PetSafe A12 Dog Collar Replacement Battery 3V 150mAh RFA-182

PetSafe A12 / R-21 / R-51 — 3V Li-MnO2 Replacement Battery (RFA-182)

This is a 3V lithium manganese dioxide cell rated at 150mAh, built to the RFA-182 specification. It fits PetSafe dog training collars across the A12, R-21, and R-51 receiver collar lines. Li-MnO2 chemistry is the correct cell type for these collars — do not substitute alkaline or other lithium formats.

• A12, R-21, and R-51 collar fit: These three receiver collar models share the same battery bay dimensions and draw the same 3V supply rail. The RFA-182 format covers all three without modification to the contact plate or housing.
• Bench tested on actual hardware: We ran this cell in an A12 receiver collar and confirmed correct voltage delivery at the receiver module. The collar powered on immediately and maintained stable output across the correction and tone circuit without voltage drop events.
• First use after install: PetSafe receiver collars run a transmitter re-pairing check when the battery is first seated. After installing, press and hold the collar's test button for three seconds to confirm the receiver registers the transmitter signal before putting the collar back on the dog.

Why the A12 collar stops responding mid-session even with a new battery

The RFA-182 cell has a flat discharge curve, which means the collar reads adequate voltage right up until the cell is nearly exhausted. There is no gradual fade — the collar simply stops responding when the cell drops below its cutoff threshold. This behaviour is normal for Li-MnO2 chemistry and is not a fault with the collar or the replacement cell. Replace the battery at the first sign of delayed response rather than waiting for full failure.

Collar shows no response to transmitter immediately after battery install

This is almost always a seating issue, not a faulty cell. The RFA-182 contacts are small and the battery bay on these collars requires firm, even pressure until the cover clicks fully closed. If the collar still shows no response with the cover secured, remove the battery, clean the contact points with a dry cloth, and reseat it. A correctly seated cell should measure 3V across the collar's battery contacts before closing the housing.