Battery Disconnect

Here’s another good question we got from a customer.

“I normally install in a battery disconnect switch when I wire a car.  When I install inRESERVE, do I need to wire in a separate battery disconnect switch?”

The answer is “no”.  Just like all of our other products, our products are versatile and serve multiple functions.  inRESERVE is our active battery management system.  It works in conjunction with our 10 or 20-Circuit Harness Kits to actively protect your battery from drain.  There are lots of things in your car that are pulling current from the battery when the car sits idle.  The ECU pulls power, the audio system pulls power and our Infinitybox hardware pulls power while the car is sitting.

Before we get into the details of inRESERVE, there are a few things that you can do to maintain the health of your battery and to make sure that you always have a good charge.

First, we always recommend leaving the battery on a maintenance or trickle charger.  Good ones are made by CTEK, Optima or Battery Tender.

From there, we always recommend adding a disconnect switch between the battery and the electrical loads in your car.  That way you can manually kill all of the power demand from your battery when the car is sitting idle.  This is a thing where there are lots of good products out there and lots of bad ones.  The disconnect switches that we recommend are made by Littelfuse or Pollak.  This is one of our favorites.

There are a few important warnings about wiring in disconnect switches.  First, you do not want to run your starter motor through the disconnect.  With the exception of a few switches, most are not designed to handle the current surge from when you crank the engine.  You want to leave the main feed from the battery to the starter motor uninterrupted.  Second, you never want to interrupt the feed from the alternator to the battery.  This can lead to a situation called a load dump and it can cause significant damage to the electrical systems in your car.  This link will get you more information.

Our inRESERVE Active Battery Management System combines a disconnect switch with the intelligence of our Infinitybox system.  Click on this video to learn more about the specifics.

The Infinitybox system is always monitoring the battery voltage in your car.  If the voltage gets too low, a POWERCELL output pulses the special solenoid included in the inRESERVE kit and disconnects all of the draw from the battery.  To do this a few conditions need to be met.  First, the ignition must be off.  We don’t want inRESERVE shutting down power with the ignition on.  Second, the battery voltage must drop below 12.2 volts.  For most battery chemistries, this is less that 10% stored energy.  Lastly, the voltage needs to stay below 12.2 volts for more than 15 minutes.  We do this so that momentary sags in battery voltage will not trigger inRESERVE.

inRESERVE does two very important things by actively disconnecting the battery when the voltage gets low.  First, it always leaves enough of a charge in the battery so that you can crank the engine and get it started again.  Second, it never lets the battery voltage get too low.  Deep cycling of a battery will damage it and will shorten its life.

This link will take you to the wiring diagram for the inRESERVE system.

You will note that there is a manual reset button that is included with the inRESERVE kit.  inRESERVE actively kills power to the system by sending a signal to a special solenoid.  After it does its job, the Infinitybox system is asleep.  You need to manually reset the system by pressing a reset button.  This button must be placed in a location that can be accessed when the battery is disconnected, which means somewhere on the outside of the car if you have power locks or poppers.  We usually recommend installing the button under a fender for easy access.

This same manual reset button can be used to manually disconnect the battery, which is the answer to the question asked at the beginning of this post.  You can press this button to manually disconnect the battery and press it again to reengage the battery, just like a typical battery disconnect switch.  Adding inRESERVE to your system eliminates the need for a manual battery disconnect switch.

There are a few last things to consider when wiring in inRESERVE.

  1. You must not run the starter motor current through this solenoid.  That must run directly between the battery and the starter motor.
  2. You must not run the alternator feed through the inRESERVE solenoid.  The electrical path from the alternator to the battery must not be interrupted.
  3. The solenoid included with the inRESERVE kit is a special solenoid.  It is not like a typical starter solenoid.  It has a special latching mechanism in it.  A momentary pulse to the coil will latch it open.  Another momentary pulse will latch it closed.  Follow the wiring diagram carefully when wiring it.  Also, you may not substitute other solenoids.  They will not work correctly.

Please give our technical support guys a call if you have any questions about wiring a Battery Disconnect into your car.