No boxes, no cables: how SOHpro pulls a score from a photo of your scanner

No boxes, no cables: how SOHpro pulls a score from a photo of your scanner

If you start digging into how to verify a battery's health, you'll run into a pattern: nearly every serious solution in the world mails you hardware. A box that plugs into the car's OBD port — one you have to order, wait for, plug in, and sometimes ship back. It works, but it puts up a barrier: you need the gadget, and the shop needs one for every work bay.

SOHpro took a different road, and understanding why says a lot about how it's built for Latin America.

The key idea: the data already exists

Here's the observation that changes everything. When a technician diagnoses an EV, their scan tool —the one they already own— spits out a report: battery capacity, cell voltages, temperatures, fault codes. That data already gets generated. Getting it was never the problem; the problem was that it stayed trapped on a screen or in a PDF nobody ever looked at again.

So why mail a new box if the diagnostic is already sitting right there? SOHpro doesn't capture the data — it reads it. You —or your shop— upload whatever the tool already produced, in whatever format: a photo of the scanner screen, a PDF of the report, a CSV from a diagnostic app. SOHpro handles the rest.

The bottleneck was never measuring the battery —shop tools already measure it well—; it was turning that raw diagnostic into something readable, comparable, and able to travel with the car. That doesn't need a new box: it needs intelligence.

How a photo gets read (and turned into data)

The heart of this process is what we call SOHpro AI. When you upload an image or a PDF, the AI doesn't just "see" the screen: it understands it. It figures out which number is battery capacity, which are the individual cell voltages, where the temperatures are, and —this is subtler than it sounds— it tells a real fault code apart from a plain status flag. (In diagnostic-speak, "high-voltage connector locked: OK" is a normal state, not a fault; confusing the two sets off false alarms.)

Every tool shows things its own way —millivolts or volts, different names for the same reading—; SOHpro AI levels it all out, clean, in seconds.

And it works with what your shop already uses: Launch X-431, Autel, Topdon, Foxwell, SmartSafe, Car Scanner, OVMS, VCDS and more —as a photo, PDF, or CSV (CSVs are read directly, no photo in between). The goal is always the same: take what you already have and make it structured.

From clean data to a score (and why it doesn't take everything on faith)

Once the data is structured, the calculation engine takes over —the same one we described in Anatomy of a score. It cross-references the six signals (capacity, cell-to-cell voltage spread, degradation rate, efficiency, voltage consistency, and temperature uniformity), weights them, puts them in the context of that specific model's climate and chemistry, and produces the SOHpro Score from 0 to 100.

And crucially, it doesn't just take the raw reading and parrot it back. A set of sanity checks validates that the numbers make physical sense: that the cell count is coherent, that temperatures fall within the real possible range (a battery doesn't run at -50 °C or 150 °C), that cell voltages sit at plausible values for that chemistry, that no signals contradict one another. It even detects when the pack was measured right after driving or charging —with no rest— and, instead of inventing a result, waits for a clean reading. If something doesn't add up, it flags it and lowers the confidence of the result. It's the difference between blindly trusting whatever the screen says and actually analyzing it —especially important with chemistries like LFP, whose flat voltage curve makes it easy to misread the state of charge if you don't know what you're looking at (that nuance lives in charging to 100%, yes or no?).

Chemistry changes the rules

The same number can mean different things depending on the battery's chemistry, and SOHpro takes that into account. First it identifies the chemistry —from the model catalog or, if it doesn't know, from the average cell voltage (around 3.2 V smells like LFP; near 3.65 V, like NMC); if there's no way to tell, it assumes NMC, the most common one—. And from there it adjusts how it reads everything else.

The clearest case is LFP. Between 20% and 80% charge, its voltage barely moves —the famous flat curve—, so in that range cell imbalance can't be spotted "by eye": what looks like a weak cell may just be sensor noise. SOHpro knows this, and instead of misreading that stretch it looks at the "knees" (very low or very high charge) and the history, where the signal actually shows up.

And the yardstick changes too. An LFP usually survives more cycles than an NMC, so a wear rate that would be perfectly normal in an NMC would be high in an LFP. Measuring both with the same yardstick is like taking the temperature of two different species with one thermometer: the number lies. That's why the reference bands are per chemistry, not one for all.

Why this approach fits the region

The no-hardware road isn't just an elegant technical choice; it's strategic for Latin America:

• No equipment logistics. Nothing to ship, wait for, install, or return. A shop in any city can start today with the tool it already has.
• Scales without friction. There's no "one box per bay" ceiling. If the shop can generate a diagnostic, it can generate a passport.
• Works with what's already out there. In a region full of diverse brands, tools, and formats, reading "any diagnostic" is worth more than demanding one specific gadget.
• The cost isn't passed to the user as hardware. What matters is the analysis and the record, not selling boxes.

How to scan well: notes for the shop

The score is only as good as the scan that feeds it. A couple of habits make all the difference between a clean reading and one full of warnings:

• Let the car rest. Park it at least an hour before scanning (two is better). After driving or charging, the cells stay "agitated" and add 50 to 200 mV of noise that muddies the voltage reading. (LFPs between 20% and 80% can skip this step: the curve is flat there anyway.)
• Use the mode that gives the most detail. Any of the scanners above will do, but the "EV / New Energy" level following the manufacturer's BMS path unlocks far more than basic mode: lifetime counters (Ah/kWh), charge histories, isolation resistance, the pack's identity. More fields = a richer passport and a score with more confidence.
• Put the car in READY, not "ignition on without starting." Only in READY are the high-voltage contactors closed and the BMS exposing the good data; the other way, almost nothing useful comes out.
• Aim for mid-charge (40–70%) on NMC/NCA packs: that's where the voltage reading is sharpest.
• Check the 12V auxiliary battery (healthy, ≥ 12.4 V at rest). A weak 12V cuts the scan short, leaves cells unread, and trips false fault codes.
• Don't start a charge mid-scan, and wait a few seconds before unplugging the cable —the BMS needs to close the session.

None of these are mandatory: SOHpro builds the passport anyway and tells you what was missing. But the cleaner the scan, the more reliable the result.

The result: a passport, not a stray photo

This whole process —upload, read, structure, validate, calculate— ends in something that lasts. The score doesn't drift off: it gets saved to your electric's passport, tied to the VIN, adding onto the earlier scans and waiting for the ones to come. Every visit builds more history —which is exactly why it pays to start from the very first scan. And that history travels with the car when it changes hands.

What we deliver isn't a pretty number: it's continuity. So that today's diagnostic talks to the one from two years ago and the one from three years out. Pulling a score from a photo is the flashy part; turning those photos into a single coherent story of the car is what really matters.

Next time you hear that checking a battery requires a box in the mail, you'll know there's another way. The diagnostic already exists. All it took was someone who knew how to read it, make it trustworthy, and keep it forever. That's what SOHpro does — no boxes, no cables.

Does your shop already scan batteries? Upload that diagnostic and turn it into a passport. See how it looks in the SOHpro simulator or get started at SOHpro.