Disclosure: Honey Hen Homestead is a Full Battery affiliate and may earn a commission if you buy through links on this page, at no extra cost to you. Prices and specifications below are as listed by Full Battery on September 25, 2026 and can change, so confirm them on their site before you buy.
The short answer
Full Battery sells DC-powered hydronic heat pumps, which they call water chillers and heaters, that make hot or chilled water directly from a battery bank with no inverter in between. The 1-ton 48 V model is listed at 12,000 BTU/h of cooling and 13,000 BTU/h of heating, a COP of 4.3 and a rated input of 680 W, starting at $2,490. It heats water to a maximum of 140°F (60°C) and chills it to a minimum of 50°F (10°C).
What we have and have not done: Honey Hen has not published installation or test results for this unit. Everything on this page comes from the seller’s published specifications, and the sizing examples use assumed numbers, clearly labeled. If we install one, we will document what actually happens here.
What it is, and how it differs from a packaged water heater
A hydronic heat pump moves heat into or out of a loop of water. That water can feed radiant floor loops, fan coils or a storage tank, depending on how you plumb it. It is not a complete potable hot-water appliance with its own tank.
This page used to cover the Sanden SANCO2, a packaged heat pump water heater with a storage tank that uses CO2 (R744) as its refrigerant. That is a different kind of product. If your only goal is domestic hot water from a tank, ask each vendor exactly how their system would be plumbed and how its efficiency is rated, and compare the figures under the same test standard. If you also want space heating or cooling from the same DC source, a hydronic unit like the one below becomes more interesting.
Why DC-direct matters off-grid
Most heat pumps run on AC, so a battery-based system needs an inverter to feed them. Full Battery’s units take DC directly: 46–57 V DC on the 48 V models and 21–30 V DC on the 24 V model. That skips the inverter’s conversion losses and idle draw for this load. The 46–57 V range covers a typical 48 V nominal battery bank, but confirm that your bank’s charge voltage stays inside it, and have the wiring, fusing and disconnects sized by a qualified installer.
Listed specifications
The 48V DC Hydronic Water Chiller & Heater comes in four sizes. Prices are “from” prices as listed.
| Size | Cooling / heating (BTU/h) | Rated input | Listed price |
|---|---|---|---|
| 1-ton | 12,000 / 13,000 | 680 W (15 A) | $2,490 |
| 2-ton | 24,000 / 27,000 | 1,250 W (28 A) | $3,250 |
| 3-ton | Not detailed on the page we checked | Not detailed | $3,950 |
| 4-ton | Not detailed on the page we checked | Not detailed | $4,480 |
- Efficiency: COP 4.3 and SEER 32, listed for the 1-ton and 2-ton models
- Input voltage: 46–57 V DC, with a 48 V brushless DC compressor and variable-speed (PWM) control
- Water side: 5.2 GPM (20 L/min) pump, 42 ft (13 m) of head, 3/4 in NPT female connections, copper plate heat exchanger
- Water temperature range: 50°F (10°C) coldest to 140°F (60°C) hottest
- Refrigerant: R-32, pre-charged and tested
- Size and weight (1-ton and 2-ton): 34 in wide by 12 in deep by 29 in tall, 120 lb net, 18 in minimum distance to a wall, thermostat on a 25 ft cord
- Noise: listed as 60 or lower (the seller writes the unit as “dBi”)
Full Battery also lists a 24V DC Hydronic Water Chiller & Heater at $2,490 and labels it “domestic hot water capable.” It is listed at 12,000 BTU/h cooling, 13,000 BTU/h heating, COP 4.3, 680 W and 32 A on 21–30 V DC, with R134a refrigerant. Its product page describes a connection to an external pressure tank, so treat any domestic hot water setup as a plumbing design question to settle with the seller, not an assumption.
How to size one for your homestead
- Find your load. Estimate your heating need with the heating calculator, and read our guide to off-grid cooling with earth tubes and DC heat pumps for the cooling side.
- Match it to a size. Compare your load in BTU/h with the listed ratings. The 1-ton is rated at 13,000 BTU/h of heating and the 2-ton at 27,000 BTU/h, at the manufacturer’s rating conditions, which the product page does not spell out. Ask what the output is at your coldest expected outdoor temperature.
- Turn the rated input into an energy budget. Rated watts times hours of run time equals watt-hours. Example with assumed numbers, not a measurement: the 1-ton at its listed 680 W running for 4 hours uses 680 × 4 = 2,720 Wh, or 2.72 kWh. Real draw will vary with outdoor temperature, water temperature and load.
- Check that your batteries and solar can carry it. Put that daily figure into the battery bank runtime calculator and the off-grid solar system calculator, then see the full cost in the off-grid budget calculator.
Questions to ask Full Battery before you buy
- What is the warranty? The product pages we checked did not list one.
- What are the rating conditions behind the COP and BTU/h figures, and what happens to heating output in cold weather?
- How should the water loop be protected from freezing where you live?
- If you want domestic hot water, what heat exchanger, tank and potable-water isolation do they recommend, and does it meet your local plumbing code?
- What are the shipping time, freight cost and support arrangements for a 135 lb unit?
Frequently asked questions
Can it run without an inverter?
Yes, according to the listings: the 48 V models take 46–57 V DC directly, and the 24 V model takes 21–30 V DC. You still need correctly sized DC wiring, fuses and disconnects, which a qualified installer should confirm.
How much power does it use?
The listed rated input is 680 W for the 1-ton and 1,250 W for the 2-ton. Actual consumption depends on conditions and load, so treat the rated figures as a starting point for planning, not a guarantee.
Is this the same as a SANCO2 heat pump water heater?
No. The SANCO2 is a packaged heat pump water heater with a tank and a CO2 refrigerant. The Full Battery unit is a DC-powered hydronic heat pump that heats or chills a water loop. They can serve overlapping needs, but they are plumbed and specified differently.
Has Honey Hen tested it?
Not yet. We have not published installation or test results for this unit, so this page relies on the seller’s specifications. See more of the equipment we cover on our shop page.
Planning a whole-home 48V DC system? Our book No Inverter Needed: The Complete 48V Off-Grid DC Wiring Guide covers DC-native heat pumps, hot water, breakers, fusing and grounding in depth.
This page provides general planning information, not an engineering design. Consult a qualified installer or licensed professional for electrical, plumbing and refrigerant work, and follow local codes.
