Reviews of INNOVA 3721 Battery and Charging System Monitor

Customer Ratings:
List Price: $25.57
Sale Price: $13.83
Today's Bonus: 46% Off

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.

Click Here For Most Helpful Customer Reviews >>

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.

Best Deals for INNOVA 3721 Battery and Charging System Monitor

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

Honest reviews on INNOVA 3721 Battery and Charging System Monitor

Our family love going to the Drive In Movies but we were always concerned about would we have trouble getting home due to the fact that our truck was running its radio the entire time so that we could hear the movie. This device helped a lot. We knew when we needed to start the truck so the battery wouldn't go dead. YAY!

Find helpful customer reviews and review ratings for INNOVA 3721 Battery and Charging System Monitor

I purchasted this unit to use in a small aircraft that has no built in battery monitor.

The unit failed within one hour of use.

It was too cheap to bother to send back so I took it apart.

I found two loose screws holding the circuit board and display in place and a bad solder joint.

I repaired the solder joint and tightened the screws and the unit has been working fine ever since.

Unless you are an Electronic Engineer like me I would not recomend this unit.

Strangely enough, the internal components appeared to be high guality.

It was not assembled correctly.

It's OK if it works.