Equus 3721 Battery and Charging System Monitor

by Equus

Product Features

• Displays the condition of the battery and charging system
• Designed for 12-volt negative ground systems
• Protects the engine computer and 12-volt accessories from surges
• Easily plugs into a cigarette lighter or power receptacle
• Head pivots for easy viewing and angle adjustment

Product Details

• Product Dimensions: 10 x 1 x 6.5 inches ; 1 pounds
• Shipping Weight: 2.4 ounces (View shipping rates and policies)
• Shipping: This item is also available for shipping to select countries outside the U.S.
• ASIN: B000EVWDU0
• Item model number: 3721
• Average Customer Review: 4.5 out of 5 stars  See all reviews (143 customer reviews)
• Amazon Best Sellers Rank: #101 in Automotive (See Top 100 in Automotive)
  • #1 in Automotive > Performance Parts & Accessories > Ignition & Electrical > Gauges > Volt Meter
  • #1 in Automotive > Interior Accessories > Gauges > Voltmeter
  • #5 in Automotive > Replacement Parts > Lighting & Electrical > Electrical

Product Description

This 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. You can easily plug into the vehicle's cigarette lighter or power receptacle to monitor battery and charging system voltage. It has an LCD screen which displays the measured voltage with a bar graph to indicate battery charge level and it also has color-coded LEDs which quickly identify the battery's charge status. The head pivots for easy viewing and angle adjustment.

Customer Reviews

Most Helpful Customer Reviews

62 of 63 people found the following review helpful:

5.0 out of 5 stars Great value, good product, July 31, 2007

By 

H. Wang "jwangamazon" (San Jose, CA) - See all my reviews
(REAL NAME)   

Amazon Verified Purchase

This review is from: Equus 3721 Battery and Charging System Monitor (Misc.)

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.

44 of 46 people found the following review helpful:

4.0 out of 5 stars 12 Volt battery Monitor, April 16, 2008

By 

J. B. Syrett "Barry Syrett" (Gig Harbor, WA USA) - See all my reviews
(REAL NAME)   

This review is from: Equus 3721 Battery and Charging System Monitor (Misc.)

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.

13 of 13 people found the following review helpful:

5.0 out of 5 stars Does the job, February 20, 2008

By 

Liu Hao (Singapore, Singapore) - See all my reviews
(REAL NAME)   

This review is from: Equus 3721 Battery and Charging System Monitor (Misc.)

just got the monitor from amazon based on the reviews here. the actual device is slightly different from it looks in the picture, with rounder edges. i guess the new product has been revised. also the protective plastic film is extremeply easy to peel off, a bit too easy i would say. or it might have something to do with the weather. here in singapore it's 30C all the time. the device has good build quality. the monitor can show two different tiny icons above voltage reading, under the battery and charging modes. the LCD is clear with bright blue backlight. basically it doesnt cost arm or leg but does all i expected. i will leave it plug in all the time in my car. i am sure i will be alerted by the unusual low voltage one day to realise the time to replace my battery. that will be the time i can recover the cost of this product by saving the expensive recovery service.