SMA Sunny Boy SB 2500 fault finding. - Page 1
Forum section: electronics / repair

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 07, 2017, 03:04:16 pm
content: Hi, I'm wondering if anyone know how to trouble fault this SMA Sunny Boy SB 2500.I know nothing about this unit, it was bought as spares or repair. I dont even know how to set it up, but this is what I've done so far. ( Not a Lot) lolI plugged in a solar panel, Plugged in some kind of disconnect and supplied 240v ac and nothing is coming up on the display.I've checked there is 240v going to the board, I don't know where it goes after that, I also cant see any fuses except the big fuse by the solar input which checks ok.The unit is consuming 20 watts.

author: mmagin
author_rank: Frequent Contributor
timestamp: May 07, 2017, 06:10:10 pm
content: Haven't repaired any solar inverters, but I see that there's at least a block diagram inhttp://files.sma.de/dl/5673/SB2500-11-EE4801.pdfBesides reading through that and making sure your test setup is valid, I would take a look at it with the power off and see how the block diagram maps to the board and do a lot of ohmmeter checks while also looking for damaged components.Hmm, I read further.. Starting at page 30 they have the information on how to decode the 3 diagnostic LEDs. It looks like if the DC side is <85 volts, all lights will be off and it'll be in standby mode. You probably need more than a single solar panel.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 07, 2017, 07:19:55 pm
content: Thanks mmagin, perhaps it might be working after all. i'll keep you posted.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 11, 2017, 06:18:34 pm
content: Oh well, I got another solar panel off my mate, Connected 3 panels in series and got 125v and it lit up, but that's all it did. I'm not sure if it needs more voltage or if it's busted. Has anybody trouble shot something like this?

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 11, 2017, 06:43:08 pm
content: I just found this in the manual, looks like it's initialization mode, " whats that mean "

author: mmagin
author_rank: Frequent Contributor
timestamp: May 11, 2017, 07:25:51 pm
content: Does it start to load the panels down enough they drop below the minimum DC level and then it drops out?

author: station240
author_rank: Unknown
timestamp: May 11, 2017, 07:31:36 pm
content: Most of these need more than 150V DC input to produce output power, otherwise it stays in standby/initialisation mode.Check the relays and film capacitors on the AC side for bulges/burns, as it's a common fault on cheaper inverters (eg not anything SMA make)

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 11, 2017, 07:59:53 pm
content: Just found this in the manual, I need more panels. Thanks to the person who found this manual.

author: Simon
author_rank: Unknown
timestamp: May 11, 2017, 08:59:07 pm
content: You will probably need 5 or 6 panels to make it work. Check the label that specifies the input voltage.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: July 12, 2017, 10:23:14 pm
content: Long time waiting but I've bought some new solar panels and I'm getting 280vdc of solar into the unit, It looks a bit more promising as its doing it's checks then it sits there waiting to connect to the grid with the green led flashing. I thought this was normal but after half an hour it still waiting.I'm not sure if I have to connect a pc and configer something.I've found a video on youtube with the same problem but he dont explain the fix.https://youtu.be/lIAKg3WtwtgCan someone help please, I really want this up and running.Thanks

author: Simon
author_rank: Unknown
timestamp: July 13, 2017, 08:08:22 pm
content: sounds like it's broke, I plugged it all together and it just worked. I have 6 panels on my 1.7KW version (1.5KW in reality)

author: EPTech
author_rank: Regular Contributor
timestamp: July 14, 2017, 12:02:28 pm
content: Is your inverter also showing the message Vac BFR? At some point the display will also show Vac. What does it say. It may be to high or to low. The reading of the display should be more or less the same as you would measure with a multimeter. If not, the measuring circuit may be defective. This could be a lightning victim, where lightning struck on the mains.

author: webgiorgio
author_rank: Regular Contributor
timestamp: November 23, 2018, 07:50:21 am
content: Did you fix it? I am also trying to repair a SMA inverter.https://www.eevblog.com/forum/repair/7-kw-photovoltaic-inverter-unstable-output/Here my comments on your fault:The display is telling that the Vac is outside the limits.It should be about 230V, but the inverter is reading 314V. It looks like a wrong reading of the mains voltage.Search on the boards some resistors in series (like 4 r of them, equal values) that form the top part of a voltage divider. Then there should be a ADC chip, maybe an optocoupler, and the signal traces goes towards the DSP.It may simply be a shorted resistor in the voltage divider.

author: Simon
author_rank: Unknown
timestamp: November 23, 2018, 07:52:57 am
content: No I have not. I am thinking spares or repairs if anyone wants it. I have an 8.2KW replacement coming in a month.

author: bessem2fr
author_rank: Newbie
timestamp: June 02, 2019, 11:31:23 pm
content: hello . i need more photo of this sma sunboy sb 2500 ...