Direct answer
For the iRobot Roomba j9/j9+ robot vacuum, outlet, charger, dock contacts, battery temperature and pack condition should be proved before replacement. First, cool to room temperature and use the specified charger/outlet.
What this covers
- iRobot Roomba j9/j9+ robot vacuum (j9, j9+)
- iRobot Roomba; mapping, obstacle avoidance, self-emptying and mop functions vary.
- The specific fault this record addresses: will not charge
What it does not cover
- ×The same symptom on a different iRobot product line, which has its own record and its own cited source
- ×An on-screen error code whose meaning has not been checked against this exact model's manual
- ×Live electrical, gas, sealed-system, internal battery-cell or structural repair — a technician boundary, not a self-service step
Differential
What actually causes this, and how to tell them apart
These are ordered by how often each one is the answer, not by how easy it is to try. The point of the middle column is that two causes producing the same headline symptom rarely produce the same detail — that detail is what tells you which one you have before you change anything.
- 1
Dock or plug contacts are dirty or not making a clean connection
What separates it Charging is intermittent, or works when the unit is pressed firmly into the dock but not when simply set down.
How to confirm Inspect and clean the contacts on both the unit and the dock/charger with the power disconnected, and confirm dry contact with firm, flush seating.
- 2
The charger or cable itself has failed rather than the vacuum
What separates it No charging indication at all, regardless of contact cleanliness or seating.
How to confirm Swap in the specified charger/cable if a spare is available, or test the vacuum's charge port with a different known-good charger of the exact specified type.
- 3
The battery pack itself has failed
What separates it Confirmed correct temperature, clean contacts and a known-good charger, and still no charge indication or progress.
How to confirm This is the conclusion only once the accessory and connection points are ruled out.
Before you touch a setting
Record this first — changing settings destroys the evidence
Every item below stops existing the moment a reset, re-pair or settings change is made. Written down first, they are what separates the causes above; recovered afterwards, they are guesswork.
- Whether the unit was hot from recent use or cold from storage right before the failed charge attempt.
- Whether charging is fully absent or just intermittent depending on how firmly the unit is seated.
- Whether a specified replacement charger/cable is available to swap in as a test.
Let the unit reach room temperature before attempting to charge
ReversibleBoth very hot and very cold batteries can refuse to charge as a safety measure.
Inspect and clean dry contacts on both the unit and dock or plug
ReversibleConfirm firm, flush seating rather than a loose or angled connection.
Test with a specified replacement charger if available
ReversibleIsolates a failed charger/cable from a failed battery or charge port.
Confirm charge indication and useful runtime after correction
ReversibleA charge light alone isn't sufficient — confirm it actually holds a useful charge.
Model-specific
What is true of this model and not of its siblings
Generic advice for the product line fails here. Each item below is a property of this specific model family that changes which of the steps above apply to you.
- Model scope
- j9, j9+. iRobot Roomba; mapping, obstacle avoidance, self-emptying and mop functions vary.
- Type — ROBOT vacuum
- A ROBOT vacuum with camera-based obstacle avoidance (PrecisionVision) and a Clean Base self-empty dock — symptoms are navigation, docking, brushes and the base, not a handheld's. It maps and cleans in neat rows and avoids obstacles like cords and pet waste.
- Clean Base self-empty
- It empties into the Clean Base automatic dirt disposal dock. 'Won't empty' is a full bag or a clogged path; 'won't dock/charge' is usually dirty charging contacts, the dock moved/unplugged, or blocked clearance around it.
- Brushes, wheels & sensors
- Two rubber brushrolls, a side brush, drive wheels and sensors — clear hair from the brushes and wheels and wipe the sensors and camera if it gets stuck, misses areas or avoidance behaves oddly.
- Symptom boundary
- This record covers iRobot Roomba j9/j9+ robot vacuum when it will not charge. A different symptom on the same hardware, or this symptom on a different iRobot product line, has its own record with its own causes and its own cited source.
Stop boundary
When this stops being a self-service repair
Continuing past any one of these costs more than the repair saves — in safety, in warranty, or in evidence a technician needs.
- !Stop for swelling, heat, an odor, liquid exposure or visibly damaged contacts — do not continue attempting to charge a battery showing any of these.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Where the manufacturer's article stops. iRobot Support publishes this as "Why does my Roomba® or Braava® not turn on or charge properly?". iRobot's own device-agnostic ("Roomba or Braava", all series) not-charging article. Verified reachable and content-matched via the Browser tool 2026-08-28 after direct fetch was refused. What that article does not carry is the model boundary — it is written for a product line, and j9, j9+ is the scope applied here. Where a control label, terminal, indicator pattern or reset sequence differs on your unit, the manual for that exact model is the authority, not this page and not the article.
Exact questions
Common follow-ups
My Roomba j9 won't return to its dock or charge.+
Check the dock and contacts first: the Clean Base must be plugged in, on a level spot with clearance on the sides and front, and the metal charging contacts on both the robot and the dock must be clean (wipe with a dry cloth). If the robot's battery is fully depleted it may need to be placed on the dock by hand to start charging. Hair on the wheels can also stop it driving back — clear the wheels and brushes.
My vacuum won't charge right after I finished using it.+
Let it cool to room temperature first — a battery that's still warm from use is often outside the charging circuit's allowed temperature range, which is a safety feature, not a fault, and resolves once it cools.
Does this answer apply to every iRobot model?+
No. It is scoped to j9, j9+. iRobot Roomba; mapping, obstacle avoidance, self-emptying and mop functions vary.
What should I record before troubleshooting not charging or battery?+
Record the complete model identifier, exact message or indicator, software/firmware where visible, the operating stage and what still works.
Why is a factory reset not the first step?+
A reset can erase accounts, networks, maps, schedules or preferences without distinguishing not charging, battery. The ordered checks preserve that evidence.
When should I stop and use qualified service?+
Stop for swelling, heat, odor, liquid or damaged contacts.
Answer for the exact device and software version shown above.