On our big road trip, we discovered that our favorite campgrounds didn’t have hookups. In fact, many of the best places to camp don’t have a place to plug in. While we enjoy being off the grid, we still need a power source for a few things like lights and water. 🙂
Our battery did a great job powering the Santa Fe–sometimes for five days at a time. While the battery never left us without power, there were several times where we were unsure just how much juice we had left. We weren’t sure about our usage, and we had forgotten to bring a good voltmeter to check the battery. We also realized that the battery was located under the king bed side, and when popped up, the bunkend would make it difficult to access and check our power source. So when our summer fun was over, we tackled our first post-trip project: a battery monitor.
The Pop Up Portal has all kinds of takes on this project. All you really need is an LCD voltmeter and a toggle or momentary switch. For our project, we used this 7.5v-20v Blue LCD Digital Voltmeter Volt Panel Meter
from Amazon, a toggle switch from Radio Shack, a nylon switch plate, and approximately two feet each of 16ga black and red electrical wire. Honestly, Mr. TypeTwoFun did this whole project alone. I just took pictures. 🙂 But he isn’t an electrician by any means, and he says the project is really quite simple.
The first thing Mr. TypeTwoFun did was use a conical grinding bit on the drill so the toggle switch would fit in the plate. We looked high and low for a switch that we could use in the face plate without any modification, but we didn’t find anything. Be very careful when enlarging the opening for the toggle switch. Some of the switches don’t have very much overlap, and you can easily make your hole too big very quickly.
Our voltmeter didn’t fit in the cut out either, so Mr. TypeTwoFun had to use the Dremel to widen the hole there, too. Again, be very cautious and keep checking for a proper fit.
Once you have your openings large enough to accommodate your toggle switch and voltmeter, you can attach your switch and voltmeter to the switch plate. We just used a little bit of epoxy to do that. Then you are ready to solder your lengths of electrical wire into place. This is the part that makes my brain hurt, so I had Mr. TypeTwoFun draw up a sketch to explain it.
Now, once you’ve got your switch and voltmeter all wired up, you want to install it. We decided to tap into the wiring from the porch light near the door. It seemed like the easiest way to go, and placing it next to the outlet by that door would make it easy to access. We had to cut an opening into the wall of the inside of the camper to access the wiring, but it is hidden inside the cabinetry. You’d never know it was there.
Then, to mount the plate, we used the jigsaw to cut an opening wide enough to fit our electrical components.
Once everything fit nicely, Mr. TypeTwoFun used a wire nut to connect the red wire from the switch to the black wire from the porch light. Then he connected the black wire from the voltmeter to the white (ground) wire, also from the porch light.
Then we popped the switch plate into place and used wood screws to secure it. The wood screws were silver, so I just dabbed a little white nail polish on the heads to help conceal them.
Once you are all wired up, flip the switch, and you can see how much battery you have left. If you are like me, all those numbers look like a foreign language. I had no idea what they meant. I did a little research, and found several charts that helped me figure out all those numbers. I plugged them all in to a little graphic and made a little chart to help me translate.
Now I know that I’ve got just under 60% of my battery left. I printed this chart off, and I keep it in the cabinet near the battery monitor. I’m sure after awhile, those numbers will become second nature to me, but for the time being, I’m going to rely on this little chart a lot. Our new battery monitor is going to come in so handy when we are dry camping!
Just a few helpful tips for using the voltmeter to check your battery life…
- The best time to check your voltage is when you aren’t using any power. You want to make sure you aren’t drawing from the battery when checking the state of your charge.
- The switch is there to keep your LCD panel from drawing from the battery constantly. Remember to switch the voltmeter off after you have checked the battery charge. If you have a momentary switch, you won’t need to worry about this.
- You don’t necessarily have to tap into the porch light if you have a more convenient place to access your trailer wiring. I’ve seen people put their voltmeters near their converter panels under the dinette or even behind the sink. Just remember… the closer you are to the battery, the less chance you have of something disrupting your reading, and thus it will be more accurate.
Everything fairly clear? If you have installed a voltmeter to monitor your camper battery life, I’d love to hear your comments! 🙂
Happy Camping!
i wonder i getting one to my pop up camper and still thinking where to put one inside
We have the Santa Fe popup as well, and we are trying to find the correct size fire extinguisher that fits within the holder. The old one needs to be replaced. Could you tell me where you found your new fire extinguisher that you replaced your old one with that also fits into the same mount? Also, if you could provide any specs like maker size etc. so that we could order the same for ours. Thank you so much for your time!
Sadly, Paul, we have not been able to find a fire extinguisher locally that fits that space either. That’s our original, which I’m sure needs to be replaced very badly. We’ve seen a couple on Amazon that might work, we just haven’t gotten around to ordering one. Thanks for the reminder! I’ll be sure to let you know if we find one that works. 😉
This is the correct fire ext. I looked around and found it for $20 shipped and it is an exact replacement with the same BC rating. Only difference is that it is white rather than red. I don’t mind. Very cheap insurance rather than trusting an old one that may or may not work.
Kidde 466636PWC
Hi,
Thanks for the article, just installed one of these in my pop up. My meter is reading 13.0 so my question is if I have 2 batteries should it read 26.0? I do have 2 batteries so just wondering.
Thanks for the pics, made this very straightforward.
No the voltage will remain the same as the batteries are wired in parallel. Your available power is doubled though. 13V is very good. That must be after a good charge. 12.6-12.8 is a good state for 12v batteries that have settled.
Thanks, Curt! We just got back from our epic road trip, and I’ve been trying to catch up on all my blog comments. I love it when readers can answer other reader’s questions. It’s awesome! 🙂
I’m just wondering, (I don’t have a super handy hubby and electrical wiring makes my brain numb) is the DIY above effectively the same as plugging in a voltmeter to an outlet? I understand being able to switch this on and off is a nice feature rather than plugging and unplugging… but is there a difference in what they’re reading? Like AC vs. DC or battery remaining vs voltage strength. I don’t know anything about this stuff. Is it the same, is it different? I linked an example below. Thanks in advance.
https://www.amazon.com/gp/aw/d/B00M4W6T8O?sn=email&vs=1&vs=1
My wife had me check out you site and I have to say I’m impressed. I’m about to wire in a voltage monitor but it wasn’t going to be as professional looking as your setup. I guess I’m a nuts and bolts guy and I have a monitor and switch. I guess I have to get it installed and trim it off somehow. It’s a must have IMO
We used ours over and over throughout our three week road trip. They really are great to have! 🙂
Is there a reason you tied into the porch light rather than the wiring to the outlet right above where you mounted the meter? I’m about to attempt this myself and have a spot very near an outlet that would be very easy to access. Thanks!
There is, Scott. The outlets work on shore power only, not off battery. The porch light runs back to the battery.
that makes sense! Guess I could try tying into my 12v outlet then. Thanks!
Very helpful thank you
This is a great idea. I plan to add one to our pop up camper before our next trip.
I already added a 2nd battery a charge controller for a solar panel and a power port inside next to the bed to run an inverter off of for my CPAP machine. (Without it no one sleeps) I wired the port directly off the battery with a fused connection. This would be a good place to add the panel and switch.
I also purchased a battery float (a few dollars at harbor freight) I plug in the batterys when the camper is stowed in garage to maintain a full charge.
Hi there – great post! I find a lot of great ideas on your site so thanks for the great Mods. I took this idea and ran with it – I found a voltmeter that also had a 12v power outlet and a USB charging outlet included in Amazon for $12 and bought a 5 pack of switches for $7 and wired it in. I ran mine directly off the battery with a separate power source because I wanted it by the bed to charge the iPhone (if the voltage allows)… Plus I’m no electrician so I didn’t want to mess with the campers existing wiring. So, it was a great mod, cheap, and super useful so thanks again for the great idea!
I am curious why you have not mentioned adding a solar panel to the power application. This would top off the battery and carry a load during the day.
Solar panels are next on our “to-do list,” John. We are super excited about them, but just haven’t gotten around to implementing them in our setup. 🙂
Can I ask what kind of battery you have? We are planning a Yellowstone trip ( your trip is a wonderful resource for us!) for next summer and are finding that most campgrounds don’t have hookups. Our current battery lasts about 3 hours (my husband is Mr. TightwadMcScrooge!) and that won’t cut it on a 7 day trip!
You can find all the info on our battery in this post here, Kelly.
Have fun in Yellowstone. We LOVED it there. I can’t wait to go back. 🙂