I have the VAT1300 model, had it for a few years at my old house working trouble free.

Now I'm slowly getting my off grid stuff ready at my new house (solar panel installation not yet done) but the battery bank is all set up. I have a mains charger to keep the batteries topped up and to monitor their voltage, the Juntek unit is located inside the house on my fridge door.
It has the odd habit of starting to beep some kind of alarm at random times, usually late evening or late at night. There is no mention of any kind of alarm in the manual and the official Juntek how to use Youtube video does not mention any alarm function either.

I'm curious to know what's going on there and if anybody else has this monitor and, perhaps, some suggestions to offer.

The temperature sensor at the Shunt is not connected, I read somewhere it does not influence the workings of the unit, please correct me if I'm wrong there.

Lastly, a question about the time display function. I have not yet figured out what it is used for (range is 0-99 days??) nor how to set or re set it.

Very badly documented even in the later units that I use, I had assumed that it was for KWh accumulated time range, but can not see any setting for that. I have not found an entry field for it in Bluetooth app or LCD settings.

There are a number of alarms for U/O-Current and U/O-voltage etc, but in mine I would have to add an external buzzer to hear them, as I don't use them I'm afraid I can't help there.

Great to hear you are getting another off grid setup going .

You are correct, the temp sensor is not needed and no issues if left off.
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Edited 2026-06-10 09:16 by KeepIS

I think I tracked it down Mike. Mine too has the U/O current/voltage relay outputs; I have nothing connected there.
Regardless, the voltage limits have to be set for that or the alarm starts beeping. Fortunately, it shuts up beeping by itself after a short time.

After setting the battery O/U voltage range outside to what it ever may be, the alarm has been silent.

All I want this gadget for is to monitor the battery from inside my house.

  Murphy's friend said  

All I want this gadget for is to monitor the battery from inside my house.

Back in '04 when I got our Selectronic inverter it came with a display in the house which is very handy as I have been telling my wife the fridge is gone as it running all the time and that remote keypad is great to stop the beeping it does as the house batteries go under 22 volts.

Now the new SP inverters have a usb connect that shows everything where I found helping out a guy on our local facebook group who had a battery problem. Now the SP inverter just rocks with the info.

With the homebrew inverters we make as the nano outputs to a LCD could the nano output serial to say as pico2W if wifi is around or a pico2BTH if bluetooth is around so a remote display of the battery info can be displayed.

It's just serial data, many simple ways to take serial data and send over a Bluetooth or WIFI serial link to whatever.

I'm working on a Touch screen colour display (local and remote) that also lets you check and adjust settings, just so busy at the moment to find time to get back to it.