Dell

Dell RWFFJ Replacement Battery

Brand:: Dell
Capacity Wh:: 99.5 Wh
Nominal Voltage:: 11.7 V
Expected Firmware State:: full_function

Quick facts

RWFFJ is a battery that fits 1 laptop model: Dell XPS 16 9640 (Core Ultra 9 185H, RTX 4070, 32GB). It is also sold as J8FK9.

Part number	RWFFJ
Part type	Battery
Also sold as	J8FK9
Capacity	99.5 Wh
Voltage	11.7 V
Cells	6
Last checked	2026-10-10

Compatible models (1)

Dell XPS 16 9640 (Core Ultra 9 185H, RTX 4070, 32GB)

Laptops compatible with RWFFJ

Fits 1 laptop: 1 OEM confirmed, 0 seller listed, 0 reported by users.

Also sold as: J8FK9

Dell XPS 16 9640 (Core Ultra 9 185H, RTX 4070, 32GB)OEM confirmedMatched on: part number RWFFJ

Consumercarts is reader-supported. Learn more

Disclaimer: The price and specification of the given product may differ from the actual product. Please confirm on the retailer's website before buying.

Manufacturer: Dell Last updated: 2026-10-10

Report an error

Dell RWFFJ Replacement Battery Review

Dell RWFFJ replacement battery, an 11.7V 99.5Wh six-cell pack for the XPS 16 9640.

This pack also sits at the common 99.5Wh air-travel threshold, confirmed by iFixit's own teardown listing.

What to check before you buy

Confirm RWFFJ or the alternate J8FK9 code against your existing pack before ordering.

Our verdict

Reviewed by Burooj Alam. Rated by us, not by users.

Best for

XPS 16 9640 owners

Not for

Other XPS 16 revisions without independent confirmation

Specifications

What these specs mean

Brand	Dell
Battery Model Code	RWFFJ
OEM Spare Part Number	J8FK9
Nominal Voltage	11.7 V
Cell Count	6
Series Configuration	2S
Capacity Wh	99.5 Wh
Capacity Basis	OEM Label
Expected Firmware State	full_function
Shipping Classification	UN3481
Compatible Models	Dell XPS 16 9640 (Core Ultra 9 185H, RTX 4070, 32GB)
Replaces Part Numbers	J8FK9

FAQs

Which laptops does the Dell RWFFJ battery fit?

The RWFFJ is listed for the Dell XPS 16 9640 (Core Ultra 9 185H, RTX 4070, 32GB). Check the model code printed on your current battery before ordering.

What is the capacity of the RWFFJ battery?

The RWFFJ is rated at 99.5 Wh at 11.7 V, 6 cells. Source of the figure: oem label.

Which part numbers does the RWFFJ replace?

It is listed as replacing J8FK9. A battery with any of these numbers on its label is the same part.

Is the RWFFJ an original Dell battery?

Yes. The listing is for an original Dell (OEM) battery.