A GPS ankle monitor typically stays charged for about 24 to 60 hours, which means you need to plug it in every day. How long does an ankle monitor stay charged overall depends on the type of device: radio frequency units run 12 to 18 months on a sealed internal battery, and alcohol-detection bracelets like the SCRAM CAM go up to 90 days between charges. If you’re wearing a GPS tracker, daily charging isn’t optional, and letting the battery die can be treated as a violation.
Battery Life by Monitor Type
The technology inside the device decides how often you have to think about charging, or whether you have to think about it at all.
GPS Monitors
GPS monitors are the most power-hungry because they constantly communicate with satellites and cell towers to report your location. Most last between 24 and 48 hours on a full charge. Some newer models stretch further; the BI LOC8 XT advertises up to 60 hours on a single charge.1BI Incorporated. Location Tracking and GPS Monitoring One-piece GPS units that combine all components into a single housing can reach about seven days between charges, though they’re less common. For almost everyone wearing a GPS device, the rule is simple: charge every day unless your supervising officer tells you otherwise.
Radio Frequency Monitors
Radio frequency (RF) monitors don’t track your precise location. They detect whether you’re within range of a base unit installed in your home, essentially enforcing a curfew or house arrest. Because RF uses far less power than GPS, these devices run on sealed internal batteries that last 12 to 18 months of continuous use.2Sentinel Advantage. RF Patrol PTX2 Datasheet You don’t charge an RF monitor yourself. The monitoring company handles battery replacement when the time comes.
Alcohol-Detection Monitors
Devices like the SCRAM CAM bracelet sample perspiration through your skin to detect alcohol consumption. They don’t need the constant satellite communication GPS units require, so their batteries last much longer. The SCRAM CAM runs for up to 90 days on a single charge.3AlphaBiolabs. SCRAM Continuous Alcohol Monitoring FAQs When the battery runs low, a technician recharges or replaces it during a scheduled office visit.
What Drains a GPS Battery Faster
A GPS monitor sitting on your couch in a room with good cell reception uses far less power than one tracking a commute across town. Several factors push the battery down faster than the headline numbers suggest.
- Movement and location updates. The more you move, the more GPS fixes the device calculates and the more data it transmits. A quiet day at home barely dents the battery; a day of errands across multiple locations drains it noticeably faster.
- Signal strength. When the device struggles to find a satellite or cell tower, inside concrete buildings, in rural areas, or underground, it boosts its transmission power to compensate. Poor reception is one of the biggest hidden battery killers.
- Temperature extremes. Lithium batteries lose efficiency in very cold and very hot conditions. If you work outdoors in winter or spend time in high heat, expect shorter battery life on those days.
- Battery age. Rechargeable batteries degrade. A unit that held 48 hours when new might only manage 30 hours after months of daily cycling. If you notice the battery draining much faster than when you first received the device, tell your monitoring officer.
How to Charge the Device
Your monitoring company provides a charging cable specific to your device. Don’t try to use anything else. Plug one end into a standard wall outlet and connect the other to the port on the bracelet. When the connection is secure, the device usually vibrates briefly and shows a light, often blinking green, to confirm it’s charging.4SCRAM Systems. SCRAM GPS Help A solid green light generally means the charge is complete.
A full charge from a low battery takes roughly two hours.1BI Incorporated. Location Tracking and GPS Monitoring Some models offer cordless charging through an attachable battery pack, which helps when you’re away from an outlet. The cables are generally long enough that you can sit on a couch or at a table while the device charges.
Most people fold charging into a daily routine, plugging in while watching television in the evening or first thing in the morning. Consistency is the point. Waiting until the battery is nearly dead and then scrambling for a charger is how violations happen.
Low Battery Warnings
Ankle monitors don’t quietly die. They warn you, usually more than people expect. When the battery drops below a threshold, the device will vibrate, beep, or flash a light, often red or amber. The alerts escalate as the battery drops, from gentle reminders to persistent signals that are hard to ignore.
At the same time the device alerts you, your monitoring agency receives an electronic notification that the battery is low. Your supervising officer knows exactly when you were warned and how long you waited to plug in. That timeline matters if the battery eventually dies and you need to explain what happened.
Treat any low-battery alert the way you’d treat a check-engine light: stop what you’re doing and charge the device as soon as you reasonably can. “I didn’t hear it” or “I was busy” doesn’t carry much weight if the situation turns into a formal violation.
What Happens If the Battery Dies
When an ankle monitor loses power, it stops transmitting your location. The monitoring system registers this as a signal loss, which automatically flags your supervising agency. From their end, a dead battery looks identical to someone cutting off the device. They can’t tell the difference until they investigate.
The consequences depend on your jurisdiction, the terms of your supervision, and whether this is your first incident. A single low-battery alert that you promptly address is generally treated as a minor technical issue. Actually letting the device go dead is different. Your supervising officer may contact you to verify your location, or law enforcement may be sent to your last known position to check on you. For someone on pretrial release, a serious monitoring violation can lead to revocation of bail and a return to custody.
Some jurisdictions treat a dead battery the same as tampering with the device. Washington, D.C., for example, specifically makes it unlawful to intentionally fail to charge an electronic monitoring device, with penalties of up to 180 days in jail. Several states classify removing or disabling a monitor as a felony for defendants facing felony charges. Even where the law doesn’t specifically address battery neglect, courts have broad discretion to treat a dead monitor as a violation of release conditions, which can mean additional charges, revocation of probation or parole, or re-arrest.
There’s no scenario where a dead ankle monitor works out in your favor. Even if the cause was genuinely accidental, a broken charger or a power outage, the burden falls on you to explain it and to show you took reasonable steps to prevent it.
Habits That Keep You Charged
Most battery-related violations are preventable. A few habits do most of the work.
- Set a daily alarm. Pick a consistent time to charge. Treat it like medication: same time, every day, no exceptions.
- Charge before you need to. Don’t wait for the low-battery alert. If your device lasts 40 hours and takes two hours to charge, plugging in every evening keeps you well inside the safe zone.
- Keep your charger accessible. Leave it plugged into an outlet you use daily, next to the couch or your bed. If you carry a portable charger, keep it in the same bag every time you leave the house.
- Report charger problems immediately. If your charging cable breaks, frays, or stops working, call your monitoring company right away. Document the call with the date, time, and the name of whoever you spoke with. That record protects you if a violation is alleged later.
- Have a plan for power outages. If you lose electricity, contact your supervising officer as soon as possible. Some monitoring companies can provide a portable battery pack. At minimum, notifying them before the battery dies creates a record that you acted in good faith.
A Note on Water Exposure
Most standard ankle monitors are water-resistant enough for daily showers without any special precaution. You don’t need to wrap the device in plastic or hold your leg out of the water. Water-resistant is not the same as waterproof, though. Submerging the monitor in a bathtub for an extended soak, swimming in a pool, or jumping in a lake can damage the device and trigger a tamper alert, which carries the same kind of consequences as a dead battery. When in doubt, keep the monitor above the waterline and ask your monitoring company about restrictions specific to your model.