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I have a Smart Solar 75/15 and a 100/20. Both are to 12v nominal with temp compensation turned off (at the moment)
I also have the bluetooth temp/voltage sensor.
I'm finding that the 75/15 is pumping out over 15v whilst the 100/20 stays comfortably within my set limits. This is despite both controllers being set to 14.74v for absorption and 13.5v for float.
So are these both connected to the same battery bank?
And you have a smart battery sense fitted?
If so are both MPPT in the Smart Network? I ask because only 1 has the Smart Network symbol, but that MPPT has no battery temperature displayed...
The 2nd MPPT is still in absorption phase, so if connected to the same battery is still holding the voltage high, dispite the 1st being in float.
I'm not too sure yet why the 1st is showing a higher voltage. Could be to do with not both MPPT's being in the Smart Network.
Yes, both are connected to the same bank, they are situated next to each other, they have the same length wiring, same guage wiring, and are both on the VE.Smart Network along with the sense.
The sense unit is about 1.5 metres away, but regularly seems to drop out and come back. None of this affects the 100/20 controller.
In those images MPPT #2 does not seem to be in the VE Smart Network as it does not have the networked symbol.
But ironically MPPT #2 is the unit displaying battery temperature - that it would receive from the Smart Battery Sense...
If MPPT #1 is in float it's most probably just displaying the battery voltage, as measured by the Smart Battery Sense. This is supported by the fact that the charge current is ~0A.
Accordingly, the high voltage reported by MPPT #1 is probably being caused by MPPT #2 (if the voltage is true).
Why it's so high I don't know, maybe there is a loose/bad connection somewhere. Maybe there is an issue with the Smart Battery Sense accuracy or the fact that the Bluetooth connection is dropping out.
It would be best to confirm the voltage at the battery terminals independently with a multimeter, then work from there.
Also as an exercise, if this happens again (MPPT #2 in absoption & MPPT #1 in float with high voltage measured) try to disable charging on MPPT #2 and see if the voltage drops down to the correct float voltage - the issue could actually be with MPPT #2 overcharging.
It looks to me like the 75/15 isn't picking up anything at all from the battery sense we can completely rule that out. The poor bluetooth performance of the battery sense is another issue.
You could be right about the two controllers interfering with each other. It's a shame they can't be networked and work together. Now that they are both in float, they both read in the 13.5 range.
I just have to be careful as my radio will fail if the over 15v reaches it, as unlikely as it is.
has the latest 1.41 Fw been installed. and is everything on the latest F/W
also try disconnecting all the Bluetooth devices and then re setup the smart network
Check the voltage readings AT the MPPT units and then at the Battery itsself
I have the same mppt controller - fresh out of the box - with the GEL Spiral preset in a 24v bank - same issue - latest firmware versions. should be putting in around 28.8 but instead over 30v. Could be a bug - seeing a few comments regarding overcharging by the 75/15 mppt. I am running mine in the network - with a BMV-712 and temp sensor - but even changing the settings to the preset did not help.
If I read this, could it be best to use a battery protect on the charge side as well as on the load side? This is a small investment, but some things could go wrong, and batteries are expensive...
What kind of battery are you using? LifePO4 is usually 14,6V in bulk but Victron suggests 14,2V
