just installed this smart controller about 3 weeks ago. The victron connect app always shows .5 to 1 volt higher on the battery than our on board gauges and multi meter. This means it is changing to absorbation too soon and just now stayed in float mode when switching on the invertor and watching our on board gauge show the battery dropping from 13 to 12.10 whilst the victron app never changed from showing battery volts around 13.60.
Thanks for any input on this
It would seem that the fuse between the mppt and battery has blown.
Thin or long wires between the mppt and battery will cause voltage drop.
The fuse is good as it wouldn't charge if the fuse was vblown. The victron controller is live and moves from bulk to absorbation to float... Our issue is that the app displays a higher voltage for the battery throughout the Day, thus moving into absorbation mode too soon because it thinks the battery is over 14 volts when it's only in the low thirteens. Our multi meter also displays at the battery input on the victron the same incorrect voltage. Does any one know why there is a discrepancy in the battery voltage readings between the victron dashboard and our multi meter and 2 other gauges we have that display leisure battery voltage.
Thank you
The victron app reports what the MPPT says. Probably the voltage difference comes from a poor connection or cabling between the mppt and the batteries.
Did you check the voltage on the mppt output terminals while charging?
Yes, this is because of cable and or connections where voltage is lost due to resistance.
If the proper wire diameter is used, then make sure the wire terminations are good and clean.
When a high current goes through the cable/connections the resistance change..
Rob
Hi guys. Could someone tell me what is the recommended cable size to use between mppt and our led acid battery. 100 /15 model and what amp fuse to use inline, I would assume a 15amp fuse. What is the maximum length of cable before the connection starts to become weak ?.
Thank you for your input.
Hi, did you ever solve this issue?
im having the same issue on my boat.
MPPT showing roughly .5v higher than battery monitor and multimeter at batteries and switching to Float prematurely.
I have a 75/15 smart controller. The voltage on the app is 13.24v and the actual voltage is 13.00 volt. The battery went into float prematurely. The cables are fine, no loose connections anywhere to be found. A friend had the same issue today. His voltage diff is 0.23 and mine is 0.24. The max PV voltage and power average, over the past few days, are very close. Any advice will be appreciated.
When you say the "actual voltage" is 13V, how do you know, according to what? Is it possible that whatever is giving the 13V reading is incorrect and the 13.24V is correct? If it is a multimeter you are using, what reading does it give on the battery terminals of the MPPT? If it doesn't agree with the reported voltage in the app, then the multimeter is at fault. If it agrees with the app then the other possibility is volt drop in the cable.
Volt drop is proportional to the length of the cable multiplied by the current flowing in it. What size is the cable, how long and what was the current flow at the time the voltage reading was taken?
I too have the same issue on my easysolar.
24/3000/75. With a built in Victron MPPT
Voltage at batteries is .3 volt lower than what the easysolar shows.
Bolts are tight, cable is correct and short. Have used 3 different multimeters as well.
I would think if it was voltage drop, it should be higher at batteries, not lower
Then the question is, should I alter the charging voltages to compensate for this voltage difference?
The problem then is if something goes wrong the inverter history would show incorrect charging for the batteries.
Your Easy has a Multiplus and an mppt. Both read V, compare them. From another thread, you also have a Smartshunt that reads V too. Make sure any discrepancies are investigated thoroughly, and don't overlook things like isolators or fuses which might contribute.
You should also have a working GX device. Look to it's manual for a description of DVCC, which can share a V across the whole system. No need to compensate settings anywhere with that enabled. It would normally choose the shunt as the V source, right at the batteries.
All of the people describing this problem above were talking about it happening during charging from the MPPT, so you would expect the voltage at the MPPT to be higher than the battery voltage. You don't state when your 0.3V difference is detected.
Also, as suggested above, have you used the same meter to test the battery terminals at the MPPT and then at the battery, or are you comparing the easy solar reading to the multimeter?
0.3V on a 24V system is approx 1% discrepancy, unless you have a high-quality, calibrated meter you don't even know it's even real.
I'm comparing my multimeter readings to the easysolar display.
My electrician stated the difference is so minimal it's nothing to worry about.
