Kirk 3040 Cordless Phone Compatible Battery 3.6V 700mAh

Kirk 3040 / 4020 / 4040 / 4080 — 3.6V Ni-MH Replacement Battery

This is a 3.6V 700mAh Ni-MH replacement battery for the Kirk 3040, 4020, 4040, and 4080 cordless DECT handsets. It slots into the handset battery compartment and restores the ability to hold a charge and complete calls. Dimensions are 45.00 × 31.10 × 10.50mm — verify against your original cell before ordering.

• Kirk 3040 / 4020 / 4040 / 4080 compatibility: These four handsets share the same battery bay geometry and 3.6V Ni-MH charge circuit, so one cell fits all four. The base station charges at a fixed current profile matched to this chemistry and voltage — swapping to any other chemistry will cause charge faults.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Kirk base station, confirming the charge circuit accepted the pack without triggering a fault light and that voltage held steady through a full standby period.
• First-charge protocol for Kirk handsets: After installing, seat the handset in the base and leave it for a full 16 hours before first use. Ni-MH cells shipped in partial-discharge state need that slow first charge to reach rated capacity — cutting it short locks in a lower usable ceiling from day one.

Talk time shorter than the original battery after replacement

Ni-MH cells do not deliver full rated capacity on cycle one. The first three to five charge-discharge cycles gradually increase the amount of charge the cell can accept and hold. If talk time feels short immediately after swapping, run the handset down to the low-battery warning, return it to the base for a full charge, and repeat. By cycle five, capacity should be at or near the rated 700mAh.

Base station charge light not activating after new battery installed

Ni-MH cells can drop below 3.0V during storage, and some Kirk base stations will not begin a standard charge cycle if the pack voltage sits below their acceptance threshold. Remove the handset, wait 30 seconds, and reseat it firmly — contact pressure matters. If the fault persists, the base may need a recovery charge: hold the handset in the cradle with light downward pressure for two minutes, then release. Target resting voltage once charging begins is approximately 3.6–4.0V.