I spent the extra coin forost of my setup from Victron because, when I'm out boondocking in my RV, I want no issues as I'm many hours or days from home.
Thought I'd share an experience so that others might learn and avoid a very expensive mistake. If you're new to this stuff and just leaning, I think my story is worth a read because this mistake is costing me several thousand dollars to fix. Hope this story helps someone else avoid what I've incurred. Also, I'm hoping for some intelligent ideas (trolls and anyone with snarky comments should move on) to what could have gone wrong so that this could have been avoided and never happen to me again.
About a month ago I finished installing my 4 Newpowa 210W PV in series and my 4 Lion UT1300 12V 105Ah LiFePO4 in parallel. My charger is a Victron MPPT SmartSolar 150/70 (yes oversized but wanted room for expansion later) with the LED display module.
Batteries connected through the Victron Lynx PowerIn with the controller all sharing the same bus. 25A 300V breaker installed between the PV and controller.
I installed the Victron Connect on my smartphone and paired it with the controller and allowed it to install a software update. Seemed reasonable.
I finished installing late one evening as sun was nearly set and could see very low voltage coming from the PV which I expected. The charge controller was reading 13.3 V from batteries. All good. I hooked up the coach feed to PowerIn and all was well. Generator could start in case I would need to run A/C for the weekend some. Plans were to install 3K inverter after this trip. Flipped the breaker to disconnect PV and headed in for the night.
Next day we departed for our trip. We get to destination and I unhitch and get ready to level. I flipped the breaker on and went about completing my other arrival activities. Then I smell electrical burning. This happened in just a couple minutes.
I opened up the front compartment where all my gear is and I see smoke coming out of the front of the front slide controller. The leads coming into on the right side are arching. I flipped the PV breaker and quickly disconnected the coach 12V from the PowerIn. What happened?!?!?
I followed the manual on the install of everything to the tee. Made sure batteries where connected to controller before the PV was. Upon investigation there were 12V fuses blown in coach panel. We replaced and they blew immediately. Fridge was off line. Front slide wasn't going to move. Determined that my weekend was shot. We headed back towards home.
Next day I visited a recommended repair shop of a good friend. I needed at least to move out the main slide so that I could open and empty the fridge. While still cool, I ended up throwing out most of the items that just weren't worth talking the risk and getting sick due up possible spoiling.
The RV tech looked at my situation. We flipped on the PV breaker - 72V coming across the batteries. Quickly flipped that off. How could that be? The controller is designed to auto sense the battery voltage. Upon initial connection it was showing 13.3V on the LED panel - about what I'd expect from nearly fully charged batteries under no load. So this makes no sense. Upon further investigation while I had it home waiting for the RV guy to get into his schedule, I look again at the VC app one evening. I'm looking at settings.....
BATTERY VOLTAGE WAS SET TO 48V?!?!? What the heck?!?? This controller auto detects the voltage! I saw it read 13.3. It's BRAND NEW for Pete's sake!!!
I'm dumbfounded and looking for answers. Did I FOUL THIS UP??? I'm no licensed electrician, but I've worked with electricity since I was old enough to put a house key into a120VAC outlet at 3 years of age. I took electronics in school. Took EE courses in college. I'm a licensed General Ham amateur radio operator and I did all the electrical study for that so that I knew it down pat. And I thoroughly planned out this system and vetted with others who I respect.
Here is where I am now. The smoking (bedsides the slide controller and about 8 other boards) gun is the 48V setting in the controller and I did not set it manually. In all my pondering, I have surmised that one of two things went wrong for that to not be set to 12V.
First possibility is that the software in the controller had a bug in it. Perhaps the update didn't go just right. Possible, but not as probable. Second possibility is that my controller was not as brand new as I thought it to be. I purchased through Amazon. The box looked new and everything looked factory fresh.
Studying the manual further I found out that the auto detection of battery voltage happens on first connection and remembers that until the voltage is later detected to be below 7V. My batteries where above 13V. My deduction at this point is that someone installed or setup this controller before me, connecting it to a 48V source. Then packagedmitbback all neat and pretty. And since my batteries were above 7V, it kept the 48V setting.
Nothing was wrong until I flipped the PV breaker on in full daylight. The RV tech looked at the aftermath and was reading 72 V. I would think that the controller would have been at most about 56V (14.4 *4). The OCV of each of my panels is about 20V, delivering 80V max while in series. Fortunately the batteries are smart enough that they went offline or I'd have a few more thousands in damage.
I'm interested in any ideas or to confirm my suspicions. I'm now contemplating a voltage regulator to the batteries and to the coach to prevent anything beyond 12.8V going in but the tech says that's not needed.
Hope this helps and I can ease my mind as to where I might have gone wrong or didn't. I can accept the blame, but I'd love to learn from this as it's a costly mistake somewhere. And despite the pain I'm feeling, like women and childbirth, I'll probably do this on my own again with the next rig. Thanks in advance. Hope this story makes for some learning for all.
