TPMS Sensor Battery Life and the Case for CR1632 Sealed versus replaceable TPMS sensor cells is a service-life decision, not a spec-sheet one. Here is how to choose, and what a coin cell change really costs.

The decision buyers actually make

Two TPMS sensors can share identical radio specifications, identical pressure accuracy and identical sealing, and still be completely different products, because one has a sealed battery and the other has a cell the owner can change. That single difference decides how the product behaves in year three, and it is usually settled by accident rather than on purpose.

The choice is not about which is technically better. It is about who is expected to service the sensor, how long the vehicle is expected to be in service, and whether the sensor can be reached at all once it is installed.

What sealed buys you

A sealed sensor with an internal cell is simpler in every respect except one.

• No user access point. Nothing to unscrew, so nothing to cross-thread, drop or lose. The seal is set once at the factory and never disturbed.
• Better for inaccessible mounting. If the sensor sits inside a housing, behind a valve cap or in a position the owner cannot comfortably reach, a sealed cell is not a compromise — it is the only sensible choice.
• Fewer support questions. A product with no replaceable part has no replaceable-part complaints, no wrong-cell fitments and no re-pairing queries after a battery swap.
• Predictable servicing. Instead of supporting an owner during a cell change, the servicing interval becomes a whole-sensor replacement, which a distributor can plan around.

The cost is that the sensor's life is fixed at manufacture and the servicing action is a replacement rather than a coin cell. For a fleet buying in volume, that is often the easier thing to administer.

What replaceable buys you

A replaceable cell, such as the CR1632 in our standard sensor, keeps the sealed body and adds an owner-accessible compartment.

• Lower lifetime cost of ownership. A coin cell is a fraction of the price of a sensor, and the radio and pressure element are still good.
• No re-pairing. On our platform, changing the cell does not disturb the pairing, which is the detail that makes a field replacement practical rather than a workshop job.
• Better for long-life vehicles. A motorcycle may be in use for a decade. Replacing a cell twice over that period is a different economic proposition from replacing the sensors.
• Better for distributors. A dealer can stock cells instead of stocking sensors, which is a much smaller inventory commitment.

The cost is that the owner has to do something, and some owners will not. A replaceable cell only delivers its advantage if the maintenance happens.

The comparison, stated plainly

Factor	Sealed cell	Replaceable CR1632
Factory cost	Slightly lower	Slightly higher
Lifetime cost in the field	Higher — replace the sensor	Lower — replace a coin cell
Sealing risk	Lowest — sealed once	Slightly higher — a compartment exists
Suits inaccessible mounting	Yes	Sometimes awkward
Suits long-life vehicles	Weaker	Stronger
Support burden	Lower	Higher, but minor where re-pairing is not needed
Distributor inventory	Sensors	Cells, which are smaller and cheaper

There is no universal winner. The useful question is who performs maintenance on the vehicle, and what they are willing to do.

Why the re-pairing detail matters more than the cell

A replaceable battery is only a genuine advantage if the electronics preserve their identity through the change. On some systems, removing the cell loses the pairing and the sensor has to be associated with the vehicle again, which turns a two-minute job into one that requires the right app, the right sequence and sometimes the right tool.

This is worth checking explicitly before choosing a sensor, because it is invisible on a specification sheet. Ask whether the pairing survives a cell change. If the answer is no, the replaceable battery is a convenience for a technician rather than for an owner.

What the cell actually does

A CR1632 is a lithium coin cell, chosen because it has enough capacity for a low-duty-cycle radio and is small enough to fit a valve-mount housing. Current draw is dominated by the radio, and the radio's duty cycle is dominated by how often the sensor transmits. A sensor that reports every few seconds draws far more than one that reports on a longer interval or on change.

This is why battery-life figures vary so much between products with the same cell. A quoted life is only meaningful alongside the transmit interval and the operating temperature, and cold reduces the usable capacity of any lithium cell. A sensor rated for a long life at room temperature will not deliver it in a cold climate at a short interval.

For our own sensors, the operating range is −20 °C to +80 °C and storage is −40 °C to +85 °C, with a replaceable CR1632 in the standard variant. That is the honest scope: the life depends on how the sensor is configured and where it is used, and a buyer who needs a specific figure should ask for it against their intended transmit interval rather than accept a headline number.

The practical recommendation

For most aftermarket and retrofit programmes, a replaceable cell is the better default, because the vehicle outlives the cell and the owner is already used to small maintenance tasks like checking pressure.

For programmes where the sensor is difficult to reach, where the customer prefers not to have any user-accessible part, or where the operator would rather schedule a sensor replacement than support a coin cell change, a sealed sensor is the better answer.

Both exist in our own range for exactly that reason: the standard BPU100 uses a replaceable CR1632, and the BPU110 is the same platform with a sealed cell. Choosing between them is a servicing decision, and it is the kind of question worth settling while the specification is still open — because it is far cheaper to decide before production than after.