Coast Resorts Open Roads Forum: Our custom true flatbed truck camper build thread

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Topic: Our custom true flatbed truck camper build thread

Posted By: sabconsulting on 02/10/14 01:51pm

I think the spring action of the tie-down will be very important:

[image]

This picture was shared by Chris Scott in a thread in his Horizons Unlimited overland travel forum relating to the building of camper bodies on flatbed trucks. I don't think you will be facing this extent of chassis twist, but you are right to consider it and allow for some twist in your tiedown design now rather than end up with structural damage to your newly built camper.

FYI this looks like a British Army Bedford MK someone is converting. I've driven these offroad and they are designed to flex.

Steve.

'07 Ford Ranger XLT Supercab diesel + '91 Shadow Cruiser - Sky Cruiser 1
'98 Jeep TJ 4.0
'15 Ford Fiesta ST
'09 Fiat Panda 1.2

Posted By: bka0721 on 02/11/14 11:08am

sabconsulting wrote:

I think the spring action of the tie-down will be very important:

>

This picture was shared by Chris Scott in a thread in his Horizons Unlimited overland travel forum relating to the building of camper bodies on flatbed trucks. I don't think you will be facing this extent of chassis twist, but you are right to consider it and allow for some twist in your tiedown design now rather than end up with structural damage to your newly built camper.

FYI this looks like a British Army Bedford MK someone is converting. I've driven these offroad and they are designed to flex.

Steve.

This is the exact reason I went with a service body, over a flat bed. While I am a big fan of Flat bed, without needed modifications, like a headache rack and other boxing, you will have twisting, the longer you go. With a service body, all the compartments provide protection to minimize twisting. For this reason, my TC is attached to the Service Body, not the Frame. The TC and Service Body works as one unit. While I am a fan of Flat Beds, one must plan for this issue, the longer the bed becomes and the OP looks like he is doing this well.

b

Posted By: Desertboy on 02/11/14 02:17pm

Interesting, Glad I followed this thread so I can head this problem off on mine. But I don't think my camper is long enough to have to worry about it a whole lot. Ill just use spring loaded Tie downs.

1969 AVION
3/4 12 VALVE

Freightliner/24' Flatbed 50,000 miles/ Titan 4000 receiver Hitch, no Mods needed.

Posted By: countrycampers3 on 02/11/14 09:42pm

2008 Ford F-350 Dually Flatbed

2013 NorthStar Arrow 8.5 with side storage compartments.

Posted By: Jfet on 02/15/14 07:10am

This weekend we are finishing up the water system, so I will have some pics of that soon. I had no idea water could require so many trips to Home Depot. Sharkbite took a bite out of my wallet! Fun stuff though...like Legos for water.

I am doing a 180 on refrigeration, even though we already have a brand new Norcold 6.3 3-way ready to install. The fridge is one of the first things we bought when starting this build and at that time I didn't really know what I was doing.

We are going to go with a Nova Kool RFU9000 9.1cuft 12V compressor fridge. There are some benefits to this:

1) 9.1 cuft is 44% more volume than the 6.3 cuft Norcold and fits in the exact same space.

2) No worries about flame, ammonia leaks, or driving with the propane running.

3) Fridge vents to the front so I can seal up the two giant holes I have in the side of the camper (probably will just leave the screen installed but seal it with aluminum behind the screen).

On the solar, we are thinking of going with four 265 watt monocrystaline panels made by solarworld. Each of these panels is 37.5 x 66 inches. In full sun they would provide 1000+ watts. The fridge will probably need around 800 to 1000 watt-hr per 24 hours. Assuming 6 hours of full sun, we would have a surplus of 5000+ watt-hr for other needs. In cloudy weather we could expect about 500 to 1500 watt-hr per day.

I need to figure out what MPPT controller I need and what wire size would be acceptable. A series parallel configuration would be about 60V at 18 amps. I^2R losses in a 25 foot run (50 feet of copper) would be 6.5 watts total for 6AWG cable. In a 30V 36 amp configuration, I^2R losses in the same cable would be 26 watts. I have not looked into what maximum voltage a MPPT controller can take.

These are the panels I am considering, although I do not know yet how they mount or how they handle vibration and wind loads:

http://www.solar-electric.com/solarworld........e-sw265-monocrystalline-solar-panel.html

This is what the four panels would look like on the top of the camper (still a bit of room for other stuff):

[image]

Posted By: bka0721 on 02/15/14 10:30pm

1060w will be a big plus to have, but what type of battery bank are you planning for. I have followed your thread, from the beginning but can't remember if you have talked about your battery bank. I am a big believer of having excess Solar, to allow for those weaker days of hazy days, especially winter, smoke from Forest Fires (interesting in how that impacts Solar production), cloudy days and cold weather, that will greatly reduce your S.O.C., to keep a battery bank fully charged. What does concern me is when large Solar Panels are used for non residential use. Will you be tilting these panels? It does not appear so, in the way you have the panels configured. If so, you will be opening up issues of panel deflection and support, due to wind load. If not, there are still the same factors of traveling down the road, with wind load and deflection. After a few Wind Storms and watching how much my 27X60 Panels concave from wind load, I can only wonder what a panel the size of yours, will deflect. Also, snow load can be an issue as well as accessibility of cleaning these panels. It appears your only access will be a ladder, leaned up to the side of the camper. Which will necessitate your need for one.

b

Posted By: Jfet on 02/16/14 06:38am

Bka, you bring up some great points.

We made room for two group 31 batteries on the inside of the camper and planned to have more batteries under the flatbed (both for space reasons and to try and keep the CG of the whole system low. Talking with some guys on a solar forum, it seems you do not want to tie in a whole bunch of batteries in parallel. They actually recommend going with a higher voltage system and batteries as low as 2V per cell (but these are 2V 900ah batteries) to have all the batteries in series.

I can't do the 2V per cell thing and still have a separate battery system in the camper. When the camper is not on the truck I still want it powered. Even in a 12V system I don't have room for 6 batteries inside the camper.

If I go with a 24V system, I can have two group 31 AGM 100ah batteries inside the camper connected in series. Under the camper I could have four 6V golf cart size 220ah batteries connected in series. Instead of connecting the different types of batteries as one bank (and the resulting problems with voltage drops and unequal draw because of long interconnects between the banks), I am thinking I could install a bank switch, either manual or automatic that lets me pull 24V from either bank when the other is low. The charging would be more complicated, but I am pretty sure I could work it out nicely.

A 24V system would mean I would get the 4000 watt 24V input Magnum inverter which is actually similar price to the 3000 watt 12V version but is more efficient. The Nova Kool fridge can also run on 12V or 24V. 24V charging from the MPPT controller on the solar system would mean half the amperage and a lower cost charger. Wiring I^2R losses would be 1/4 that of a 12V system.

To generate 12V for things that must have 12V (furnace fan, water heater, some accessories) I would use a 24V to 12V DC-DC converter capable of at least 20 or 30 amps. I think this would be a lot better than trying to tap off of a single battery.

You bring up a good point about the size of the panel. Perhaps it would be smart to go with a smaller frame and maybe a few more panels instead of trying to get the cheapest price per watt in the large frame residential panels. I am flying a bit blind there as far as knowing wind loads and stresses.

Posted By: Jfet on 02/16/14 08:04am

Thinking a little bit more on the solar panels, I have the idea of mounting them off-center and a different orientation so they could be tilted 0 to 45 degrees. This would obviously mean I need to build a more complicated and beefier roof mounting rack but it might get me a lot more solar power in the northern climate where the sun stays low all day.

If I mount them off-center on the roof, it establishes a bit of a path around the panels where one might be able to crawl to check/work on things. I do plan on carrying a ladder.

I could design an air dam into the frame, especially on the leading edge to protect some against wind loads when the panels are in the zero degree position while driving. I don't know if that would help the flex. Still could go with smaller panels...

[image]

Posted By: sabconsulting on 02/16/14 08:22am

Alternatively you could have two separate rows with a gangway down the middle. This would be safer as you wouldn't be walking along the edge of the roof but down the middle. Although if you raised them high enough then one row would start to shadow the other, I guess that by the time the sun got that low it probably wouldn't be generating much power anyway (early morning / late evening), so might not be too much of a problem.

It would also mean you aren't raising such a high sail-like structure as a single row of panels illustrated above. It would of course mean more construction as you'd need double the number of hinges / latches.

Steve.

Posted By: travelnutz on 02/16/14 08:49am

I have no idea why not to tie a line of 12V deep cycle batteries together in a parallel series? I have had 5-7 of the group 31 12V wet cell batteries paralleled together in our 5th wheels since 1993 to run the 2000 to 2500 inverters I installed in the 2 5th wheels. 2 more batteries are in the back of the pickup tied to gether always. ALL batteries in my systems are the same size!

My last 2 trucks have had dual alternators with #2 gauge fine strand welder cables in their split plastic wire protector cable tied to the upper inside of the truck's frame. 1+ and 1- going back to the bed batteries with an 80 amp slow blow marine fuse on each end of the cable and an 80 amp slide switch under the hood to disable the cables.

Battery life of all has been 5-7 years before I replace them and they still weren't going bad but I don't want to be in some remote place and have a battery failure. I use the old batteries in our boats etc and a couple are over 10 years old now an still going strong. Not taking a chance of either can't get a replacement or have to pay about double for who knows how old the new battery/batteries actually are when boondocking in the wilderness. Murphy's law!

In the 5th wheel, one battery on each side in the OEM battery compartments and 3-5 in the front storage area in a covered mounted box vented out thru the floor with either 3/4" ID or 1" ID PVC white water plumbing glued together. Installed a 500 amp marine barrel switch under the overhang with the #2 gauge from the batteries to disable them. Then there's 2 of the same cables coming out of the back of the pin box that go to the junction block's 3/8" brass wingnutted studs just behind the bed batteries that also connect the alternators and the bed batteries. When driving even a short distance or running the diesel engine and short time all 7-9 batteries are quickly recharged and at full charge long before we get to where we are going. 1575 - 1785 minutes at 23 amp draw max! Never have drawn them down to even 50% yet. Also charges the 2 truck's batteries from the alternators of course.

For our TC's, 2 in the bed and one in the TC paralleled together for the 1500 watt inverter inside. 675 minutes at 23 amp draw max!

My various systems have worked perfect and the batteries last so long. Of course, I don't use sealed batteries or gel batteries because I keep the water level well above the plates on all batteries. I also recondition all the batteries once a year individually with my 2 higher grade battery chargers. One is a 25 amp and one is a 40 amp auto with digital readouts. Takes 24 hours each for reconditioning which cleans all the plates in the batteries and brings them back to 100%. In all those years, only 2 batteries have ever failed (shorted) after their term in the RV's. Still got $10 each exchange for them when buying new ones and back in 1993 they only cost me less than $60 new.

Why would it be any different for solar as you could never over-charge a large bank with solar trickle type charging and there's an auto cutoff anyway when fully charged on the systems we looked at? To me, solar is a very expensive way to go and their service life is not long enough. Be sure to check that out as it may be in fine print or not even stated! 2 of our camping friends found out the hard way and don't use solar anymore!

Just have to think outside the box and use what long proven not be swayed by gimicks or expensive rube goldbergs that may or may not do what you want!

A superb CC LB 4X4, GM HD Diesel, airbags, Rancho's, lots more
Lance Legend TC 11' 4", loaded including 3400 PP generator and my deluxe 2' X 7' rear porch
29 ft Carriage Carri-lite 5'er - a specially built gem
A like new '07 Sunline Solaris 26' TT

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