Unless you’re using the 450/100 or 450/200 models, which are galvanically isolated, it’s essential to install a BatteryProtect. With non-isolated MPPTs, an internal failure can result in high voltage appearing on the low-voltage side—a serious risk to your system.
A BatteryProtect device is designed to disconnect in the event of such a fault, preventing damage. There are numerous examples where BatteryProtects have successfully prevented overvoltage issues caused by MPPT failures. I use them on all my systems, and in my opinion, not including one is a mistake.
The picture you have is a description of 2 different systems; you will not get installation instructions from this. You can ask your supplier for help with system design and how to install a battery protect to protect the system from a fault in the MPPT. I have blown up a few Victron products and found they can help, and very knowledgeable.
I have no idea, just an example I found of a battery protect between the MPPT to the battery to protect from an MPPT fault. This is how it’s done. Most people with small systems will put a 12V panel on a 12V system or a 24V panel on a 24V system and will not see multiples of the system voltage if there is a failure. If you want to fly close to the sun and run at near MPPT max voltage input, then you really need to look at something like this.
Pretty sure high voltage shutdown is around 66v, but the 48v system might only have a design insulation voltage of 80v, like fuse holders etc. The system would have definitely alarmed and shut down, but would not have been able to protect itself from extreme voltage.
I have given up on communicating with the Victron guys. They never replied on questions for the reasons why the safety measures didn’t work. They only point towards me for causing the voltage to go above the capacity of the MPPT.
The last mail I received even stated that there are no safety measures in the MPPT that will help preventing accidents caused by overvoltage. Then I have had enough of it.
I have passed the issue on to my lawyer to see if they can get an answer that will give more clarity to the situation. I wil wait and see…
When switched on, the “run” lights were on, but there was no voltage on the terminals.
I have fitted new BMS cards to the units and now they are operational again.
I will keep them in case something else goes wrong with the new cards or I might repair them in the future.
I know which parts are damaged in the old cards and maybe I will repair them. The current problem is that the onboard fuses are only sold in quantities of thousands. Maybe I can get my hands on a smaller number of them.
If I am going from a high-voltage to a low-voltage, I will always use a galvanically isolated product or install a battery protect. I think any charge controller above 32V should be galvanically isolated for safety. That would be ideal. Relays can fail.
Even though the MPPT isn’t isolated, it has built-in protection circuitry that monitors the system.
If the voltage or current coming from the solar panels goes out of safe range, that protection circuitry will shut off power to the converter before anything bad happens.
Because of this protection, there is no risk that a dangerously high voltage will reach the battery side — the MPPT will disconnect it first.
However, he emphasizes that you must stay within the maximum input values (voltage and current) stated in the datasheet, because that’s the limit the protection circuitry is designed to handle.
As long as you respect those limits, the MPPT will stay safe under all conditions.
Basically,
The MPPT watches itself and can disconnect if something goes wrong — but you still have to wire and design it properly, because if you exceed its absolute maximum ratings, no amount of smart circuitry can save it. Did you also go over current? I know if the current is over the rated input the reverse polarity circuitry will be damaged.
I fail to understand how the addition of a Battery Protect with a voltage range of 6-35VDC in a circuit where the PV can output 150VDC is going to protect anything. What am I missing?
The 48V version can handle up to 60V safely. The voltage won’t jump instantly to the panel’s open-circuit voltage; instead, it will gradually rise. As soon as it exceeds the high-voltage limit, the system will disconnect. If the voltage continues to rise unchecked, damage will eventually occur — you’re right about that. This approach gives you some buffer time, and you can set an alarm for added protection. However, for full protection, you’d need a much more industrial setup. It’s much simpler and safer to operate within the equipment’s designed voltage range.
Looking at the image, it appears the tracker was still functioning above 68V. If the battery had been disconnected at that point, the tracker might have stopped tracking, possibly preventing a complete short, although, as shown, a short eventually did happen.
OK, so this is my take on the situation and my experience with my 100/50 solar controller.These units are rated @ an absolute maximum with a peak that should never be exceeded even for a microsecond. I’ve not exceeded 100V, but I’m scary close @ 95.6V when my batteries have reached full charge and the absorption cycle has been completed. I’ve also seen 50.4 amps output and the controller just shuts down to zero output for 90 seconds or so. On advice from another awesome member I pulled the charge rate down to 48 amps and I’ve not seen a current dive to zero since… However, that controller is hot, too hot to touch which means over 140F with my calibrated welder hands. I get it, if it’s rated at whatever, why can’t I do that for 4-6 hours a day? Let me make a comparison.. Say I bought a Dodge Hellcat with a rated HP of 707. Dang I paid a lot of money for it so I’m going to run it around a 3 mile track for 4 hours at full throttle for a day. After a few weeks it sends a rod through the pan and crap! I’ve got a major fire and I darn near died! What the heck, why didn’t Dodge put a throttle limiter in! I’m suing them!
Rattle that around your brains. Just because you can, doesn’t mean you should. Maybe Victron should down rate their products to prevent people from hurting themselves. Point in context… I have a 900W (BTW, VA doesn’t equate to watts) water distiller that came with a 18 gage cord. I saw temps of over 150F at the outlet, yikes. I swapped out a well made cord of 14 AWG and the temp has never reached 100F.
Be your own policeman or be destined to be disappointed.
