BatteryMole® Monitor Frequently Asked Questions
Do you have information that tells what the normal operating ranges are for a good battery?
Whether a battery is good or bad is determined by monitoring it when the engine is started. Consumer Reports evaluates new batteries by using a special device to simulate the dynamic load put on a battery when the engine starts. The BatteryMole® Monitor does one better and uses the engine as the load tester. A comparative analysis is performed by the monitor with previous measurements taken at the same approximate temperature to determine if the battery is becoming unstable. Start voltages and start times are effected by temperature, engine size and battery type. Absolute start voltages and start times are not meaningful.

The charge state is more a reflection of trip duration and trip frequency. It says little about the battery's health. When the charge drops below 40% the unit will sound an alarm. It is then time to have your battery charged (or perhaps drive more).

A low voltage alarm (i.e. below 12v) is always qualified by time. Newer cars with auto stop/start will drop the battery's voltage at a stop light but that means nothing with regard to the battery's health. Honda in 2011 tried to use an unqualified voltage alarm on their Odyssey minivan. Power doors and dome lights were causing unwanted and unnecessary alarms. Honda abandoned this technology in 2012.
Every time I start the car (mornings going to work, going to lunch and coming home in the evening) the BatteryMole will beep once or twice or not at all. There are no alert messages. What do these beeps indicate?
The beeps reflect the state of the BatteryMole's internal power supply. No beeps indicated that it is fully charged, one beep it is less than fully charged and two beeps it is discharged. The monitor is designed to work under all 3 conditions and we only used this information to assist in our product development and prototype testing.
AMAZON Customer Review: September 22, 2012 ,... in my car the 12v is cut upon engine start. Therefore, the device can only be used a voltage meter, a bit expensive though.
Irrespective of the start voltage, the following additional functions are performed in all cars: 1) The output of the alternator is monitored when it is predetermined that the temperature under the hood will approximate the temperature read from the BatteryMole®'s built-in temperature sensor. An alarm is generated when the battery is either being over or undercharged. 2) A Low Voltage alarm, qualified by time, is generated whenever the battery's voltage drops below a predetermined threshold. 3) The charge state of the battery is calculated once the engine has been off for more than four hours. For those cars that switch off power to the 12V receptacle, this calculation is based upon multiple voltage samples taken during the first 50 milliseconds as the ignition switch transitions from the OFF position to the START position. 4) The time it takes the engine to start is sampled whenever the engine is started after it has been off for more than four hours. This measurement is used by the software to determine the health of the battery and if there is probable cause to raise an alarm. This function neither requires nor makes use of the start voltage. 4 Peaks Technology has one issued and three pending patents that describe the behavior of the BatteryMole®. This does suggest that there is far more to the BatteryMole® than just start voltages. If 4 Peaks Technology had tens of thousands of customers (which it does not) and if many could provide accurate feedback as to how their 12V receptacles behave, it would be possible to generate a list of those cars that don't capture start voltages or have excessive electrical noise and/or voltage attenuation at the 12V receptacle. The accuracy of this information could not, however, be guaranteed since some ignition switches and 12V receptacles, as they age, behave erratically. Results in the same make, model and year could differ. It is far simpler and foolproof to let Amazon provide a full refund, for any reason, during the first 30 days. For those customers so inclined, an aftermarket 12V receptacle is another option. And a third option, if there should be a problem at any time, is to contact We always strive to quickly do what's right and fair.
I noticed this morning that the BatteryMole in my car indicates 1% battery charge; I'm quite sure my battery is in good shape. Could it be related to the cold temperature? Also, why is it that sometimes when I hit the display button, I either get the battery % charge, the start time, or nothing (keeps displaying the current voltage)?
The issue you're seeing is most likely related to either electrical noise in the 12v receptacle that the software is, at times, incapable of filtering or an intermittent attenuation of the voltage caused by the ignition switch. We have even seen both problems on the same vehicle, a Toyota product. On this particular vehicle, an aftermarket 12v receptacle was installed that bypassed the ignition switch. The noise and the attenuation were completely absent in the new receptacle and very accurate charge readings are obtainable. It's important to note that the charge state is more a reflection of the performance of the alternator and trip length than battery health. Also note that a battery in poor health will be successfully detected in either receptacle since the algorithms are designed to look for voltage and time differences, not absolute values. With regard to start information and state of charge, these things are only measured after the car has been off for at least 4 hours. Also, if the power to the BatteryMole® remains off for more than a few days (which can happen in cars that turn off power to the 12v receptacle when the ignition key is removed), neither the start time nor the charge state will get displayed when the engine is first started. This information will, however, get displayed the next time the car is started after the engine has been off for 4 hours. Neither of these restrictions apply to aftermarket 12v receptacles nor to vehicles that never turn power off in the 12v receptacle.
I have a 2005 Ford F-450, 6.0 L Diesel which uses two batteries. The starting voltage is not reported. What happens is when the starter is engaged, the voltage goes to 11.48 and stays there for perhaps 30 seconds after engine start at which time there is a sudden jump to 13.5 to 14.5 charging voltage
This problem was reported by a very helpful customer who resides in Tucson, AZ. After the exchange of several emails and performing some experiments of our own on a similar truck we found a design problem in the BatteryMole®. This problem will occur on any diesel engine that performs post heating (i.e. the glow plugs remain on for extended periods after the engine has started). Please contact us at if you have a diesel engine and are perhaps experiencing this problem. Your BatteryMole® mush have firmware version 4.90 or higher. If necessary we will make arrangements to exchange your unit with a new unit. You can determine your firmware version by resetting the unit (i.e. holding down the display button for approximately 6 seconds). The firmware version will be displayed during the reset sequence. If you do, however, have firmware version 4.90 you need only set your unit to Slow Alarms (this option can be selected during the reset sequence). We do sincerely apologize for this inconvenience to our customers with certain diesel engines.
I have a 2006 Volvo S60 turbo with a nearly new battery. Why do I get occasional low charge alarms?
Some newer cars, yours included, put a heavy load on the battery when the ignition key is first turned on. Since power is normally shut off in your car's 12v receptacle, the only chance the BatteryMole® has to sample your battery is the brief moment between when the key first switches on and when the engine starts. We have measured the initial load in these cars and it is between .1v and .2v. This is enough to trigger an alarm if your car isn't frequently driven. The demand put on batteries in luxury cars, such as yours, is significant. Our recommendation is to set the BatteryMole® to Slow Alarms. This will compensate for the initial battery load while still providing ample Low Charge warning. And on a very positive note, the health of your battery is still accurately monitored when the engine is started.
How can my 2007 Chevy Uplander get frequent Slow Start alarms when the battery's charge state is typically 95%?
This question came from an engineering friend who volunteered to test a pre-production unit. The short answer is there are many things that will cause a slow start, not just a weak battery. The long answer is that we took multiple oscilloscope traces of this vehicle as it was being started. The traces confirmed that the start times were erratic (the slowest start time captured was nearly 5 times slower than the fastest). This battery is over 3 years old, is perhaps approaching its end of life in our hot Arizona climate and successfully passed a standard battery load test. The next step will be to take this vehicle in for a tune-up. We'll update this FAQ when the car comes back from the repair shop. Update: The battery on this vehicle died before it could be taken to the shop. And although a standard load test is a very good method for determining the health of a battery it does not compare to the stress generated in the first 20 to 30 milliseconds by the engine when it is started. It is 4 Peaks Technology's position that monitoring the stress put on the battery when an engine starts is the very best method for determining the health of a battery.
My battery nearly died overnight with your device installed. I'm now afraid to leave the unit plugged in.
When the monitor is active, the amount of power it consumes is quite small. The total current is less than 150mA and almost all of that is used to drive the LCD panel. It would take over 300 hours to drain a typical car battery at this rate. There are, however, two very important points. First, most cars turn off power to the 12v receptacle when the ignition key is switched off. There is nothing that could be plugged into these cars that would cause the battery to drain. Second, in those cars that keep the 12v receptacle powered, the BatteryMole® Monitor automatically shuts itself off some minutes after the engine has been turned off.
My car had a loose battery cable and wouldn't start. Why was there no warning?
We have seen this problem on a car that had a stripped battery cable bolt. In our case, perhaps, it was road vibration that was the culprit. The BatteryMole® Monitor showed 9 volts when the car wouldn't subsequently re-start. It's obviously very unsettling that this could happen without warning. Loose and corroded battery cables are a very common occurrence and if cable contact degrades over time the BatteryMole® Monitor will provide warning. If not, there will be no warning. Even a brand new battery will fail without proper cables.
My ScionXB occasionally gets Low Charge alarms but I have had my battery tested at a local parts store and it is fine. What's going on?
Your vehicle shuts off power to the 12V receptacle when the ignition key is turned off. In these vehicles the BatteryMole® has a very limited amount of time to sample the battery before the engine is started. Unfortunately when the ignition key is switched on, many other things in the car also turn on (e.g. radio, climate control fan, etc.). Normally the BatteryMole® has no problem getting accurate samples under these circumstances except when the battery posts are corroded or the battery cables are not properly tightened. Also a particular problem we have seen on the Scion is the point where the negative cable attaches to the frame. It was necessary to remove the paint at this point so that good electrical contact could be made between the cable and the frame. This may be your situation. Please have someone qualified remove the battery cables, clean both the battery posts and battery cable terminals with a wire brush, remove the paint where the negative cable attaches to the frame, remove all the corrosion and properly re-install the cables. This should do the trick. Please let us know if this did, indeed, fix the problem.