JuncTek Battery Monitor vs Victron SmartShunt

[Horsefly]

Ooops - duplicate post deleted.

 

[robby]

So what’s the consensus, does this unit track SOC as good as the Victron unit?

Mine had enough wonky moments that I just packed it away in a drawer.
Yes it works and it reads accurately but the reliability factor is not good enough IMHO.
If money is tight then this is your best option. If your looking for reliability and durability I would stick with the Victron.

 

[Horsefly]

Mine had enough wonky moments that I just packed it away in a drawer.
Yes it works and it reads accurately but the reliability factor is not good enough IMHO.
If money is tight then this is your best option. If your looking for reliability and durability I would stick with the Victron.

Hey @robby - Can you describe a bit of the wonky you saw? I'm not questioning your experience, but would love some details. As I've said, I only had it hooked up for a couple of weeks to test it out and didn't see anything that I would put in the "unreliable" category. Since I'm about to install it permanently at our cabin, I need to hear about more negative experiences.

 

[robby]

Hey @robby - Can you describe a bit of the wonky you saw? I'm not questioning your experience, but would love some details. As I've said, I only had it hooked up for a couple of weeks to test it out and didn't see anything that I would put in the "unreliable" category. Since I'm about to install it permanently at our cabin, I need to hear about more negative experiences.

Freezing issues with the display data. Everything looks normal but the numbers are not changing. It happened once on the first day and then it was fine for a few weeks and then it happened again and a couple of days later a third time. That was pretty much enough for me.

 

[Browneye]

I don't know if you can get a longer connector cable or not.
You don't need the temp probe - leave it unplugged.

No issues or failures with mine. The display is great for a quick glance, however I tend to use the Overkill bms app more. The Junctek is WAY more accurate as far as SOC though - I'm not sure why the bms gets so far off. Battery is sitting at about 85% today, bms is showing it at 51%. [shrug]

 

[Horsefly]

Freezing issues with the display data. Everything looks normal but the numbers are not changing. It happened once on the first day and then it was fine for a few weeks and then it happened again and a couple of days later a third time. That was pretty much enough for me.

Did it "unfreeze" on its own, or did you have to do something? How long was it frozen for? The reason I'm asking is that I'll probably just use the BMS or Victron (via app) to check on the SoC, but I'd like to get the rest of the family used to going down there and checking the SoC. If it freezes but unfreezes on its own after a couple of hours, I don't mind. As long as it isn't for days.

I don't know if you can get a longer connector cable or not.
You don't need the temp probe - leave it unplugged.

Ok. Thanks for that.

No issues or failures with mine. The display is great for a quick glance, however I tend to use the Overkill bms app more. The Junctek is WAY more accurate as far as SOC though - I'm not sure why the bms gets so far off. Battery is sitting at about 85% today, bms is showing it at 51%. [shrug]

Interesting. I've found my JBD/Overkill to track well with the Victron, which I think I trust. The only thing is I think they both need the battery to get to 100% periodically, and how frequently may be different between the two. Do you get back to full most days?

 

[Browneye]

In storage mode I don’t. It sits at 80% for the duration.
Tracer does a boost session one a week. It sits at 13.3 give or take. No loads.

 

[Horsefly]

In storage mode I don’t. It sits at 80% for the duration.
Tracer does a boost session one a week. It sits at 13.3 give or take. No loads.

Ok, so I'm guessing that may be the issue with your SoC not looking right. Not sure how fast it gets out of sync. Assuming you don't want to force 100% SoC, I think you just put up with it until you get back to 100% and be happy that it is correct under normal use (but not storage).

 

[Browneye]

Bms calcs soc by parameters voltage setting - this is a perfect example of how inaccurate that is.
Coulomb counting will always reflect true state/capacity.

And yes, a full charge brings the bms back to 100%.

 

[Horsefly]

Bms calcs soc by parameters voltage setting - this is a perfect example of how inaccurate that is.
Coulomb counting will always reflect true state/capacity.

And yes, a full charge brings the bms back to 100%.

Actually, the JBD/Overkill BMS uses voltages only until it thinks the battery is 100% SoC, then it uses Coulomb counting. I had always assumed that the method used by the JBD to do Coulomb counting was probably not as accurate as a smart shunt (Victron or Junctek), but I've seen some posts arguing the opposite.

 

[Browneye]

^^That has been my experience.

 

[Rickey]

Ok, I'm getting ready to install this permanently at our cabin, so I've blown the dust off the box and am looking at how to get it incorporated into the existing set-up. I have a couple of questions:

1. Is it OK to extend the 4-wire cable between the "measuring module" and the shunt? The cable that comes with it is only 7 inches long. I have a good place to put the shunt, but there isn't anywhere there to put the main module other than just lay it on a bunch of other big wires.
2. I've really got no use for the temperature module. Does it cause any harm to just unplug it? I can probably cram it into the enclosure where I hope to put the module, but it just seems sloppy.

With the firmware changes they made to the module (full voltage, tail current, and charge detection time) it now acts lots like the Victron Smart Shunt, and as I said earlier I'm pretty happy with it. Just need to plan out the details of the install.

I appreciate any comments / expertise you folks have on the above.

1. The 4P flat cable between the measurement module and the shunt cannot be extended, and the data cable between the display and the measurement module can be extended to 30 meters at most;
2. It can be used without temperature sensor, and other functions will not be affected except that the temperature cannot be displayed;

 

[Horsefly]

1. The 4P flat cable between the measurement module and the shunt cannot be extended, and the data cable between the display and the measurement module can be extended to 30 meters at most;
2. It can be used without temperature sensor, and other functions will not be affected except that the temperature cannot be displayed;

Thanks @Rickey. Good info, although somewhat disappointing. I need to re-think how I do this, or if I should do it at all. It already is going to be a mess of wires in the only area I can put the shunt, and putting the measurement module a few inches from it may just not work. I may have to just stick with the Victron Smart Shunt, at least for now. I need to go think about it, but some of my thinking will have to be up at the cabin, which is a 6 hour drive away.

 

[Rickey]

Freezing issues with the display data. Everything looks normal but the numbers are not changing. It happened once on the first day and then it was fine for a few weeks and then it happened again and a couple of days later a third time. That was pretty much enough for me.

Freezing issues with the display data. Everything looks normal but the numbers are not changing. It happened once on the first day and then it was fine for a few weeks and then it happened again and a couple of days later a third time. That was pretty much enough for me.

I suggest you describe your problem in detail (add pictures) and explain what data will not change. If it is a product of juntek, maybe I can help you solve it.

 

[dfwjr1973]

I just got mine but it seems to have a cable for the connection between the measurement box and the display that doesn't fit the sockets... The cable looks to have RJ11 on both ends but the box and display (and the RS485) ports look to be something smaller... Any ideas?

 

[dfwjr1973]

 

[DJSmiley]

RJ10

RJ10 = 4 pins, 4 contacts (4P4C), smaller (8mm wide), mainly used eg on handsets of a desk phone
RJ11 = 6 pins, 4 contacts (6P4C), 10mm wide.
RJ12 = 6 pins, 6 contacts (6P6C), 10mm wide. (Same as RJ11, only with 6 contacts)
RJ45 = 8 pins, 12mm wide, the normal ethernet plug (8P8C)

 

[dfwjr1973]

YEP I just realized MY bad. I was trying the RJ11 cable I bought to connect to my data logger not the cable supplied.

BTW...their customer service was good. It is a RJ9 cable actually so I bought a new RJ9 cable for the RS485 cable I will make to connect to my Arduino data logger.

Well...if that is the dumbest thing I do in a day, it's a pretty good day!

 

[Deek Johnson]

Newbie here...bought this battery monitor to finish my solar install and read entire post and looks like this monitor is getting better by the day. I know this may seem simple to you folks but does this wiring diagram look correct? All the instruction vids I see have cables that run off screen and hard to tell what they're connected to. This look right? Thx!

 

[Horsefly]

Newbie here...bought this battery monitor to finish my solar install and read entire post and looks like this monitor is getting better by the day. I know this may seem simple to you folks but does this wiring diagram look correct? All the instruction vids I see have cables that run off screen and hard to tell what they're connected to. This look right? Thx!

Assuming the two gray boxes you have labeled "300A Fuse" then yes, you have it right.

I installed mine permanently at our cabin earlier this month. Like you @Deek Johnson mine is a 24V system. Seems to work fine, reporting SoC pretty much in line with the Victron Smart Shunt. Having the display is good, because most people who go to the cabin are never going to install an app for this on their phone, much less look at the app. I've not seen the freezes that were reported earlier by @robby, but it's early.