If the batt monitor is reading '-ve' in the scenario I discribed above then I expect it to be only momentarily or a very small '-ve' reading could also be posdible due to measurement error / lack of calibration. So, you should only be concerned if the battery is dropping under its voltage setpoint & staying there while there is plenty of sun available for the MPPT to increase its output (and bring the voltage back up). During the few seconds following the load increasing it will be normal for a a '-ve' current draw from the battery (until the MPPT compensates) If the load changes then yes it will effect battery voltage & the MPPT will need to slowly react by adjusting it's output current to compensate The rest of the MPPT output will go directly to covering the load The battery will only take/require a very small current (somewhere near 0 & upto a few A) to maintain the float voltage setpoint Battery is already at float set-point voltage Yes that's exactly what I'm saying that the behaviour should be. So you will need to COMPARE the MPPT output current to the battery monitor/BMV to understand this - unless you have a CCGX or similar that can monitor the lot at once. If the battery monitor is indicating a '-ve' current flow then to me that indicates that you actually don't have enough PV to cover BOTH the loads & the current required to maintain the battery voltage set-point (for the particular phase it's in).Īlso remember that the current flowing from the MPPT directly to the load will NOT be measured by the battery monitor/BMV. If you have a load on at the same time then part of the MPPT output will go direct to the load & the remainder will go to the battery (as measured through the battery monitor/BMV) If you are at the end of the absorption phase the battery will inherently need less & less current to maintain the voltage set point. The MPPT should be providing whatever the system NEEDS to maintain the voltage set-point for the particular phase - obviously within the limitations of available PV. How are you measuring/establishing the current that the load is drawing? What phase is the controller in when this is noticed? All?ĭoes the battery voltage drop below the set-point for the particular phase? Bill BMV Battery Monitor smart solar set-up help Is there something (maybe a BMV) that can let the charge controller know the battery is not getting charged and up the amperage till its back at +5amps again or whatever the CC thinks it should be pushing right then. as it thinks it wants to charge the batteries at 5 amps due what I assume is an algolrythm and maybe the batteries chemical reactions pushing back.

The solar irradiance at that time of the day could easily produce 300-400w 80v but the charge controller appears to be limiting it to 25-75 watts at 80v. In actuality, for my RV its pretty normal for the inverter to be pulling 8-10 amps from the battery all day long due to network devices, DVR, Fridge, radio, weather radio, TV, phone chargers, cameras and 12v 'phantom draws' of which there are many also. But the controller is thinking it should only be producing 5 amps as the battery is getting closer to 95-100% SOC. From what I can tell the BMV's won't talk to the controller to help with that.Įxample, Its just past midday and my 640w of panels could be producing 350-400 watts then. I am wondering if there is something that can make the 'smartsolar' controller be a bit smart? Let it put out more amperage than it thinks the battery can accept so solar panels can help overcome the loads in the RV (or boat)? It pains me to see the negitive numbers on my trimetric when I know there is plenty of sunshine to keep charging the battery but the smartsolar controller is not aware we really need more power.

Tri metric battery monitor