Wolf Island Diver
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Historically, the term “dual battery” meant a second battery under the hood of the same type as the starting battery that can provide additional power for the winch, welders or anything else. The overlanding community has broadened the term. With DC to DC chargers you can now run N number of additional batteries, mounted where convenient and of any chemistry and size for the purpose of running fridges, ac, powering appliances, etc. This is what I’ve done here. I think the original meaning of “dual battery” kept this solution off my radar until recently. But I think this is a better solution than the portable units from Goal Zero, Jackery, et al. Personally I’ve never needed additional batteries for the winch as I’ve never needed to winch for prolonged periods of time with the truck off. Believe it or not you can now buy battery powered TIG welders! So I’d go that route if I really wanted a portable welder.
I’ve been using a Goal Zero Yeti 500x (500Wh) with good success, but it requires me to keep it plugged in when not in use, I’ve got to find a place for it in the truck and it’s bulky. It and it’s wires are always in the way. All nitpicks but combined with its limited capacity, I decided to upgraded to a built in system based around a 100AH self heating LiFePO battery. This is the equivalent of a 1200Wh Goal Zero for a lot less money. It’s also easily upgradeable by buying additional or larger batteries.
For this project I used a Renogy DCC50S DC to DC MPPT charger. There’s some debate about these, but so far I’m happy with it. They will do 50A charging. Those settings supposedly require the app to activate. Mine was already set up at max amps. The Bluetooth module works fine. It even works from inside the house about 30 feet away. I’ve not had it disconnect. Personally I like the way this hooks up better than the competing RedArc and it’s cheaper. I’m using a Renogy self-heating 100Ah battery, which is both much smaller and much lighter than a typical AGM. In total, with the 4th of July sale, the charger, battery box, battery and BT module came to $800, $200 more than a GZ Yeti 500x.
All of this is mounted to my bed molle panels. I used circuit breakers instead of fuses so I can easily isolate stuff. These are mounted to 50lb capacity plastic pegboard. Wiring runs behind the pegboard. The molle panel can be unbolted to remove the whole thing as 1 piece. The battery box is pretty cheap and bulky but it works. It’s bolted to the bed with sheet metal screws sealed with RTV. The strap just holds the top on and adds additional protection to keep the battery from flying out but it’s woven through the molle panel. Everything is solid. The battery box is about 120% the size of the battery so I may be able to fit a 200Ah battery later on.
Close up of the breakers. There’s a breaker for my outlets and one for the fridge port in addition to power from the starting battery, the solar port and an isolator between the Dcc50s and lithium house battery. I can easily disconnect Solar. I can easily isolate the battery itself and disconnect the system from the starting battery/alternator
I cut the bedliner from the plastic cap at the back of the bed. Three glands seal the 6AWG cable to the battery and to the ground which goes to the chassis above the spare tire. The third penetration is for a 2 conductor 10AWG cable that runs up under the Front Runner basket for a Anderson Powerport solar connector. I RTV sealed this cap back in place. The Renogy ignition detection wire runs through here as well with the hot cable.
close up of the Anderson port. I sealed this to mounting plate made from scrap HDPE. The dedicated outlet for the fridge is done the same way. These connectors are run in parallel as the Renogy solar charger is limited to 25V. My panels are all around 20V
The solar port is well sealed but it’s also well protected by the overhang of the Front Runner basket/tray. I used a ring to secure the front of the outlet assembly so that I’d have something to secure plugged in cables to. That cable plugged in is the mounted solar panel. More on that below. By mounting this outlet outside I can avoid having cables from my solar panels cluttering up the back of the truck and posing a trip hazard. Also I often put the panels on the roof when parked.
I left excess cable for the solar outlet so I can move is farther outboard if needed. That other cable is my WeBoost running to its mast at the back of the truck.
The port for the fridge goes on the drivers side. My 63qt ARB just fits so I don’t really need a slider. Now I don’t have to deal with wires all over the place and this is a locking ARB type outlet so I don’t have to worry about it getting knocked out of the Yeti.
I ran the same 10/2 AWG cable as the solar port over the center framing of the Diamondback, secured with 3M zip tie mounts. The Diamondback doors will still open with the wire in place.
Renogy makes a cheap ($120) flexible 100W Solar panel. I’ve temporarily zip tied it in place. I’m going to make some HDPE mounting plates for it. But the CONOPS are that I’ll leave this on the truck. When I’m carrying gear, I’ll just move the panel up on top of my gear and strap it down. It’s super light and flexible. The Renogy DCC50s will trickle charge the starting battery off of solar when the house battery is full. It does prioritize solar, but I can easily disconnect this via the circuit breaker, if I’m not getting enough amperage into the batteries when driving. But I suspect that this will be more than adequate to power things while underway. This is a much cheaper panel than the Cascadia Systems hood mount panel and 3 times the wattage. I’ve got 2 other folding 100W panels for at total of 300W at about 20V. Ideally the battery in a system like this should mostly be a buffer/storage for solar. Solar is really what’s important. At this wattage I’m getting pretty close to the threshold of running everything off of solar and only using battery power at night. The 200 watts of panel already changes the Yeti 500x from 20% to 100% in a few hours. This really reduces if not eliminates my fridge anxiety.
I don’t like the idea of USB and 12V power ports mounted inside the bed where they’re inconvenient. I mounted 2 65W PD USB-C, USB-A combo ports and 2 150/300W 12-24V power ports inside this box. Also, inside is a fuse distribution block that takes regular ATC/ATO fuses instead of those goofy glass tubes. This is attached to the panel with a 10 foot cable. I think this will be much more useful and I can secure it in various places with Velcro. It will reach into my tent when parked in camp sites like Ocracoke or Hatteras where the tent is close. It velcros to the battery box when not in use and is run through its own circuit breaker for safety and isolation. I limited this 10Ft due to the 10AWG wire assuming full draw
Sitting upright on the battery box. It also rides flat. That extinguisher has been mounted there for a while. It’s on a quick release. It’s not a reflection of my confidence in my wiring but rather a reflection of my tendency to use accelerants when starting camp fires
Velcroed to the underside of the Diamondback.
I don’t have a big inverter mounted yet. I currently have one or two devices that I take that require 120v, a Dewalt battery charger and a JBL Boombox3, but I have the truck’s bed inverter which is still accessible. I will probably add a 1000W sine-wave one at some point but it’s not a priority.
Building this was actually a major PITA. I went through a few designs. I had to figure out what parts I needed. I had to get the pegboard mounted with stand-offs. I had to cut out the panels to fit the space and the battery box with a dremel. Getting these pegboard panels right was a pain as holes didn’t line up. I used 3d printed metal molle panel plates on the backside but their holes were in weird places and ended up being more like big nuts than recessing nicely into the molle. I used Loctite or nylar nuts for everything. Almost all of the hardware is stainless and metric. I went through multiple iterations of the battery box. It nests in the pegboard up against the molle panel to be more secure but without bolting it down, it was impossible to get it secured without wobbling. I really didn’t want to drill into the bed but I wasn’t happy with how secure the box was. I mounted most everything to the panel removed from the truck but had to compete the wiring while lying in the bed. You have to be good with working in a hot confined space for hours. I used to work on nuclear submarines and this felt a lot like that, working blindly behind panels on my back, in a tight space I had to crawl into, working by flashlight in the heat. You could certainly do this in a more simple way but I didn’t want to use wood or shove it all in a box. I wanted to have quick access to the circuit breakers and I had to figure out where the battery was going to go. There’s also lots of airspace around everything. There’s also room for placing a cover over the whole thing. I’m thinking about a combination positive pressure and air exchange system for the bed anyway but honestly with the ARB the Yeti and it’s 120W charger, even in hot weather it surprisingly doesn’t get that hot in the bed. We’ll see how temps go with this additional equipment. Side to side there’s still plenty of room for my fridge and a kitchen slide out I’m going to build next. The battery extends very little past the wheel arch.
I’ve been using a Goal Zero Yeti 500x (500Wh) with good success, but it requires me to keep it plugged in when not in use, I’ve got to find a place for it in the truck and it’s bulky. It and it’s wires are always in the way. All nitpicks but combined with its limited capacity, I decided to upgraded to a built in system based around a 100AH self heating LiFePO battery. This is the equivalent of a 1200Wh Goal Zero for a lot less money. It’s also easily upgradeable by buying additional or larger batteries.
For this project I used a Renogy DCC50S DC to DC MPPT charger. There’s some debate about these, but so far I’m happy with it. They will do 50A charging. Those settings supposedly require the app to activate. Mine was already set up at max amps. The Bluetooth module works fine. It even works from inside the house about 30 feet away. I’ve not had it disconnect. Personally I like the way this hooks up better than the competing RedArc and it’s cheaper. I’m using a Renogy self-heating 100Ah battery, which is both much smaller and much lighter than a typical AGM. In total, with the 4th of July sale, the charger, battery box, battery and BT module came to $800, $200 more than a GZ Yeti 500x.
All of this is mounted to my bed molle panels. I used circuit breakers instead of fuses so I can easily isolate stuff. These are mounted to 50lb capacity plastic pegboard. Wiring runs behind the pegboard. The molle panel can be unbolted to remove the whole thing as 1 piece. The battery box is pretty cheap and bulky but it works. It’s bolted to the bed with sheet metal screws sealed with RTV. The strap just holds the top on and adds additional protection to keep the battery from flying out but it’s woven through the molle panel. Everything is solid. The battery box is about 120% the size of the battery so I may be able to fit a 200Ah battery later on.
Close up of the breakers. There’s a breaker for my outlets and one for the fridge port in addition to power from the starting battery, the solar port and an isolator between the Dcc50s and lithium house battery. I can easily disconnect Solar. I can easily isolate the battery itself and disconnect the system from the starting battery/alternator
I cut the bedliner from the plastic cap at the back of the bed. Three glands seal the 6AWG cable to the battery and to the ground which goes to the chassis above the spare tire. The third penetration is for a 2 conductor 10AWG cable that runs up under the Front Runner basket for a Anderson Powerport solar connector. I RTV sealed this cap back in place. The Renogy ignition detection wire runs through here as well with the hot cable.
close up of the Anderson port. I sealed this to mounting plate made from scrap HDPE. The dedicated outlet for the fridge is done the same way. These connectors are run in parallel as the Renogy solar charger is limited to 25V. My panels are all around 20V
The solar port is well sealed but it’s also well protected by the overhang of the Front Runner basket/tray. I used a ring to secure the front of the outlet assembly so that I’d have something to secure plugged in cables to. That cable plugged in is the mounted solar panel. More on that below. By mounting this outlet outside I can avoid having cables from my solar panels cluttering up the back of the truck and posing a trip hazard. Also I often put the panels on the roof when parked.
I left excess cable for the solar outlet so I can move is farther outboard if needed. That other cable is my WeBoost running to its mast at the back of the truck.
The port for the fridge goes on the drivers side. My 63qt ARB just fits so I don’t really need a slider. Now I don’t have to deal with wires all over the place and this is a locking ARB type outlet so I don’t have to worry about it getting knocked out of the Yeti.
I ran the same 10/2 AWG cable as the solar port over the center framing of the Diamondback, secured with 3M zip tie mounts. The Diamondback doors will still open with the wire in place.
Renogy makes a cheap ($120) flexible 100W Solar panel. I’ve temporarily zip tied it in place. I’m going to make some HDPE mounting plates for it. But the CONOPS are that I’ll leave this on the truck. When I’m carrying gear, I’ll just move the panel up on top of my gear and strap it down. It’s super light and flexible. The Renogy DCC50s will trickle charge the starting battery off of solar when the house battery is full. It does prioritize solar, but I can easily disconnect this via the circuit breaker, if I’m not getting enough amperage into the batteries when driving. But I suspect that this will be more than adequate to power things while underway. This is a much cheaper panel than the Cascadia Systems hood mount panel and 3 times the wattage. I’ve got 2 other folding 100W panels for at total of 300W at about 20V. Ideally the battery in a system like this should mostly be a buffer/storage for solar. Solar is really what’s important. At this wattage I’m getting pretty close to the threshold of running everything off of solar and only using battery power at night. The 200 watts of panel already changes the Yeti 500x from 20% to 100% in a few hours. This really reduces if not eliminates my fridge anxiety.
I don’t like the idea of USB and 12V power ports mounted inside the bed where they’re inconvenient. I mounted 2 65W PD USB-C, USB-A combo ports and 2 150/300W 12-24V power ports inside this box. Also, inside is a fuse distribution block that takes regular ATC/ATO fuses instead of those goofy glass tubes. This is attached to the panel with a 10 foot cable. I think this will be much more useful and I can secure it in various places with Velcro. It will reach into my tent when parked in camp sites like Ocracoke or Hatteras where the tent is close. It velcros to the battery box when not in use and is run through its own circuit breaker for safety and isolation. I limited this 10Ft due to the 10AWG wire assuming full draw
Sitting upright on the battery box. It also rides flat. That extinguisher has been mounted there for a while. It’s on a quick release. It’s not a reflection of my confidence in my wiring but rather a reflection of my tendency to use accelerants when starting camp fires
Velcroed to the underside of the Diamondback.
I don’t have a big inverter mounted yet. I currently have one or two devices that I take that require 120v, a Dewalt battery charger and a JBL Boombox3, but I have the truck’s bed inverter which is still accessible. I will probably add a 1000W sine-wave one at some point but it’s not a priority.
Building this was actually a major PITA. I went through a few designs. I had to figure out what parts I needed. I had to get the pegboard mounted with stand-offs. I had to cut out the panels to fit the space and the battery box with a dremel. Getting these pegboard panels right was a pain as holes didn’t line up. I used 3d printed metal molle panel plates on the backside but their holes were in weird places and ended up being more like big nuts than recessing nicely into the molle. I used Loctite or nylar nuts for everything. Almost all of the hardware is stainless and metric. I went through multiple iterations of the battery box. It nests in the pegboard up against the molle panel to be more secure but without bolting it down, it was impossible to get it secured without wobbling. I really didn’t want to drill into the bed but I wasn’t happy with how secure the box was. I mounted most everything to the panel removed from the truck but had to compete the wiring while lying in the bed. You have to be good with working in a hot confined space for hours. I used to work on nuclear submarines and this felt a lot like that, working blindly behind panels on my back, in a tight space I had to crawl into, working by flashlight in the heat. You could certainly do this in a more simple way but I didn’t want to use wood or shove it all in a box. I wanted to have quick access to the circuit breakers and I had to figure out where the battery was going to go. There’s also lots of airspace around everything. There’s also room for placing a cover over the whole thing. I’m thinking about a combination positive pressure and air exchange system for the bed anyway but honestly with the ARB the Yeti and it’s 120W charger, even in hot weather it surprisingly doesn’t get that hot in the bed. We’ll see how temps go with this additional equipment. Side to side there’s still plenty of room for my fridge and a kitchen slide out I’m going to build next. The battery extends very little past the wheel arch.
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) and mounted rod holders on it which I just leave on the truck. There’s a WaterPort mounted to the right side under the awning along with an OVS shower awning. I’ve enclosed the space between the Diamondback and Front Runner which I use for additional gear like NATO jerry cans, the awning walls, etc. I’ve added both yellow and white LEDs to each awning arm controlled with a rheostat
