Basement Watchdog battery backup sump pump
Basement Watchdog makes three backup-only systems — the Emergency, Special CONNECT, and Big Dog CONNECT — plus a combo that pairs a backup with a cast-iron primary pump.
The Special CONNECT (BWSP) is the midrange choice: 1,850 GPH at 10 ft, weekly self-testing, and optional Wi-Fi alerts.[4] The Big Dog CONNECT adds a 20 A charger that can run the pump continuously from AC when the primary pump fails — useful if the power stays on but the float switch sticks or the main pump dies.[1] The Emergency is an entry-level unit with no self-test and a 0.4 A trickle charger.[3]
Basement Watchdog battery backup lineup
All flow figures come from Basement Watchdog's product pages. The manufacturer does not state the test voltage or battery condition used, so the numbers cannot be directly compared with Zoeller's or Liberty's battery-based curves.
Basement Watchdog backup pump comparison
| Model | Flow at 0 ft (GPH) | Flow at 10 ft (GPH) | Max head | Charger | Batteries | Wi-Fi alerts | Self-test | Warranty |
|---|---|---|---|---|---|---|---|---|
| Emergency BWE | 2,000 | 1,000 | 11 ft | 0.4 A | up to 1, sold separately | none | no | 2 yr |
| Special CONNECT BWSP | 2,600 | 1,850 | 16 ft | 1.6 A | up to 2, sold separately | optional (BW-WiFi2) | weekly | 2 yr |
| Big Dog CONNECT BWD12-120C | 3,500 | 2,200 | 16 ft | 20 A | up to 2, sold separately | optional (BW-WiFi2) | weekly | — |
| Big Combo CONNECT CITS-50 | 2,600 | 1,850 | 25 ft | 1.6 A | up to 2, sold separately | optional (BW-WiFi2) | weekly | 2 yr |
Each model in detail
Emergency (BWE) — entry level
The Emergency is Basement Watchdog's simplest system.[3] At 0.4 A, the charger is sized to maintain the battery between infrequent uses, not to recharge it quickly after a long outage. The controller has indicator lights and an audible alarm but no auto-test — you need to test it manually once a month. Wi-Fi is not available: the controller has no USB data port, so the BW-WiFi2 module cannot be connected. Maximum head is 11 ft, the lowest in the lineup.
Who it fits: a backup for a shallow pit (8–10 ft total lift) in a finished basement where alerts are handled by a separate water alarm and Wi-Fi matters less than a lower upfront cost.
Special CONNECT (BWSP) — midrange
The Special CONNECT nearly doubles the flow at 10 ft (1,850 GPH vs. 1,000 GPH) and adds weekly automatic pump exercise so you know the pump will run when it matters.[4] The controller has a USB data port for the optional BW-WiFi2 module, and a dry-contact remote terminal for wiring into a security system. The 1.6 A charger is a multi-stage smart charger that shuts off completely when the battery is full — its design assumption is that the pump will cycle briefly during storms rather than run continuously. Runtime is about 48 hours on one BW-27AGM battery at a 10% duty cycle, or 96 hours with two batteries (Parallel Jumper Cable sold separately).
Who it fits: most households with a typical 10–15 ft discharge run. The weekly self-test is the main reason to choose it over the Emergency if remote alerts aren't needed.
Big Dog CONNECT (BWD12-120C) — high capacity
The Big Dog adds two things the Special cannot do: it moves 2,200 GPH at 10 ft,[1] and its 20 A charger is large enough to power the backup pump directly off AC power. That second feature matters when the main pump fails mechanically while AC is available — the backup runs continuously off the charger without draining the battery, providing what Basement Watchdog calls "unlimited runtime" under those conditions. The controller also monitors for backup pump failure and shows battery charge percentage on the front panel, neither of which the Special offers.
The Big Dog supports two batteries (with the PJC jumper cable), giving 80 hours at 10% duty cycle on two BW-27AGM batteries. The battery fluid level sensor monitors wet-cell batteries and alarms if the electrolyte drops.
Who it fits: pits with heavy inflow during storms, or any basement where the primary pump is aging and a longer-term standby is needed. The 20 A charger also recharges a depleted battery about twelve times faster than the Special's 1.6 A charger.
Big Combo CONNECT (CITS-50) — combo system
The CITS-50 pairs a 1/2 HP cast-iron primary pump (4,400 GPH at 0 ft, 3,540 GPH at 10 ft) with the same backup pump found in the Special CONNECT.[5] Both pumps arrive pre-assembled and pre-plumbed. The backup uses the same 1.6 A charger and BW-WiFi2-compatible USB port as the BWSP. Maximum primary pump head is 25 ft; the backup is limited to 16 ft.
Who it fits: a new installation where the homeowner wants a known-good matched pair rather than buying primary and backup separately. The combo does not carry the Big Dog's 20 A charger, so the backup still depends on battery power during a primary failure.
Battery options and runtime
Every Basement Watchdog backup pump works with the BW-27AGM, their maintenance-free AGM battery, or a compatible wet-cell battery. The manufacturer does not publish the standard group size, but the BW-27AGM fits the battery box. Wet-cell batteries require the fluid level sensor that comes with the Big Dog CONNECT.
Runtime figures use a 10% duty cycle — the pump runs 6 minutes out of every 60. Real-world duty cycle depends on how fast water enters the pit. Basement Watchdog does not publish a continuous-run hour figure or the test voltage used for flow ratings. For a site with heavy inflow, treat the duty-cycle numbers as an upper bound.
Two batteries connect in parallel with the Parallel Jumper Cable (PJC), sold separately and compatible with the Special CONNECT, Big Dog CONNECT, and Big Combo CONNECT. The Emergency is single-battery only — the manufacturer advises against connecting a second.
Alerts and monitoring
The Emergency controller has LED indicators and an audible alarm; it alerts for pump activation, battery replacement needed, and power issues.[3] The Special and Big Dog add a USB data port and dry-contact terminal. Plug the BW-WiFi2 module into the USB port to get text, email, or push notifications through the Basement Watchdog app, with no monthly subscription. The Big Dog also alerts when the backup pump fails a test — the Special does not.
The remote terminal allows wiring to a standard alarm panel or auto-dialer as a dry-contact input. This is independent of the Wi-Fi module, so you can have both or just one.
Model confusion: Big Dog vs. Big Dog+ vs. Special
Older Basement Watchdog marketing used "Big Dog" for what is now sold as the Big Dog CONNECT (BWD12-120C). Some sources mention a "Big Dog+" as a successor to a prior Big Dog model. As of November 2026 the manufacturer's product page shows no separate Big Dog+ SKU — the Big Dog CONNECT is the top backup-only model in the current lineup. If you see Big Dog+ in an installation manual or old brochure, verify the current model number at the manufacturer's site before buying replacement parts.
The Special CONNECT (BWSP) and the Big Dog CONNECT share the same two-year base warranty and the same external connector protocol, but differ in pump capacity, charger size, and whether the charger can sustain continuous pump operation from AC.
How Basement Watchdog compares to other brands
Zoeller publishes flow data measured on a 12V deep-cycle battery and explicitly warns that some competitors use DC pump test standards that show 40–80% higher flow than battery-powered performance. Basement Watchdog does not state its test condition, so its published GPH figures may not be directly comparable. Zoeller's Aquanot Fit 508 shows 1,800 GPH at 10 ft on battery; the Big Dog CONNECT claims 2,200 GPH at 10 ft without a test condition — the gap may be real or may reflect a different test method.
Liberty Pumps publishes two curves (one at fixed 12.1 V, one with AC power on) for the same pump; see the backup sump pump pillar page for a full brand comparison. The Zoeller page and Wayne page cover those lineups in the same format.
Frequently asked questions
What is the difference between Basement Watchdog Emergency, Special, and Big Dog?
The Emergency (BWE) is the entry-level model: 1,000 GPH at 10 ft, no self-test, no Wi-Fi option, 0.4 A charger.[3] The Special CONNECT (BWSP) moves 1,850 GPH, adds weekly self-testing, and supports two batteries.[4] The Big Dog CONNECT (BWD12-120C) moves 2,200 GPH and adds a 20 A charger that sustains continuous pump operation from AC.[1]
What battery does Basement Watchdog use?
The BW-27AGM maintenance-free AGM battery is recommended across all models. All backup-only models also accept wet-cell batteries. Batteries are always sold separately. The Special, Big Dog, and Big Combo accept two batteries in parallel with the PJC jumper cable (sold separately) for roughly doubled runtime.
Does Basement Watchdog publish runtime data?
The manufacturer publishes duty-cycle runtimes (hours of protection at 10% pump-on time) but not continuous-run hours. The Special CONNECT gives about 48 hours (one battery) or 96 hours (two batteries) at 10% duty cycle.[4] No test voltage is stated for the GPH flow ratings.
What does Basement Watchdog CONNECT mean?
CONNECT refers to the USB data port on the Special, Big Dog, and Big Combo controllers. Plug in the optional BW-WiFi2 module to receive real-time text, email, or push alerts through the Basement Watchdog app. No subscription fee is required. The Big Dog also includes a dry-contact terminal for wiring to a security panel.
Is the Big Dog+ the same as the Big Dog CONNECT?
The Big Dog CONNECT (BWD12-120C) is the current top-tier backup-only model. Earlier Basement Watchdog materials referred to a "Big Dog+" as a potential or transitional name. As of November 2026, no Big Dog+ SKU appears in the manufacturer's current product catalog; the Big Dog CONNECT is the model in production.
Sources
- Big Dog CONNECT battery backup sump pump brochure (BWD12-120C) — Basement Watchdog, document dated 2018-06. Accessed 2026-11-03. Manufacturer brochure hosted by Home Depot.
- Big Dog CONNECT Battery Backup Sump Pump product page (BWD12-120C) — Basement Watchdog. Accessed 2026-11-03. Current product page. Lists max head 16 ft, 2,200 GPH at 10 ft, 20 A charger, 40-hour runtime at 10% duty cycle with one BW-27AGM battery.
- Emergency Battery Backup Sump Pump System product page (BWE) — Basement Watchdog. Accessed 2026-11-03.
- Special CONNECT Battery Backup Sump Pump System product page (BWSP) — Basement Watchdog. Accessed 2026-11-03.
- Big Combo CONNECT Primary and Battery Backup Sump Pump product page (CITS-50) — Basement Watchdog. Accessed 2026-11-03.