March 4, 2014 • 0

The SyncroBo Build: Part 3 – Interior & Electrical

Interior Design/ Layout
Since our van started as a tintop, we didn’t have any of the camper items. We researched a lot of different options. We looked at buying a Westfalia interior, but the more we researched the more we didn’t like that option. For our use, a lot of the Westy design choices didn’t line up with our subsystem (water, power, heat) choices. So that set us up for a search for a custom interior that could fit our choices and configuration. We found a European vendor that was willing to ship to the US and configure the unit for our use. They shipped the unit flat packed, but the ordering process took forever and shipping constantly got delayed. We are happy with the final product and quality but the process took 6+ mos. given we are filmmakers we need as much storage as possible. So where possible we have moved tanks, appliances, etc. out of the cabinets and place themed in “dead” space in the van. Inside the cabinets we had custom boxes made that fit the interior dimensions of the cabinets. For border crossings you often have to empty the van. By having custom boxes in each area of the cabinet you can just pull them out and quickly empty the cabinets of the van. In addition, it just makes life easier to get items in the cabinets and keep them from rolling all over off road.

For the actual interior panels, we ordered a set from Sewfine. We chose to go with a black interior, as it would be easy to match several different vendors and I personally like black. Working with Sewfine was a pleasure, since they do every order individually you can ask for custom stuff and it doesn’t really cost you any extra. We went with mainly black with a gray horizontal stripe and inset in the seat to tie it all together.

To round out the interior we went with a bamboo floor with a proper vapor barrier and reused the factory cork underpayment as ours was in perfect condition and it prevents the floor from being hard on the knees. In the front we went with carpet to help with sound, and then rubber mats on top of the carpet to help with cleaning. We then wrapped the ceiling headliner in a black brushed metal look material, and had the interior exposed metal covered in a matching black vinyl with a insulating backing to bring the interior together visually. At first we were concerned about going with such dark colors and heat, but with the tint this hasn’t been an issue and it always looks clean!

Flat packed interior

Interior Boxes 000033 by RandallBrownIII, on Flickr

Main Cabinet (minus rear cabinet)

2012-07-28-0066 by RandallBrownIII, on Flickr

All together

IMG_0590 by RandallBrownIII, on Flickr

Electrical/ Power
Since we are filmmakers, electricity is our livelihood. Without it, we can’t charge the cameras, edit footage, upload, etc. the design approach we took for this was redundancy and weight focused. Here were our goals
– Multiple ways to charge batteries both starting and house batteries
– Batteries can’t take up any cabinet space
– Have to be able to self-recover from a dead starting battery
– Stationary boon docked power supply of ten days of no driving

I’ll spare you the long journey to why each component but be assured we tested a bunch of different options as well as spoke with most of the manufacturers and other users.

First up are batteries. We wanted at least 300ah of useable power in the van to meet our requirements. If you try and get that from standard AGMs then prudence says you plan for 50% discharge to prolong battery life, so then we are hunting for 600ah of battery power. While you can get 3 225 amp hr Trojan batteries and achieve that, we get hit with where to put them and the associated weight. It simply wasn’t going to work. So we moved to looking at Lithium batteries. They promised a lot less weight and the ability to use 90%+ of the capacity without much life impact and the big feature is that short cycle charging doesn’t hurt them (charging them only part way to full). This is a big one because traditional battery chemistries want to be charged to 100% every time and then when discharged they want to be charged right up. This is fine if we defined a generator as part of our design but we didn’t. We found an awesome vendor through the technonomads.com for lithium battery bulk cells. The company typically deals with people in the EV market but will sell to anyone. We purchased two 200amp hr. batteries and the accompanying battery monitoring system. This is important to note that the batteries should have a battery monitoring system (BMS) attached to track cell voltages, provide under and over current protection and fault detection. Lithium batteries are robust but can be fatally killed by being over discharged. Lead acid batteries are more tolerating. The battery monitoring system drives a series of external relays so if the BMS detects an issue it can disconnect the battery from the system on it’s own. These two batteries would serve as the main house batteries giving us 360ah of useable power. The BMS system has a video out port that shows the capacity remaining, and a host of different information on each battery. In addition to the main house battery we wanted to have an emergency battery that would basically sit off line charged and ready for action when needed. This would be our emergency back up battery in the event the house was drained and we still needed to self-jump the starting battery or some other unforeseen circumstance. We decided to go lithium for this one as well so all of the house batteries have the same charging profile. For this we went with a different vendor. This battery looks like a standard battery and has the BMS features built in, but lacks some of the advanced features of the other batteries’ bms. But for an emergency battery it’s perfect, small and dead simple to install. With the batteries selected we needed to find a home For them. We long decided that a heater was going under the rear seat, so we decided the emergency back-up battery would live there with the heater as it could fit. For the main house batteries we made a steel battery box, painted it, and installed it as a center console between the front seats. This was the perfect size for the width of the batteries. We created a door on the top and rear of the console so you can open it to service the batteries. The shelf separating the batteries is removable as well. While our batteries use a lithium chemistry that is not prone to catching fire when shorted or punctured, it was still comforting to make the console of steel. This location also put the house batteries close to the starting battery, which is convenient for alternator charging, self recovery, etc. and allowed us to use smaller gauge of wire than if the batteries were in the rear of the van. Having decided this was our “power substation” we made another box out of wood, and put our inverter in that. This vertical stack allowed the cables to be pretty simple. We carpeted is all to make it a useable arm rest and use it to put drinks, food, and other items on top while driving.

Lithium battery

IMG_0281 by RandallBrownIII, on Flickr

Battery box/ Center Console

IMG_0270 by RandallBrownIII, on Flickr

IMG_0321 by RandallBrownIII, on Flickr

Battery Box in Place and carpeted

IMG_0392 by RandallBrownIII, on Flickr

Inverter
For our inverter we chose a Magnum Energy MMS1012, which is a 1000watt pure sine wave inverter and charger and it’s fully programmable to fit the charging profile of our lithium batteries. We looked at others but when we actually called manufactures with detailed questions it was only Magnum Energy and Mastervolt who got back to us in a timely manner and seemed really interested in their products and our needs. Also the user reviews and feedback is very strong. It has performed flawlessly for us and actually delivers better performance than it’s rating. We cut the connection ports into the side of the van and one of them is our AC in.

IMG_0572 by RandallBrownIII, on Flickr

Solar
We knew from the beginning that solar was going to be a big part of our electrical system. We basically wanted to go as big as possible. We decided on a 255-watt monocrystalline panel, tied to a Morningstar MPPT, and remote meter so we can see what the panel is producing. We purchased an uprated controller for some network and logging features as I am a huge dork and wanted to see what we produced over time. The panel is not removable; it is mounted directly to the fiberglass top with z brackets. We were worried about these being robust enough mounting points but they have held perfectly find on all of the places we have come. In addition to the top mounted panel we also wanted the option to put some panels outside in a better position if we parked in the shade. Though with the awning, we find that parking to face the sun when the top is parked puts the van to have the narrowest footprint in the sun during the evening hours when we are hanging out side. But I digress. We decided to install a second charge controller and wire a “solar port” as one of the connections on the side of the van. This would be an easy plug where we could plug in the second set of foldable / moveable panels and out them out in the sun to augment our charging. We investigated a ton of proprietary plug and ports, but we settled on the ubiquitous 12v plug, as it was cheap and common and was easily wired for the purpose. We purchased 120 watts of foldable mono crystalline solar panels that pack up flat and small. We worked with the guys at CTSolar.com on our set up. The system performs great. In sunny summer conditions we produce more energy than we ever need. A good sunny day the roof panel puts back 90 -115+ ah back into the batteries. We don’t have the same logging capability on the second controller but we have seen the rated output of the panels. If we are somewhere sunny we can boondock indefinitely from an electricity perspective.

IMG_0733 by RandallBrownIII, on Flickr

Alternator Charging
To charge both the house and the emergency battery we used Blue Sea Systems range of Automatic Charging Relays. We initially had their simple model, but what we found out is that because of the higher resting voltage of the lithium batteries (~14.4 when full) the relays stays connected even when turned off. So then the starting battery was pulling on the lithium batteries. So we swapped that model out for a model that allowed manual switch control so we could manually disconnect the batteries. We looked at the more sophisticated alternator battery chargers from Sterling power and they look awesome but we decided for our system to stick with this set up. Since the lithiums don’t mind being short cycled it doesn’t matter for us to go multistage charging off the alternator.

Wiring/ Switches/ Breakers
We have taken a lot of inspiration from the boat world, and for our wiring we went with all marine grade products. We found a decently priced supplier of marine wire and layed-out the wiring schematic. We measured runs and used voltage drop calculators and ampacity tables to come up with the right wire gauges. This was by far the most surprising cost line item for the build. I really didn’t think about the costs of high quality wire. We decided we wanted a fuse free van as we could be in places where fuses could be hard to come by. All disconnects for the batteries and relays are marine breakers, for the main loads we built a custom panel with Blue Sea Systems that had circuits for every appliance and load in the DC system. We also used their VSM system to monitor a bunch of information, more on that in the remotes and monitor system. The panel comes pre wired to your specifications and makes install a lot easier. You feed one major power and then connect the circuits to their breaker. It includes a negative bus bar and everything you need to install it. Not cheap but nice for a clean install that’s reliable.

Breaker Panel

2012-07-28-0047 by RandallBrownIII, on Flickr