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: BoonHauler on 02/17/14 02:29pm

Cool, I do recall some conversation of that now that I think about it. 1" is better than the 3/4" I'll have.

I'll be interested in hearing about the space heater as I believe it's the same I'll be using.

05 RAM 3500 CTD 4x4 Q/C Laramie DRW/NV5600/3.73, B&W Gooseneck, MaxBrake, PacBrake PRXB, Brite Box Fogster, BD steering Box Brace
2014 BoonHauler 3614

Posted By: BoonHauler on 03/02/14 03:02pm

Posted By: BoonHauler on 03/30/14 02:08pm

Jfet:

Are you going to cut the MC4 connectors off your panels or are you going to buy cables for both positive and negative home runs?

Posted By: silversand on 03/30/14 02:44pm

Jfet wrote:

We are just going to move around the country more often. In Florida in Jan it is sometimes 80.

.....Florida is a very large state, with fantastically varying climate (during winter).

We froze our a$$es off at Crescent Beach (St Augustine: Anastasia Island) during February this winter (in the 30sF and 40sF). My better half bought a North Face Pertex winter jacket just to stay pliable during our beach walks (these Pertex jackets are used to summit Mount Everest; we could trade it$ in for a new 3/4 ton truck!), during the 28F real-feel of the steady 21 MPH winds, 24/7. I actually ventured into the 50 deg ocean water, but not for long. All in all, thank goodness we weren't in an RV "down there" during winter (we had a comfortable 1700sq ft condo on the beach, with a 60,000 btu heat pump). The only decent warmth I had was behind a 6-foot high fully enclosed garden patio wall, on the south side of our condo (the only place to catch a few rays, when the rays were actually there!).

Our friends waaaaay down south of Boca almost froze, too (thank goodness they were in their condo and not in an Rv).

Solar in Florida:

I tell you, there wasn't enough incoming solar radiation this winter in FL (even in full unobstructed beach) to generate any current from any solar panel this winter in Florida (unless you were in the keys: another climate regime entirely).

Silver
2004 Chevy Silverado 2500HD 4x4 6.0L Ext/LB Tow Package 4L80E Michelin AT2s| Outfitter Caribou

Posted By: Jfet on 03/30/14 07:37pm

BoonHauler wrote:

Jfet:

Are you going to cut the MC4 connectors off your panels or are you going to buy cables for both positive and negative home runs?

I was planning on getting the very expensive combiner MC4 connectors to allow me 2s2p 64V 18 amps and then buy a short MC4 cable and cut it in half. I would then splice this 10 gauge MC4 cable into the 8 gauge tinned marine wire I have already run to the solar panel area. I hate regular copper wire...turns black after a few years. The marine grade stuff is what I used for all of our wiring.

I will be updating the thread soon with new pics...I got our NovaKool fridge in and we have been building the cabinetry for it and the furnace/stove/sink. I have to plug up the holes we made to vent the propane fridge since they are no longer needed (the RFU9000 compressor fridge vents to the front). Bummer. I will just Sika aluminum over the giant holes from the inside and install the outside grills so it looks like it would have with the propane fridge.

Posted By: Jfet on 03/30/14 07:39pm

silversand wrote:

Solar in Florida:

I tell you, there wasn't enough incoming solar radiation this winter in FL (even in full unobstructed beach) to generate any current from any solar panel this winter in Florida (unless you were in the keys: another climate regime entirely).

Yes I meant the Keys, although here in WA state the other day I was getting near 200 watts per panel, so 800 watts total, during my testing of our solar setup. I have to think Florida sun is a bit better than Washington state sun!

Posted By: BoonHauler on 03/30/14 07:58pm

Jfet wrote:

BoonHauler wrote:

Jfet:

Are you going to cut the MC4 connectors off your panels or are you going to buy cables for both positive and negative home runs?

Thanks for the reply. Looking forward to the progress pixs!!

Posted By: Jfet on 04/03/14 02:53pm

While thinking about the solar panel mounts I started to have some concern/curiosity about the vertical CoG of the combined truck/camper (yes I realize this could have been analyzed earlier). I have downloaded the body builder's manual for the 2006 Isuzu N series and located the correct pages relating to CoG. I am not concerned right now with horizontal CoG but rather vertical CoG as it would affect sway and possible rollover.

The first inclination is "eh, it will be alright" but that is not how I roll. So...

*Danger* Math Ahead, Proceed With Caution

The important number is the VCg or total average vertical center of gravity of the complete truck/camper. To calculate this you use the formula:

VCg = (Mv + Mb + Mp + Me) / (Wv + Wb + Wp + We)

Where Mv is the moment of vehicle, Wv is the weight of vehicle, Mb is the moment of body (flatbed in our case), Wb is the weight of the flatbed, Mp is the moment of payload (camper), Wp is the weight of the camper, Me is the moment of equipment (we will call it solar panels/frame for this), and We is the weight of equipment.

With me so far? Amazing. Shouldn't we be discussing dry rot or something by now? Anyway, continuing...

From the body builder's guide, our Isuzu NRR with 176" WB has a vehicle weight of 6184 pounds and the distance from the ground to the vertical CoG of the vehicle itself is 18.9" (the 176" WB has the lowest CoG, so that is nice)

We can then calculate the moment of the vehicle Mv = 6184 x 18.9 = 116878 lbs-in

For the weight of the flatbed, we know the last time we went over the scales the truck weighed in at 8700 pounds. Since the bare truck is 6184 pounds, the flatbed must weigh about 2516 pounds. The distance from the ground to the top of the flatbed is 41" and if we use this as the distance to vertical CoG it should be a very conservative guess even though the headache rack is much taller. Most of the mass is actually below the 41".

We can now calculate the moment of the flatbed Mb = 2516 x 41 = 103156 lbs-in

The combined VCg for just the truck and flatbed is
(116878 + 103156) / (8700) = 25.29 inches

So far so good. The body builder guide says the max VCg for the entire vehicle/body/payload should not exceed 63 inches. At least now we know the empty truck and flatbed shouldn't tip over :-)

Now the hard part. I have NFC what the weight or vertical CoG distance is for the camper. I can't load it up on the truck yet and drive to the scales, plus we have not installed the batteries, inverter, sofa, cabinets, etc.

What I can do is figure out what the maximum camper weight and vertical distribution can be to still keep the vertical CoG under 63" for the entire truck/camper. I will still have to make some assumptions but at least it will be something to keep in mind until I can figure out a way of better estimating the actual weight and distribution.

Assume we keep most of the mass in the camper low, we might expect the vertical CoG to at least be less than half the height of the camper. Our camper is 8 feet tall, so we will plug in 48" + 41" = 89" for the vertical distance to CoG. This now leaves just one variable Wp which is the max weight the camper can be at that 89" vertical CoG distance for the entire unit vertical CoG distance to stay under 63".

So we have the formula:

63 = (116878 + 103156 + Wp*89) / (8700 + Wp)

(Sorry for the aneurysm but you were getting on in years anyway.)

Solving for Wp we get Wp = 12618 pounds

Wow, is that right? So if we keep the camper CoG at least distributed so the vertical distance from the ground to the camper CoG is no more than 89" we can have a 12,000 pound camper?!?

Lets double check those numbers by plugging 12,618 and 89" into the VCg formula:

Mp = 12,618 x 89 = 1123002 lbs-in

VCg = (Mv + Mb + Mp) / (Wv + Wb + Wp)

VCg = (116878 + 103156 + 1123002) / (8700 + 12618)

VCg = 63 inches

Relief. Since I know our camper is nowhere near 12,000 pounds and I believe the mass will be distributed more in the lower section, I think we can proceed with our solar panel mount on the roof even if it ends up being several hundred pounds at 12 feet high.

(hello to my wife, the only one who could have possibly read this far)

[image]

* This post was edited 04/03/14 04:31pm by Jfet *

Posted By: cewillis on 04/03/14 04:36pm

Hey -- I'm not your wife.
But good thinking. Also, a 12000 lb camper would put you almost 2000 lb over GVWR -which you're not going to do.

Cal

Posted By: jefe 4x4 on 04/03/14 05:12pm

Jfet,
It's good to see you're still working at your second full-time job. Here's hoping that all those specs and GVWR are for a 4WD zuzu, not, i'm assuming, a lower CG and weight 2WD. You've got your fingers in lots of unbaked pies right now, and I'm waiting patiently for the Zuzu Camper to roll out of the oven.
regards, as always, jefe

'01.5 Dodge 2500 4x4, CTD, Qcab, SB, NV5600, 241HD, 4.10's, Dana 70/TruTrac; Dana 80/ TruTrac, Spintec hub conversion, H.D. susp, 315/75R16's on 7.5" and 10" wide steel wheels, Vulcan big line, Warn M15K winch '98 Lance Lite 165s, 8' 6" X-cab, 200w Solar

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