# How long does the battery last on the Roborock S8 MaxV Ultra vs Roomba j9+?

> Battery life and runtime comparison

*Published: 2026-03-20 | Updated: 2026-03-20 | Source: https://shopsavvy.com/answers/how-long-does-battery-last-roborock-s8-maxv-ultra-vs-roomba-j9*

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## Product: Roborock S8 MaxV Ultra
**Brand:** Roborock

The [Roborock S8 MaxV Ultra](https://www.amazon.com/dp/B0CSKBXQ68?tag=shopsavvy-20) lasts longer on a single charge: up to 180 minutes versus the [Roomba j9+'s](https://www.amazon.com/dp/B0C415NHBM?tag=shopsavvy-20) 120 minutes. Those are manufacturer numbers though, and your mileage will vary.

## Real-World Runtime

The [S8 MaxV Ultra](https://www.amazon.com/dp/B0CSKBXQ68?tag=shopsavvy-20) has a 5,200 mAh battery. On normal settings with mixed flooring, expect 165-175 minutes per charge. That's enough for 3,000+ square feet in one go.

Crank it up to maximum suction (10,000 Pa), and you're looking at maybe 60 minutes. The powerful motor drinks battery fast.

The [Roomba j9+](https://www.amazon.com/dp/B0C415NHBM?tag=shopsavvy-20) runs about 75-90 minutes in normal operation. That's enough for most average-sized homes, but larger spaces might need a recharge break.

## Does It Actually Matter?

Both vacuums return to their dock, charge up, and continue cleaning. Even if your home is too big for one battery cycle, the vacuum eventually finishes.

**Big home (3,000+ sq.ft)?** The [S8 MaxV Ultra's](https://www.amazon.com/dp/B0CSKBXQ68?tag=shopsavvy-20) longer battery means fewer charging breaks and faster total cleaning time.

**Average home (under 2,000 sq.ft)?** Either vacuum finishes on a single charge. The battery difference doesn't affect you.

**Using max suction often?** The [S8 MaxV Ultra's](https://www.amazon.com/dp/B0CSKBXQ68?tag=shopsavvy-20) larger battery gives more runtime even in power mode.

## The Fast Charging Advantage

The RockDock Ultra charges faster than the Roomba's Clean Base. If your vacuum pauses mid-clean, the [Roborock](https://www.amazon.com/dp/B0CSKBXQ68?tag=shopsavvy-20) gets back to work sooner.

For large homes needing multiple charging cycles, this adds up. An extra 15-20 minutes per charging break can mean the difference between finishing before you get home or not.

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*Where this comes from: This answer is based on ShopSavvy's product database, real-time pricing from thousands of retailers, and analysis of user reviews to give you a well-rounded picture.*