Monday, September 4, 2017

Today I tried my vents

I put my hand up to the vents from which the hot inside air blows and there was quite a breeze. I doubt the vent filters will take much more. It might be a better option to go back to my original plan which was to pump cooler outside air in through a vent in the floor. I'm probably going to go with unfiltered air initially but that's always subject to change. Pumping air out at 130 CFM is a good idea but it's not making it that much cooler inside which is a bit strange. Either I need to pump air out faster or I need to pump cool air inside as well.

In its current orientation, the front of the bus heats up first, meaning that the bedroom starts off cool. The bedroom is, of course, where I sit when I'm blogging. The front is very hot in the morning from the morning sun while the bedroom isn't so hot. When I had the bus oriented the other way, the front would be cooler before the bedroom but then the opposite would be true at the end of the day. My current thoughts are to try an induction fan in the galley in order to pull cooler air in from outside or to double-up the extraction fans. Having said that, properly functioning extraction is a must. At the moment the system is just messing about with the fan running for 45 seconds at a go. That, I suspect, is due to a faulty charge controller and possibly the charge controller has damaged my 10ah battery.

Today being a trip to the hardware store, I'll pick up some wiring. I've thought about an underbus crawler and decided that I do want one but I'm going to see how much it costs just to buy a piece of plywood (that can be used later for other things) and some castors. I might even have some plywood in the shed so I might just go for the castors.

Regarding the wiring, I thought I was being clever when I installed a single extra wire when I installed my last cable run. It turns out I'd inadequately predicted the future. I need more cabling running along the underside. It doesn't help that two charge controllers will fight each other. So, I have to redesign my wiring layout.

So many people have cast aspersions on my welding that I begin to doubt it myself. I've jumped up and down on my welds and hit them with a sledgehammer but still I get the nasty comments. Maybe I just need to shut up about my welding and just get on with it and not mention it. Anyway, I need to weld together a battery cradle for my 35AH battery. I'll put a little roof over it just in case the battery catches fire. That'll serve as a heat barrier from the underside of the floor. I have a 30A self-resetting breaker. That'll stop me accidentally overloading my battery cabling and might also protect the battery in the eventuality of a short circuit. Perhaps I might go for belt and braces and put a fuse as well - close to the battery.

With the battery mounted behind the differential, I'll be protected should those that I suspect are just plain idiots actually be right. If the welds break and the battery falls out, it becomes a road hazard rather than going under my rear wheel which could be fatal for me. Fear of things falling off and going under my rear wheel is why I have 5 chains supporting each 15 gallon barrel. Each chain is attached by four 5/16 bolts to the ribs. Thus, at 135lbs for a full waste tank, each chain is supporting no more than 25lbs and no bolt is supporting more than 6lbs. The chains are specified at 550lbs with the weak point being the turnbuckles, specified at 130lbs each. 5 of them should hold 650lbs which is way in excess of any road forces on a 135lb barrel. The sides of the barrel would give way first.

I've got two charge controllers in place right now - one at the front from the front solar panel and that charges the battery that powers my magic box. That's the one thing that really works well. My extraction fans used to work well when they were just plain CPU fans but when I switched to a single bilge blower that's when it all went to pot.

My charge controllers are rated for 30A but reviews say that's more than they can provide. I noticed the PWM charge controllers don't control output voltage. They just supply it. That makes me suspect that if I need more amperage than they can provide, I can simply put a relay in place where the controller controls the operation of a relay and the relay provides the power from the battery.

It seems the charge controllers go bananas if the battery negative is connected to any other negative on the controller. That's just plain nuts and the sign of poor design. There should be just one negative and all the other connections should be positive. That actually gives me the thought that I should maybe dump these charge controller things and go with a simple battery protector that stops the battery going too low and one that prevents it from being overcharged. The charge controllers don't seem to do anything else.

Designing the wiring system, I need a 1 gauge wire to go from the charge controller to the battery. I need to run a dual wire from the solar panels at the back to the solar panels at the front in order to combine the output of both. That output goes into a charge controller. The thick wire from the charge controller goes to the battery and should be fused at both ends. Because I might still change what I'm going with my ventilation fans, I need to future-proof the wiring. Thus, keeping the bus body as negative, I need two wires that will carry 10A. I'll likely only use one but just in case I decide to replace my exhaust fans with 7 inch car radiator fans, the possibility is there. I need a 7A wire from my magic box and a 1A wire from the front fan. I need a 1A wire from my bedroom fan and since I'm putting in wiring then I'll put in a 7A wire just in case I put a second magic box.

Since I'm not getting too much luck with LED lanterns I'd best also possibly put an extra wire that allows me to run at least some lighting to the galley and the bedroom. I'm not sure how I'd do that to the bathroom though. I really, really want to use lanterns as opposed to wired in lights.

Then there's siting the charge controller and fuse box. I had been keen on having it all at the front of the bus. That was when I was going to run everything from smaller batteries housed in ammunition boxes. Initially I was thinking that I might be using far less power. Now it seems my power system is growing almost out of control.

My first conduit from the front to the back of the bus contains wiring for the reversing horn and the reversing camera. It also contains a spare cable that I've been using to power my extraction fan. Thus, there is no dedicated house wiring system set up yet. With that in mind, siting my battery and arranging my cabling is much more flexible.

Running the charge controller from the rear, I need..

  • 20-30 feet of conduit. 
  • 7A cable from the magic box to the charge controller - say 30 feet
  • 1A cable from the galley fan to the charge controller - say 30 feet
  • An extra 5A cable for lighting (just in case) at the front - say 30 feet
  • An extra 5A cable for lighting from the bedroom for lighting or in fact that could be 10A to provide light for both bathroom and bedroom since they're on opposite sides of the same partition. - say 15 feet (it could even be two 5A cables)
  • 2A dual cable from the front solar panels to the back. - say 30 feet
  • 1A fan cable from the bedroom to the back - say 15 feet
  • Mount the charge controller at the back
  • Mount my timer at the back
  • Mount my fuse box at the back.
  • Short run of 30A cable to the battery.
  • 20 feet of 5A cable to where I'll install my induction fan
Running the charge controller from the front, I need...
  • 20-30 feet of conduit
  • No extra cable from the magic box
  • No extra cable from the galley fan
  • 6 feet of 5A cable for lighting
  • An extra  5A/10A cable from the bedroom to the charge controller - say 20 feet.
  • 3A dual cable from the back solar panels to the front (say 30 feet).
  • 1A cable from the bedroom to the front - say 20 feet
  • Mount the charge controller at the front
  • Mount the fuse box at the front
  • Mount the timer at the front
  • Long run of 30A cable to the battery
  • 20 feet of 5A cable to where I'll install my induction fan.
Looking at it, theres precious little to choose between front and rear mounting systems. The advantage with mounting at the front is that I can simply control everything pretty much from the drivers seat. Mounting at the back means that I can make use of the existing rear compartment for mounting switches etc. It also means I don't have to hide the wiring - as long as it's not a birds nest, it should be fine. I might want to put a simple solenoid switch in, powered from that simple extra cable in order to power everything off from the driver's seat.

So, I sat down and worked out what was needed in terms of wire. Given that most of the wires run 30 feet and that none of the sources I encountered online ever seemed to agree with wire sizes, I took the plunge and did my own calculations - which took forever.
Of course, when I got to the hardware store, I found the amperages given for the different wires was different from what I saw online. Feeling that the online figures were largely bollocks, using the vernacular, I went with the store figures. Needless to say on my way down to the store, I'd had some new ideas (as I often do). Currently the battery is earthed to the bus body. It won't take much to earth the appliances to the body and have the battery earth going straight to the charge controller. In an ideal world, the solar panels, battery and appliances would all be earthed to the body together. This being some kind of funky Chinese screwed up world where logic and electronics don't go together, I can't combine the earths on my charge controller. Thus it works out more economical in wire just to earth the appliances. That means that I need from the front a dual cable from my solar panel and three wires from my fan, magic box and possible future lighting unit. That ends up being two dual cables and a single cable. That's absolutely perfect as far as I'm concerned. As my dual cables are somewhat heavy duty, I can exceed my estimated amperages. Both my duals are 14 gauge which should carry at least 8 amps. This means that should I wish to tie in an extra solar panel, I could easily add a stand-alone 50W panel.

I decided against adding an induction fan on the basis that it was too complicated to figure out all the wiring while standing in the middle of the hardware store. Instead I will have two extraction fans running. That should have the same effect but gets around extra engineering to install the induction fan and believe me, I like things to be simple. I almost decided to say stuff adding the ability to add lighting running off the main battery. I'm now fairly confident I have almost all the wire I need. I did forget to buy wires from the battery to the charge controller but that is no biggie. That's a very short run.

Looking underneath the bus I found a double set of opposing C section pairs just behind the differential. I'm not sure how much the differential swings when in use but it looked a possibility for attaching my battery. Alternatively I could put two 35AH batteries, each behind a rear wheel. That's a thought for the future and tying them together would not be a huge challenge.

The wiring came in at quite a price. I won't say I was shocked because after yo've seen some of the things I have, it takes very little to shock me! While in the store I priced castors for use with some plywood that I could use as a creeper. Some were horrible prices and as I needed 4, the price of a Harbor Freight creeper began to look much more attractive. Then I spotted some casters that were end of line for $3 each. I bought two plus two of those that can be steered for $5 apiece. That came to $16 or about half the price of a Harbor Freight creeper. On my return I found I'd got some 7 ply leftover from when I built the top of my toilet and my bedroom desk. that came in very useful as did some of my leftover 1/4 and 5/16 bolts. One set of castors needed a 1/4 inch bolt and the other needed a 5/16 so I was well prepared.
A few minutes of drilling and bolting and my creeper was ready. I only did some of the bolts because it's not intended to be used more than a couple of times. Hence, of course, I jibbed at spending $30 on a creeper. I'd been thinking I'd have to work harder on construction but the plywood though short and wide looked a pretty decent size so my creeper was born. My next task - to tape my two dual cables and extra cable together so that I can put it all in a sheath. For this, I don't mind using extra sheathing for the bedroom/bathroom cables. I can easily have extra runs of conduit.

No comments:

Post a Comment