Looking for some Feedback on Mppt

So I've been running a Victron SmartSolar MPPT 100/50 for about two years now on my LDV Convoy camper conversion, and it's been absolutely rock solid — but a mate of mine has recently acquired a secondhand MPPT 250/100 from a Facebook Marketplace listing, and something about it doesn't quite sit right with me.

The unit arrived looking a bit rough around the edges — some scorch marks near the input terminals and one of the MOSFETs looks suspiciously discoloured. A few questions I'm hoping the collective wisdom here can help with:

1. Possible damage causes?
My gut says either a reverse polarity incident or the PV array was seriously oversized for the controller. Could sustained overvoltage do that kind of localised thermal damage to the input stage specifically?

2. Country of manufacture
Victron are a Dutch company obviously, but I've seen mention that some units are assembled elsewhere. Does anyone know where the 250/100 is actually manufactured? The listing mentioned "USA" which immediately raised an eyebrow.

3. Genuineness
This is the big one. There are clones floating about — some convincing enough to fool a casual inspection. Is there a reliable way to verify authenticity beyond the VRM portal registration? Victron UK (or their distributor Bimble Solar / Evolution Energy) — can they check a serial number for you?

My mate paid decent money for this and I'd hate for him to have bought a well-disguised brick. I'm tempted to tell him to cut his losses and get a fresh unit from a reputable UK supplier, but wanted to canvass opinion first.

Anyone had experience authenticating secondhand Victron kit?

@LDVCamper the SmartSolar range is hard to beat for reliability tbh. For your mate's secondhand unit, first thing I'd do is hook it up to the VictronConnect app via Bluetooth and check the firmware — older units sometimes need updating before they'll play nicely with newer batteries, especially lithium.

Also worth checking the history tab in the app, it logs errors and you can see if the previous owner had any issues. If it's showing a history of over-temp warnings that could explain a dodgy deal.

One thing I've noticed on my own setup — make sure the battery voltage is configured correctly from the off. A mate of mine fried a brand new Fogstar Drift because someone had left a unit set to AGM profile. Easy mistake, painful consequence.

Great thread! To add to what @CurrentAffairs96 is saying — once your mate's got the basics checked over, it's well worth downloading the VictronConnect app and connecting via Bluetooth. Even on older SmartSolar units you can pull up the history tab and see if there's been anything dodgy going on — fault codes, days where yield dropped off unexpectedly, that sort of thing. Gives you a really good picture of how the unit's been treated previously.

Also worth checking the firmware version while you're in there and updating if needed — Victron have pushed some decent improvements over the years. I did this on mine after buying secondhand and it sorted a minor absorption phase quirk I'd been scratching my head over. Free fix, five minutes tops. 👍

Secondhand Victron is usually fine but pull up the history in VictronConnect before trusting it — if the previous owner had it misconfigured charging lithium with AGM settings, your mate's cells have already had a rough life they don't know about yet. 🔋

Also worth checking the absorption voltage isn't set mental high — seen "bargain" units on eBay that were cranked to 15V+ by some cowboy and never reset. My 100/30 on the motorhome came secondhand and the load output had been wired backwards at some point, took me an embarrassing amount of head-scratching to find that one.

If the unit's showing any fault codes in the app history, post them here — Victron's documentation is actually decent and we can decode it pretty sharpish.

What @FormerCop said about VictronConnect history is spot on — I'd also check the firmware version straight away and update it if needed. Victron's been pretty good at pushing fixes through.

Running a SmartSolar on my shepherd's hut and had a dodgy secondhand unit years back — turned out the charge profile had been set up all wrong by the previous owner for a completely different battery chemistry. Took ages to figure out why my Fogstar lithiums weren't charging properly.

Make sure your mate sets the correct battery preset from scratch rather than assuming whoever had it before knew what they were doing. Fresh config takes 5 mins and saves a lot of head-scratching later.