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Hendon Publishing

Battery Saving Devices

As law enforcement embraces more and more mobile technology, we often forget the demands this places on a vehicle’s electrical system. In addition to the traditional laptops and land mobile radios, becoming more commonplace are license-plate recognition systems, mobile video systems, infrared cameras, and e-ticketing systems.

Aftermarket equipment parasitic amp draw is a real and significant fleet management and fleet maintenance issue. Today’s batteries simply are not able to be completely drained and then return to a full charge capacity.

The following is a roundup of timers, voltage sensors, and combination timers-sensors. Each company makes a wide variety of such devices, and we picked just one representative device per company. In most cases, we simply picked what was the most popular choice for police vehicles, as opposed to other applications like fire apparatus. Please visit the website for each company to see what other devices are available, such as more features, less features, different connection options, etc.


AC/DC Industries

AC/DC Industries makes proactive products that manage battery loads, prevent battery damage, incorporate safer flasher features in a vehicle electrical system, prevent loss of memorized settings, and allow use of communications equipment when the engine is off, yet reserve power to start the vehicle again.

The MZL delay timers built by AC/DC Industries can be programmed with the flip of a switch to cover a range between 15 minutes to 8 hours. Load management can be controlled with a central source that turns off all electronic equipment at the same time. If the battery output drops below 10.5 volts, the unit shuts down equipment to provide enough cranking amps to restart the engine. And if the alternator has a problem, the delay timer will protect from random spikes. Such features not only eliminate battery failures and reduce maintenance costs, but also reduce fuel costs and equipment failures.


AC/DC ignition-sensing delay timers (starts timing when the ignition turns off) include the MZL-10, MZL-10SW (with spade and wire); MZL-26 (combination delay timer with 6-fuse panel); MZL-FD (heavy truck load, delay timer); and USB-1036 (programmable via USB for selecting and adjusting time delay, laptop shutdown option); all for 12v 30amp; the MZL-100 (12v 75amp); MZL-90 and MZL-90SC (combination delay timer with fuse output and ignition override for 12v 90amp); MZL-200 (high current, 12v 200amp); MZL-1024 (24v 30amp); and MZL-124 (24v 50amp).

The voltage-sensing delay timers include the MZL-18 and MZL-52 (12v 30amp); MZL-180 (12v 75amp); and MZL-1824 (24v 30 amp). They start timing when the voltage starts dropping. Low voltage sensors (always on, not a delay timer) include the VS-10 (12v 30amp) and VS-100 (12v 75amp).


BLI International

The PriorityStart! from BLI International is a small electro-mechanical device driven by a computer chip that has a bi-directional motor and 10-gear system to deliver 243-to-1 gear drive ration to handle a maximum of 1,000 starting amps. Its housing is polypropylene—the same material as a battery case. The device passively monitors battery voltage and detects any drains on voltage.


When a drain is detected and voltage gets below 11.7 volts for a full minute, the battery is disconnected to prevent deep discharge and to save starting power, thus saving down time, maximizing battery life, and preventing computer or electrical system damage. To reconnect the battery, operate a light switch, push on the brake pedal, or activate any other accessory that draws at least 0.2 millivolts, and then turn the key.


The device is not meant to be used with high-amperage accessories that are running continuously for an extended period, but most police accessories such as computers, spotlights, cameras, ALPR, radios, etc. are safe. The device fits either top or side post batteries, attaching the cable from PriorityStart! to the positive post on the battery and attaching the ground wire to the negative battery post. No hard wiring is needed and the unit is transferable to a new battery. The company manufactures PriorityStart! for 12-volt and 24-volt batteries, and marine batteries.



Cole Hersee

Cole Hersee, a subsidiary of Littelfuse, manufactures electronic switches and connectors for vehicles. SureStart™ features low voltage-disconnect switches and harnesses. A variety of battery isolator controllers is available including the FlexMod™ model that preserves starting battery voltage by isolating when the system voltage drops below 12.7 volts. It isolates the main and auxiliary batteries, and then automatically reconnects battery banks at 13.2 volts. This preserves starting power, and eliminates downtime and jump starts. It is compatible with modern, electronically controlled alternators (unlike some diode battery isolators).


It is compact (4”x3”x1”) and is waterproof, dustproof and vibration-proof. It can be mounted even in places where road splash occurs. The FlexMod™ models have two inputs (one analog and one digital) and two solid-state outputs (one 10amp and one 200mAmp) that can be programmed. The FlexMod™ models are rated for more than 1 million on-off cycles, and use simple wiring for easy installation. An ultra-low 1mAmp standby current uses minimal battery drain.

A typical application for a police vehicle could be the 48541 FlexMod VSRT, which combines two functions in one small unit that opens options for mounting in a small space and simplifies wiring. It protects starting power with simultaneous sensing of time and voltage. For police boats, the 48540 FlexMod Smart Isolator Controller turns the existing solenoid charging system into a smart system to protect the alternator with priority charging, and to allow shore power connected to the house battery to charge the starting battery as well.



Copeland Engineering

Copeland Engineering manufactures a variety of vehicle electrical products to deliver power management. Most provide automatic power-off after a user-determined time to reduce or eliminate battery service calls and extend battery life and vehicle availability. Each product has a warranty.


The Power Tamer is a solid-state, self-contained unit with a low, 5mAmp standby current. It can be programmed from 15 minutes to 31 hours. Waterproof, it can be mounted anywhere on a vehicle. An optional direct-ignition sensor is available and recommended for emergency vehicle applications. In the “auto sense” mode (yellow wire not connected), the unit senses the charging system pick-up with the engine running to turn on equipment. It starts timing when the engine stops. If the yellow wire is connected to a circuit that is hot when the ignition switch is on, equipment will come on immediately with the ignition—recommended for emergency service vehicles to guarantee equipment operation in case of alternator failure.


The Power Tamer VS (voltage sense) eliminates a dead battery because of “forgotten” electrical equipment such as data terminals and radios. The unit features voltage sensing and auto-ignition sensing, and programmable times ranging from 15 minutes up to 15 hours and 45 minutes. Low voltage disconnect occurs at 10.5 volts for 15 seconds to filter voltage dips caused by the lightbar, ignition, etc.


The TOP H.A.T. also eliminates problems caused by forgotten electrical equipment and features both voltage sensing and ignition sensing, with programmable times ranging from 15 minutes to 16 hours.


The Cycle Pal is developed especially for motorcycles with a battery saver time, and an ultra-low self-power drain (70 mAmp). It is available in 60-, 30- and 15-minute models and has high power capability of 12amp. The unit is encased in epoxy and is waterproof. When the ignition switch is turned off, it begins timing in anticipation of turning off the connected loads. It can then reset and re-energize the electrical loads when the ignition switch is turned on again.


Wiring requires high-quality crimp connectors—red to positive, black to negative, orange to electrical equipment such as radio, radar, or strobe, and yellow to any hot circuit when the ignition is either on or in “accessory” position.


D&R Electronics

D&R Electronics offers a wide variety of police vehicle products including its Watchdog-B60 and Watchdog-B120, units designed to protect the vehicle battery from excessive discharge when the ignition is off. Between 13 volts to 18 volts, the Watchdog remains on, but if the battery voltage drops below 13 volts and the ignition is off, a countdown delay occurs, at the end of which the unit shuts off and goes into a standby mode. If the battery voltage recovers and rises above 13 volts, the unit goes into “on” mode.




The ChargeGuard CG-X from Havis is a self-contained unit for vehicle and electronics power protection. The CG-X is small enough to mount on a sedan trunk or interior, under the dash, or inside a radio console. This unit is not waterproof and wire connectors are exposed; therefore, underhood mounting is not recommended.

The unit handles a maximum of 30 amps and should be wired directly to the vehicle battery positive post using an installer-supplied fuse and fuse holder of suitable rating for the anticipated electrical load. If multiple devices are connected to its output, each item can be fused individually again with an installer-furnished fuse and holder. Wires are run to screw post lugs on the outside of the ChargeGuard.

Time-delay setting DIP switches turn on the sense mode selector. There is also a 15-minute override switch, which is easily accessible under a protective rubber flap on the face of the box. Delay time has eight settings available with the switch setting guide on a decal on the bottom of the unit as well as the instruction sheet.


Also, a 15-minute override button allows the timer to be bypassed if it has timed out. This allows a two-way radio, for instance, to be used temporarily without starting the car. It also automatically protects attached devices against low and high battery voltage by shutting off if any of those conditions occur. When this happens, a diagnostic LED on the face of the box blinks to tell of its status and condition. (devices 30amp or less) and is regulated by a programmable timer.

Unlike most LEDs that only show on or off, the unit has LED color and blink codes for easy troubleshooting of voltage conditions. The unit indicates under-and over-voltage conditions.


There is a choice of sensing modes of automatic detection, battery sensing (DC rise), or ignition connection. An accessible slider switch makes the unit more user-friendly. Power is not needed to change the timing. Recommended installation is in the vehicle or trunk, but not under the hood, due to risk of heat or water damage. It should be wired through a fuse directly to the battery.



Kussmaul Electronics

Kussmaul Electronics’ Load Manager P is one of over a dozen of their DC power management devices. Load Manager P is an engine off, timeout timer, voltage sensing device. When it senses that the engine is not running, an internal timer is started. At the end of the timing cycle, power to the load will be disconnected. If battery voltage drops below its set point at any time during the timing cycle, power will immediately be disconnected.

The Load Manager P is not sealed, so a protected mounting location is highly recommended. Kussmaul makes a sealed Load Manager in the line, the Load Manager 1HP, but it doesn’t have a timer. Timer control wiring is done through a connector on the side requiring a lead for power, ground and an input from the starter crank circuit. The circuit-board edge connector for this is provided with the new unit, but don’t forget to take it along when transferring the Load Manager P to a new vehicle.

Once the engine is started and system voltage rises 0.5 volts above the shutoff point, the timer is reset. A sense wire at the PC board connector leading to the starter crank circuit keeps the Load Manager from shutting off if battery voltage drops too low during the engine start cycle. The timer can be disabled by removing a diode on the circuit board to make the Load Manager strictly a voltage-sensitive shutoff device. A timer potentiometer is preset at one hour but can be changed for a maximum delay of up to two hours.


Lind Electronics

The Lind Electronics T2 Shut Down Timer (model SDT12-12-081) prevents over-discharge by shutting off up to single 30amp and 20amp loads at a pre-set time, using two independent timing circuits. Power loads can be managed separately through the two independent timing circuits. The emergency switch provides up to 15 minutes of operation after the timer shuts down the equipment. There is a 0-4 hour time delay adjustment range (available on each timing circuit).


The economical 18-hour shut down timer (fused with terminal block connections), model SDT1230-016 and the 2-hour shut down timer (non-fused with screw terminal connections), model SDT1230-022 each protect the vehicle battery from over-discharge, and equipment from low and high voltage damage. The devices turn off electrical loads at a pre-set time after the engine shuts down.



RAM Mounting Systems

The RAM Safe-T-Charge™ Battery Protection System is a solution to the parasitic amp draw from aftermarket electronic devices. It is inexpensive, easy to install, and easy to operate. With multiple configurations available through onboard dip switches, the RAM Safe-T-Charge™ can be configured to shut down connected devices either by a trigger coming from the ignition of the vehicle or by sensing a drop in the DC voltage below a level capable of starting the engine.

Each agency can easily select a predetermined duration of time before the connected devices shut down. The RAM Safe-T-Charge offers an audible tone starting five minutes before the timer shuts off power to the devices, and continuing every minute until the power is shut down. This ensures the user is aware that battery power to connected peripherals will shut down. The onboard over-ride switch enables the user to bypass the timed shut-off feature in the case of an emergency or other event that requires immediate access to device power.

The RAM Safe-T-Charge is a shutdown timer, which is sometimes referred to as a delay timer. It protects the vehicle’s battery from over discharge and equipment from low voltage and high voltage damage. Specific to the RAM Safe-T-Charge is the easily accessible manual override switch that can be quickly initiated by an officer without the need to move a protective cover or touch any wires. Engaging the override switch circumvents the timer logic to ensure power is supplied to all connected devices, such as the land mobile radio or laptop computer.


Smart Energy Solutions

The Smart Energy Solutions Battery Brain is a low-voltage battery disconnect and is available in a number of configurations and current ratings. The BB412S with dash-mounted pushbutton reset switch lends itself to patrol car installation. The controller has to be installed directly to the battery positive post with the battery cable, then going to the output terminal of the box. A ground wire then is run to the negative terminal. The reset pushbutton switch and an override wire have to be run inside the car.

Smart Energy Solutions ships straight, angled and side post adapters with each unit to help with installation, but there may be some times when space is so limited, the Battery Brain has to be remote mounted next to the battery. In those instances, you have to source a battery cable of appropriate length and bolt the Battery Brain to a flat surface next to the battery, connecting it to the positive post with the cable.

Battery Brain constantly monitors the system voltage and will disconnect the main cable if it should drop below 12.1 volts for a specific period. A heavy-duty contactor inside the main box driven by a solid-state circuit alongside it takes care of making and breaking the circuit.


Stephenie Slahor, Ph.D., J.D., writes in the fields of law enforcement and security.

Published in Law and Order, Apr 2015

Rating : Not Yet Rated

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