Victron Smartshunt 500a Intall With Photos

Several others have installed the Victron. Victron Smartshunt Bluetooth Battery Monitor My install location was a little different so I thought I'd post separately.

After putting in the DC -DC charger, and getting wilding disparate open-circuit voltages from a variety of devices, at a variety of locations throughout the system, I came to realize that relying on OCV alone to determine (or even come close to estimating) the battery's state of charge was a fool's game. Hence the need for something a little more accurate to determine my battery's discharge "floor".

Compared to other shunts, with and without an actual visual display, the Victron was the obvious choice for quality and reliability. The fact that it was reasonably priced (compared to, perhaps, say a Balmar) was a bonus. It has built-in Bluetooth (that connected without fuss) and which negated the need for a wired dongle, or a display and the additional mess that goes with those things.

Had I not installed my DC-DC fuse in the open space on wood tray-panel, I would have installed the Victron shunt there (third photo in the list). My other location (which was strongly encouraged by Sweeney when I mused to him about taking the easy road and locating it in the bin) was under the counter where there is lots of space, but where there is, unfortunately, not a lot of room for two arms and a head in the bin. I was able to blindly (and by feel alone) install it on the cleat that holds the countertop:

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The cleat is softwood and no pre-drilling is required for the screws to grab and seat. It also avoids the hazard of accidentally penetrating some of the buried AC wires that you can see are routered into the back wall birch panel, were I to install it there. This was just for getting screw holes. I torqued down on the actual wiring and terminals without the shunt mounted, oriented the cables so they would fold up neatly, and then put the shunt and wood screws back in, blindly. Some double-sided tape helps hold the shunt in place while you fumble with the screwdriver and screws and finding the holes again.

I used 24" of 6 gauge wire to reach the neg terminal of the battery, and 12" of same to reach the main negative post where many of the trailers wires converge:

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8 gauge would likely still be plenty, and a little more flexible than my 5 and 6 stuff. You may want more length than you anticipated, just to be able to double back to the connection post and have the terminal end laying flat and "pointed" in the proper direction, relative to the other factory ring terminals. Premade lengths are available on Amazon if you don't want to invest in a large crimping tool or solder kit (I didn't). Terminal posts on the Victron take a 3/8" ring terminal' while my battery took a 5/16". Shop for your cables accordingly lest you end up with a bin of cables that are too short, too long, won't bend sufficiently, or won't fit on the terminal posts. (This post doubles as a Camper Confessional.) As well, that visible marrette in the last photo is getting replaced with a spade connection that I can easily remove.

You may notice that the battery neg post is relatively barren. The only other connection is the small black wire that goes to the DC-DC charger to allow it to accurately monitor the battery voltage and to do its job. The Victron shunt does all its calculations through the neg battery post and the single wire coming off it. Any other loads that you may have have connected to the battery neg terminal will by-pass the shunt, will not get calculated by the shunt, and the shunt will consequently underestimate the Ahrs that have flowed out of the battery. To your and your battery's detriment.

I have several other connections to the battery's pos terminal, including my separate solar charger, on a fuse, the DC-DC voltage monitor, and the Victron's + low-voltage (and fused) power supply, which it needs in order to function. None of these affect the Victron's calculations.

There is (currently) an unused micro-terminal outlet on the Victron. This is for a temperature monitor for the battery. I have to do a deep dive into this feature to determine if and how I can properly take advantage of this.

I post this install with some hesitation as I am concurrently still trying to fully digest the information available about where these shunts can lead you astray if you don't understand their limitations and necessary work-arounds which will allow you to squeeze the greatest amount of utility out of them and prevent you from inadvertently deep-draining your battery. Shunts are not an install-and-forget-about-it Silver Bullet.

To be very brief on this subject: battery age, imperfect charging efficiency, imperfect battery testing and labeling, battery temperature, among a host of other variables which no battery owner has any control over, may (and probably will) result in very erroneous "battery percentage remaining" read-outs that can cause you to actually harm the battery when you thought you were doing good by it. This is especially so if you simply install the Victron, plug in the stated manufacturer parameters and continue to use the 50% SOC read-out as your gospel turnaround-recharge point, until the battery dies. Which could occur far sooner than you had ever expected.

If you want to get a head start my next post, I'm going to do my best to paraphrase these very informative web pages: Installing A Battery Monitor - Marine How To and Making Your Battery Monitor More Accurate - Marine How To and come up with a simple battery and monitor routine that is both manageable and practical. They're a tough, long read, for a non-engineering type like myself. However, without doing at least some of the things on a regular basis, as he suggests, the Victron can actually, and probably will be, working against you.

 

Thats exactly where I put mine, and it works perfectly. Which charger are you using for the shore power charger?

Great write-up...

 

Thanks Sweeney. Now I understand why you didn’t post pictures. Getting those pics was almost as difficult as doing the install.

Factory Marinco. Just fully charged it today from shore. Letting it rest for 24 hrs and then will look at the app stuff.

I think I have a good handle on the many variables, inherent inaccuracies, and limitations of the shunt (or any shunt, really), and some practical compensations that can be made, to get it spitting out good, reliable, usable data. Or at least, data that isn’t deceiving. But that will be a separate post, shortly.

I was directed to those pages on Marine Howto by a marine fabricator friend who has a decent working knowledge of these electrical things. All the cautions contained therein, aren’t widely covered on other sites that discuss shunts. Or discussed at all, for that matter. Had I been aware of these obstacles, I likely would have thought more than twice before diving into the shunt pool. As it, is I’m wet, and have to start swimming. Besides, any learning process can’t be a complete waste of time.