On the 1.5T and 2.0T 10th-gen Accord this is one of the easiest jobs on the car. Everything you touch is 10 mm: both terminal nuts and the single hold-down bracket bolt. The only real trick is that the hold-down bolt sits low at the base of the battery box, so you need a 10 inch extension (ideally with a wobble adapter) rather than trying to get a ratchet in there. The battery is a Group 51R — reverse terminals — and if your trim has auto idle stop, buy AGM, not flooded.
What people get wrong is skipping the memory saver and then assuming something broke. After a disconnect the power windows lose auto-up, the moonroof loses its auto function, the clock and presets are gone, and the idle can hunt for a few minutes. All of that is normal and is fixed by the relearn procedure, not by a trip to the dealer. Also: negative off first, positive on last, and keep the key fob out of range while you work.
| Item | Type | |
|---|---|---|
| Memory saver OBD-II or 12V accessory-socket type with 9V/AA supply Keeps the clock, radio presets and window/moonroof learned positions alive while the battery is out. | Recommended | shop |
| Socket, 10 mm 10 mm 6-point, 3/8 in drive Fits both battery terminal nuts and the hold-down bracket bolt. | Required | shop |
| Ratchet 3/8 in drive, 72-tooth or finer Drives the terminal and hold-down fasteners. | Required | shop |
| Extensions 3/8 in drive, 6 in and 10 in The hold-down bracket bolt is at the base of the battery box and cannot be reached with a bare ratchet. | Required | shop |
| Wobble/swivel adapter 3/8 in drive wobble extension adapter Helps line the socket up with the recessed hold-down bolt at an angle. | Recommended | shop |
| Combination wrench, 10 mm 10 mm open/box end Backup for the terminal nuts if the socket will not clear the fuse box or hood hinge area. | Recommended | shop |
| Battery terminal puller Small two-jaw clamp puller Frees a corroded terminal clamp from the post without prying on the lead post. | Recommended | shop |
| Battery terminal brush Post and clamp wire brush Cleans oxide off the posts and inside the clamps for a solid connection. | Required | shop |
| Battery strap or carrier Adjustable lift strap A Group 51R battery is awkward to lift out of the deep tray by hand. | Recommended | shop |
| Trim tool set Nylon pry tools Needed on the Hybrid to pop the trunk side trim/cover over the auxiliary battery without breaking clips. | Recommended | shop |
| Digital multimeter DC volts, 20V range Checks resting voltage of the old and new battery and confirms charging voltage after the swap. | Recommended | shop |
| Torque wrench 1/4 or 3/8 in drive, 3-25 Nm range Terminal nuts and the hold-down bolt are low-torque fasteners into thin metal and plastic; overtightening cracks the battery. | Recommended | shop |
| Replacement battery Group 51R, ~410-500 CCA (flooded or AGM); hybrid uses the smaller AGM auxiliary battery The correct case size and reversed post layout for the Accord tray. | Parts | shop |
| Battery terminal protector Spray or felt washers Slows corrosion on the posts and clamps. | Consumables | shop |
| Baking soda and water / terminal cleaner Aerosol battery cleaner Neutralizes and washes acid residue out of the tray. | Consumables | shop |
| Nitrile gloves and safety glasses Acid-resistant Protects against acid residue and accidental sparks at the terminals. | Safety | shop |
1.5T and 2.0T are identical for this job: Group 51R battery in the driver's-side front of the engine bay, 10 mm terminals, one 10 mm hold-down bolt reached with a long extension. The Hybrid uses a smaller AGM 12V auxiliary battery with a different hold-down and, on many builds, a different location behind trunk side trim, so you may need nylon trim tools in addition to the 10 mm socket. Trims with auto idle stop (including the Hybrid) must use AGM.
| Battery terminal clamp nuts (10 mm) | about 4-6 Nm (35-50 in-lb) — snug only; verify in the service manual |
| Battery hold-down bracket bolt (10 mm) | verify in the service manual (snug, roughly 8-10 Nm) |
| Hybrid auxiliary battery hold-down / trunk trim fasteners | verify in the service manual |
The 10 mm terminal and hold-down fasteners, the long-extension requirement and the Group 51R size for the 1.5T/2.0T are solid for this generation; double-check the exact auxiliary battery location and size on Hybrid models and confirm whether your trim has auto idle stop (AGM required) before buying the battery.
The 1.5T and 2.0T use a Group 51R, typically around 410-500 CCA, with reverse terminal layout. If your trim has auto idle stop, use an AGM of the same group size; the Hybrid uses a smaller AGM auxiliary battery — match the part that came out.
No. Honda does not require battery registration or scan-tool coding on this generation. You only need to reset the clock and radio, and relearn the power windows and moonroof.
A 10 mm 6-point socket, a 3/8 in ratchet, and a 10 in extension for the recessed hold-down bolt. A memory saver, terminal brush and a battery carry strap make it much easier.
The window motors lost their learned limits. For each window, hold the switch fully down until the glass is all the way open and keep holding one more second, then hold it up until fully closed and hold one more second. Auto-up and pinch protection return immediately.