Ram and ProMaster are trademarks of their owner. Amp Hour Supply isn’t affiliated with Ram or Stellantis.
Short answer: If your ProMaster has the factory Auxiliary Power Connector, that’s your charger feed. On 2016 and newer vans it’s fused at 70 A, and Stellantis says the fuse can’t be upsized. A 30 A DC-DC charger with a 60 A input fuse fits under it. If your van doesn’t have the connector, you can’t add it later.
The ProMaster’s numbers
| What | Ram / Stellantis figure | Source |
|---|---|---|
| Alternator | 180 A standard, 220 A available (2018) | 2018 ProMaster brochure |
| Battery | “800-amp, maintenance-free” (2018) | 2018 ProMaster brochure |
| Auxiliary Power Connector (BC1) | Factory order only, base of the passenger-side B pillar | Body builder instruction, 2021 |
| Connector fuse, 2014-2015 | 50 A, max continuous 53 A, 10 mm² wire | Body builder instruction, 2021 |
| Connector fuse, 2016 and newer | 70 A, max continuous 75 A, 16 mm² wire | Body builder instruction, 2021 |
| Fuse upgrade | Not allowed; “the vehicle wiring will not support it” | Body builder instruction, 2021 |
| Upfitter Interface, Aux 1 / Aux 2 | 20 A each (F86 battery-fed, F87 ignition-fed), 2016 and newer | Body builder instruction, 2021 |
| Aux Run Relay Control | 300 mA max, goes to ground when the engine runs | Body builder instruction, 2021 |
Can a ProMaster charge a lithium battery from the alternator?
Yes, through a DC-DC charger, and the factory connector’s limits make the case for one. A lithium bank wired straight to that 70 A circuit has nothing limiting its current, and Victron’s manual warns that direct charging can overload the alternator because lithium has such low impedance. The Victron Orion-Tr Smart 12/12-30 isolated DC-DC holds its output to 30 A, and Victron calls for a 60 A fuse on its input. That stays under the connector’s 70 A fuse on 2016 and newer vans.
The 2014-2015 connector is a different story. Its fuse is 50 A, below the charger’s 60 A input fuse, so check with Stellantis’ instruction and the Orion manual before you use it, or find another factory feed.
Skip the Upfitter Interface’s Aux 1 and Aux 2 outputs for the charger. They’re 20 A each. Good for lights or a fan, too small for a 60 A charger input.
What the Upfitter Interface does give you is a clean engine-running signal. Pin 2, Aux Run Relay Control, pulls to ground when the engine runs, and it can handle up to 300 mA. That’s enough to drive a small relay, and the relay can switch the Orion’s remote input. Victron recommends an engine-running signal for alternators whose voltage doesn’t track the engine, so it’s worth doing.
For the full combiner vs DC-DC comparison: Charging lithium from a boat alternator: 3 ways compared. Written for boats, same charger logic.
You’ll need
- A ProMaster with the factory Auxiliary Power Connector (BC1), ideally 2016 or newer
- A Victron Orion-Tr Smart 12/12-30 isolated DC-DC
- A 60 A fuse for the charger input (Victron’s figure)
- A small automotive relay for the engine-running signal (optional, recommended)
- A Victron SmartShunt 500A
- A Victron SmartSolar MPPT 100/30 if you’re putting panels on the roof
Steps
- Find the connector. Pull the panel at the base of the passenger-side B pillar. No connector means no BC1, and Stellantis says it can’t be added after the fact.
- Check your year. 2016 and newer: 70 A fuse. 2014-2015: 50 A, which is below the charger’s input fuse, so stop and rethink the feed.
- Leave the factory fuse alone. It sits on the bus bar on top of the battery under the driver floor. Don’t swap it for a bigger one.
- Run the connector’s 12 V supply and ground to the charger input, with the 60 A fuse inline.
- Wire the output to the house bank, fused at the battery.
- Add the engine-running relay from Upfitter Interface pin 2 to the charger’s remote input.
- Set the lithium profile in VictronConnect, add the shunt, then drive and watch the numbers.
Shore power and inverter-to-outlet wiring belong with a licensed electrician.
Does this page fit your van?
It fits a full-size Ram ProMaster with the factory Auxiliary Power Connector. The connector and interface details cover 2014 and newer (70 A from 2016). The alternator and battery figures are from the 2018 brochure only.
It doesn’t fit the ProMaster City, the electric ProMaster, or a van without BC1. For other years’ alternator size, check your own build sheet or owner’s manual.
Products for this setup
| Product | Why it’s here |
|---|---|
| Victron Orion-Tr Smart 12/12-30 isolated DC-DC | 30 A output keeps its 60 A input fuse under the connector’s 70 A fuse. |
| Victron SmartShunt 500A | Shows what’s actually charging the house bank. |
| Victron SmartSolar MPPT 100/30 | Roof solar, up to 100 V of panels. |
| Victron Smart BatteryProtect 100A | Cuts house loads at low voltage. |
Prices show live from the store.
Bundles for this job: Dual-battery DC-DC charging kit, Van solar starter kit
Quick answers
Can I add the ProMaster Auxiliary Power Connector later? No. Stellantis says it’s factory order only and can’t be added by a dealer or the aftermarket.
Can I put a bigger fuse on the ProMaster aux connector? No. Stellantis says the vehicle wiring won’t support it.
What alternator does a ProMaster have? The 2018 brochure lists 180 A standard with a 220 A option. Check your build sheet for other years.
Sources
- Ram, 2018 Ram ProMaster Catalog eBrochure: https://www.ramtrucks.com/content/dam/fca-brands/na/ramtrucks/en_us/brochure/download-brochure/US%20-%2018MY%20Ram%20ProMaster%20Catalog_eBrochure.pdf
- Stellantis N.A. Body Builder Instruction, “ProMaster Auxiliary Power Connector,” 03/30/2021 (ramtrucks.com/BodyBuilder, ProMaster section)
- Stellantis N.A. Body Builder Instruction, “ProMaster Upfitter Interface Connector,” 04/12/2021 (ramtrucks.com/BodyBuilder, ProMaster section)
- 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
