From charging prices to a wallbox in your building. Ask your AI assistant.
ohmigo connects ChatGPT, Claude and Grok to the prices at every public charger in Portugal published on the National Access Point (NAP), and to a trusted guide to electric mobility, with the law cited.
Pick a topic
I'm in Coimbra with 15% battery. Where's the cheapest place to charge to 80%?
ohmigo
I give your assistant the total cost and time at each charger, for every way to pay, and whether it's free right now.
Source:NAP, MOBI.E's tariff file and CEME pricesThe right price, at every charger, for every way to pay.
Say where you are, what you drive and how much battery you have. Your assistant asks ohmigo and answers with the total cost and time.
- Every way to pay: your CEME card, a bank card at the charger, and the operators' own apps. The same charger can cost very different amounts.
- Free or busy, from the NAP's official data, which can be 5 minutes old or more.
- Nearby or on the way: the cheapest option near you, or along a trip, say from Lisbon to Porto.
- Nothing tied to you: no accounts, no sign-up, no tracking. ohmigo doesn't know who you are.
💡 Tip: tell your assistant once what car you drive and which charging card (CEME) you use. It remembers, and the math fits you.
Illustrative example. The names and prices above are made up.
Did you know…? 💡
An LFP battery can, and as a rule should, charge to 100% regularly. With NMC, keep 100% for when you need the full range, like before a trip.
Says UVEWhen you pay by bank card, the charger can hold far more than you'll spend, and that money can stay unavailable for several days.
Says UVEThe “60 days” and “two thirds” for condominiums were 2010 rules. Today the building has 30 days to object to your wallbox, and only in the cases the law lists.
Decree-Law 93/2025, art. 23What your assistant gets to know.
Written in Portuguese, with today's law, for people who drive, people about to buy and people who run a fleet. Your assistant answers in your language.
Charging at home
Socket or wallbox, who installs it, which papers to ask for, solar panels, V2H.
In your building
What the condominium can refuse, the deadlines, who pays, the sub-CPE.
Electrical installation
Dedicated circuit, RCD, cable, and which board to wire the charger from.
Grants and tax
Fundo Ambiental, IUC, ISV, VAT and municipal parking, always with dates.
Battery and range
How far to charge, the cold, LFP or NMC, how to check a used car.
Public charging and trips
How to pay, queues, broken chargers, and charging elsewhere in Europe.
Companies and fleets
VAT, autonomous taxation, and paying for charging at the driver's home.
The law, explained
AFIR, Decree-Law 93/2025, the NAP, network access tariffs, and what changed since 2010.
No “I heard that”. Every answer says where it comes from.
What ohmigo knows comes from Voltaria, an open set of guides on electric mobility in Portugal, reviewed before every change.
The law, cited by article. Diário da República, EUR-Lex and the official bodies: DGEG, ERSE, MOBI.E.
Who says what. A tip from UVE or from DGEG's FAQ is marked as such. A recommendation isn't law, and never shows up as if it were.
Grants with dates. Each grant comes with its source, start, end and the day it was checked. A grant that has closed never shows up as open.
Let's do it! It's just a few clicks.
All you need is to copy one web address and paste it in the right place. It serves both the prices and the guide. Pick your assistant and follow the steps.
⏱️ About 2 minuteshttps://ohmigo.ocarroeletrico.com/mcp
This is ohmigo's address. You'll need it at the “paste” step. Opening it in your browser does nothing, and that's fine: it's for your assistant, not for you.
On claude.ai or the Claude desktop app. On work accounts, your admin may need to add it.
- Click your name (bottom left), then Settings.
- Open Connectors and click Add custom connector.
- For the name, type ohmigo. For the URL, paste the address you copied above.
- Click Add. That's it: no account, no password.
- In a new chat, click the + or the tools icon and check that ohmigo is turned on.
Do this in a browser (ChatGPT at chatgpt.com), on a computer or your phone's browser — not the ChatGPT app, which doesn't let you add connectors yet. Menu names change now and then; if something looks different, look for “Plugins” or “Connectors”.
- In the left sidebar, click Plugins.
- In the top-right corner, click Add and choose Custom (custom MCP server).
- Name: ohmigo. URL: paste the address. Under Authentication, switch to No authentication.
- Tick the box saying you trust the server.
- Click Create as a plugin. In a new chat, check that ohmigo is turned on.
On grok.com. Works on the free account. Menu names change now and then; if something looks different, look for “Connectors”.
- Open grok.com/connectors (or Connectors in settings).
- Click New Connector and choose Custom.
- Name: ohmigo. URL: paste the address. No authentication.
- Save. In a new chat, check that ohmigo is on.
The phone apps don't let you add new connectors yet. But there's an easy trick:
- Add ohmigo once on a computer, following the Claude, ChatGPT or Grok steps.
- Open the app on your phone with the same account. ohmigo shows up there by itself.
- No computer around? Open the website (claude.ai, chatgpt.com or grok.com) in your phone's browser and follow the same steps.
For people using other AI tools. Any app that accepts an MCP server over HTTP works, no authentication.
- Claude Code, in the terminal:
claude mcp add --transport http ohmigo https://ohmigo.ocarroeletrico.com/mcp
- Cursor, Windsurf and friends, in the MCP config file:
{ "mcpServers": { "ohmigo": { "url": "https://ohmigo.ocarroeletrico.com/mcp" } } } - In other apps, look for “MCP”, “Connectors” or “Tools” in the settings and paste the address.
Didn't work? No harm done! Go back to step 1 and try again. There's nothing you can break. 💚
FAQ
How much does it cost?
ohmigo is free. You just need a ChatGPT, Claude or Grok account. Grok lets you add ohmigo on the free account; ChatGPT only on some paid plans.
Does ohmigo learn anything about me?
Only what each question carries. There are no accounts, it keeps nothing linked to you and doesn't know who you are. Your assistant remembers your car and cards and sends them with each question. ohmigo only uses them to do the math.
Are the prices exact?
They're good estimates, not a bill. ohmigo combines your CEME's energy price, the charger operator's fees and taxes, and works out how long and how much energy the session takes. Every answer says what it assumed, so you know where the number comes from.
Where does what ohmigo says about laws and grants come from?
From Voltaria, an open set of guides written from the legislation and the official pages (DGEG, ERSE, MOBI.E, Fundo Ambiental, the Tax Authority). When a tip comes from an association, such as UVE, the answer says it's theirs.
Can I apply for a grant based only on what my assistant says?
Use it to learn what exists and whether it applies to you. Before you apply, check the official page: every grant comes with its link and the date it was checked. ohmigo explains the law, but it doesn't give legal advice.
What's a CEME?
It's the company that sells you the energy when you charge on the public network, usually through a card or app (EDP, Galp, Via Verde, Miio and many more). Don't know yours? No problem: your assistant will ask, or show you the options.
Does it work at every charger?
At every public charger in Portugal published on the National Access Point (NAP), on every network: MOBI.E chargers, where you pay with your CEME card, and those outside it (like Tesla or Continente), where you pay the operator directly. When an operator doesn't publish a full price, the estimate is marked with an asterisk.
So what's an “MCP”?
It's a connection that gives your assistant information it doesn't have, like what charging costs right now at that charger, or what Portuguese law says today. Think of it as installing an app on your phone, except the app is for your assistant: you add it once, with one web address, and from then on it uses it by itself whenever you talk about your EV.
I opened the address in my browser and nothing shows up…
That's normal! The address is for your assistant, not for people. Paste it into ChatGPT's, Claude's or Grok's settings, as explained above.
Ready to charge for less, with no doubts?
Two minutes now, plenty of euros and searches saved later.
Install ohmigo ⚡