Hi - Newbie here. Please help us figure this out. We are desperate. Any help you provide is truly appreciated. We recently had a Multiplus II installed at our dealership. As we were looking at the setup we found multiple problems. I.E. wrong size wires, wires not running through the shunt, wires connected incorrectly to the MultiPlus, among others. Thus, we didn’t trust them to correct the errors properly so my husband did the rewiring. I did hours and hours of research on this forum, the Victron website and the Victron FB page. Before we made the changes to the wiring, the solar panels were charging the battery. (Picture - Before Rewiring) We did not have the trailer plugged into shore power between the time that they installed the MultiPlus and when we rewired it. After we rewired it and prior to testing the charger on the MultiPlus, I turned off the fuse to the WF-8955-AD-MBA charger so that the two chargers were not competing. After an hour to two hours of being plugged in , with the switch set to Inverter, the readings on the Shunt/MultiPlus/MPPT were the about the same same as earlier. The MultiPlus read Absorption. The MultiPlus readings on the two screens are different even though they were taken minutes apart. (Pictures - MultiPlus The Readings on the Two Screens Do Not Match Taken Minutes Apart) The battery wasn’t full yet the solar panels are not charging it despite being in full sun. (Pictures - Before Wiring/After Wiring) The voltage readings on the Shunt, MPPT, MultiPlus and the multimeter do not match. They differ from .3 to .7 volts, that I have seen. I do not remember if the battery was charging at the time these pictures were taken. (Pictures - Readings Do Not Match Multimeter) The solar panel is overcharging the battery. This was not happening prior to rewiring. These pictures were taken while the solar panels were charging the battery. (Pictures - Solar Panels Over Charging The Battery) I hope that I have explained everything correctly and in enough detail for you to help me solve this issue. Please, we are desperate to finish this project. Thanks in advance for all of your help. If you have additional questions, please let me know. Cindy [T@b_Wiring] [20260618_161216] [20260618_161452] [20260618_161501] After/Before Rewiring [Screenshot_20260619_132214] [Screenshot_20260619_132222] Settings [Screenshot_20260619_131621] [Screenshot_20260619_131651] [Screenshot_20260619_131614] [Screenshot_20260619_131929] [Screenshot_20260616_174523] Solar Panels Over Charging Battery [20260619_140630] [Screenshot_20260619_131921] [20260619_140716] [Screenshot_20260619_132222] MultiPlus The Readings on the Two Screens Do Not Match Taken Minutes Apart [Screenshot_20260619_131810] [Screenshot_20260619_131441] Readings Do Not Match Multimeter [Screenshot_20260619_145301] [20260619_145241]

I assume you mean that your charged voltage is 14.2 not 4.2. Looking at your screenshots above your absorption should be at 14.2 and the charged voltage at 14.0. I assume this is what you changed. If your settings are correct you should never need to manually calibrate. When the battery reaches the “charged voltage” setting the shunt will set to 100%. This is one reason why it is important to regularly charge your batteries to 100%.

New MultiPlus 3000 120. Solar panels overcharging. Readings don't match

DIY

woodnbaskets 2 July 2026 01:46 21

I think that we have everything under control, for now but thanks for the links.

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New MultiPlus 3000 120. Solar panels overcharging. Readings don't match

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