I recently added another Renogy RSP200D solar panel for total of four in series in front of my 100/50 Smart Solar Charger. I haven’t run into any overvoltage issues with a high of 95V in the last few weeks, however I have seen the controller clip when hitting 49.7 to 50.3 amps. I thought it might just regulate it, but it seems to shut down for a minute. Not a huge issue as it only seems to last 60-90 seconds or so. Am I damaging the unit? Using my Fluke IR Thermometer I’m seeing about 136 F on the rear cooling fins. Definitely warm, but not outrageous hot either. My plan to reduce clipping, increase efficiency and lower the controller temperature is to get a Victron Energy MultiPlus-II 24/5000/120-95 120V - 24V Inverter and re-wire my 8 100Ah batteries for two groups of 4 in parallel, then in series for 400Ah @ 24V. Obviously I’ll have reprogram the charge controller for 24V output. Does this make sense? Eventually I’ll add some dedicated 24V batteries and add another inverter for two 120V legs so I can run my air compressor and welder (30A draw)… The other option would be to rewire the batteries for 48V @ 200Ah and just get the 48V version of the Multiplus but I’d have to buy a 48V compatible controller. Which would you do and what makes the most sense from an efficiency and expandability view? Edit: I pulled the data sheet and according to notes 1a,b) and 2) damage will occur if over amping the input from the solar panels, but no mention of overvolt? Interesting… Not that I would try it. I’m maxed out as it is..
1a) If more PV power is connected, the controller will limit input power.
1b) The PV voltage must exceed Vbat + 5 V for the controller to start.
Thereafter the minimum PV voltage is Vbat + 1 V.
2) A PV array with a higher short circuit current may damage the controller.
I see your other thread where you mentioned the risks already with the Voc. Clipping is normal and shouldn’t shutdown the controller. I would be looking at cables, fuses and connections.
Running the MPPT that close to its max Voc stays a bit risky imo.
Clipping is normal for over current, its not normal to shat the scc down everytime.
I ran 4 x 500W panels on a 100/50 into a 24v system, it clipped the amps the whole day but I got 50 Amps out constantly (almost)
the most important factor is the VOC, do not exceed EVER!
The scc will “pull” the max amps from the panel upto the max amps of the scc, it cannot “pull” more amps from the panels into the scc, that is the moment clipping happens
I have a SmartSolar 100/50 that also exhibits the same behavior. MPPT would shutdown or throttle for a short while when 50 amps output was hit, even when PV input voltage was much lower than max 100V and input current lower than 50 amps. MPPT was not hot.
I was able to stop the shutdown/throttling behavior by setting the max charge current to 46 amps. The MPPT could then charge at 46 amps continously even though there was sufficient PV to have full 50 amps output charge current.
If I can reply to all.
1: After digging further into the MPPT logs I saw a high of 95.7V when the battery bank was fully charged. I’m really right on the edge and the temps in the morning were around 0 to 2c.
2: I totally agree with what @jcharlebois posted above. I pulled my charge current to 48 amps and I saw no dips to Zero.
3: However, I still ordered a 5000VA/24V Multiplus ii. Not because I have money to throw away, but because I could eventually expand to run my air compressor and welder with enough solar panels to recover.
4: I plan on replacing my 100/50 with a couple of 150/70’s in syncronis, solar is addicting.
5: My Giandel 2200W pure sine has been amazing.. We’re talking on it right now, lol. I can run my table saw for a few minutes, my drill press for a few minutes, not too shabby
I know it’s a bit late, but it’s hard to recommend anything other than 48V.
And instead of getting a 150/70 MPPT, get 2 150/35 MPPT’s. It’s actually cheaper that way and you get redundancy if one of them ever fails. The MPPT’s are usually 12/24/48 capable and 48V is where you get the most capacity so there’s that too.
I agree that the 48V version of the Multiplus 2 would be the most efficient and expandible for the future, but that also require another solar controller as my present 100/50 is only capable of charging up to a 24V battery array. My plan is to upgrade to two 150/70’s for a total of 140 amps which would be close to a 1c charging rate in a 8 -12V battery array in 4S 2P. However, that would be reasonable in a 2S 4P array. I also wanted to mention that while reviewing solar charger history I saw peaks of 95V when the controller shut down charging after absorption cycle completed and the only load was the Giandel inverter stand by. Yikes! It’s not even cold here. Another thing of note is when I discharged my system hard, down to 12.5 resting, when I had great sunshine day and the Solar Controller was pushing 48 amps @ 12V for hours, the 150/50 controller got way hot, I didn’t get a chance to use my Fluke IR but it was almost too hot to touch to me which tells me it was well above 140F. That’s just too hot for electronics to function for hours and hours… The plan for now is to switch to 24V and watch the temps drop at the controller and switch to a 150/70 (or two if I can get my Fire Fighter Stepson to help me out getting my other 4 panels up on the roof) for a max of 140 amps for the 400ah battery array. I wish I could edit my Over Volt post to post my new findings, but it’s been closed. Just something to rattle around a person’s mind is that these Renogy panels “Over Perform” in every aspect and to be aware when selecting a solar controller. They are rated at 23V Voc, I’m seeing close to 24 @ 70F ambient air temp.
