Battery Voltage Monitors

Gliddenwoods

I am exploring purchasing a battery voltage monitor for my 2019 TAB 400 Boondock Lite. Would appreciate any advice on what you use and/or recommend I purchase. Thank-you.

ScottG

It depends what sort of functionality you seek. Many T@bbers (myself included) get by with a cheap (~$10-15) plug-in monitor like this:

These have limitations however, as they only tell you voltage under current conditions, and that can vary depending on what loads may be placed on the battery.

On the other end of the spectrum, many owners have installed the Victron brand monitors. These utilize some sort of magic to provide info about your usage and true state of charge regardless of operating conditions. These go for around $200, I think, but someone recently reported finding a knock-off brand for ~$30 that looked pretty good for the price.

There are quite a few discussions here on this topic, with comments from people more knowledgeable than I about installation and functionality of these units. If you are interested, I suggest you search around and do some reading!

rkj__

I use a plug in monitor similar to the one ScottG pictured above.  Since there is often no significant draw on our battery, it gives a sufficiently useful reading. 

N7SHG_Ham

I have a Victron BM712 installed, there are cheaper alternatives but I doubt any others that have more info.

Marceline

I use this. It’s just a step above the plug-in meter so it’s not as good as a Victron. But it sends data to my phone via Bluetooth and will send alerts if battery voltage drops to preset levels. 
~~~~~~~~~<<

Quicklynks Battery Monitor BM2   Wireless Car Battery Tester 12V Battery Load Tester Bluetooth 4.0 Digital Battery Analyzer Battery Voltage Charging and Cranking System Monitor for Android & iOS https://www.amazon.com/dp/B071JR1JPM/ref=cm_sw_r_cp_api_i_edpdDbGA0V6JA

gspdx

I noticed with the Victron MPPT 75/15 solar charge controller there is also a section for the state of the battery in the phone app.  Shows voltage and current.  From what I have seen online if the current is positive it is in a charging state from the solar panels (currently not connected to shore power).  If the current is negative then we are consuming energy from the battery.

Not sure if I would need another monitor. 

Fergie

While not everyone might want to tackle a project like this, a few years ago I built a direct battery monitor for our then new T@B before moving up to Alaska with it. The link is below with the pdf file on the whole project. 

https://tab-rv.vanillacommunity.com/discussion/3903/direct-reading-voltmeter-for-battery-monitoring#latest

Even if you aren't into doing such a project, it's worth reading the introduction I wrote about what I learned as a new RV owner and what I learned about batteries. By the way, the monitor has worked perfectly for all the years and miles.

Fergie

Photomom

Gliddenwoods said:

I am exploring purchasing a battery voltage monitor for my 2019 TAB 400 Boondock Lite. Would appreciate any advice on what you use and/or recommend I purchase. Thank-you.

Did it come with a SeeLevel monitor? Are you looking for more functionality?

VictoriaP

Photomom said:

Gliddenwoods said:

I am exploring purchasing a battery voltage monitor for my 2019 TAB 400 Boondock Lite. Would appreciate any advice on what you use and/or recommend I purchase. Thank-you.

Did it come with a SeeLevel monitor? Are you looking for more functionality?

The 2019s have the KIB monitor, which for battery monitoring is one step above worthless. It uses LEDs to show E  1/3  2/3  F. No voltage, no percentages.

Rollingztone

I installed a BMV-700 with bluetooth dongle on my 2012 T@B and used it for several years. It worked flawlessly and the software was updated pretty regularly. I just bought a 2018 T@B Boondock and I'm having the dealer install a BMV-712 before I even pick it up.

Spectre9

Honestly, one of the cheapest way to get Bluetooth monitoring is to install the same solar controller used by factory in 2018. SR-HP2440 is about $20 and has Bluetooth and keeps an log of voltage extremes and has a decent app. 

Awca12a

This is covered rather extensively in this 400 manual.  

https://tab-rv.vanillacommunity.com/discussion/8650/unofficial-nucamp-t-b400-resource-guide-finalized

Sharon_is_SAM

Here is a faster route to that info - pg 95.  @Awca12a, is there a Table of Contents that I am not seeing?


https://us.v-cdn.net/5021717/uploads/editor/7i/hvlhnphtcl1i.pdf

jkjenn

Just to be clear, a voltage monitor and a  battery monitor are not the same thing. A voltage monitor  tells you essentially what the load is on the battery at that moment. A battery monitor will tell you the state of charge of your battery and has a shunt to measure what comes I  and out of your battery in terms of charging and draw.

Rollingztone

To jkjenn's point, the Victron BMV-700 (and newer models) monitor the voltage state your battery is at that moment, and the amps being drawn off the battery at that moment as well. As you turn on a fan or a light, you instantly see the drain on the battery. Also, you can set the amp hour (AH) capacity of your battery when fully charged to 100% and watch it deplete as you draw amps off during the day. You can set an alarm to go off when either the voltage of the AH capacity reaches a certain minimum so you don't damage your battery. And as you recharge the battery, you can see the voltage and AH increase. There is a free app for your smartphone that allows you to monitor and set alarms remotely through bluetooth even from your car while driving down the road. This thing is indispensable for boondocking off the grid, in my opinion.

ChanW

I have not experienced the alarm function yet.

One thing I was curious about with the alarm, does it notify the phone app when it alarms, or must you be able to hear the monitor itself?

Rollingztone said:

To jkjenn's point, the Victron BMV-700 (and newer models) monitor the voltage state your battery is at that moment, and the amps being drawn off the battery at that moment as well. As you turn on a fan or a light, you instantly see the drain on the battery. Also, you can set the amp hour (AH) capacity of your battery when fully charged to 100% and watch it deplete as you draw amps off during the day. You can set an alarm to go off when either the voltage of the AH capacity reaches a certain minimum so you don't damage your battery. And as you recharge the battery, you can see the voltage and AH increase. There is a free app for your smartphone that allows you to monitor and set alarms remotely through bluetooth even from your car while driving down the road. This thing is indispensable for boondocking off the grid, in my opinion.

jkjenn

ChanW said:

I have not experienced the alarm function yet.

One thing I was curious about with the alarm, does it notify the phone app when it alarms, or must you be able to hear the monitor itself?

There is an audible alarm from the monitor, itself.

ChanW

Ok. I wonder if the app developers are willing to take suggestions, or if the firmware in the device itself actually has any room for additional 'features'.

I'd put in a request for a notification popup on the phone. 

But then again, the phone app only works when in the Bluetooth vicinity of the monitor, so it would be of limited use, I suppose. In the car, or in the campsite, might be helpful, though.

jkjenn said:

ChanW said:

I have not experienced the alarm function yet.

One thing I was curious about with the alarm, does it notify the phone app when it alarms, or must you be able to hear the monitor itself?

There is an audible alarm from the monitor, itself.

Rollingztone

Here is a link to the Victron BMV manual.  https://www.victronenergy.com/upload/documents/Manual-BMV-700-700H-702-712-EN-NL-FR-DE-ES-SE-PT-IT.pdf

davel4wa

Discharging your deep cycle battery is not going to do irreparable damage to your battery in all likelihood. Deep cycle batteries are called deep cycle batteries because they are designed to be discharged. Repeatedly discharging the battery beyond a certain level will shorten the lifetime of the battery but not ruin it forever.