Victron EnergySmartSolar MPPT Solar Charge Controller (Bluetooth) - Charge Controllers for Solar Panels - 75V, 10 amp, 12/24-Volt

I needed to light a tree in less-than-ideal solar conditions using solar power only (charging a 12V battery). I first tried a 12V solar panel with a PWM controller, but it could not keep the battery charged. I found I needed a more sophisticated MPPT controller, so I purchased this Victron Energy SmartSolar MPPT 75V, 10 amp Solar Charge Controller to replace the PWM controller. It worked with the 12V panel OK, but still not good enough to keep the battery voltage in the "safe" voltage drain zone in the poor and varying sun conditions I had (Winter weather, often in low-angle tree shadow).The SmartSolar MPPT controller documentation recommended a 24V solar panel for a 12V battery. I changed to a 24V panel, and it worked great! Using daily measurements from the MPPT controller (via the Bluetooth VictronConnect app), I found that the 24V panel's voltage kept the PV input voltage often at over 20V even on a cloudy day and/or in the shade of trees. The SmartSolar controller converted the extra voltage to the charging power I needed. Keeps my battery charged at above-minimum voltages even on snowy days! Just what I was hoping for! See my chart for my testing results.

I have two of these connected to lead-acid deep-cycle batteries. One drives a remote bird-house camera and one powers a pump in a bird bath. They were easy to set up and the instructions are clear. They have enormous programmability. The phone app is great for checking on the battery performance, solar power level, load, etc.There are a couple of features I wish it had. One is more pre-programmed battery types. They offer a few basic battery types and a custom program of gazillions of charging parameters for experts. I'm an electrical engineer and could get out the data sheet for my specific battery and program all the parameters, but what a hassle, and what if I make a mistake? It would be nice to have a few more standard lead-acid battery types in the menu.The unit has a streetlight function for turning on a light at night, but I want a general purpose timer that turns on the load in the day. That would be a small amount of software for Victron to add to the unit and the application. I want our birdbath to run only during the day. I could have used a smaller solar panel and smaller battery if this unit had a timer feature.This unit keeps a history of solar power generated and load power consumed that goes back at least a few weeks. I haven't looked to see how far back it goes, but it's interesting and useful to see how the panels are doing, or if the load is drawing unexpected power. It was also useful to see if my calculations were correct.

I replaced a budget controller that stopped working after a couple of years. Installation is a little complicated. The manual included required a magnifying glass to read and seemed to be written for someone that already knows what they are doing. It didn't mention one of the most important things, the PIN to program the device with a smart phone. The manual says it's somewhere on the unit. It helps to watch a few Youtube installation videos. At least one gave me the PIN. 000000.Once I figured that out it was still a little difficult to navigate the settings in the app.It's now working like it's supposed to. It quickly topped off two batteries.

This Victron charge controller is a good choice for small projects such as keeping a vehicle or sump pump battery charged from a 25 Watt (or larger) solar panel. Ability to tailor parameters and monitor performance with a Bluetooth connection is a plus. The unit is dust and moisture resistant when mounted with the terminals facing down. As expected the MPPT buck/boost circuitry assures your battery gets the most possible charge given variable solar exposure. The Victron is more expensive than some, but is brand offers better than average quality and features. It makes sense to invest in a good quality controller to get maximum use and lifespan from your expensive batteries.