Review on Renogy Rover 40 Amp MPPT Solar Charge Controller - 12V/24V DC Input, 🌞 LCD Display, Auto Parameter Adjustable, Compatible with Gel Sealed, Flooded, and Lithium Battery Systems by Fredo Zhan

Last update - bluetooth died in one day. Tried everything to revive it but nothing worked. It should also be noted that there are quite a few solar charge controllers that claim to be compatible with lithium batteries, which I don't think is true. These solar chargers appear to be only minor upgrades from chargers that used to work with sealed, AGM, or gel batteries. Lithium batteries have a very narrow operating voltage. A tenth of a volt means peace. So these charge controllers that just try to regulate charge based on voltage cannot do the job. You always have cable losses, and whether your controller shows high or low readings depends on the amperage and load. With charge controllers for lithium batteries you need to be able to read the voltage across the battery terminals and to be honest you need to be able to read the current going in or out of the battery so you can coulomb can count. Without this, it's probably impossible to know the true state of charge of the battery. Many voltage-only charge controllers will regulate the amount of current at the battery whether the battery is discharging 20 or more amps into the load or is overcurrent (i.e., charging) since the battery voltage is nearly the same. If my charge controller can source 20 amps (assuming the panels can source that) and I have a 25 amp load, then my charge controller MUST go all out and source all the amps it can. However, when your battery is almost fully charged, the charge controller sees this full voltage and reduces the current. On the other hand, if the charge controller can determine the input and output current, it can do what it is supposed to do in this case. In short, the Renogy solar controller's bluetooth failure and only voltage detection made me return it today. I'll try Victron which combined with its smart shunt seems to be able to do what needs to be done. Just take a look. *************** To update. I've found that when using the Renogy Lithium preset in an application, it's possible to still edit some values and disable alignment. At least it seems so. The manual doesn't explain this and the first values I tried to change didn't let me select. Finally, on a later visit, I kept scrolling and found some elements in a lighter shade of gray that could be changed. If you changed them, the other elements were adjusted automatically and you cannot change them. Fortunately, this is a situation I can probably live with. Another issue is that when I measure the voltage at the battery terminals, Renogy sees a different voltage than I do. This is not surprising as there is always some leakage in the line, but I suspect that this value will not be constant and will vary depending on load current and whether charging or discharging. The problem is if you want to move the presets in the renogy BT app to accommodate this you can't do that as you need different presets for different situations. What Renogy and everyone else needs to do (and good solar charge controllers do) is a separate dedicated line to measure the voltage at the battery terminals. Renogy would be doing itself a huge favor by improving its manuals and discussing some of the settings in more detail. Also, why not stick with the same terminology used by battery manufacturers (like volume, adsorption, etc) instead of using boost (which they never explain, but it looks like it's the same as volume). Since I was able to change the settings, my biggest concern is that I changed my Renogy rating from 1 star to 3 stars. You can make it work, but your BMS will still do some of the hard work. **************** My overall opinion of Renogy products has really deteriorated over the past few days. . This product claims to be compatible with lithium batteries, but when you look at the values listed for lithium, many of them are too high and almost unsafe. Of course, they don't allow the LFP battery to be kept in the 20-90% range recommended for long life. Yes, they have user preferences where you can change the values, but you cannot turn off the float or flatten modes in the user preferences. That being said, Renogy offers so little documentation on lithium charging advice and issues that it's difficult to find anything on the web to resolve my issues. And in some cases, not only are their software and programming skills inadequate, they don't even bother to let you enter values or read values for 24 volt systems. Instead, they want you to multiply or divide by two! It's not that difficult, it's just so unprofessional and clumsy that it makes you think about the whole product and the company behind it. It really looks like a product that was never intended for lithium by a medieval company. Needless to say I sent the product back.