rechargeable battery back

[Garcia]

I am thinking of getting a rechargeable battery pack big enough to run the pump and refrigerator in the event of a power outage. They are relatively rare on Bear.

I'll put a soft start adapter on the pump to minimize the load needed at start up. The stove is propane.

Because this will (hopefully) be used infrequently, I am looking for ease of annual maintenance, hence staying away from a generator that needs oil changes and fuel drained annually. I'm also not a fan of the constant noise of a typical generator.

I don't need to power the whole house.

Anyone go this route and/or have suggestions?

[FlyingScot]

I would do a search for a small stand alone solar system. Will not be reliable in winter due to snow coverage, but should be more than enough for the summer. Keep in mind you need only to keep the battery topped up

[TomC]

Originally Posted by Garcia

I am thinking of getting a rechargeable battery pack big enough to run the pump and refrigerator in the event of a power outage. They are relatively rare on Bear.

I randomly came across this YouTube video the other day (i was watching a lawn care video by the same creator). Perhaps you will be interested:

https://www.youtube.com/watch?v=iyQk6K8ABlw

[ITD]

My son did this with his solar panels, he added solar to his existing system, then added like 40+ kw of battery. It weren't cheap.

You need to define how long you want those devices to run, look up the power consumption, then go from there. Sounds like you just want to charge it from the electric company. Not a bad plan, unless it's a real long outage.


Edit: Here is what co-pilot had to say about it. Use this as a point of reference, I haven't confirmed that it's right, remember, ai sometimes hallucinates, and co-pilot isn't the best one out there.....

### Backup battery system for well pump + refrigerator (3 days, grid‑only, lowest practical cost)

You want: **no solar, no generator**—just a battery kept topped up from the grid, sized to run:

- **1× well pump (240 V)**
- **1× refrigerator (120 V)**
- **For 3 days of outage**

Below is a concise design you could hand to an electrician and then print as a PDF.

---

## 1. Load and battery sizing

### 1.1 Estimated energy use

**Well pump (typical ½–1 HP submersible, 240 V)**
- **Run power:** ~\(800\ \text{W}\)
- **Runtime:** ~1 hour/day total
- **Daily energy:**
\[
0.8\ \text{kW} \times 1\ \text{h} = 0.8\ \text{kWh/day}
\]

**Refrigerator (modern full‑size)**
- **Average draw:** ~\(120\ \text{W}\) while cycling
- **Duty cycle:** ~10 hours/day equivalent
- **Daily energy:**
\[
0.12\ \text{kW} \times 10\ \text{h} = 1.2\ \text{kWh/day}
\]

**Total daily energy:**
\[
0.8 + 1.2 = 2.0\ \text{kWh/day}
\]

**For 3 days:**
\[
2.0 \times 3 = 6.0\ \text{kWh}
\]

### 1.2 Inverter and system losses

Assume ~85% overall efficiency (inverter + wiring + battery losses):

\[
\frac{6.0}{0.85} \approx 7.1\ \text{kWh usable}
\]

Add ~25% reserve so you’re not running the battery to the floor:

\[
7.1 \times 1.25 \approx 8.9\ \text{kWh}
\]

**Target usable capacity:** ~**9–10 kWh**

With LiFePO₄ at ~80% usable depth of discharge:

\[
\frac{9}{0.8} \approx 11.25\ \text{kWh nominal}
\]

**Practical spec:** **one ~10–12 kWh LiFePO₄ battery** is right in the pocket.

---

## 2. System architecture (simple, low‑cost)

### 2.1 Core components

1. **Battery bank**
- **Type:** LiFePO₄ (lithium iron phosphate)
- **Size:** ~10–12 kWh nominal
- Example: **48 V, 200–250 Ah rack battery**
- Reason: lowest lifetime cost, low maintenance, compact, good surge capability.

2. **Inverter‑charger (split‑phase)**
- **Output:** 120/240 V split‑phase
- **Continuous power:** **4–6 kW**
- **Surge:** ≥ **2×** continuous for pump start (6–10 kW for a second or two)
- **Charger:** built‑in grid charger to keep battery full when utility is on.

3. **Critical loads subpanel**
- Fed from inverter output.
- Circuits moved here:
- Well pump (240 V breaker)
- Refrigerator circuit
- (Optionally a couple of lights and a receptacle, but you said only those two loads are required.)

4. **Automatic or manual transfer**
- Most inverter‑chargers handle this internally:
- When grid is present: loads run on grid, battery floats.
- When grid fails: inverter switches to battery in a fraction of a second.

---

## 3. “Least expensive” practical configuration

This is the **cheapest setup that will reliably start a 240 V well pump** and run both loads for 3 days.

### 3.1 Suggested spec

- **Battery**
- **1× 48 V 200 Ah LiFePO₄ rack battery**
- Nominal energy:
\[
48\ \text{V} \times 200\ \text{Ah} = 9.6\ \text{kWh}
\]
- Many 200 Ah units are actually labeled ~10 kWh; some 250 Ah units give ~12 kWh.

- **Inverter‑charger**
- **Rating:** ~6 kW, 120/240 V split‑phase
- Features:
- Built‑in transfer switch
- Built‑in grid charger
- Programmable charge profile for LiFePO₄

- **Balance of system**
- Critical loads subpanel (6–8 spaces is plenty)
- Breakers, wire, conduit, disconnects
- Battery cabinet or rack
- Misc. hardware and labeling

This keeps it to **one battery, one inverter, one small subpanel**—no solar, no generator.

---

## 4. Estimated installed cost

These are **ballpark “turnkey” numbers** for a licensed electrician/installer in New England, not DIY pricing.

### 4.1 Hardware cost estimate

| Component | Qty | Unit cost (approx.) | Extended |
|-----------------------------------|-----|----------------------|----------|
| 48 V 200–250 Ah LiFePO₄ battery | 1 | \$2,000–\$2,800 | \$2,000–\$2,800 |
| 6 kW 120/240 V inverter‑charger | 1 | \$1,400–\$2,000 | \$1,400–\$2,000 |
| Critical loads subpanel + breakers| 1 | \$200–\$400 | \$200–\$400 |
| Disconnects, wire, conduit, misc. | — | \$300–\$600 | \$300–\$600 |

**Hardware subtotal:** **\$3,900–\$5,800**

### 4.2 Labor and soft costs

| Item | Estimate |
|---------------------------------|----------|
| Electrical labor (1–2 days) | \$1,200–\$2,000 |
| Permitting / inspection (if any)| \$150–\$400 |
| Configuration, testing, labeling| \$250–\$500 |

**Labor + soft costs:** **\$1,600–\$2,900**

### 4.3 Total installed range

- **Low end (value components, simple install):** ~**\$5,500**
- **High end (premium components, more complex wiring):** ~**\$8,500**

A realistic target for a straightforward install is **\$6,000–\$7,000 fully installed**, given:

- One inverter‑charger
- One rack battery
- Short runs to panel and pump breaker

---

## 5. Operating behavior (no generation)

- **Normal grid conditions**
- Inverter passes grid power through to the critical loads panel.
- Battery is kept at a high state of charge (e.g., 95–100%) via the built‑in charger.
- **Outage**
- Inverter switches to battery in <1 second.
- Well pump and refrigerator continue to run as usual.
- With your usage assumptions, you have **~3 days** of runtime before hitting your reserve.
- **Grid returns**
- Inverter reconnects to grid.
- Battery recharges automatically over a few hours.

---

## 6. Summary (for the PDF “front page”)

**Objective:**
Provide **3 days** of backup for **one 240 V well pump** and **one refrigerator**, with **no solar or generator**, using only a **grid‑charged battery system**, at the **lowest practical installed cost**.

**Recommended system:**

- **Battery:** 1× 48 V 200–250 Ah LiFePO₄ (~10–12 kWh)
- **Inverter‑charger:** 6 kW 120/240 V split‑phase with built‑in transfer and charger
- **Wiring:** Small critical loads subpanel feeding only the well pump and refrigerator
- **Runtime:** ~3 days at typical usage with reserve
- **Estimated installed cost:** **\$6,000–\$7,000** (rough New England turnkey range)

---

If you want, next step we can tighten this further by assuming a specific pump HP and picking actual model numbers so you could get apples‑to‑apples quotes from local electricians.

[Garcia]

I'm looking at something like this, https://us.ecoflow.com/products/delt...54615943512137

The idea is not to have continuous power for days on end but instead prevent food from spoiling and maintain running water with the idea of using water sparingly to make power last as long as possible. Nothing would be automated or wired in and instead the pump, refridgerator, and anything else would need to be plugged in.

[WinnisquamZ]

I have a similar device. Does work. You just have to be here to plug stuff in


Sent from my iPhone using Winnipesaukee Forum mobile app

[Garcia]

Until I retire and start spending more time early and late in the season on the island, I can't justify the expense of a full, automated back up system. I just want something I can use if I am there and the power goes out - with the added bonus of portability

[codeman671]

Anker makes good stuff. I bought 2 of the F3800's with extra batteries and solar panels a while back to be a backup to my backup. Still sitting in my garage, but I'll get to them some day.

[Garcia]

With the sale going on, I ended up puling the trigger on an EcoFlow DELTA 3 Max Series Portable Power Station (2048Wh). I plan to install a soft start adapter on the pump which seems like a good thing to have.

Of course once I have it at the island charged up and ready to go, the power will never go out again.

[ITD]

The power will go out, I installed an LP whole house generator about 2 or so years ago, and I thought the same, this thing will never run, 5 days later we had the Christmas storm, it ran for 4 days straight. It's probably had about 8 times of running 5 or more hours since, and at least one or two more multiday outages. I'm not sure that will run your well pump, I'd get the specs and call and ask. I hope it works out for you.

[Garcia]

Originally Posted by ITD

The power will go out, I installed an LP whole house generator about 2 or so years ago, and I thought the same, this thing will never run, 5 days later we had the Christmas storm, it ran for 4 days straight. It's probably had about 8 times of running 5 or more hours since, and at least one or two more multiday outages. I'm not sure that will run your well pump, I'd get the specs and call and ask. I hope it works out for you.

Thanks! I did check and it will run the water pump. To be extra safe I will install a soft start adapter which, if I understand correctly, minimizes the start up draw which is a good thing even when on regular power