We are officially on Lithium battery power and it feels great! We are seeing longer battery life and much more consistent operation. If you want to know more about Lithium batteries and why we made the switch, check out Part 1 of our battery upgrade. But for those of you who have been asking about the details of our setup: read on!
The installation was relatively easy for us since we already had an auxiliary battery installed, but we wanted to take this opportunity to rethink our setup a little bit and make it even more robust than it had been. We were moving away from our two Lead-Acid deep cycle batteries (120AH combined) to a single 100 AH LiFePO4 battery.
Since the RELiON RB100 battery (LiFePO4) is about the size of one of the two batteries we were removing, we ended up with extra space as a result of the upgrade. The RB100 is a bit too large to fit in the stock auxiliary battery location in the westfalia (under the driver’s seat) so we opted to install it under the sink cabinet and used the space under the driver’s seat to house a new electronics panel for the battery system. Our main concern was finding a space that could house the battery and keep it stable and safe. Unlike lead acid batteries, Lithium batteries do not need to be vented so it can really be put anywhere that is convenient and safe. The under-sink cabinet is a perfect spot since there is plenty of space, both to store the battery and to keep the terminals clear of any metal. We made a few lightweight aluminum brackets to anchor the RB100 in place under the sink, so it won’t move even over the roughest roads.
Setting up the battery is straight forward. The RELiON battery has a built-in controller which protects it from over or under discharging, so it can basically be hooked up directly in place of our old batteries. In our case, the battery gets charged from two different sources: our solar panel via a charge controller, and from the van’s alternator via a smart relay connected to the van’s main battery.
The solar panel will provide the primary charge to the battery and will keep it topped up during sunny days. The controller is set to use the charge profile for an AGM battery which is the charge profile recommended for LiFePO4 batteries. We connected the charge controller to the battery through our auxiliary fuse box to give it a protected connection.
The connection to the van battery was one place where we wanted to make a change from what we had before. In our old system we just used a solenoid switch triggered by the ignition to interconnect the two batteries when the engine was running. This time around we wanted to upgrade and use a smart relay make the connection. The Victron relay we used is a microprocessor-controlled relay that senses the voltage either side of it and opens to make a connection when either side reaches charging voltage. So if the engine is running and the alternator is supplying 14+ Volts to the van battery, it will allow that to charge our auxiliary battery as well; or if the solar is sending charging voltage to the aux battery, it will open to keep the van battery topped up. We also included a breaker to protect the auxiliary system from power spikes from the alternator.
The other major change we made to the system was to replace our voltage meter with a shunt and battery meter. The reason for this change has to do with the way LiFePO4 batteries deliver power differently than a lead acid battery: lead cells loose voltage as they discharge meaning they have a voltage of about 13V at full charge, and then decrease to about 10.5V at full discharge. The volt meter will read out the voltage of the battery system which can be equated to it’s capacity. At about 50% or 12V you need to stop discharging or risk damaging the battery.
In contrast, LiFePO4 batteries deliver a constant voltage across almost their entire range. The RELiON battery we have delivers 12.8V all the time. So, the volt meter won’t tell us much about the battery’s capacity and because the RELiON battery can be basically fully discharged and has it’s own built in protection from over-discharge there is no need to monitor the voltage anyway. The Victron shunt and meter is connected to the negative terminal of the battery and tracks all the power in and out of the battery in real time. This allows the meter to tell the capacity of the battery as a percentage of the total.
The Victron battery gauge is a standard 3” dial gauge size but we needed to find a place to mount it that was visible from the back seat of the van. The Westfalia was equipped with a shore power connection for connecting to 120V power at campgrounds. There’s a small breaker in a standard wall outlet frame associated with the 120V system. Since we have never connected to shore power since owning the vanagon, we decided to move the breaker to behind the cabinets. We grabbed a blank wall outlet plate from home depot, cut a 3” hole, painted it brown, and voila! The perfect spot for our battery meter! We now have a readout of our usable capacity. The meter we used will even connect to a smartphone by Bluetooth so you can track your usage if you’re into that sort of thing (we are!)
The LiFEPO4 battery now powers our fridge, lights, stereo, chargers, and inverter all through an auxiliary fuse box behind the driver’s seat!
A few stats on the upgraded system:
Lead-Acid System (old) LiFEPO4 System (new)
Total battery power: 120AH Total battery power: 100AH
Total useable power: 60AH Total useable power: 100AH
Batteries: 2 Batteries: 1
Weight: 75.5 lb (1.25 lb/useable AH) Weight: 32 lb (0.32 lb/useable AH! )
Over-discharge protection: No Over-discharge protection: Yes
Leave us a comment below if you have any questions about the system!