Sump pump backup system: the battery backup kit, and the check valves it won't run without
Updated 2026-11-10 · Kit: Sump pump battery backup kit: one Amazon link that puts all three in your Amazon cart: https://www.amazon.com/gp/aws/cart/add.html?AssociateTag=dealectric-20&ASIN.1=B07GJXRZ1V&Quantity.1=1&ASIN.2=B000O1WN78&Quantity.2=1&ASIN.3=B000BQSCMG&Quantity.3=1
Short answer. A battery sump pump backup system that works is the Wayne ESP25n backup pump, a Wayne WSB1275 12 V 75 Ah battery and a check valve for its line. Wayne's manual says the system will not function without two check valves, one on each pump's discharge.
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How this table was made: each figure comes from the maker's own US product page or manual, or from the reviewer named next to it, checked 2026-11-10. Dealectric does not test units itself. Rows with a Buy link are products Dealectric lists: the links are affiliate links, and their codes are re-tested in the brand's own cart every day (last check 2026-11-13).
| Model | Job in the backup system | Deciding figure | What it needs to work | Covers a failed main pump? | Price | Buy |
|---|---|---|---|---|---|---|
| Wayne ESP25n | Second pump with its own float; starts above the main pump's 'on' level | 1,500 GPH at 10 ft; up to 10,000 gal per charge (Wayne) | Check valve on its own discharge and on the main pump's; GFCI outlet within 6 ft (Wayne manual) | Yes: separate pump and float | $283.64 on Amazon (checked 2026-11-12) | Buy on Amazon |
| Wayne WSB1275 | Battery for the backup pump (sold separately) | 12 V, 75 Ah, maintenance-free (Wayne) | Sealed lead-acid, up to group 27, to fit the case (Wayne manual) | Yes: runs the backup pump in an outage | $276.62 on Amazon (checked 2026-11-12) | Buy on Amazon |
| Wayne 66005-WYN1 check valve | Stops pumped water draining back into the pit | 1-1/2 in. (North 40 listing) | One per pump discharge; 'System will not function without two check valves' (Wayne manual) | Yes: needed for either pump to empty the pit | $22.50 on Amazon (checked 2026-11-12) | Buy on Amazon |
| BLUETTI Apex 300 | Battery and inverter that keeps the existing AC pump running | 2,764.8 Wh; 11.0–16.6 h on a 1/3 HP pump running 10–15 min per hour (BLUETTI) | UPS mode; peak rating at least 1.5× the pump's start watts; a 1/2 HP pump starts at 2,150–4,100 W (BLUETTI) | No: power cuts only | $1,499 on bluettipower.com, 2026-11-05 | $1,424.05 through this link discount applied by the link; tested 2026-11-13 |
| BLUETTI AC180 | Battery and inverter for the existing AC pump | 1,152 Wh; 1,800 W rated; ≤20 ms UPS switchover (manual) | ECO off (it cuts AC after 1–4 h below 15–30 W) and Grid Enhancement off (manual) | No: power cuts only | $499 on bluettipower.com, 2026-11-07 | $474.05 through this link discount applied by the link; tested 2026-11-13 |
| BLUETTI Elite 100 V2 | Battery and inverter for the existing AC pump | 1,024 Wh; about 1.0 h of continuous running on a 1/3 HP pump (BLUETTI) | BLUETTI limits it to secondary systems or 1/4 HP utility pumps | No: power cuts only | $499 on bluettipower.com, 2026-11-07 | $474.05 through this link discount applied by the link; tested 2026-11-13 |
What the differences mean
- Wayne ESP25n: 10,000 gal per charge ÷ 1,500 GPH at 10 ft ≈ 6.7 h of nonstop pumping. Consumer Reports says a fully charged deep-cycle battery typically gives 7–8 h of active pumping; it tests backup pumps on a 12 V 75 Ah AGM battery at 10 ft of lift.
- BLUETTI Apex 300: BLUETTI's formula is Wh × 0.8 ÷ running watts. 2,764.8 × 0.8 ÷ 800 W ≈ 2.8 h of continuous running on a 1/3 HP pump, or 11.0–16.6 h if the pump runs 10–15 min per hour.
- BLUETTI AC180: 1,152 × 0.8 ÷ 800 W ≈ 1.2 h of continuous running on a 1/3 HP pump. BLUETTI says a 1/3 HP pump draws 1,300–2,900 W to start, and its 1.5× rule gives 1.5 × 1,300 = 1,950 W, already above the AC180's 1,800 W rated output. Its 2,700 W Power Lifting mode is for resistive loads only, so test your pump's start on it first.
- Any power station: it keeps your main pump powered and nothing more. If that pump jams or its switch fails, nothing empties the pit. The ESP25n has its own pump and float, so it covers both cases.
| Your situation | What fits |
|---|---|
| Working main pump; you want cover for outages and for a failed main pump | The Wayne kit below |
| You can't fit a second pump in the pit, and outages run long | BLUETTI Apex 300 in UPS mode, sized to your pump's start watts |
| Long outages and a pump that could fail | The Wayne kit, plus a power station for the main pump |
Why the check valves decide whether the backup works
The backup pump sits in the same pit as your main pump. If either discharge line has no check valve, water pumped up the pipe can run straight back down into the pit. Wayne's ESP25 manual: 'A check valve will be required in the discharge line of BOTH the Main AC pump and the back-up pump', and 'System will not function without two check valves.'
- Plumbing: Wayne prefers a separate discharge line for the backup (Method 1), with a rubber check valve that is sold separately. You can also tie into the existing line (Method 2), with the valves above the sump. The pump has a 1-1/2 in. NPT outlet and installs on 1-1/4 or 1-1/2 in. rigid PVC. A 1-1/4 in. line needs an adapter, which is not included.
- Float: mount it at least 10–12 in. above the bottom of the pit, so the backup only runs once the water is above the main pump's normal 'on' level.
- Battery: the oversize case holds a 12 V sealed lead-acid battery up to group 27, and Wayne recommends its WSB1275 75 Ah. The manual describes sealed lead-acid batteries only, so a 12 V LiFePO4 battery is not a documented match for its charger.
- Power: plug the charger into a separately fused, GFCI-protected 115 VAC outlet, with the battery within six feet of the sump.
The kit: The kit: Sump pump battery backup kit (WAYNE ESP25n 12 Volt Battery Backup Sump Pump + Wayne WSB1275 12 V 75 Ah Maintenance-Free Standby Battery for Backup Sump Pumps + Wayne 1-1/2 in. Sump Pump Check Valve), one Amazon link that puts all three in your Amazon cart: https://www.amazon.com/gp/aws/cart/add.html?AssociateTag=dealectric-20&ASIN.1=B07GJXRZ1V&Quantity.1=1&ASIN.2=B000O1WN78&Quantity.2=1&ASIN.3=B000BQSCMG&Quantity.3=1 the ESP25n, the WSB1275 battery and one check valve for the backup's line. Most main pumps already have a check valve on their line. If yours doesn't, add a second one.
If you power the main pump from a power station instead, the AC180 manual describes ECO mode: it switches the AC outlets off after 1–4 h at a load of 15–30 W or less. A pump draws next to nothing between cycles, so turn ECO off and run a test before you count on it.
Not recommended
The BLUETTI Elite 100 V2 as the main backup for a sump pump. BLUETTI's own sump-pump guide gives it about 1.0 h of continuous running on a 1/3 HP pump and limits it to secondary systems, water alarms or 1/4 HP utility pumps.
Sources
- ESP25n flow at 0/5/10/15 ft, gallons per charge, housing; Wayne's Amazon link to ASIN B07GJXRZ1V — www.waynepumps.com
- ESP25 needs a 12 V battery; WSB1275 75 Ah recommended, sold separately — www.waynepumps.com
- WSB1275 12 V 75 Ah maintenance-free; Wayne's Amazon link to ASIN B000O1WN78 — www.waynepumps.com
- Two check valves required; float 10–12 in. above pit bottom; GFCI outlet, battery within six feet — www.manualslib.com
- Rubber check valve sold separately; 1-1/4 or 1-1/2 in. rigid PVC; 1-1/2 in. NPT outlet; adapter not included — www.manualslib.com
- Designed for SLA batteries; case holds up to a 27-frame battery — www.manualslib.com
- ESP25 limited warranty: two years from purchase, repair or replace at Wayne's option, receipt and return authorization required — www.manualslib.com
- 7–8 h of active pumping per charge; 75–120 Ah; tested with 75 Ah AGM at 10 ft lift — www.consumerreports.org
- Sump pump running and start watts, 1.5× surge rule, runtime formula, Apex 300 and Elite 100 V2 runtimes — bluettipower.com
- AC180 ECO auto-off, ≤20 ms UPS, Grid Enhancement, Power Lifting for resistive loads only — www.manualslib.com
- AC180 capacity and rated output — www.bluettipower.com
- Apex 300 capacity and output — www.bluettipower.com
- Elite 100 V2 capacity and output — www.bluettipower.com
- Wayne 1-1/2 in. sump pump check valve — north40.com
Published 2026-11-10; updated 2026-11-10. The buy links are affiliate links; see the disclosure. Corrections welcome at [email protected] or /feedback.