Garmin Astro 220 Replacement Battery 3.7V 3400mAh

Garmin Astro 220 / DC20 Series — 3.7V Li-ion Replacement Battery (010-10806-00)

This 3.7V, 3400mAh Li-ion battery replaces the original power cell in the Garmin Astro 220 and Astro 320 GPS dog tracking collars and their DC20 and DC30 collar units. It matches OEM part numbers 010-10806-00, 010-10806-01, 010-10806-20, 361-00029-00, and AC00-12542. The collar runs GPS acquisition, radio transmission to the handheld, and motion logging — all from this single cell.

• Astro 220, 320, DC20, DC30 fitment: These collar and handheld units share the same battery bay dimensions (66.20 × 20.60 × 18.50mm), connector pinout, and BMS handshake protocol, which is why one part number covers the full family. Swapping between models requires no adapter or firmware change.
• Bench tested on actual hardware: We cycled this battery across GPS acquisition, active UHF radio polling, and idle standby states. The BMS held voltage above 3.5V through sustained polling bursts and tripped cutoff cleanly at the low-voltage threshold with no false shutdowns.
• First GPS fix after installation: After installing a new battery, take the collar outside immediately — the unit performs a cold-start almanac download that can take 5 to 10 minutes outdoors. Subsequent power cycles use cached satellite data and lock on significantly faster. Waiting indoors extends this window.

Why the Astro collar drains faster in open rural terrain

In dense woodland or areas with partial sky obstruction, the GPS receiver amplifies signal processing load trying to resolve weak satellite geometry — this draws more current than a clean open-sky fix. Simultaneously, the UHF radio link to the Astro handheld polls more frequently when the dog moves fast or signal path includes tree cover. Both loads hit the battery at the same time. Reducing poll rate on the handheld from the default setting lowers the transmission duty cycle and cuts draw on the collar cell noticeably.

Collar shows a full charge but drops to low-battery warning within the first hour

This usually means the old battery has enough surface charge to read full on the indicator but has lost internal capacity — the cell voltage collapses under GPS and radio load rather than at rest. A new cell at 3400mAh will sustain voltage above 3.6V through the load cycle instead of sagging immediately. After fitting this replacement, charge the collar fully before the first tracking session and confirm the charge indicator clears to solid green before heading out.