We have built a basic DIY Solar Generator for temporary house power in our Weekender Van Life Ram ProMaster Conversion. Now we need a better way to charge it. As a simple way to disconnect our house power systems from the Conversion Van alternator, we have installed a Sure Power Battery Isolator.
Installing A Battery Isolator In Our Ram ProMaster Van Conversion
What is a Battery Isolator?
A Battery Isolator, also commonly referred to as a Smart Solenoid or Battery Separator, automatically separates the two batteries in a dual-battery system.
The Battery Isolator will monitor the voltage coming from our conversion van Start Battery and Alternator. When the engine is running and the system voltage is above 13.2v the Solenoid Relay will close sending power to the Auxiliary/House Battery allowing it to charge. When the engine is shut off and the system voltage drops to below 12.7v the Solenoid Relay will open, effectively disconnecting the two batteries.
Why You Need A Battery Isolator In Your Van Conversion Auxiliary Battery Setup
Unless you want to possibly destroy your start battery and increase your chances of being stranded, and unable to start your engine. Some type of Battery Isolator is a must-have when installing an Auxiliary/House battery in your Van Conversion. The Battery Isolator will allow you to draw down on your Deep Cycle house battery and leave your engine start battery ready for its intended use.
Our Experience With The Sure Power Battery Separator
We had a great experience with our Sure Power Battery Separator. It has actually been installed in two different vehicles working as intended for years. Installing a Battery Isolator in our ProMaster was a no-brainer.
Now Let’s Take A Closer Look At How We Installed A Battery Isolator In Our Weekender Van Life Ram ProMaster Van Conversion
Installing A Battery Isolator In A Van Conversion – How We Did It
Step-1 Collect All The Tools And Materials.
Keeping Costs Low!
There are two major parts required for this project.
We were lucky enough to have a Sure Power Battery Separator 1315 from a different Van we sold a little while back. This will keep our costs for this project lower, which is great!
Large gauge wire is expensive, here is a tip to get low-cost large gauge wire; Use Booster Cables. I picked up a set of 20-foot 6 gauge booster cables for $20.
Tools and Materials
- 16 Foot 6 Gauge Booster Cables
- Battery Isolator/Separator
- 6 Gauge Ring Terminals
- Heat Shrink
- Split Loom Flex
- ¼ 20×1/2” Machine Screws
- ¼ 20 Lock Nuts
- Rubber Splicing Tape
- Vinyl Insulation Tape
- 6 Gauge Anderson Connectors
- Crimp Tool
Step-2 Mounting The Battery Isolator Inside The Ram ProMaster Battery Box
The battery for our Ram ProMaster is located in a box below the driver’s legs. There is just enough extra space to fit our Sure Power Battery Separator inside this box! To do this, we fabricated a simple stand out of plywood.
Step-3 Wiring Up The Battery Isolator
Next, we pre-wired the battery Isolator priority to install using a small amount of 6 gauge wire and ring terminals. To prevent any possible short circuit we taped it up with Rubber Splicing Tape. Also as recommended by the installation manual we installed a 10A fuse for the solenoid coil ground / neutral.
Step-4 Tying Into The ProMaster Up Fitter Auxiliary Power Connection
Newer Ram ProMaster models (2016 and up) come standard with a 70 Amp Up Fitter Power Connection.
What is the Ram ProMaster Up Fitter Power Connector?
The Up Fitter Power Connector is a pre-installed power cable between the vehicle start battery and the base of the passenger side B-pillar. This allows contractors to run high-amperage accessories directly off the battery and alternator.
We have installed our Battery Isolator in series with this pre-installed circuit. This saves a significant amount of time as we did not have to fish wiring into the battery box.
Step-5 Plugging into The B-Pillar Connector
I could not easily find a supplier for the MTA P/N 4440400 required to connect to the Vehicle Power Harness, so I decided to use Anderson Connectors instead. Anderson Connectors are easily sourced through Amazon.
Step-5 Splicing a Split Into The 6 Gauge Auxiliary Battery Wiring
The auxiliary battery wiring will split in the middle of the van, one end will go to the auxiliary battery and the other will go to the house DC fuse panel. I had thought about using insulated blocks to split the cables but instead opted to just bolt the ring terminals together with ¼” machine screws. Once bolted together, I wrapped the splice with Rubber Splicing Tape, then covered it with a little extra split loom.
Step-5 Connecting To Our DIY Portable Solar Generator
To connect the auxiliary battery wiring to Our DIY Portable Solar Generator we added used Anderson Connectors. This connection is fused with a 40 amp Maxi fuse.
Van Conversion Battery Isolator – Plugged In And Working
Now that our auxiliary power station is plugged into the Vans alternator we can start to draw some decent loads. Prior to this project, our power station was being charged by an Optimate charger. This worked great to “maintain the battery, but it didn’t work to quickly get the battery back to full after being drawn down.
What’s Next
DC Fuse Panel.
All our power circuits will need to be fused. To start with we can use the USB and 12v sockets built into our power station, but for convenience, we plan on running a basic but comprehensive wiring system including power for USB and 12v sockets in 3 corners. Ceiling and cove lighting. Powered Ventilation. 12v for the Gasoline Parking Heater and power for the fridge.
Ceiling Lights
Before installing the ceiling, we ran wiring for our ceiling lights, now we are ready to install them. We designed the ceiling so to lose as little headroom as possible. We have found some super thin recessed puck lights that will work perfectly.
Wall Panels
Some wall panels will soon become a priority to make the van look more complete and comfortable. We will use the same material we used on our Campervan Ceiling.
Here Are Some Of The Van Electrical Systems We Have Installed So Far
Gasoline Parking Heater
Van Roof Vent Fan
Check Out Our Simple and Portable Solar System
Lastly, if you have any questions, post a comment below, we would be happy to help.
Thanks for reading, and remember to always take the road less traveled!
Thank you for all the great, helpful information. I am learning so much. I have found some additional information on the Up Fitter connections that may be helpful to some readers.
https://www.ramtrucks.com/BodyBuilder/service/Image?imageId=MtQrP%2FFqLY5r%2Fest8MtGjGgHzAHGUTU0WB3rWuqSY7YmQ2vEhuBWBPBUb3oRTb8F
Hi! I’ve been converting a 2019 Promaster and have found your site incredibly helpful—thank you!! Would you mind sharing in more detail how you used the Anderson connector to plug into the B-Pillar? We’re having a lot of trouble with this one!
Best,
Emma
Hi Emma,
I could see how this type of connector could be difficult if you are unfamiliar with it. They are actually quite simple. Just crimp the terminal onto the wire ends and push them into the correct connector plug socket.
I hope that helps,