Battery Saving Devices

Protect your battery from upfitting power drains.

The following is a complete roundup of timers, voltage sensors and combination timers-sensors. Each company makes a wide variety of such devices. We picked just one representative device per company, as close to apples-to-apples as possible. We took into consideration both cost and simplicity. 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 Web site for each company to see what other devices are available, such as more features, less features, different connection options, etc.

AC/DC Industries

Model: Delay Timer MZL-10SW

Device type: Timeout timer, low and high voltage disconnect

The MZL-10SW timer has a voltage sensing turn on lead that must be connected to the ignition switch to start its timing cycle. A single 6-inch length of 10 gauge wire extends from the potted chassis to be connected to the battery with a user supplied fuse with a maximum draw of 30 amps. Three exposed 1/4-inch male spade terminals provide timer output for devices. It is up to the installer to provide fuse protection.

Time delay is again made using the top mounted DIP switches giving eight delay settings from 15 minutes to eight hours. A red LED indicator next to the switches flashes when the unit goes into its countdown cycle. There is also a pushbutton override next to the DIP switches that will turn the timer on temporarily without using the ignition switch.

BLI International

Model: Priority Start! PSI-12V-PROMAX

Device type: Low voltage battery disconnect

The PriorityStart! is a battery rundown protection device wired into the main battery positive cable in a 12 volt negative ground electrical system. It monitors at rest battery voltage and if it should drop to 11.7 volts or less for one full minute it will open the circuit and disconnect the battery from the vehicle. An LED on the front of the PriorityStart! housing shows green if the unit is connected and red if the unit has been activated and disconnected from the battery.

PriorityStart! is furnished with battery cable adapters for top post and side terminal batteries, a 12-inch long, 6 gauge main input cable, a black 18 gauge ground wire and a black “rubber band” to hold the case against the battery.  The basic installation requires removing the vehicle battery cables from their posts, cleaning the battery cables and posts to insure good electrical contact, reconnecting the cables—negative first with the black PriorityStart! lead attached to it and the PriorityStart! Unit—then the red positive cable.

Anything that draws power should be run through the PriorityStart! device. The last step is to slide the unit under the band holding it to the battery case. To test the unit, first make sure the key is out of the ignition, turn on the headlights and let them take battery voltage down to the disconnect threshold. While you’re doing this, it’s a good idea to monitor the system voltage with a digital volt meter just to double check the installation and operation.

Once the unit trips, wait a full minute; then reconnect the unit by turning on another load in the vehicle such as the spotlight, stepping on the brake pedal or turning on anything that will draw 2 millivolts (0.2mV) or more. It’s the sudden load transient that the PriorityStart! needs to see to reset itself.

Cole Hersee Co.

Model: FlexMod 48541-01 Voltage Sensing Relay & Timer

Device Type: Battery monitor with timeout timer, low and high voltage disconnect

The new FlexMod device from Cole Hersee is said to be weatherproof, dust and vibration proof, therefore underhood mounting should not be a problem. Wires are connected to the main unit with an 8-pin Amphenol weatherproof connector with 5-inch jumper wires extending from it. Make sure any wire splices are correctly done if it is to be mounted under the hood.

This makes swapping out units very easy if one should fail. However, make sure you take the pigtail jumper along when moving the box from car to car at changeover time. Otherwise, you will have to order a replacement harness because there is no other way to connect it. Importantly, the Voltage Sensing Relay and Timer is sold separately from the Mating Connector (Harness) Kit. You need both.

Shipped with the jumper pack are additional jumper wires, blanking pins to insert into unused positions in the connector body to maintain the weather seal, and a locking wedge to keep everything locked in place once it’s assembled. The jumper can be configured for a variety of applications, so it’s left to the installer to complete it as needed.

The FlexMod is rated at 10 amps directly but will easily operate customer supplied auxiliary high current relays if more capacity is required. Switching is done with solid state devices, not relays, for improved reliability and smaller packaging. Shutdown time is factory programmed for 15 minutes. The familiar DIP switches from other timers are not present.

Copeland Engineering, LLC

Model: Power Tamer VS Delay Timer

Device type: Timeout timer, low and high voltage disconnect

Copeland’s Power Tamer is the only product with its circuitry potted in a metal housing. Long, 15-inch jumper wires extend from the top of the box for power input and output, ground and ignition control. A nice touch is the weather resistant fuse holder with installed 25 amp ATO fuse that’s factory installed in the power input wire. The yellow ignition control and red output feed are stamped with the wire function so there is no questioning their function.

There is no override switch to turn the output power on once the unit times out. The delay time is set with the traditional DIP switches which are on the bottom of the case following a time setting chart in the installation instructions. After setting the time a label provided in the parts pack with the mounting screws must be put over the DIP switch opening to protect them from contamination. Failure to cover the switches will void the warranty. Two LED’s next to the wires monitor the power in and power out wires.

Power Tamer VS can be wired using only the power in and power out leads. In this configuration the unit will turn on power when the input wire sees 13.6 volts. This may take some time especially when the battery has to recover from high cranking loads (diesel engines).

This timer is a departure from other devices because it uses solid state Field Effect Transistor (FET) for output switching instead of relays for improved reliability. The metal housing is used for reliability as well as heat sinking for the switching transistors when they operate at near capacity.

D & R Electronics Co., Ltd.

Model: Watchdog-B battery monitor with timer

Device type: Timeout timer, low and high voltage disconnect

D & R Electronics Watchdog Timer, as with other timers, is not waterproof, so underhood or exposed installation is not recommended. However it should be mounted as close to the battery as practical because there is a voltage sense wire that must be attached directly to the battery and voltage drop across long wire runs should be avoided. 

Aftermarket mounting of the unit wiring is straight forward with a main power feed run to the battery positive terminal, a ground lead to the vehicle chassis, a lead going to the vehicle ignition switch and a second separate smaller 18 gauge lead going to the battery positive terminal. Input and output terminals are 1/4-20 studs extending from the potted chassis. No fuses or wire are furnished with the unit. 

Havis Inc.                                                         

Model: ChargeGuard CG-X

Device Type: Timeout timer, low and high voltage disconnect, surge protector, reverse polarity protector

During the past several years, ChargeGuard Inc., now a part of Havis Inc., has released several innovative models onto the market. The latest model, 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 water proof 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.

Lind Electronics

Model: LPT1230-052 Shut Down Timer

Device Type: Timeout timer, low and high voltage disconnect, reverse polarity protector

This unit is a low profile version of other timers offered by Lind Electronics. As with other units, this one is not waterproof and has exposed screw terminals so interior or trunk mounting is recommended. The 30 amp maximum input should be run directly to the battery and protected with an installer supplied fuse.

A wire gauge chart in the instructions tells you what gauge wire is recommended based on expected equipment current draw and wire length. The two outputs are rated at 15 amps each, and any device connected to the output should have its own circuit with fuse protection.

Setting and checking the time delay is easy as all controls are out in the open. A potentiometer on the face of the unit is rotated with a small screwdriver to the desired time and you are done. To speed up checking the delay timeout a test switch speeds up the timer by 100. For example, a delay of 2 hours (7,200 seconds) will time out in 72 seconds.

Smart Energy Solutions

Model: Battery Brain BB412S Gold w/ pushbutton

Device type: Low voltage battery disconnect

Smart Energy Solutions offers the Battery Brain in a number of configurations and current ratings. We chose the BB412S with dash mounted pushbutton reset switch because it 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.

Published in Law and Order, Oct 2012

Rating : Not Yet Rated

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