|Item Weight||3.2 ounces|
|Product Dimensions||10 x 1 x 6.5 inches|
|Item model number||3721|
|Manufacturer Part Number||3721|
|OEM Part Number||3721|
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INNOVA 3721 Battery and Charging System Monitor
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- Enter your model number to make sure this fits.
- 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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From the Manufacturer
INNOVA 3721 Battery and Charging System Monitor
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.
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Top Customer Reviews
--- Update ---
Amazon has updated the new photo for the product. The picture is correct now.
--- Update 5/30/2016 ---
Lately, my wife's car won't start. I plug in this battery-Charging System monitor and turn on the power. The monitor shows 11.65V. Right there, I know something is wrong either with the battery by itself or the car's charging system. At this voltage level, the battery won't have sufficient power to crank up the engine. A typical reading before turning engine on should be around 12.34V.
Nevertheless, I replace the old battery with a new one. The monitor now shows 12.30V when I turn on power. I drive around with the battery-Charging system monitor plugged in. I see voltage level is at 14.34V. That's good. This means the charging system is charging the battery.
After driving around for about 15 minutes. I turn off engine. The monitor now shows battery is at 12.74V (higher then the initial 12.30V) . This confirms the new battery is taking charge from the charging system when I drive the car around.Read more ›
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.
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
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.Read more ›
Most Recent Customer Reviews
This works great in my camper to let me know what my batteries are at. The built in battery meter is too generic but this gives you a reading out to the hundredths place. Read morePublished 53 minutes ago by Kenneth J Stoll
I was able to verify random drops in system voltage and eventually pinpoint them to connections at the battery, thanks to this handy device, I did not end up throwing money away on... Read morePublished 18 hours ago by nalz
I use this to watch a battery that is solar charged. It draw 8 mA, which is ok given that it is showing the voltage with a backlight and has LEDs. Read morePublished 4 days ago by trailblazer
Great little tool. Gives you peace of mind regarding battery condition and when you need to charge..Published 7 days ago by John Reller
The meter is great, accurate, useful, but the male plug in is to short for a older ash tray, (should be 1.5 In longer)Published 8 days ago by Amazon Customer
This monitor works well to tell the voltage of the RV battery. I have found that I get some false results depending on what other items are currently drawing power when I'm... Read morePublished 10 days ago by Eddy