JuncTek Battery Monitor vs Victron SmartShunt
- Thread starter Horsefly
- Start date
Yes, voltage, current and temperature can be calibrated by themselves
However, it has been calibrated with a high-precision voltmeter and ammeter when it first leaves the factory
You don't need to calibrate yourself
Unless you find a little error after many years of use, you can calibrate it yourself.
The newly added full power voltage and full power current functions can automatically calibrate the SOC value
Hi @dmking ,
Just performed the updates today for myself. When I downloaded the app, it saved it as KG.apk.zip I had to rename it, don't unzip it. Then even the icon showed up for its apk. APK's are actually able to be a zipped up package, but in this case, you don't want to be unzipping. Sometimes google and chrome block downloading apks due to some permissions, but the zip style can at least get to your phone.
AH, edit, sorry, I didn't see that you resolved this yourself and updated the thread.
@Rickey, thanks for the support. The improvements are nice and the updates worked. I like that there's an alarm now for % low remaining. That I'm looking to leverage in turning on an AC smart switch with automation or changing the charge controller source.
While an open serial 485 connection is nice feature to have on this device, it would be wonderful if the Juntek could describe how to make a bluetooth GATT connection and monitor the stats wirelessly with other devices. I have ESP32's running ESPhome and PipSolar that I would like to utilize the bluetooth stack from the ESPhome setup and get the KG140f into the same dashboard and mqtt that I'm using.
You can copy this and connect it to your mobile browser. After downloading it successfully, click Install.
I don't have a Victron unit to compare to, but it matches up with with the Overkill BMS really well, actually appears more accurate as it only relies on coulomb counting alone.
I really like mine, the app is good, and it keeps track of everything really well. For the $40 or whatever that I paid for it, it's a stone cold bargain.
When it reaches 100% SOC and the charge sources are still adding watts and amps, it just resets itself to when charging terminates, remains at 100%. Then it starts over amps in and out.
I also like that you can set the charging and voltage meter range, for good visual on your actual battery.
I really like mine, the app is good, and it keeps track of everything really well. For the $40 or whatever that I paid for it, it's a stone cold bargain.
When it reaches 100% SOC and the charge sources are still adding watts and amps, it just resets itself to when charging terminates, remains at 100%. Then it starts over amps in and out.
I also like that you can set the charging and voltage meter range, for good visual on your actual battery.
Horsefly
Solar Wizard
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:
I appreciate any comments / expertise you folks have on the above.
- 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.
- 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.
I appreciate any comments / expertise you folks have on the above.
Horsefly
Solar Wizard
Ooops - duplicate post deleted.
robby
Photon Vampire
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- May 1, 2021
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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
Solar Wizard
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
Photon Vampire
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- May 1, 2021
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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 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]
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
Solar Wizard
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.
Ok. Thanks for that.
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?
Horsefly
Solar Wizard
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).
Horsefly
Solar Wizard
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.
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
Solar Wizard
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.
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.
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?
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