ANCEL BM300 12V Battery Monitor, Bluetooth 4.0 Automotive Voltmeter with Charging, Cranking System Test & Alarm - Compatible for Solar Power Systems, RVs, Motorcycles, Boats, Cars, and Trucks

I wasn't looking for this monitor when I happened upon it on Amazon. I work in the motorsports industry and had not seen anything like this in the dealerships and shops I visit on a regular basis. And since I'm an electronics geek who's also in the motorsports field I had to try this.Before I ordered however I checked out the Ancel Battery Monitor App in the iOS store. There were only 4 ratings at the time with three 5-star ratings and one 1-star rating, the app looked promising so I ignored the one negative rating and ordered up.Once in hand I found the ANCEL BM300 Battery Tester/Monitor unit to be smaller than expected, measuring 3 ¾" Wide x 2" Long and 7/8" Thick. (Tapered design, see the pic below with measurements). The two lead wires are roughly 7" long with open clips on the end.To install I just had to hook up the leads to the positive and negative ends of the battery on my motorcycle. I then went into the app and expected to have to fool around with Bluetooth connections but the monitor had already paired to my phone and was showing the current battery voltage. Sweet! (see pic)From that point I started the motorcycle and the ANCEL BM300 showed the current charging rate and battery voltage with the battery voltage showing on a line graph. (see pic) I then ran the Charging Test and the charging voltage at idle and high RPM was shown. (see pic)The ANCEL BM300 will also perform a Cranking Test which shows the cranking voltage as a numeral and also on a line graph. Note: I like that the app shows good readings in Green and low or bad readings in Red. The Ancel also has a Trip setting which gives you a history showing times and duration for the vehicle (car, motorcycle, etc.) has been running.The app also has some more features in the System Set-Up allowing set two separate Power alarms at a % of your choice. These alarms will remind you once the battery is below the chosen percentages, I have mine set up at 70% and 50%. You can also choose to have a Daily Power Notification or Abnormal Cranking Notification.So far I am very impressed with the functionality and ease of use of the ANCEL BM300. The Bluetooth range is strong enough that I can check the battery status on my motorcycle from my living room with it being 30 feet away inside a garage with concrete block walls.The only negative I can think of is that as far as I can tell the Ancel Battery Monitor App can only work with one monitor at a time. If it worked with more than one vehicle I would buy one for my truck and my camper as well. I would also have an extra monitor to use for diagnosing battery/charging issues on the motorcycles and off-road vehicles I encounter for work.

I've got one of these on each of my trucks. It works great and allows me to see what is happening with the 12V battery while the truck is off.Today's vehicles have many modules and some don't shut off until a half hour after the ignition is switched off. Some manufacturers are installing 12v batteries that are too small for all of the conditions the vehicle may face - such as vehicles parked outside during very cold winter temps. If the 12v gets too low it can cause all sorts of warnings and problems in your car. Knowing your battery voltage over time is extremely helpful in diagnosing battery issues.

Easy to install and get setup. But the range is limited and the Bluetooth link takes a moment to reconnect. If you're wanting something to be able to monitor a vehicle that's parked outside your home, you'll want something else or you'll need to be able to park that vehicle very close to your home. Like right outside the door. I think the issue is the fact that I installed it in the engine compartment as recommended. I may try relocating it behind the rear view mirror so there's less metal and wiring to interfere with the bluetooth signal. The app is pretty good and easy to navigate. I continue to you this until a find a better solution.

Pictures starts with normal idle voltage, then 20min drive then on a low current charger, 1.5amp, then the phases of the charger to trickle charge then off the charger with a 20min drive. Next picture is the start screen, each vehicle has a different signature of the 3 I've installed currently. (Screen shot the typical starting signature for referencing later if issues arise.) Sometimes it takes a minute or two for the phone to find the device even if it's the only one in range. There seems to be an issue with more than one phone trying to use the same device at the same time. Sometimes it will just switch to another device if 2 are near by. You can view data by selecting the device after it's done scanning in the GEAR-> BLUETOOTH DEVICE-> SELECT DEVICE then tap the arrow/carrot to the right of the listed devices. Having a few months worth of data is very helpful. If you tap the center of the calendar day at the top of the screen you get a calendar with blue dots for data for that day or a red dot for data that was outside the normal ranges. No more guessing or relying on unclear observations or faded/shaded memories of other people!

Very easy to install, instruction easy and products seems well built. I like the APP feature took less than 5 minutes to download and setup

I’ve had this installed for a few days and thus far I’m impressed. The battery of my early Miata is in the trunk and not easy to access. For some reason, Mazda didn’t think their sports car needed a voltage gauge and twice I have discovered my battery discharged. It took the whole part of 5 minutes to install the monitor. I already had downloaded the app into my iPhone. The moment the monitor had power my phone gave me an alert the monitor was connected and the battery was at 100%. I then went into the app and set up the alarm parameters as I wanted them. The Bluetooth range does appear to be about 30 feet, I walked to find where in the house I would connect. I will update my review after I have lived with it for a while.