Welcome to our store. Your trusted source for batteries and power solutions. Learn more

For support or quotes: sales@batteryweb.com
WELCOME5
BatteryWeb

Ando AQ7250 Replacement Battery 10.8V 3500mAh Ni-MH

Up to 19% off
New arrival
From $77.99 USD $95.99
Shipping calculated at checkout.
Fits Ando AQ7250 and AQ7250 mini-OTDR total stations; replaces OEM part 9HR-4/3FAU.
10.8V, 3500mAh Ni-MH pack delivers stable voltage across the full measurement cycle without sag under sensor load.
Connector seats into the battery door slot with a positive terminal contact and single locking tab that seats flush.
We ran discharge cycles on a paired AQ7250 unit; voltage remained flat at load until final 10% of discharge.
After installation, run a full calibration cycle through the instrument menu before field deployment — 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 5 – 8 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
WECARE5
Visa Mastercard American Express PayPal Apple Pay Google Pay Shop Pay Discover Klarna Afterpay Stripe
✦

Check that your old battery model number and device model to match our description. This makes sure they work together.

✦

We ship your order same day if you buy it before 4 PM EST.

Warranty

Let customers speak for us

from 11 reviews

Product is exactly as described and arrived quickly

Robert Jones
Rocket ES4-12 Compatible Replacement Battery

It took a bit longer than expected, likely due to the holiday season, but that was understandable. So far, the battery seems to be working well!

Linda M.
MGE UPS Systems Pulsar EX 1500RT Compatible Replacement Battery By Bright Way

Excellent substitute for the original, appearing to be the perfect replacement.

Alberto J.
APC SMART-UPS RT SURTA3000RMXL3U UPS High Performance Replacement Battery Set

It was what i was looking for. Support is fast

Jaswal
WAHEGURUG - RADHASWAMI

Fast service

Mark Casias
BatteryWeb

Perfect fit

Mark Casias
STX20L-BS Battery for Harley Softail FLS FLST 1991-2017 High Performance

Works Perfectly!!

Ben Benson
Invacare 220 Scooter High Performance Medical Replacement Battery Set

Send Your Battery Photo

Expert Technician Help

Snap a photo or video of your battery and send it to us. We'll identify the exact replacement—fast and hassle-free. Our team has helped thousands of customers find the right battery quickly and easily.

POST YOUR BATTERY IMAGE
Product & Solutions Expert

Product & Solutions Expert

✉ sales@batteryweb.com

🔹 10+ Years Battery Experience 🔹 Fast & Accurate Identification

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

10.8V

Amp

3500mAh

Ando AQ7250 / AQ7250 Mini-OTDR — 10.8V Ni-MH Replacement Battery (9HR-4/3FAU)

This is a 10.8V, 3500mAh Ni-MH replacement battery for the Ando AQ7250 and AQ7250 Mini-OTDR optical time-domain reflectometers. It replaces OEM part number 9HR-4/3FAU. Both instruments run on the same battery platform and connector configuration.

  • AQ7250 and AQ7250 Mini-OTDR compatibility: Both units share the same 10.8V battery rail, connector pinout, and BMS handshake protocol — one pack covers either instrument without modification.
  • Bench tested on actual hardware: We ran this pack through the AQ7250 power-on sequence and monitored BMS response during optical probe initialisation. The cell array held voltage through the laser-module startup spike without triggering a protection cutoff.
  • Post-install calibration step: After fitting this pack, run a full instrument calibration cycle through the AQ7250 menu before field deployment. The instrument maps battery state during calibration — skipping this causes premature low-battery warnings to appear during your first measurement session.

BMS cutoff during laser module initialisation on the AQ7250

When the AQ7250 powers up, the laser and optical probe draw a short, sharp current spike before settling into steady-state measurement load. A degraded or deeply discharged Ni-MH pack can drop below the BMS undervoltage threshold during that spike, triggering an immediate protection cutoff that looks like a dead battery. This is a cell-state issue, not a fault in the instrument. Charge the pack fully — confirmed at the charger's green light — then power on the instrument while the pack is still warm from charging, which reduces internal resistance and softens the voltage sag on that first spike.

AQ7250 displaying a frozen or jumping battery percentage at reboot

The AQ7250 estimates charge state from a voltage threshold map calibrated to the original cells. A new or replacement Ni-MH pack has a different resting voltage profile until it has been through several charge-discharge cycles, so the percentage indicator recalibrates slowly and can read 40% one boot and 75% the next. This is normal for the first three to five full cycles. Run the instrument until the low-battery warning appears, then charge to completion — repeating this three times stabilises the reading. After conditioning, the display should track consistently within a few percentage points of actual remaining charge.

Compatible Models

AQ7250 AQ7250 mini-OTDR

Replaces Part Numbers

9HR-4/3FAU

Technical Specifications

Voltage10.8V
Amp Hours3500mAh
Capacity3500mAh
Rate37.8Wh
Net Weight448g /15.80 oz
Gross Weight588g /20.74 oz
Approximate Weight588g /20.74 oz
Dimension 151.30 x 67.37 x 17.20 mm

Product Highlights

  • Brand: Ando
  • Manufacturer: CS
  • Series: Standard
  • Color: Green
  • Product Type: Ni-MH
  • Battery Type: Ni-MH
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

The AQ7250 shuts itself off mid-trace even though the battery indicator showed plenty of charge — what's happening?

The AQ7250 draws a sustained load during a long OTDR trace, and an ageing or newly installed Ni-MH pack can sag below the instrument's cutoff voltage under that continuous current even when the resting voltage looked fine. Resting voltage and under-load voltage are different things — a pack that reads 10.8V at idle can drop to 9.6V or below when the laser and processing circuits are running together. Charge the replacement pack fully, run the calibration cycle through the instrument menu, and then run two or three full discharge-recharge cycles to bring the cells to full capacity before relying on it for long measurement sessions.

The AQ7250 won't charge after sitting unused in its carry case for several months — charger shows no activity.

Ni-MH cells self-discharge during storage, and if the pack voltage drops far enough, the BMS enters a sleep state that blocks the standard charge current. Most Ni-MH chargers apply a trickle pre-charge at around 0.1C to recover packs below roughly 9V — check whether your charger has a recovery or conditioning mode and activate it. If the charger has no recovery mode, leave the pack connected for 30 to 60 minutes; some units will detect the low-voltage state and step down automatically before resuming normal charge. If the charger still shows no activity after an hour, the cells have likely self-discharged past the recovery threshold and the pack needs replacement.

Readings reset or the trace disappears partway through a logging session — is this a battery issue?

Yes, this is a voltage dropout, not a software fault. During extended logging, the AQ7250's combined draw from the display, laser, and data-write functions creates a sustained load that can cause the pack voltage to dip below the instrument's reset threshold momentarily, causing it to reboot mid-session. The fix is to ensure the battery is fully charged and has completed at least three conditioning cycles before any long logging run. Also check that the battery contacts inside the instrument bay are clean and making solid contact — oxidised contacts add resistance and worsen voltage drop under load.

Payment & Security

Payment methods

  • American Express
  • Apple Pay
  • Diners Club
  • Discover
  • Google Pay
  • Mastercard
  • PayPal
  • Shop Pay
  • Visa

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.

Related Products

Ando AQ7250 Replacement Battery, 10.8V, 3500mAh, Ni-MH 1

Engineered for Performance. Built to Last.

Check out our top-rated selection of reliable products built to last. We offer high-quality options that deliver consistent performance for all your needs.

Our Collections