Installing a Battery Monitor or Shunt into a 59PX

Update March 2022 #

Since installing the tr16, it has been so much easier to deal with the batteries. With a quick look, we can see exactly the current charge and the amount of ah going in/out of them.

Now that we have that information, it only seems natural to want a history of the data as that would help with trends and changing our behavior so that the batteries last even longer.

The only way to do that is to move to a different shunt. After a but of research, we decided on the Victron BMV-712. It will work with the Victron MPPT controller we installed too.

Swapping the tr16 out should be pretty simple. Only real annoyance will be re-sealing the hole in the floor under the jump seats. Other than that the install should be easy

Shunt install #

The stock battery gauge and solar controller are a very ineffective way of knowing the current State Of Charge (SOC) of the batteries. In order to know accurately what the SOC is, a battery shunt must be installed.

The shunt attaches to the negative side of the batteries and then connects to the chassis negative. Essentially all negative power goes through the shunt allowing the shunt to keep track of power going in or out of the battery.

There are many shunts on the market, the inexpensive Aili TR16 is the unit used here, but all shunts install in the same way. The two biggest challenges to installing a shunt in a van like the Winnebago Solis are

• Shunts are not weatherproof. They will need to be protected from water/damage
• Identifying a good placement for the display and routing the control wire from the shunt to the display. This isn’t necessary on the Victron Smartshunt as it used a smartphone as the interface

Identifying where in the under carriage to mount the equipment.

On the Solis 59PX, where to place the display, how to route the control wire and where to mount the shunt are all pretty straight forward as there is ample room.

Weatherproofing the shunt is a lot harder. A mountable weatherproof enclosure just big enough for the shunt and some fairly thick cable connections can be found on Amazon. There are many options, just make sure there is enough room for the 2/0 cables to be maneuvered inside.

I’ve been trying to figure out the art of reading the 4 red light battery meter + looking at the Xantrex Solar Charger to find our current battery level is. Well in short, I gave up. Mostly due to the fact that reading the battery % remaining is impossible when really the only indicator you have is the voltage. The voltage varies wildly and the only time I felt confident I knew how much remaining power was after the battery had time to “level out”, which can take awhile.Also there is no way of knowing how much power you are using and which devices consume the most 12v power. More frustratingly, it is impossible to see how much power is getting into the batteries from the different charging methods.I decided to install an inexpensive battery monitor (AiLi TR16 Battery Monitor). The idea being that if the cheap one frustrated me, I would just move to the Victorinox BMV-712. Swapping to a different unit should be easy after I have all the main wiring/components in place. Anyway, I installed the TR16 shunt and display this weekend. It isn’t the perfect device, but it seems to tell me what I want to know.What the shunt/display does:* When calibrated, shows the Amp Hours left in the battery in % and in ah. Calibration consists of telling it the total ah of the batteries and resetting to 100% when you know the batteries are fully charged.* Easily display the amount of amps going in/out of the battery. Seems to be fairly accurate. In the approximate, Fridge is ~4amps when running, lights 1 amp, WeBoost is 1.5 amps, Mofi Router is like 1.25 amps, etc. When plugged into shore power, I can see 26+ amps going into the batteries.* Shows the voltage at the batteries. I’ve only played with it for about 1/2 a day thus far. Seems like something that should have been included by Winnebago as it is so useful and really inexpensive overall. I’m guessing my total investment w/o labor is <$100. No idea what an RV mechanic would charge to install. ************************************************************My notes which may or may not be useful to anyone else and more importantly may be confusing . I took pictures, but they didn’t come out well enough to clarify anything. Essential the shunt is installed between the battery negative and the rest of the electrical system. For the negative side of the battery I ended up with this chain:Front Battery Negative to Back Battery Negative (already there) – Back Battery negative to Shunt Battery Side(w/2ft cable I added) – Shunt Distribution Side to distribution terminal block (w/2nd 2ft cable I added). Distribution terminal has the two leads which I previously removed from the back battery (Main negative to 12v electrical system of RV and another lead which I don’t know what it was).* I used the back battery negative as my starting point. (Pretty sure this is right as my gauge is accurate and I couldn’t find any leads off the front battery negative except for the cable to the back battery).* In the PX there is plenty of space just in front of the back battery for mounting items and running cables.* Initially when I was checking to see if I could even do this, I went under the van to review setup. The only thing I found that was difficult to deal with was getting access to the top of the back battery. I left the battery in place for all of this and just crammed my hand/ratchet into the space to remove leads.* I drilled a hole under the rear seats near the drain valves so that I could pass the control cable up to the electronics center behind the rear seats. Used a grommet on the metal and spray foam to seal it up. Had to break up a lot of the spray foam that was already there to even see where I could get access. Which is almost directly above the propane tank.* There are 4 connections to the shunt. 1. Battery Negative, 2. Load Negative, 3. Battery positive (to power shunt display and to read battery voltage) 4. Shunt Display cable. * I ran a 18awg wire from the battery positive to a waterproof inline fuse to the positive connection of the shunt * Shunt display cable (26’ extension cable) was very difficult to get through the waterproof nylon bushings. I ended up going with a larger bushing and using caulk to seal.* I used these components (no Amazon links sry): * 2 x 2ft black 2awg power cables with 3/8” lug ends. ( I would recommend 1 x 2ft and 1 x 3ft to make mounting things easier) * 1 x TR16 350A Battery Capacity Tester.Monitor * 1 x 26’ TR16 Extension cable * 1 x 3/8” lug 2 terminal distribution block * 1 x 5a inline fuse * 1 x waterproof project box (this was the hardest part, getting one that fit the cables and the shunt while also being small enough to mount easily) * 3 x Waterproof IP68 Nylon Firewall Bushings. I had an assortment of sizes * 1 x Grommet for protecting control cable that comes through the floor underneath the back seats. (I tried a bunch to get the right one from a grommet assortment pack) * 1 x spray insulation foam (it is what I had) * ? x med length zip ties * ? X Stainless steel self tapping screws to mount project box and distribution block* Tools * 12V electrical tools (crimpers, nippers, various barrel connectors, etc) * Cordless drill * Ratchet and sockets, all common measurements * Stepper drill bit to drill holes in project box * 2 1/8” (2 1/4” might work better) hole saw or forstner bit to drill hole in panel and mount display. I made a 2” bit work, but scratched the laminate a little when widening the hole.