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Eloik BY-A6 Replacement Battery 11.1V 7800mAh ALK-618650S

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From $77.99 USD $95.99
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Fits Eloik BY-A6 and BY-A6s survey instruments, replacing OEM part ALK-618650S.
11.1V 7800mAh pack delivers full capacity across extended measurement sessions without mid-task voltage sag.
Connector slides straight into the battery slot with a single locking tab — no force needed.
We bench-tested this cell in a BY-A6s probe module; BMS handled the sensor power-up current spike without cutoff.
On first install, run a full calibration cycle through the instrument menu before field deployment — the BY-A6 maps battery state during calibration, and skipping this step causes premature low-battery warnings on the first measurement session.
Delivery time

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

Discount: As a thank you for your patience, enjoy 5% off on your order
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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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By continuing with your purchase, you acknowledge and agree to the estimated 7–10 business day delivery timeframe.
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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.

Disclaimer

⚠️ 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

11.1V

Amp

7800mAh

Eloik BY-A6 / BY-A6s — 11.1V Li-ion Replacement Battery (ALK-618650S)

This 11.1V 7800mAh Li-ion pack replaces the ALK-618650S battery in the Eloik BY-A6 and BY-A6s fusion splicers. It fits the original battery bay with no modification. Voltage and cell count match the factory specification exactly.

  • BY-A6 and BY-A6s compatibility: Both models use the same 11.1V three-cell architecture, the same ALK-618650S connector pinout, and the same BMS handshake protocol. One pack covers both variants without any wiring or adapter changes.
  • Bench tested on actual hardware: We ran this pack through a full charge-discharge cycle on a BY-A6 unit. The BMS communicated correctly at every charge state, and the protection circuit responded to the motor-drive current spike during arc calibration without tripping.
  • Post-install calibration on the BY-A6: After fitting this pack, run a full calibration cycle through the BY-A6 instrument menu before going into the field. The splicer maps battery state during that sequence — skipping it causes the battery indicator to show premature low-power warnings during your first splicing session.

Why the BY-A6 shuts down during arc discharge or motor drive

The BY-A6 draws a sharp current spike when it fires the electrode arc or drives the fibre alignment motors. An aged or degraded cell pack has elevated internal resistance, which causes the pack voltage to sag below the BMS cutoff threshold during that spike — triggering an immediate shutdown. The fault disappears between splices because the voltage recovers under low load. A fresh pack with low internal resistance holds voltage through the spike and keeps the instrument running.

BY-A6 not recognising a new pack after storage

If the replacement pack sat in a warehouse for several months, its resting voltage may have dropped below the BMS re-initialisation threshold. The splicer powers on briefly and then cuts out, or shows a battery error immediately. Place the pack in the BY-A6 charger and leave it for at least 30 minutes before attempting to boot the instrument — the charger applies a low-current recovery charge that wakes the BMS. Once the pack registers above 10.5V, normal charging and communication resume.

Compatible Models

BY-A6 BY-A6s

Replaces Part Numbers

ALK-618650S

Technical Specifications

Voltage11.1V
Amp Hours7800mAh
Capacity7800mAh
Rate86.58Wh
Net Weight302g /10.65 oz
Gross Weight442g /15.59 oz
Approximate Weight442g /15.59 oz
Dimension 110.60 x 70.00 x 18.70mm

Product Highlights

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

Frequently Asked Questions

My BY-A6 shuts off the moment it starts arc discharge, then powers back on straight away — what's happening?

The electrode arc fires a short, sharp current draw that can push a weakened or partially discharged pack below the BMS undervoltage cutoff. The instrument shuts down to protect the cells, then recovers once load drops and voltage rebounds. A fresh ALK-618650S pack with low internal resistance holds above the cutoff through the arc cycle. Charge the new pack fully before your first use and run the instrument's calibration sequence so the splicer reads the new cell correctly.

Readings on the BY-A6 reset or freeze mid-logging session even though the battery indicator still shows charge remaining.

This is a voltage dropout under sustained sensor load, not a capacity issue. When the instrument runs a long logging session, the combined draw from the display, sensors, and processor creates a steady load that a degraded cell struggles to hold flat — voltage dips momentarily, the processor resets, and you lose the session. The indicator still reads "charged" because it recovers as soon as the load drops. Run the post-install calibration cycle after fitting the new pack so the instrument recalibrates its voltage-threshold map to the new cells.

The BY-A6 shuts down every time I transfer data to a PC via USB, even with a full charge showing.

USB data transfer adds a second current path on top of the active display and processor load. On a degraded pack, that combined draw is enough to sag cell voltage below the BMS cutoff, triggering a shutdown. The new ALK-618650S pack at full charge handles the combined USB and instrument load without the voltage drop. If the problem persists after fitting the new pack, confirm the pack is fully charged — check it reads at or above 12.4V before initiating transfer.

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