Comments on: Engine On Signal Via Ford Transit Vehicle Interface Connector

By: Robin Hoad

Robin Hoad — Sat, 29 Aug 2020 21:18:21 +0000

We have found that there is not enough current between ignition line and engine-on signal to close the relay 🙁 Any one else had this and solved it?

By: Felix Brecht

Felix Brecht — Tue, 19 May 2020 06:54:04 +0000

Hi Matt,
thank you! As i dont have a free AUX switch I am building one into the side of the driver seat directly. Others put the + of the starter battery on pin 30 and the active ground on pin 86. If i understand correctly your switch turns the relais on/off. Can I achieve the same buy stopping one input signal (e.g. the active ground), i.e. can I also put the switch in between the active ground and the relais?

By: Matt

Matt — Fri, 15 May 2020 16:49:09 +0000

In reply to Felix Brecht. Sometimes I don't want to charge the batteries while the engine is on, the upfitter switch allows me to be in control of that. The main reason is that the inverter/charger sits right behind the driver's seat and has a loud fan, the switch allows me to turn it off.

By: Felix Brecht

Felix Brecht — Wed, 13 May 2020 21:15:40 +0000

This is great stuff! I have a 2018 Transit and just need to search for this interface. I am debating if I really need to put it to a switch? Why did you choose to do so? Doesnt the relay automatically ensure that the vehicle battery doesnt run out of power? When does a switch come in handy for you?

By: Craig

Craig — Tue, 27 Aug 2019 00:03:58 +0000

What gauge wire did you use for the Engine Run output (from Pin 87 to the destination)? I bought the relays you linked (thanks!), which have 16 AWG pigtails. I was thinking of using 16 AWG for the balance of the wiring. In my case, I’m running the signal to a Renogy 20A DC-to-DC charger located about 6 feet away (12-ft. circuit).

By: Ian

Ian — Tue, 02 Jul 2019 07:10:30 +0000

Thanks for this writeup! Thanks to it, I managed to hook up a SPST relay to our Transit’s rear 12V aux port and have it switch on only when the engine is running. Normally, the 12V aux ports are on the 30 minute timer circuit that keeps them on, even after the engine has been shut down. That’s great for small low current accessories if you want them to keep running for a bit while parked, but we were worried about draining our Transit’s starter battery since on this rear aux plug, we have a 12V DC charger supplying 120W to our Goal Zero 1400 lithium battery. That sounds like one way to drain a starter battery.

With the relay switching off when the engine shuts off, we can now leave the 120W Goal Zero charger plugged in, since it will only draw power while the engine is running. Perfect!

By: Matt

Matt — Sun, 02 Jun 2019 00:42:45 +0000

In reply to Ben. I would use a relay to keep the 2 systems isolated.

By: Ben

Ben — Sat, 01 Jun 2019 22:15:19 +0000

In reply to Matt.

the switch they show there is for the start assist (in case car battery is dead). But I know I can have a switch on the negative wire of the Cyrix, Victron confirmed that.
Question is : is it wise to connect the ground wire of the Cyrix to Pin 3 of the C33-E so the “loop” can only be closed when engine is running.

By: Matt

Matt — Sat, 01 Jun 2019 15:53:06 +0000

In reply to Ben.

I would take a look at the data sheets, https://www.victronenergy.com/battery-isolators-and-combiners/cyrix-battery-combiners. They show examples with switches.

By: Ben

Ben — Fri, 31 May 2019 22:32:50 +0000

First of all, thanks a lot for all the info you give here and on the ford transit forum !
I’m in the process of installing a battery combiner, a Victron Cyrix, and like you I’d like the batteries only to be combined when the engine is running AND when a switch allows it to.
The Cyrix is a very simple unit : you plug the + from both batteries to the Cyrix, then plug a ground so the internal electronics can do their magic.
My plan was to put the switch on the ground wire (low amps). Originally I was planning on using a relay, powered by a “engine-running-only 12V” to close the ground wire but do I really need that ? Do you think I could directly plug my ground wire from the Cyrix to PIN 3 of the C33-E ? (with a switch halfway so I can turn it off even with engine running if I want to). Then if I understand correctly my Cyrix would only be grounded when engine’s running.
Thanks !
Ben