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Short answer: A gas V6 Transit comes with a 250 A alternator, and Ford offers a second one. That’s plenty for a 30 A DC-DC charger. The bigger question is where you connect. Ford sells an Auxiliary Fuse Panel and an upfit module for exactly this kind of add-on, so check your van’s option codes before you pick a wire.
The Transit’s numbers
| What | Ford’s figure | Source |
|---|---|---|
| Alternator, standard | 250 A (3.5L PFDi V6 and 3.5L EcoBoost V6) | 2025 tech specs; 2026 order guide |
| Alternator, optional (41E) | Two, 250 A each, comes with the Auxiliary Fuse Panel | 2025 tech specs; 2026 order guide |
| Battery, standard | One 70 Ah, 610 CCA (AGM on 2026) | 2025 tech specs; 2026 order guide |
| Battery, optional (63E) | Two AGM, 70 Ah each | 2025 tech specs; 2026 order guide |
| Auxiliary Fuse Panel (87E) | Includes dual AGM (63E) and Modified Vehicle Wiring System (53K) | 2026 order guide |
| Upfitter Package (67C) | Includes the Auxiliary Fuse Panel; not on E-Transit | 2026 order guide |
| Vehicle Integration System 2.0 (55A) | Ford recommends it for any aftermarket upfit | 2026 order guide |
Does a Ford Transit need a DC-DC charger for lithium?
Yes. Two reasons.
The first is the battery. Ford’s 2026 order guide lists AGM batteries, and AGM wants a different charge than lithium. A DC-DC charger gives the house bank its own lithium profile, set to your battery maker’s voltages, while the van keeps charging its AGM battery the way Ford set it up.
The second is current. A lithium bank will pull as hard as the wiring lets it. The Victron Orion-Tr Smart 12/12-30 isolated DC-DC caps it at 30 A, and against a 250 A alternator that’s a small, steady load.
One thing to watch: newer vans often run alternators whose voltage doesn’t simply follow the engine. Victron’s answer is to wire an engine-running signal to the charger’s remote input instead of relying on voltage alone. Ford’s VIS 2.0 module and the upfitter options are the factory places to look for a signal like that. We couldn’t reach Ford’s Body Builder Layout Book for the exact pin, so use your van’s own upfit documents.
More on combiners vs DC-DC chargers: Charging lithium from a boat alternator: 3 ways compared. It’s written for boats, but the charger side is the same in a van.
You’ll need
- Your van’s option codes (window sticker or build sheet). Look for 87E, 67C, 41E, 63E and 55A.
- A Victron Orion-Tr Smart 12/12-30 isolated DC-DC
- A 60 A fuse for the charger input (Victron’s figure)
- A Victron SmartShunt 500A
- A Victron SmartSolar MPPT 100/30 if roof panels are in the plan
- Ford’s Transit Body Builder Layout Book for your model year
Steps
- Read your option codes. A van with 87E or 67C has Ford’s Auxiliary Fuse Panel. A van without it needs a different feed point, and the Layout Book is where Ford shows the options.
- Find Ford’s rating for the circuit you’ll use. The charger input needs a 60 A fuse. Make sure the feed is rated for at least that before you connect.
- Mount the charger near the house bank, somewhere dry with air around it.
- Run the input feed from the point you picked, fused at the source end.
- Wire the output to the house bank, fused at the battery.
- Add an engine-running signal to the charger’s remote input if your van’s alternator voltage moves around.
- Set the lithium profile in VictronConnect.
- Add the shunt and solar, then take a drive and watch real charge current in the app.
Shore power, an inverter on 120 V outlets, or anything on the AC side: hire a licensed electrician.
Does this page fit your van?
It fits a 2025 or 2026 Transit with the 3.5L PFDi V6 or 3.5L EcoBoost V6, the years Ford’s spec sheet and order guide cover.
It doesn’t fit the E-Transit (Ford’s Upfitter Package isn’t offered on it, and the specs above are for the gas V6), diesel Transits, or older model years we didn’t check. On those, go by your own owner’s manual and Ford’s upfit documents for your year.
Products for this setup
| Product | Why it’s here |
|---|---|
| Victron Orion-Tr Smart 12/12-30 isolated DC-DC | Lithium profile for the house bank; 30 A cap; remote input for an engine-running signal. |
| Victron SmartShunt 500A | Shows charge in from the alternator and solar. |
| Victron SmartSolar MPPT 100/30 | Roof solar, up to 100 V of panels and 30 A of charge. |
| Victron Smart BatteryProtect 100A | Low-voltage cutoff for house loads. |
Prices show live from the store.
Bundles for this job: Dual-battery DC-DC charging kit, Van solar starter kit
Quick answers
What size alternator does a Ford Transit have? Ford lists 250 A as standard on the 3.5L gas V6 engines, with an optional second alternator, also 250 A.
What is Ford option 87E? The Auxiliary Fuse Panel with High Spec Interface Connector. Ford bundles it with dual AGM batteries and the Modified Vehicle Wiring System, and includes it in the dual-alternator option and the Upfitter Package.
Can I add lithium to a Transit without the Auxiliary Fuse Panel? Often yes, but the feed point changes. Check Ford’s Layout Book for your year for an approved connection point and its rating.
Sources
- Ford, 2025 Ford Transit Technical Specifications: https://www.fromtheroad.ford.com/content/dam/fordmediasite/us/en/library/2025/specs/2025%20Ford%20Transit%20Technical%20Specifications.pdf
- Ford, 2026 Transit order guide (Major Product Changes and Features Availability): https://www.fromtheroad.ford.com/content/dam/fordmediasite/us/en/library/2026/order-guides/2026_Ford_Transit_Order_Guide.pdf
- Victron Orion-Tr Smart DC-DC Charger Isolated manual (Rev 14, 02/2026): https://www.victronenergy.com/upload/documents/Orion-Tr_Smart_DC-DC_Charger_-_Isolated/34439-Orion-Tr_Smart_DC-DC_Charger-pdf-en.pdf
- Victron SmartSolar MPPT 100/30 & 100/50 datasheet: https://www.victronenergy.com/upload/documents/Datasheet-SmartSolar-charge-controller-MPPT-100-30-&-100-50-EN.pdf
