This page is in chronological order starting with the OLDEST entry….
The house is to be completely separate from the vehicle.
TFD is to be all electric. (ie no propane or diesel heaters etc) Power comes from shore power or a small generator (Honda 2000eu). It should also be able to be off the grid without noise for 8-10 hours. It then needs to be relatively quickly recharged by driving, plugging in to shore power or running the generator. No messing with propane bottles, no vented storage space, no chimneys and fumes and no CO or gas detectors. There is a second pick up on the fuel tank which will be used to feed the Honda so I don’t have to schlepp gas tanks around.
The design revolves around a LARGE battery bank, AH 1000+, which through an inverter powers heat, hot water (maybe), refrigeration, cooking on a small IR cook plate, air conditioning and utility outlets. Some lighting and the roof fan will be 12 volt, however that part will also be completely separate from the chassis, i.e. double wiring and no common ground.
The battery bank will be recharged by an AC charger. It will be powered either from the outside, be it shore power or the generator, or from the inverter powered by the engine. To this end I ordered TFD with the optional 250A alternator and dual battery to buffer the load.
I intend to keep it simple, robust and budget minded.
Well the build has (finally) gotten to the point where electrical is in play and real decisions have to be made. I’ve done some test camping with the Honda and a cord into a door. It works, but it needs to be more “installed”. Sooo, the first order of business is getting electricity into the van. I thought about electrical connectors, but in keeping with trying to minimize the number of holes in the van I went with a single port in the floor and installed a marine style deck filler plate. Added some pipe to it to get through my rather thick floor. It allows a cord to pass AND it allows a fuel hose to go through. So for now I can have a fuel tank inside for the Honda. When I run the line off the main tank I want to bring it inside and only outside when I run the Honda as I don’t want the connector to be out there in the dirt when driving. Simple, works.
Next is the AC side. But first, time to finish the cargo space. Insulation, paneling. A shelf for stuff. And then a “tray” for the batteries, charger and inverter. All on one piece, removable. Batteries secured to it, and the tray bolted to the floor. Hopefully it will stay put in a light to moderate crash. But, it can all come out in large pieces without cutting any wires. The bulkhead behind the seat will be the “instrument” panel, also removable with everything on it. Lastly, some panels to close the electronics bay off from the cargo space.
A couple of rattle cans of black paint and viola. Not going to win any show points, but it’s functional and I think it looks good!
Soooo, on to actual wires. As it always does the system design came together at the end. Here’s the schematic:
Shore/Generator to power the battery charger and a GFI outlet inside. I have two power strips to plug in for the forest of chargers…. Without shore/generator the inverter is fed from house bank to power fridge/heat/AC for a variety of hours. (Obviously the fridge will run overnight, the heat only for a few hours when taking a lunch break and you don’t want to get the generator out.)
When driving the inverter can be powered from the chassis bank from the three CCP’s, and then in turn power the house battery charger (85A max). This is why I have three way switching in the positive AND negative DC supply to the inverter. The house DC system does NOT use the chassis as ground. No it’s not the most efficient, but when your’e driving it doesn’t matter.
And yes, I’ve read the arguments for transfer switches and B2B chargers…… Yes, I have to remember to switch things, and HOW to switch things. For instance i have to switch BOTH the pos and neg when switching banks. Also, when the inverter is powered by the house bank I have to make sure the charger is OFF or you get that energy loop going. Lastly, when I shut down the engine I need to turn the chassis supply to the inverter off or I will drain my chassis battery while charging my house battery…. Then again I CAN combine the two banks for engine start…..
It works with a minimum amount of boxes and other than using the CCP’s, which is completely allowable by FORD, I have NOT messed with the vehicle electrics in ANY way.
Over time I will upgrade the battery bank, I plan to get to about 1000Ah. (Would LOVE to get my hands on a few Li-Ion’s but they’re slightly outside of the budget). With that I will have achieved my goal of 8 or so hours of quiet energy in most weather conditions. Before or after I will drive or run the generator to put the energy back in. This will work for the way I use it.
And here’s the layout for the switch panel. It’s in the bulkhead behind the rear seat, and not visible with the seat up, although you can peek down in there and see the AC ammeter to keep an eye on you load…..
And after drilling some holes here it is….. (Showing plugged in to shore power running the space heater at half power.)
And the “business” side of it. The outlet is for the charger. Items not showing on the front side are the box on the far left to connect the incoming wires (shore and inverter) to the system.
And, another productive day. Started with installing the batteries in a tub onto the “electric slide” along with the charger, inverter and the shunt for the condition monitor. Made all the connections and bench tested it in the shop, to satisfaction. Ran a 1200W heat gun off the inverter and then tested the charger. The batteries are what I had laying around. Out of RV’s come and gone a long time ago, and out of the Porsche belonging to the neighbor across the street. He insisted on changing his battery although there was nothing wrong with it, so I took it off his hands. I’ve had these batteries on a trickle charger for over two years, and have load tested them fairly regularly followed by a charge. They are functional. Now sure how close they are to their new rating. Technically they should be 330Ah…. I’m using 300 as a round number. The real test will be to see how the voltage holds up when the condition monitor says they are 50%. Short term testing is not looking too bad. (see below). I cut down a plastic tub to put them in, and there’s a ratchet strap across the top anchored to two through bolted U-bolts. As mentioned before the electric slide is lag bolted to the floor. So, all in all a reasonable effort to secure it all.
Of course I wasn’t going to lift this, so took out the batteries, put the slide in the van and put the batteries back in the tub. Made all the connections I could make, pushed it back in to place and made all the connections to the switch board. Minimal time crunched up under the bed, and it can ALL come out in big chunks in an hour or so!
Now…. on to testing! Brought the house bank on line and fired up the condition monitor. I LOVE this thing. All you have to tell it is the Ah of the bank and it does the rest. Then I disconnected shore power, and brought power to the inverter, and turned it on. Messed with the CM for a little and turned on the space heater at half power…..
The usual 7-ish A AC. Condition monitor showed about 80A discharge. (Yeah, that’s a lot.) In the picture it’s showing SOC (state of charge) Ran it this way for about a half hour which took the SOC down to 78%. A little less than the math would suggest, but there’s losses in this process, mostly in the inverter itself. So if you pull over and make a sandwich and a cup of coffee and run the heat….. you’re good for about an hour. Then I plugged back in and turned on the charger. It started pumping at about 75Ah…. (It’s advertised at 85Ah max, so that’s not bad). This ran the AC ammeter up to 12A, which indicates losses of about 500W or 4A AC….. this is the inefficiency of the charger…. Pretty soon it all settled down to 66Ah DC going in at 9A AC….. (still only about 80% efficient, but not too bad).
Unfortunately turning on the heater at this point is not a good idea as it would well exceed the 15A max of the system, so I had to wait until the charger settled down some more at which point I turned on the heater to 1/2 power.
Now drawing 13.7A for heater and charger and putting 42Ah into the bank. Of course nothing else was on…. including the fridge. I may add a 20Ah sealed charger to charge while other things are going on……
Made a small bus in the cabinet to collect 3 CCP wires and send them to the inverter on a 4G cable. Installed a small ammeter to keep an eye on things. And installed a small low amp bus with a master switch to power said gauge and the fan. There’s still room in the compartment. I suspect there may be a woofer living there soon!
So, with it all hooked up I brought the chassis bank on line and powered up the inverter. Worked fine until I put a load on it..(space heater at 1/2 power)… Inverter shut down yelling and screaming. Tried a few more times same result. Generally this means a voltage below minimum. Scratched my head over this one a few times and then tried it again with the engine running. Worked fine! There either is too much voltage drop with the engine off, or the “brain” actually shuts down the CCP’s when you put a load on them without the engine running, as this could leave you stranded if you do it too long. Do it know? I have to research that further. But, bottom line is that it, specifically the house bank charger, works when I’m driving and that’s all I was after. Ammeter showing load on the CCP’s while charging the house bank:
Making dinner and coffee in a rest area! Life is good.
This pretty much concludes the electrical system. Over time I hope to upgrade the house bank but that’s about it……
Well, I wasn’t happy with the modified sine inverter so I swapped it out with a pure sine. Things are just happier that way.
Also, I mounted a winch on the rear hitch. On a carrier platform, with straight runs to the house bank. No, it does not run through the condition monitor. Wasn’t sure the shunt would like that. After using the winch I’ll just have to run/charge to full and start over. Won’t happen that often.