question

All Victrons MPPT chargers will match the voltage range you need. This is not a 58V but a normal voltage range for a 48V system. Max cell voltage of LiFePO4 cells is about 3.65V, so 16 in series will have 58.4V. Lead batteries would have a peak charge voltage (Equalisation) of 62V.

I did this replacement. Volta is NMC chemistry in 14S, and I believe the Kisae manual has the CC/CV/Float parameters that Volta gave them for charging. I never saw the Kisae go to float, the BMS always shut it off well before that. If you're going to do it right, you really need to intercept the solar enable pin from the Volta BMS and use that to enable or disable the new victron MPPT. The Volta BMS appears to remotely disable all loads before throwing the contactor, probably to prevent arcing and quick failure of the contactor. The most complicating issue is that Victron's MPPTs require 5V over the battery due to their buck only design. So 58.2 peak charging voltage requires a 63.2V solar array to be able to charge at peak. You'll need a minimum of 4 x '12V nominal' solar panels for this to work, and your solar performance will suffer a bit as shading on one panel could essentially stop all charging if your string voltage drops near to the battery voltage.

Thanks for the answers. I think I will leave the Kiesa for the alternator charging since it charges at a whopping 5600W! I definitely will install a Victron MPPT for the solar though. Next concern will be the BMV-712. My battery is 12,000 Ah and the manual says it can only do 9,999 Ah. Will the % still work if I install it?

The Kisae is not doing alternator charging, as that's done with either an APS or Wakespeed controller. I'm afraid you have a lot to learn about the system, and I would recommend that you not alter your system until you learn more about it. You can get in a lot more trouble with 48V systems over 12V systems as most DC components that you see aren't rated for over 32V. And using some of these components can cause fires if they don't have proper arc protection. There's also no load dump protection, and if something you alter ever causes a load dump then a 400V load dump spike from the alternator will likely kill every component on the 48V bus. There's a lot of protections that Volta's BMS does and the BMS directly controls all the components on the system, and if you ignore this you will damage the battery. Think of the cold and high temp protection - the BMS signals to the kisae to stop charging. If you install a victron and don't listen to the BMS commands, then the solar charge controller will charge the battery at hot or cold temps and that will definitely damage the battery. I originally ran over 600W of solar on the Kisae and it actually worked pretty good, but could only top off around 570W output. You can easily run 250W of solar on the Kisae without an issue, just be sure to run your panels in series to limit incoming current 10A and stay under the Kisae input voltage max. I actually installed a smart shunt just to compare and see if the data was any different from the Volta app, and it turned out to be worthless. There's so much self-consumption in the Volta platform before it hits the battery terminals that the smart shunt is never accurate. Every 24 hours without a 100% peak charge the SoC it reports drifts about 10% higher from actual. Meaning after 2 days the Volta SoC might show 75%, but the smart shunt reports 95%.