Battery Monitor Recommendation Non-Solar

michaelroyy

I am looking for some help choosing a battery monitor to check on the remaining charge of my battery. Thank you in advance and my wishes for safe travels to you all. Michael

4ncar

Victron BMV712, or the victron smart shunt, if you can find one in stock. I use the 712.

pthomas745

Depends on how much you want to count.  The Victron shunt mentioned above will count voltage and amp hours used, pretty much state of the "art".  Cost:  200 dollars or so.  Installation extra. Not hard, but will take some time and effort.  There are other brands of battery shunt.

If you just want to watch your battery voltage, an "autoranging multimeter" is very good at the task.  Easy to use, despite the presence of scientific hieroglyphics all over them.  For battery monitoring, you just learn one symbol.   An ordinary one at the vendor of your choice can be less than 20 bucks, the "scientific" ones can get pricy.    Pros: excellent, inexpensive method of monitoring voltage.  Cons: For the best accuracy, you need to have the battery off for a while to let it "rest".  With the rise of the shunt type meters, sometimes dismissed as "not good enough" because of the lack of "counting amp hours used."  I used one for a year or so, and it works quite well for me.    An excellent tool everywhere in the campsite.  90 percent of the "my solar/battery/power isn't working" questions can be solved with a meter.

A step down from the multimeter is one of the 12V "plug in meters".  Basically, a cheap multimeter attached to a 12v plug. Pros:  Inexpensive, easy to read, only does one job.  Con: The "rested" battery issue:   you need to figure out a way to get a 12v plug attached to the battery in a way so that it can measure the battery with the switch off.  (There are several easy solutions for this).  Derided/dismissed/ignored as "toys" and worthless...but I've tested a couple side by side with my shunt and multimeter readings, and they work much better than people think.  ( I would still want to test one before trusting it, though).

The SeeLevel monitor might as well be one of the "plug in meters" mentioned above.  I have one in my 2017, and I've learned how to "interpret" it, but since it cannot be used with with trailer battery switch "off", it is not as useful as it could be.  Don't trust it! 

The newer monitors installed these days with the blue lights are very pretty.

michaelroyy

Wow, thanks for the detail. I don't know anything about this. I did an Amazon search and was wondering if either of the following would work: INNOVA 3721 Battery and Charging System Monitor or Battery Monitor ANCEL BM300 Bluetooth Voltmeter

pthomas745

The Innova has been around for a while, and many people bought them, and so did I.  Plugs right into a 12v port. 

The issue is:  you cannot accurately measure battery voltage with a battery that is "in use" or "being charged."  A battery is a stew of chemicals interacting, and if they aren't "settled down" they will give "false capacity."  A battery in use will always return low voltage values.  A battery being charged will always give a "too high" reading. Even a shunt type meter offers "false" values under those conditions.

The way to avoid this "error" for voltage for the trailer's battery is turn the battery switch off or otherwise disconnect it, and measure the battery with one of these tools after the battery chemicals have settled down....or "rested."  Usually, the longer you "rest" the battery the better, but most of the time 15 minutes has worked pretty well for me.  

The Ancel you show, if connected directly to the battery, would work well for voltage, it seems.  (I haven't looked at the rest of the features, but some of the photos in the Amazon reviews show it permanently attached to the battery.)  And the bluetooth is a bonus.

The Innova would have to be used inside the trailer, or attached to the battery directly for the "rested" reading.  (Not hard to do.)  If you tried to plug it into the trailer's 12v ports, it would only work if the battery switch is on.  See the above discussion about "rested" batteries for the disadvantages of that.

Marceline

If you don't want to spend the money on a Victron SmartShunt, I used this for a few years (similar to the newer looking Ancel battery monitor that you posted) and it did a decent job tracking battery voltage. https://amzn.to/2K28J5I

But if you are interested in the SmartShunt, Bay Marine Supply has them in stock and I can recommend them as a super reliable, helpful vendor.
Victron SmartShunt Battery Monitor (baymarinesupply.com)

michaelroyy

thanks

qhumberd

I have installed the AiLi shunt monitor following some online research and wanted to share the steps I followed. This thread provides all the information for this mod. The shunt I picked was about 45.00 on Amazon for a 350 amp shunt and monitor.

My 2019 T@B 400 has dual 6V batteries in series producing 12V and 224 Ah. They are housed under the rear bed in a formidable looking battery box with many screws and a vent tube. The first owner had the dealer put in a solar plug on the driver side wall with plans for an inverter later. There are no solar panels.

The middle compartment under the bed holds the battery box and the distribution point as shown here

Black wiring cover on left is the solar port install. Large White lead is Neg into battery box. Red is positive lead.

12V wiring to trailer exits the distribution box as white and red wire to black wiring cover on right of distribution box and goes to battery cut off switch inside storage door on passenger side. This means that the shunt is installed on live terminals, and the solar port is always live as well.

This shows a close up of the White negative stud and Red positive stud with cover removed. As @Denny16 noted earlier, you do NOT have to remove battery cover to install this shunt. But be careful as the studs are pretty close when you are working. I covered one with electrical tape while I was working with the other stud.

B- on shunt was connected to White neg lead removed from distribution box. A 2 gauge Camco battery lead was the inserted from P- on shunt back to distribution box. And a small white wire with red stripe was connected to Red positive stud from shunt to power the monitor.

Monitor powered up automatically when connected and followed setup instructions to set battery percentage at 100 as the battery was fully charged. The monitor will then calculate Ah use and % discharge automatically.

Much less than Victron, but no Bluetooth. I comes with about 7 ft of cable to the monitor itself so I am considering where to mount it. Will see how it works.

qhumberd

Here is Amazon link

AiLi Voltmeter Ammeter 100V 350A Caravan RV Motorhome 999 AH 

https://www.google.com/aclk?sa=L&ai=DChcSEwjulbmK0vHtAhWkU9UKHTxZAOkYABAWGgJpbQ&ae=2&sig=AOD64_1DSdkrSD58Z_J73DkhRfwsbdq7Ig&q&adurl&ved=2ahUKEwiSp6qK0vHtAhUJKKwKHeLzCAgQ0Qx6BAgVEAE

pthomas745

Nicely done.

Sharon_is_SAM

I am only familiar with the Victron shunt that comes in a 500 A vs 1000 A.  How do you determine what size shunt is required?

qhumberd

My reading indicated that the amp rating of the shunt (not amp hour ) is based upon the maximum draw thru the shunt itself, which is usually a function of how large your inverter is. I don’t have an inverter yet but read that this will cover up to around a 2000 watt inverter. Still learning about all this. The AiLi unit is not high end but for the money provides the data on current flow in both directions and calculates depth of discharge as well as accurately monitoring voltage. It’s about all I need right now and the price was certainly affordable. When I get an inverter and upgrade the batteries then I will have practiced and can maybe spring for a Victron.

Sharon_is_SAM

That makes sense.  Wasn’t sure if battery capacity entered into the equation.

qhumberd

I first heard about this monitor from a You Tube solar power guru Will Prowse, who has very infectious optimism about most things.

https://youtu.be/E6O76Okmt08

Happy Holidays and Merry Christmas everyone!

cyoung

I also installed a AiLi monitor and seems to work just fine. I placed the monitor next to the Alde control panel so had to get the 16' cable.