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Kirisun DP770 Compatible Battery KB-77B 7.4V 2000mAh

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From $38.99 USD $47.99
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Fits Kirisun DP770 and DP780 portable radios; replaces OEM KB-77B battery pack.
7.4V Li-ion, 2000mAh capacity delivers sustained transmit power without voltage sag during extended shifts.
Gold contact strip slides into radio battery slot with single locking tab; orientation marked on pack.
Bench tested on DP770 dock—BMS accepted charge cycle on first insertion, bar indicator tracked correctly.
If the charger dock shows fault LED on first insertion, remove the battery, wipe the gold contact strip with a dry cloth, and reseat firmly—the Kirisun platform requires a clean contact cycle to accept the new BMS handshake before charging begins.
Delivery time

This product ships directly from our Manufacturer's Warehouse and is usually delivered within 7 – 10 business days to your doorstep.

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Fresh Battery, Worth the Wait

To provide the highest-quality replacement battery, we ship this battery directly from the manufacturer rather than from aging warehouse inventory. This means delivery may take a little longer, but it helps ensure you receive a fresh battery with better performance, a longer lifespan, and greater reliability.

Estimated delivery: 7–10 business days
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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.

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🔹 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

7.4V

Amp

2000mAh

Kirisun DP770 / DP780 — 7.4V Li-ion Replacement Battery (KB-77B)

This is a 7.4V, 2000mAh Li-ion replacement battery for the Kirisun DP770 and DP780 portable two-way radios. It uses OEM part number KB-77B and fits directly into the standard battery bay on both models. Voltage and capacity match the original pack specification.

  • DP770 and DP780 compatibility: Both models share the same 7.4V battery platform, connector pinout, and BMS handshake protocol. A single KB-77B pack serves either radio without modification.
  • Bench tested on actual hardware: We cycled this pack under simulated PTT transmission loads. The BMS handled the transmit current spike without tripping overcurrent cutoff, and the cells held stable voltage across repeated PTT cycles.
  • First insertion into the charger dock: If the dock shows a fault LED on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The Kirisun dock requires a clean contact cycle to complete the BMS handshake before charging begins.

Why the DP770 cuts out mid-transmission on a new KB-77B

A new Li-ion pack ships at storage voltage — typically 3.6–3.7V per cell, not full charge. When PTT is pressed, the radio draws peak transmit current. If the cells haven't completed a full charge cycle first, the BMS may interpret the voltage sag as an undervoltage event and cut output. This is not a faulty pack. Charge the battery fully before first operational use and the BMS will calibrate its threshold to the actual cell capacity.

Bar indicator shows one fewer bar than expected after inserting the KB-77B

The DP770 uses voltage-threshold bar indicators — each bar represents a voltage band, not a percentage calculated by a chip. A new pack at storage voltage sits in the lower threshold band and will display one or two bars even though the cells are not depleted. Place the battery in the charger dock until the charge LED goes green, then reinsert. The bar indicator should read full at or above 8.2V resting voltage.

Compatible Models

DP770 DP780

Replaces Part Numbers

KB-77B

Technical Specifications

Voltage7.4V
Amp Hours2000mAh
Capacity2000mAh
Rate14.8Wh
Net Weight108g /3.81 oz
Gross Weight143g /5.04 oz
Approximate Weight143g /5.04 oz
Dimension 117.40 x 57.14 x 17.70mm

Product Highlights

  • Brand: Kirisun
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-ion
  • Battery Type: Li-ion
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My DP770 transmits fine for the first few seconds then the audio cuts and the radio resets — new KB-77B pack, why?

This is a BMS overcurrent trip caused by sustained RF output pulling more current than the cells can supply at storage voltage. The pack shipped partially charged and the cells can't hold voltage under prolonged PTT draw until they've completed a full charge cycle. Put the battery on the dock, charge it fully, and the BMS trip threshold will sit above the transmit current draw. The issue clears after the first complete charge.

The DP780 dock blinks an error pattern and never starts charging — pack seated correctly, contacts look clean, what's wrong?

The Kirisun dock checks cell voltage before it initiates a charge cycle. If the pack has been stored for an extended period, cell voltage can drop below the dock's acceptance threshold — typically around 6.0V for a 7.4V two-cell pack. Remove the battery, wipe the gold contact strip with a dry cloth, reseat firmly, and hold it in place for three seconds. If the dock still rejects it, the cells may be below recovery voltage and the BMS has locked out — at that point the pack needs replacement, not recharging.

Radio drops from full TX power to noticeably weaker output mid-shift — battery indicator still shows bars, what's happening?

The DP770 monitors rail voltage continuously and steps down transmit power when voltage sags under load, even if the bar indicator hasn't dropped a threshold yet. This happens when cell impedance rises — common in packs that have been through many shallow cycles. Bar indicators respond to resting voltage, not load voltage, so the display lags behind actual cell condition. Swap in a freshly charged KB-77B and check whether full TX power returns; if it does, the original pack's cells have degraded and need replacing.

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