Sonocaddie V350 Compatible Battery 3.7V 1700mAh HE9701N

Sonocaddie V350 / V500 — 3.7V Li-ion Replacement Battery (HE9701N)

This 3.7V 1700mAh Li-ion cell replaces the OEM battery in the Sonocaddie V350 and V500 handheld golf GPS navigators. It uses part numbers HE9701N and G-4L, fitting both units directly. Dimensions are 66.20 × 44.00 × 5.10mm — confirm these against your existing cell before fitting.

• V350 and V500 compatibility: Both models run the same 3.7V battery rail and share the HE9701N cell. The connector and BMS handshake are identical across this generation of Sonocaddie GPS units, so one replacement cell covers either device.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench. The BMS held the 3.7V nominal rail cleanly, with no voltage sag under the GPS receiver and display draw that these units produce during active navigation.
• Cold-start satellite acquisition after swap: After fitting this cell, power the V350 or V500 fully on outdoors before your round. The unit performs a cold start after any full power interruption — first satellite fix typically takes 5–10 minutes. Subsequent warm starts lock much faster. Do this at the car park, not on the first tee.

GPS accuracy dropping at low battery on the V350

When cell voltage drops toward the low-battery threshold, some GPS units reduce receiver sensitivity to protect remaining charge. On the V350, this shows up as distance readings that jump between values or fail to update as you walk. The GPS receiver draws more power during active signal processing, and the BMS begins throttling it before the low-battery warning appears on screen. Keep the cell topped up before a full round — the receiver runs at full sensitivity above approximately 3.5V.

V350 shutting off mid-round with no warning indicator

An aged OEM cell loses capacity unevenly, which throws off the voltage-based fuel gauge the V350 uses to show remaining charge. The unit's shutdown threshold gets hit before the visual warning registers as critical. This happens because the old cell's internal resistance causes voltage to sag sharply under load, even when the indicator still shows bars. Fitting a new cell with stable internal resistance brings the shutdown threshold and the on-screen indicator back into sync.