole-home off-grid system. The FR12K-B all-in-one inverter delivers 12,000 W continuous and 24,000 W surge on 120/240V split-phase, so a well pump, mini splits, a dryer and a range all work. Two MPPTs accept up to 13.2 kW of PV, and generator charging, rapid shutdown and breakers are built in. Four CoreX 5 Pro rack batteries (EVE Grade A cells, 100 A BMS, 6,000+ cycles, 10-year warranty) store 20.48 kWh, and sixteen 450 W bifacial N-type panels make about 21-29 kWh on a 4-sun-hour day.
Sungold Power FR-12K30CP - 12 kW, 30.72 kWh, 9.44 kW solar - $13,150
Same 12 kW inverter, with six CoreX 5 Pro batteries (30.72 kWh) and sixteen 590 W bifacial panels (9.44 kW). That is 50% more storage and 30% more array than the FR-12K20CP for $3,160 more - the extra half-day of autonomy that matters in the Pacific Northwest, Great Lakes or New England. It is also the lowest cost per kWh of storage in this guide (about $428). Customers also regularly send us price-check links for this kit.
Sungold Power SGK-8MAX - 8 kW, 10.24 kWh, 5.4 kW solar - $6,979
The cheapest kit here with split-phase 120/240V output and a big array. The SPH8048P inverter (UL 1741 by ETL) gives 8,000 W continuous and 16,000 W peak, handles motors up to 5 HP and has two MPPTs for up to 11 kW of PV. Twelve 450 W panels make about 16 kWh on a 4-sun-hour day - more than the 10.24 kWh battery holds, so it refills quickly in short winter days. The battery is four 12V 200Ah LiFePO4 units in series with Bluetooth monitoring and self-heating below 33.8°F. It is in our Halloween sale through November 1 (see section 9).
Sungold Power SGR-5KE - 5 kW, 10.24 kWh, 2.49 kW solar - $4,782
A balanced 120V kit for a small, efficient home: a 5,000 W inverter (10,000 VA peak, UL 1741 by ETL, built-in Wi-Fi), two SG48100P 5.12 kWh rack batteries (7,000+ cycles) and six 415 W panels. At about $467 per kWh of storage it is the best value below the 12 kW class, and the inverter takes up to 5 kW of PV, so you can double the array later. The limit is voltage: 120V only, so no 240V well pump or dryer.
Sungold Power SGR-20K32P - 20 kW, 32.14 kWh, 14.4 kW solar - $15,975
Two SPH10048P 10 kW inverters in parallel for 20,000 W of split-phase power, two IP65 PowerMax outdoor batteries (32.14 kWh, UL 1973 and UL 9540A, CEC listed, 8,000 cycles, 10-year warranty) and thirty-two 450 W bifacial panels (14.4 kW, about 43-58 kWh a day). As noted in the sizing section, the two batteries alone support about 14.5 kW continuous; add a third PowerMax if you need the full 20 kW at night.
Sungold Power SGM-5K5E - 5 kW, 5.12 kWh, 1.2 kW solar - $3,145
The entry point to our 48V off-grid line: a 5,000 W 120V inverter/charger (10,000 VA peak, 5.5 kW PV input, parallels to six units), one 48V 100Ah LiFePO4 battery (7,000+ cycles) and six 200 W panels with brackets and cables. It suits a weekend cabin and grows with a second battery module and more panels. With one module, plan continuous loads around 2.5 kW.
Sungold Power SGKT-3PRO - 3 kW, 5.12 kWh, 800 W solar - $2,485
The cheapest complete kit we stock. A 24V 3,000 W inverter (6,000 VA peak) with an 80 A MPPT, 40 A AC/generator charging with generator auto-start, and 10 ms UPS transfer; two 24V 100Ah Bluetooth batteries with self-heating and IP65 cases; and four 200 W panels (23.5% efficiency). It suits a hunting cabin or shed office used on weekends.
6. Which kit for which home?
| Your situation | Daily use | Kit | Why |
|---|---|---|---|
| Weekend cabin, no 240V loads | 2-4 kWh | SGKT-3PRO or SGM-5K5E | Battery refills over the week; low cost |
| Tiny home or full-time cabin, propane heat | 6-10 kWh | SGR-5KE | 10.24 kWh covers a night with reserve |
| Small home with a 240V well pump, northern state | 10-16 kWh | SGK-8MAX | Split-phase plus a 5.4 kW array for short days |
| Family home, propane cooking, sunny region | 15-20 kWh | FR-12K20CP or SGR-10K2M | 20.48 kWh and 12 kW (or 10 kW) split-phase |
| Family home, cloudy winters | 18-25 kWh | FR-12K30CP | 30.72 kWh, 9.44 kW array |
| All-electric home, farm or shop | 30-45 kWh | SGR-20K32P | 14.4 kW array, 20 kW of inverter |
Between two sizes? Buy the battery and inverter you will need; panels are the easiest part to add later. Browse every off-grid solar power system, or narrow by size with our 5 kW and 8 kW kit collections and the full Sungold Power kit range.
7. What to check before you order
- Delivery and handling. The 12 kW and 20 kW kits weigh about 750-1,200 lb and arrive by freight on pallets. Panels in particular are big - about 69 x 45 in each for 450 W modules - so plan for a truck that can reach your site and two people to unload.
- Where the battery lives. LiFePO4 cannot be charged below about 32°F. In an unheated cabin choose a kit with self-heating batteries (SGKT-3PRO, SGK-8MAX) or keep the bank in a conditioned space; the SGR-20K32P's PowerMax batteries are outdoor rated (IP65).
- Mounting. Kits include Z-brackets, not full roof racking or ground-mount frames.
- Warranties. Batteries carry 10-year warranties on the 12 kW and 20 kW kits; inverters are listed at 2-3 years on those kits; panels carry 25-30-year output warranties. Keep the paperwork with the system.
8. What our customers ask
Off-grid kit questions reach us by phone, text and email in a few repeating patterns (shared here without any personal details):
- "Is this price right?" Buyers send kit links - including copies of our listings on other sites - to confirm the price. We confirm and send the ecosolarkits.com link.
- "Which 10 kW kit should I get?" Customers often ask us to compare the 10-12 kW Sungold kits. Our usual answer is section 6: 12 kW split-phase for a family home, the 30 kWh version for cloudy winters.
- Sizing. We send the Solar Kit Calculator first, then check the result against the customer's appliance list - especially 240V loads and well pump surge.
9. Current codes and sales
As of October 26, 2026: the Halloween sale takes $50 off automatically on the SGR-5KE, SGK-8MAX, SGR-10K2M and SGR-20K32P (plus other kits in the sale collection), and code SPOOKY150 adds $150 off $2,000+ of sale items - both end November 1 at 11:59 PM ET. Otherwise (one code per order): SAVE500 ($500 off $8,000+, which covers the 10-20 kW kits), SAVE250 ($250 off $4,000+), ECO100 ($100 off $1,500+) and ECO50 ($50 off, no minimum). ECOBLACK2026 ($150 off $2,000+) is scheduled for November 20 - December 1; our Black Friday solar deals hub tracks every verified price and code.
10. FAQ
What is the best off-grid solar kit with battery and inverter?
For a typical full-time home, the Sungold Power FR-12K20CP ($9,990 on October 26, 2026) is the best all-round off-grid kit: a 12 kW 120/240V split-phase inverter with 24 kW surge, 20.48 kWh of LiFePO4 rack batteries and 7.2 kW of bifacial panels. Smaller homes and cabins can start with the SGR-5KE (5 kW, 10.24 kWh, $4,782), and large homes or farms should look at the 20 kW SGR-20K32P.
What size off-grid solar kit do I need for my house?
Start from daily kWh, not house square footage. A weekend cabin uses about 2-5 kWh a day, a tiny home 6-10 kWh, a small home with propane appliances 10-18 kWh, and an all-electric family home 20-30 kWh or more. Then size the array as daily kWh / (winter sun hours x 0.75), the battery as night-time kWh / 0.9 per day of autonomy, and the inverter for loads that run together plus surge.
How much does a complete off-grid solar system cost in 2026?
Complete DIY kits with inverter, LiFePO4 battery and panels in stock at Eco Solar Kits range from $2,485 for a 3 kW, 5.12 kWh cabin kit to $15,975 for a 20 kW, 32.14 kWh whole-home kit (prices checked October 26, 2026). Add racking, wiring and a licensed electrician on top. The federal 25D credit no longer applies to home systems paid for after December 31, 2025.
Can an off-grid solar kit run central air and a well pump?
Yes, if the kit has 120/240V split-phase output and enough inverter and battery current. A well pump plus 3-ton central air typically needs an 8-12 kW split-phase inverter with surge headroom, such as the SGK-8MAX (16 kW peak) or FR-12K20CP (24 kW surge). 120V-only kits like the SGR-5KE cannot run 240V loads.
How many days can an off-grid solar battery last without sun?
Divide usable battery kWh by your daily use. At about 90% usable, the 20.48 kWh FR-12K20CP gives roughly 18 kWh, about one day for a home using 18 kWh a day, while the 30.72 kWh FR-12K30CP gives about 1.5 days. Most full-time homes plan 1-2 days and use a generator for longer cloudy stretches.
Can I install an off-grid solar kit myself?
Many owners mount panels themselves, but home systems involve high-voltage PV strings, a high-current 48V bank and AC panel wiring. Most jurisdictions require a permit and inspection, so plan on a licensed electrician for the AC side and any connection to the house, and never backfeed a home through an outlet.
Is a portable power station a good alternative to an off-grid kit?
For a weekend cabin, RV or short outages, a large portable power station with panels is simpler. For a home that cycles the battery daily through winter, a 48V kit with 10 kWh or more, a fixed array and split-phase output is cheaper per kWh and easier to expand.
Want a second opinion? Send us your appliance list and ZIP code and we will match a kit - or compare our best off-grid solar systems, off-grid lithium batteries and off-grid inverters. If you are choosing an inverter for a grid-tied home instead, read EG4 vs Sol-Ark; for portable options see our solar generators for home backup guide.
Serhii Dovzhenko, Solar & Energy Storage Specialist at Eco Solar Kits · LinkedIn
Serhii is based in Vancouver, BC, and works on product data, system sizing and buyer guides for Eco Solar Kits. He attends solar and energy storage industry conferences and is involved in the community of electricians in Vancouver, BC. Credit for the data verification in this guide goes to Adsec.ca.