#161947  by Gadget
 Wed May 13, 2020 12:34 am
Interesting that the Votronic behaves like this Neville - I guess they've accounted for this overhead in their shunt amplifier/ADC design.

I wouldn't bank on the same from the Chinese ones - if they come with a 50mV (maybe 75mV?) shunt, I'd expect (to maximise the resolution), that around 50mV (or 75) would be [near] FSD (full scale deflection) for the ADC input - meaning although the shunt could take more current, the meter wouldn't be able to measure/count all of the excess.

That being said, I've not tested it - but I want to now... Not sure I want to try pulling more than 200A through mine though! :TU
 #161950  by scubadoo
 Wed May 13, 2020 9:10 am
I have the Juntek 300A shunt version in series with a Votronic 400A rated shunt.
All ADC is performed at the shunt module and resolution etc. appears identical regardless of the shunt rating.
My Juntek display maintains .01V and .1A resolution throughout its normal range. A peak reading of 742.8A when starting the truck as a quick test a few minutes ago. :shock:
Accuracy with the 500A (stamped) shunt? It follows the Votronic VA readings across the entire range within 1% and the SOC numbers are within 2% 99% of the time.
 #161954  by Neddy
 Wed May 13, 2020 9:59 am
scubadoo wrote:I have an original Juntek meter. It follows the Votronic SOC numbers within 2% 99% of the time.
When they didn't agree, I know which one I would believe!
In my experience, Votronic battery monitors signal batteries as being 100% charged well before they really are.
 #161955  by scubadoo
 Wed May 13, 2020 10:06 am
As I mentioned earlier Neviile the Votronic is now secondary and just a little redundant. Apart from the hole created I would not miss it at all. ;)
A new faceplate with the Juntek flush mounted might be my next project and the battery compartment would be a little tidier.
 #163005  by Colindo
 Thu Jun 18, 2020 7:50 am
I have just installed the Juntek VAT1100 to monitor my new 100 AH lifepo4 battery.
My problem is the Juntek monitor's battery indicator shows 100 % when the battery shows 85 %. My battery has it's own read out, showing soc, voltage, and temperature. Do I need to adjust the Juntek batterys capacity, if so what should it be set to.?
 #163006  by Neddy
 Thu Jun 18, 2020 9:12 am
Since you have already set the Juntek battery capacity to 100Ah, you don't need to do anything.
Your battery readout probably uses voltage to estimate the battery SOC. If this is so, its SOC readings will not be very accurate.
Nevertheless, let's presume that the readout is right and the Juntek wrong (ie the battery really IS just 85% charged).
As the battery continues to charge, the battery meter % reading will increase, while the Juntek will stay at 100%. When the battery is fully charged, from there on, any drawdown will lower the Juntek reading (and the battery SOC reading). From here on in, the Juntek will be an accurate figure and can be relied on - even if it is higher than the battery SOC reading.
 #163011  by petercw
 Thu Jun 18, 2020 2:39 pm
Juntek 6.. I found the best way was to charged up the batteries for a couple of days on power so that they were at 100% then press the clear button. This restarts resets the monitor to 100% and zeros the ahs.. from there it's reading the in and out amperage.
Or you can set your battery at the % you think it is and wait it out until you know your full 100% and then do the clear set.
 #163012  by Paul-Carter
 Thu Jun 18, 2020 4:06 pm
I can vouch for the first one. Be sure to pick the right shunt as it comes a number of options. go bigger rather than smaller
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