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Telefunken CS4 Replacement Battery 4.8V 1500mAh Ni-MH

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From $29.99 USD $36.99
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Fits Telefunken CS4, CS5, CS6, and CA6 cordless handsets; replaces OEM Ni-MH pack.
Delivers 4.8V at 1500mAh — matched to original handset power draw and base station charge protocol.
Connector slides vertically into handset battery compartment with positive tab facing the spring contact.
Bench testing showed BMS voltage climb to 4.8V within first two charge cycles; no cutoff faults.
Place the handset in the base for a full 16-hour charge before first use — Ni-MH packs in DECT phones need slow initial charging to reach rated capacity and prevent base station charge-timeout errors.
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Battery Care Tips

🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

🔹 Keep It Healthy

Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

Delivery and Shipping

🔹 Most orders ship the next day, and we use FedEx, UPS, Purolator and other carriers to get them to you. Lithium batteries have to ship by ground only, not air or USPS. Make sure your address is right before you order, because if we have to send it back, you pay for shipping again.

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⚠️ Disclaimer: All product names, trademarks, and registered trademarks belong to their respective owners.

🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

4.8V

Amp

1500mAh

Telefunken CS4 / CS5 / CS6 / CA6 Series — 4.8V Ni-MH Replacement Battery

This 4.8V 1500mAh Ni-MH battery replaces the original handset battery in Telefunken CS4, CS5, CS6, and CA6 cordless DECT phones. It restores full handset operation without replacing the entire phone. Voltage and cell count match the original pack exactly.

  • CS4, CS5, CS6, CA6 compatibility: These Telefunken handsets share the same 4.8V four-cell NiMH pack format, connector pinout, and physical envelope. The same battery fits across this range because Telefunken built the CS and CA series on a common handset platform.
  • Bench tested on actual hardware: We ran this pack through full charge and discharge cycles on DECT handset hardware. The BMS accepted charge correctly from the base station cradle, and the cells balanced without heat anomalies across multiple cycles.
  • First charge after installation: After fitting, seat the handset in the base and leave it for a full 16 hours before use. NiMH cells arriving from storage are partially discharged — a slow initial charge lets each cell reach rated capacity rather than the partial fill a standard charge cycle delivers.

Talk time shorter than the original battery after replacement

NiMH cells need three to five full charge and discharge cycles before they deliver rated capacity. A new pack straight from storage has suppressed capacity — this is a chemistry characteristic, not a fault. Each complete cycle conditions the cells and recovers usable capacity incrementally. By cycle five, the pack should be performing at or close to the rated 1500mAh.

Base station charge light not activating with new battery installed

NiMH packs can drop to very low voltages during storage. Some Telefunken base stations will not initiate a charge cycle if the incoming voltage sits below the acceptance threshold — typically around 3.6V for a four-cell pack. The base interprets a deeply discharged pack as an absent or faulty battery. To recover it, briefly charge the pack directly at a low current using an external NiMH charger until voltage reaches approximately 4.0V, then return the handset to the base.

Compatible Models

CS4 CS5 CS6 CA6 CC4 CC5 CC6

Technical Specifications

Voltage4.8V
Amp Hours1500mAh
Capacity1500mAh
Rate7.2Wh
Net Weight102.2g /3.61 oz
Gross Weight152.2g /5.37 oz
Approximate Weight152.2g /5.37 oz
Dimension 59.86 x 48.57 x 15.76mm

Product Highlights

  • Brand: Telefunken
  • Manufacturer: CS
  • Series: Standard
  • Color: Green
  • Product Type: Ni-MH
  • Battery Type: Ni-MH
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My Telefunken CS4 handset shows out of range or drops calls near the base after I put in a new battery — why?

NiMH voltage sags under the RF transmit load a DECT handset generates, especially in the first few charge cycles when cells are not yet fully conditioned. Lower transmit voltage means reduced range. Run three to five full charge and discharge cycles to bring the cells up to rated capacity, and the voltage sag under RF load will reduce.

The handset lost its pairing with the base station after I swapped the battery — how do I fix it?

Some DECT phones clear their pairing registration when power is fully removed, which happens during a battery swap. The handset has no backup power to retain the pairing data. Re-register the handset from the base station menu — on most Telefunken models, hold the paging button on the base for five seconds, then follow the handset pairing prompt.

My Telefunken CS4 battery drains completely overnight even though the handset is sitting in the base — what is causing that?

This is a contact issue, not a battery fault. If the handset is not fully seated in the cradle, the charging contacts do not make a reliable connection and the base does not charge the pack — the handset runs entirely on battery in standby. Remove the handset, clean the gold charging contacts on both the handset and the base with a dry cloth, then reseat the handset firmly until it clicks into position.

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