The Best Way to Know Coach Battery Voltage

On our first trip of this season, our first stop was at dealer service. (I will write about this trip in a coming article.) One of the things we wanted done was to have a 12 volt outlet that is connected to the coach or house batteries installed (the batteries for the RV, not the engine).  This was a project long in planning. It started with my idea to install digital voltage meter that would be connected to the coach batteries and the TEST button on the monitor panel. I went searching for how this would be done and it is relatively simple IF you know what wire is which and where it is connected - plus how to get to the wires.  The monitor panel - while it is similar to models made by the company that manufactures it, is made for Roadtrek by that company. Finding a schematic for the wiring and even knowing how to pull it from the wall without damaging it was not becoming a simple task. I knew that we had to be going to service anyway - if for nothing else but to get the generator oil changed for its annual change - so why not let the dealer service department do all this for me. I then started looking for a digital voltage meter that could be installed in the space that was available adjacent to the Test button and monitor panel. There are many to be found on Amazon and Ebay but most are designed to be installed into a dashboard and not the half inch wood of the Roadtrek wall in this location. I could rig something with a frame to have it surface mounted but then found this.

What is this? This is an Equus Innova Model 3721 Battery and Charging System Monitor. It is made for a vehicle battery and plugs into the 12 volt cigarette lighter or appliance outlet in a dashboard. It has an LCD digital display with both numerical voltage and a graph, and also LED lights. On the back is a chart that tells you what voltage levels indicate. The numerical voltage is the exact reading to within the accuracy of the meter. It also folds for different angle viewing. From reading the hundreds of reviews, this is supposedly one of the best of these meters and it was available through the Walmart website's "Site to Store" free delivery for just $13.86. It may be at local retailers but it was not in the several Walmarts in two three states that I looked for it. I ordered it and had it in five days.

 

This gave me a new idea. Instead of having a permanently mounted meter installed I could have a 12 volt coach outlet installed. This would enable me to use this meter and also have the outlet for any other 12 volt charger or appliance. Now, some of you with newer or older Roadtreks will say, "But there already is a 12 volt coach outlet in the Roadtrek!" Well not in the 2011 or the 2010. I am not sure when Roadtrek stopped including a 12 volt coach outlet or started including them again, but I don't have one. Newer Roadtreks have the outlet as part of the antenna booster and I could have done it that way also - probably on my own, but inside the cabinet over the TV on the  cabinet ceiling was not going to be very convenient - particularly since we keep the bed made up when traveling and opening that cabinet means climbing up on the bed. So I started looking for and found quickly a common and standard RV part - a 12 volt outlet - which it just so happened was in stock on our dealer's website's part's page. There were two to choose from. One the size of a light switch plate and the other much smaller - small enough to fit in where the monitor panel is.  A discussion with Meryl and it was decided. I sent an email to our friend at dealer service - good friends after all of the time we have spent with her over the four years of our visiting her at the service center - and told her my plan and included the part number and a photo of the vicinity that I wanted to outlet installed. She said she would show the photo and the part to the tech and see what he said. A couple of days later, we were good to go - she had ordered the part and we just had to wait the month for our appointment (more about that in my article about the actual trip). 

So once at service I showed her the spot that I wanted the outlet, she said it may need to be moved slightly lower which was fine and we left it to her and the tech to have the outlet installed. Five hours later - there were other things to be done - I had an outlet. 

 So here is how it all works - turn on the coach battery switch and just plug the meter in!

This reading is two and a half days after getting home from our trip. When this reading was photographed the "C" charge light was still lit on the monitor panel (this stays lit from a couple of days to a couple of hours after the batteries have been charging), but flickered (usually an indication it is about to drop to the next LED). A few minutes after I pulled the meter from the socket, I pushed the Test button and the panel LED was now on the "G" for "good" third up from the bottom yellow LED. I put the meter back in and the reading now was 12.4 volts. Still very good. Sitting without driving or charging even with the battery switch OFF, there is drain on the battery(ies). 

When I plugged the meter in during the trip while plugged into shore power with the batteries charging the reading was 13.8. During the trip during the day while on batteries only - with the fridge on DC (AC/DC only fridge) readings were 12.6 to 12.8. We were driving during each day and plugged in each night. Finally, I am free from the monitor panel LEDs - constantly guessing what the "G" LED and the second "F" (red) LED mean. No more guessing. 

I had a cap from a 12 volt socket splitter and it fit perfectly so now the outlet is not open when not in use. Not really necessary but a nice touch!

So without the Innova meter you are left with the option to take digital readings in the engine compartment at the Separator or Isolator. This is so much easier. 

After I purchased the Innova I came across a small plug in LED digital 12 volt meter on Amazon for only $3.00 - with Free Shipping. I wondered how this could be sold for only $3.00 and still be shipped free and I decided to take a chance and buy one of these also. The estimated delivery date was a month and a half after the purchase date. I thought that someone could put this in their pocket and walk it to my post office from just about anywhere in the country in less time. It shipped three days after purchase and arrived one week after purchase. The meter was shipped from China -in a brown mailing envelope and inside the meter was in a bubble wrap pouch. The postage on the envelope was from China. This little LED meter works. It lights up with bright red LED readings - the difference is that this meter has only three digits where the Innova meter shows four digits on the display. Used one after the other, the LED meter read the battery voltage as 12.4 while the Innova read the battery voltage as 12.42. If the Innova only had three digits, the  readings would have been the same BUT had the reading on the Innova been 12.49 and the LED meter still read 12.4 that would be somewhat different - though still not dramatic. So if you want a three dollar plug in digital 12 volt meter, search Amazon.

And just in case it needs to be said - I have nothing to do with the companies that makes these meters or this 12 volt outlet.  I get nothing from anyone and I give no "official" endorsement. If there is something good that is worth sharing I share it.