I have acquired a system composed of 3 AGP 12V service batteries in parallel each 130 Ah. An additional 80 Ah for the engine start. There is a 145W solar panel connected to a Victron 75 | 15 MPPT. I am assuming that the charge goes to both batteries sets. There’s a Victron SmartBMV to monitor the system and the MPPT has a Bluetooth module. The SmartBMV shows a total charge of 96% for the services batteries with a 12.49V voltage. The engine battery has 12.86V.
For the last few days since I connected the system the MPPT remains in FLOAT mode (not charging?). The reading from the Victron app tells me that the Solar panel voltage is about 20V but the current is 0 A. On the battery side is reading 13.84V and current 0 A. Should this be reading the battery voltage? Why is it different from the reading of 12.49V at the Smar tBMV? Why is it not charging?
In the settings of the MPPT 12V battery is selected, the max charge is 15A and the charger is enabled. The battery preset is “AGM spiral cell”. Absorption voltage 14.7. Float voltage 13.8. Equalization voltage 16.5 with automatic equalization disabled. Temp comp -16.2mV/C.
Am I missing something? When should the MPPT start charging?
Because the wiring is corrupt or the fuse/circuitbreaker is open.
I have a multimeter and I can check the fuse for continuity. Do I need to disconnect the MPPT before I remove the fuse to test it? I am not sure how to check the wiring.
Don’t check for continuity, check for voltage differences between battery , charger and fuse
I am sorry. I don’t know enough. I thought I could figure it out myself.
The battery voltage read with the multimeter directly between the poles is 12.67. The BMV says 12.57 without any loads. The MPPT keeps reading 13.85V in the app. I am not sure how to measure voltage at the charger or fuse.
With your multimeter -ve lead on the battery negative, use the +ve meter lead on the battery +ve terminal on any connection on the wiring and on the MPPT +ve battery terminal. If it is 12.7V on battery and 13.9V on MPPT then the break is between the points where these measurement are different. Do the same but keeping +ve lead on the battery and moving the negative.
Thank you. I will have to do that later as I am not at the installation now. I have these two pictures of the setup. Does this look correct?
There is also a fuse at the bottom of the MPPT, right underneath the VE.direct port.
So I went back to check. I checked the voltage between the batteries negative pole and the fuse and it read 13.7V. I unplugged the positive from the battery going in the MPPT and also de positive from the solar panel. After doing that the lights went off in the MPPT. I removed the fuse and tested it. It was Ok. I put it back in and plug back in the two positives. After a minute both lights went back on. I tried to connect via Bluetooth to get a reading and suddenly the Bluetooth connection disappeared. I looked at the MPPT and the lights slowly faded off. Now is dead. No lights. Nothing.
So is there still voltage at the MPPT battery terminals using your meter. It sounds like you have disturbed a loose connection. You need to do a systematic check of voltages with your meter as I tried to describe above. There is no need to disconnect the main cables to do this, just move the meter wires from point to point.
Did I kill the MPPT?
I didn’t kill it. This morning the lights were back on. I read 13.8 V between the pos and negt at the MPPT battery ports. Between the negative of the batteries and the positive of the battery port of the mppt I read also 13.8V. Between the positive of the batteries and the negative port of the MPPT I read 12.6V. between the pos and negt of the batteries I read 12.6 V which is the same the the BMV tells me that I have on the batteries.
I think I figured it out. That fuse is blown!
Your readings indicate a break between the MPPT and the battery. That fuse should ideally be 20A with a 15A controller.
Thanks.