Horizon Kronos C3+ Survey Battery 7.4V 2600mAh HKB10

Horizon Kronos C3+ — 7.4V Li-ion Replacement Battery (HKB10)

This 7.4V, 2600mAh Li-ion battery replaces the HKB10 pack in the Horizon Kronos C3+ survey and field measurement instrument. It fits the standard battery bay and connects directly to the instrument's power management circuit. Capacity figures match the product data — 19.24Wh at nominal voltage.

• Kronos C3+ platform fit: The C3+ runs its sensor array and GPS module from a single 7.4V rail. This pack matches that rail, the original connector pinout, and the BMS handshake the instrument expects at power-on.
• Bench tested on actual hardware: We cycled this pack through probe initialisation and sustained logging loads. The BMS held stable through the current spike at sensor power-up and did not trip under continuous measurement draw.
• First-use calibration on the Kronos C3+: After installing, run a full calibration cycle through the instrument menu before heading into the field. The C3+ maps battery state during calibration — skipping this step causes premature low-battery warnings on the first measurement session.

BMS cutoff when the Kronos C3+ probe module initialises

At startup, the C3+ powers its probe or sensor module as a single event, drawing a brief but sharp current spike. If the pack's BMS has a low instantaneous-current threshold — common in aged or deeply discharged cells — it interprets this spike as a fault and trips. The instrument may restart or display a battery error immediately after the probe initialises. This pack's BMS is rated to handle that initialisation surge without tripping under normal operating temperature.

Kronos C3+ shuts down mid-session but battery indicator still shows charge

This happens when cell voltage drops below the instrument's cutoff threshold under sustained sensor load, even though the resting voltage — what the indicator reads at idle — still looks acceptable. The C3+ draws more current during active logging than at rest, exposing voltage sag that the indicator doesn't reflect. A degraded original pack will sag to the cutoff threshold under load while still reading 40–50% at idle. If shutdown occurs mid-session, charge the pack fully and check resting voltage with a multimeter — it should read at or above 8.0V off-charger.