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INNOVA 3721 Battery and Charging System Monitor

by Innova
| 17 answered questions

List Price: $25.57
Price: $13.95 & FREE Shipping on orders over $35. Details
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  • Easily plugs into vehicle's cigarette lighter or power receptacle to monitor battery and charging system voltage
  • Designed for 12-volt negative ground systems
  • LCD displays measured voltage with a bar graph to indicate battery charge level
  • Color-coded LEDs quickly identify battery's charge status
  • Head pivots for easy viewing and angle adjustment
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3 new from $13.95

Frequently Bought Together

INNOVA 3721 Battery and Charging System Monitor + Roadpro 12V Battery Clip-On and Cigarette Lighter Adapter
Price for both: $19.81

Buy the selected items together


Product Information

Technical Details
BrandInnova
Item Weight3.2 ounces
Product Dimensions10 x 1 x 6.5 inches
Item model number3721
Manufacturer Part Number3721
  
Additional Information
ASINB000EVWDU0
Best Sellers Rank #227 in Automotive (See top 100)
Shipping Weight1 pounds (View shipping rates and policies)
ShippingThis item is also available for shipping to select countries outside the U.S.
Date First AvailableJuly 7, 2004
  
Warranty & Support
Warranty, Parts: Parts
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Product Description

The INNOVA Battery and Charging System Monitor displays the condition of your battery and charging system instantly. It protects the engine computer and 12-volt accessories from damaging surges when jump starting or recharging. Easily plugs into the vehicle's cigarette lighter or power receptacle to monitor battery and charging system voltage. The LCD screen displays the measured voltage with a bar graph to indicate battery charge level and the color-coded LEDs quickly identify the battery's charge status. The head pivots for easy viewing and angle adjustment.


Customer Questions & Answers

Customer Reviews

I ordered two, one for each vehicle, and they work fine.
Mike Kitsko
Easy to use and provides very accurate readings with swinging head which will allow you to view the excellent bright display from many angle.
Mohd Khouri
You can monitor the charging status of the battery as well as the alternator charging the system with the engine running.
A. LOCOCO

Most Helpful Customer Reviews

129 of 133 people found the following review helpful By H. Wang on July 31, 2007
Verified Purchase
The picture on Amazon site is not correct. This battery monitor shows the voltage value with .01 precision (or two digits after decimal point). That is far more then enought to tell the battery status. I put it in the car, it automatically switches between "battery status monitoring" and "charging status monitoring". When the engine is stopped, it is in "battery status monitoring mode", when engine is running, it will be in "charging status monitoring" mode. Amazon's price is even bettern then Walmart. Definitely a great value buy. Will recommend this item to my friends.

--- Update ---
Amazon has updated the new photo for the product. The picture is correct now.
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102 of 108 people found the following review helpful By J. B. Syrett on April 16, 2008
Seemingly just another auto gadget fortunately the Equus 3721 is more sophisticated than its ponderous description. A breeze to connect to any car's 12 Volt electrical system. Simply push into the lighter socket or an auxiliary power outlet now found in many newer vehicles.

With the engine running the instrument constantly displays battery condition with an LED light; amber when marginal, red if the battery is discharging. A green light indicates a correctly functioning electrical system. All is well with both battery and, most importantly, the alternator.

The Equus is also an accurate voltmeter. Digital read-outs give exact voltage in the electrical system. Potential alternator problems or a failing battery will be indicated by below normal voltages, plus an amber or red light. Extra information is a battery icon graphically showing total battery charge. Tending towards erratic read-outs, and therefore unreliability, it is not the unit's best feature.

Equus's instruction card is easy to understand. The unit is well made, sturdy, easy to connect and to transfer to any 12 volt system not having its own voltmeter. Also, as a supplemental monitor in an RV, or a bigger boat with a remote 12 Volt outlet in a sleeping area far from the main instrument panel, overall battery condition condition can be monitored while camping or at anchor.

Good value for money; very useful. From personal use, recommended.
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61 of 64 people found the following review helpful By Jesse Knight on November 10, 2010
Verified Purchase
The Honda 2005 civic has a marginal charging system. This meter is ideal for determining when it is time to turn off the radio to reduce load on the alternator. Voltage reading is very accurate, much better than 1% as measured against a small Beckman pocket meter, which in turn has been checked against a Powerex Wizard aa cell charger. Warning lights function well.

Some things to note when using this tester: Standard voltage of a 12 volt battery is 12.6 volts. Some deep cycle absorbed glass mat batteries will read 12.8. This is after loading the battery by turning on the headlights for 10 seconds, to remove surface charge. Note that while the lights are on, the voltage drops quickly at first, then the voltage stabilizes. Turning off the lights causes the voltage to rise again gradually. After a few minutes the voltage will stop rising. If the voltage settles at 12.6 (or 12.8 for AGM battery) battery is charged, assuming that the battery is near 68 degrees F. Lower temps raise the voltage, higher temps lower the voltage. For a standard battery figure about 12.66 volts at 32 F and 12.54 volts at 104 F battery temperature, not air temperature.

After a car has been running for awhile with no lights, radio, wipers, AC, heat or window defroster, the alternator may cycle letting the battery voltage drop for a while before kicking in. This is OK provided the charging is steady shortly after turning on the lights. An intermittant alternator will cause the red light to turn on and off when headlights are on.

The bar graph for battery condition is not very useful as the meter has only voltage information.

The instructions do not state that this tester is for negative ground cars only, a small quibble as positive ground is not common.

Had I bought this device six months ago I could have avoided killing a brand new battery in six months.

UPDATE: Still working fine as of May 21, 2013
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25 of 25 people found the following review helpful By T. Tom TOP 500 REVIEWERVINE VOICE on January 24, 2013
Verified Purchase
This is a useful device to have in your car but you must understand it's limitations. In many cars, it will not be as accurate as taking a reading directly off your battery, which you can do with this device, if you buy this inexpensive additional adapter:

Roadpro 12V Battery Clip-On and Cigarette Lighter Adapter

The reason for this is that in vehicles where you have to turn on the ignition to ACC in order to power the cigarette lighter port, once you do that, the vehicle's electronics are also powered and will draw power. So, you will see a lower reading on this device than if you take a reading directly from the battery with the key out of the ignition. In vehicles where the lighter port is always powered, this device can be more accurately used directly plugged in to that port.

However, for taking a reading of your charging circuit with the engine running, this can be used in the lighter port in any vehicle.

Note that you can do all of this with any household multimeter however the chances of you having that in the vehicle are slim. Most all multimeters also require a battery in them so even if you store one of those in your vehicle, the chances are high that when you need to use it, the internal battery will be dead.

This Equus unit however requires no internal battery (at least I don't think it has one), so you can just throw it in your glovebox indefinitely.

Car batteries typically last around 5 years so after about 3.5 years is when you may want to periodically use this device to check the health of your battery.
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