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diy solar

Do NOT discard a Dead Victron MPPT 100/30 or its kind

Interesting thought.

I was planning on putting 3 panels on a 100/50 to size to real world output and not oversize the MPPT, now I'm not so sure as the MPPT output limit will probably be hit regularly, input limit's not. What do you guys think?

Panels (they will live on a boat so not optimal angles, etcetc):
  • 355Wp STC
  • 265Wp NOCT
  • Voc 39.8V
  • Isc 11.52A
Combined output <40V & <36amps.

Controller being the 100/50 at 12 volt, the Voc & Isc are well within limits (100v & 60amp) , but the MPPT output of 700 watts will probably regularly be hit.

Reasons for the 100/50 with 3 panels:
  • sized to real world situation (I think)
  • physical size of the 100/50
  • reducing complexity & cost for the future when more strings are added.
what do you guys think?

(ps. first post here)
welcome to the forum!

it’s late so i don’t have advice yet ? goodnight:sleep:
 
Why can’t the MPPT controller just not utilize the MPPT?

Say the PV array can output 49v at 15a and that’s the max MPP, what’s stopping the SCC MPPT logic’s for stepping down the voltage to say 43v to stay under the max current output of the unit?

Again that’s not tossing away amps it’s just not efficiently using all the panel array can offer.
 
Interesting to note that the caps are well above the 100v rating, 160v in fact... I would think you could get away with PV higher PV volts as a result...
 
Interesting to note that the caps are well above the 100v rating, 160v in fact... I would think you could get away with PV higher PV volts as a result...
That’s what I’d expect from high quality brand name unit: rated for 100v max and can be used to every last volt of it. Should survive bit more extra and just throw error code at you. On the other hand I’d expect CCC(cheep, cheerful, chinese) to burst in flames at 101 volts and to need derate to 60% max output if you want long lifetime.
 
If I were you, I would feel perfectly comfortable running the device like that.
It's well within Victron's specifications for continuous operation.
edit: this was supposed to be a reply to @ericjanvanputten
 
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Why can’t the MPPT controller just not utilize the MPPT?

Say the PV array can output 49v at 15a and that’s the max MPP, what’s stopping the SCC MPPT logic’s for stepping down the voltage to say 43v to stay under the max current output of the unit?

Again that’s not tossing away amps it’s just not efficiently using all the panel array can offer.
I'm not understanding your question exactly. Are you asking why the charge controllers can't simply avoid an overcurrent event by operating outside of the maximum power point? The victron units are designed to do exactly this-- they will 'throttle' the output charging current to the batteries in order to stay under their maximum output power rating.
There's a problem though; they can be destroyed by an array with an input short circuit current limit which exceeds the ratings of the device. The idea here is that under certain types of voltage anomalies the charge controller can enter a type of 'protection mode' where it attempts to short circuit the array by shorting the input terminals of the device. This can blow an internal fuse if the Isc limit is exceeded.
 
It was probably taking myself through how units limit output current under and over panel scenario.

I wasn’t aware of the Isc aspects. But sounds like there is some decent wiggle room to capture more KWhr during non ideal solar days.
 
I have characterized switching circuits in a design lab. MPPT is just another control layer.
1. Current can be limited by the toroid reaching magnetic saturation. Hot and not accurate. PT (Process and Temperature variation)
2. Current can be sensed by voltage drop across components, like FETs and synchronous diodes (FETs). Not very accurate. PVT (PT + Voltage variation)
3. Temperature can be sensed. But response can be too slow. It might be a kill switch and not a taper.
4. SCC has a pretty good current readout. Questionable if the MPPT Switcher controller uses that information.
5. FETs are sensitive to over voltage. It might survive for a while with a reduced life span.
6. A switchers output current can be throttled by reducing the PWM Pulse Width Duty Cycle. Overriding the MPPT control.
7. A switchers output voltage can be regulated by adjusting the PWM Pulse Width Duty Cycle. Overriding the MPPT control.
8. MPPT is most important while charging before hitting voltage regulation. Ex. Bulk 14.4v or Float 13.6v
 
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-The volts & amps created by the panels and fed to the controller are converted by the controller to {approximately} 12V (or 24V) and corresponding amps. For example, panels that output 48V and 15A may be converted to 12V and 59A. A Victron 100|50 is designed to output up to 50 amps. It will actually limit its output to the battery only up to 50 amps, so the entire 59 amps won't make it to battery. In this example the controller is being asked to handle outputting more current than it is rated for, so it will get very hot and could burn up. It can probably handle the heat generated by the 59 amps but not much more. Supervstech (above) suggested that adding a fan to the controller's heat sink may prevent it from burning up and also extend its life.
no you are not understanding it at all. If you overpanel it, it will run the string outside of the maximum power point so effectively draining less power from the panels. Nothing will get hot or blow.
 
Not made in USA.....enough for me. No seriously Victron was a world class company years ago, their marine gear was respected worldwide but their modern solar stuff is pretty substandard. I have trouble programming them to set values for the intended use.The Bluetooth programming thing is ridiculous , you have to buy a programmer to set your set points. It might need some special phone to use their Bluetooth App as an iPhone and several assorted googling androids could not pair with the controller, I replaced it with an American made controller that had programming built in and is all aluminum casing, not glued thermoplastic......same price, no hassles. Still there. I know that the boards are not American and I can think of only one country that can outdo China in cheep junk and that is India. Outback made the mistake of having their charge controller built in India now we are flooded with fake outback units that no one will support, the builder of the fake outback’s instruct their customers to go to the Outback forum for support. I do have a few offshore units in my systems but they are well proven systems from proven manufacturers who do support their equipment.
I'm with you on that, I've had 3 victron 100 amp chargers die or the latest 1 is it won't shut down at night. They replaced 2 of them but having a fight with them now on the 3rd. Even if I do get it replaced, my next charger brand will be something else.
 
I have a 75/15 and 100/50. Both Victrons seem to be putting out only a fraction of the watts that the panels connected to them are. At first I didn’t think I could actually have a bad controller because they both show low watts and do actually charge a battery (bulk at the low wattage they report). Now though, I’m beginning to think I may possibly have two bad controllers.
 
I have a 75/15 and 100/50. Both Victrons seem to be putting out only a fraction of the watts that the panels connected to them are. At first I didn’t think I could actually have a bad controller because they both show low watts and do actually charge a battery (bulk at the low wattage they report). Now though, I’m beginning to think I may possibly have two bad controllers.
I had charging issues with low current. The cheap Chinese MC4 connectors were at fault. One of the connectors kept slipping back into the plastic barrel. I was using these on portable panels and they did not hold up to a few insertion cycles. A big clue was the Victron app showing a low voltage input.
 
I’m using appropriately sized cables with XT60 connectors that I made. The voltage I measure at the panels is exactly the same as the Victron app shows. The current from the panels measured at the Victron input terminals is what I would expect but the Victron app shows very low watts (not corresponding to the current I measure at the terminals). It still charges the battery from bulk all the way through float, it just takes a lot of time (due to low watts). Both Victrons seem to produce the same result.

I’ll re-check all connections because everything is just setup to test. I don’t know if Victrons ever fail and start “taking in” only minimal current. Sounds strange for 2 units to do this.
 
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I’m using appropriately sized cables with XT60 connectors that I made.
My old camper setup used XT45. It was only 100W portable. Also used them for quick disconnect of the SCC.
On the new Travel Trailer I considered using the larger and easy to handle XT90. Ordered with the pigtail attached.
BUT... No reason to void the warranty on the used panels from Santan Solar by replacing the MC4. Also it was easier to find a MC4 entry port.
I bought a MC4 crimp tool kit from Amazon. These MC4 give me trouble and I had to epoxy the male pin in place. The panel and entry port MC4 are trouble free.
BTW The XT are gold plated which I really like. BUT they are a potential shock hazard when wet. I would throw a towel over the panels before insertion or removal.
 
Hello all. Very interesting discussion. I have had the same situation on 3 controllers and all three simultaneously allowed smoke to escape at the same time. They were the 100/50 models, and were the Chinese version made by Fanguspan. Before you jump in and say "ah ha! Made in China, eh?", please listen to what caused them to blow. It was all my fault. I wanted to switch the dial to another battery setting because I was experimenting on which was best suited to my LiFo batteries. I shut off all the circuit breakers leading into the 3 controllers and then turned off the battery switch. Somehow, I got distracted when turning it all back on, and turned on the solar panel breakers first, before the batteries. Some have told me that theirs have survived a brief mistake like that, while others like me haven't been so lucky. I have 3900 watts of panels on board my boat, and when this happened I was in full sun, so maximum power was coming to each SSC. The smoke was quite quick to appear! However, I was too late in getting the panel breakers off, and had no working SSC's any more. Being a packrat, I didn't toss them away, and I am happy to come upon this article and what happened inside the boxe. I am not sure my fuses went, but now I will give one the surgery and look. Thanks for the pictures, so I know where to make the incision. (I did try to rip one apart, but it was stronger than I, and that blue plastic didn't tear no matter how hard I tried.) Today the setup has the Victron 250/70 and the 150/85. Of note, the newer ones have provisions for a remote switch that somehow can turn off the SSC WITHOUT closing off any power coming from the panels, or circuit breakers in my case. Why the fuse, if there is one, doesn't pop, is a mystery. However it works great, and I use the 250/70 relay to control possible over voltage on the 150/85 by just turning it off. (The LCD panel can no longer be read and therefore I cannot change any setting manually). Also, the 250/70 with its blue tooth capability, I can now change any parameter I want, including the relay, and what parameters (like high volts) I want to activate it. I will let everyone know what I find inside the box after it comes off the operating table. I seem to remember the smoke coming from the other side of the box, but also at the bottom. But then again, when smoke is coming out, who is taking notes? Further details: The solar panel feed wires go into a box near the SSC's and run thru 3 separate 400VDC miniature circuit breakers, 20amp, 16A and 10A, which break both the positive and negative wires. My lithium bank is 800ahr wired at 24v. Cheers
Hi Bob, This week I was able to resurrect another dead Victron MPPT (100/50) due to overvoltage. Again fuse is the culprit. See below pic.
Vic 100/50 and Vic 100/30 are using very similar board. So, this time the surgery is cleaner and less damage.
 

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For home use I plan to buy the RS 450/100s vs the 250/100s simply due to ease of disassembly. That way once/if the warranty is up I can swap out fuses/dried caps/mosfets etc more easily.

(Note: I don't actually have a 450/100 yet, but based on picts they don't appear to be sealed up like the smaller units)
 
Hi Bob, This week I was able to resurrect another dead Victron MPPT (100/50) due to overvoltage. Again fuse is the culprit. See below pic.
Vic 100/50 and Vic 100/30 are using very similar board. So, this time the surgery is cleaner and less damage.
ANL fuse 70A or 80A on my Victron MPPT 100/50 output? So what was on the inside? Looks like you have a Class T 80A.
I'm replacing my Bussman 60A CB to reduce voltage drop. Don't think 500W of panels would trip it. I generally point them in different directions.
 
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