Bugger! No negative ground?

Today I tested my charge controller to see if I could put a negative ground for the battery. I've got the bus body as the negative ground for all my solar powered devices so far. Intreaguingly, as soon as I connected the negative of the battery to the negative of the lines to powered devices, the devices sprang into life, despite the charge controller having left the devices turned off. Clearly the charge controller flies in the face of conventional logic and switches only on the negative side. Now that's truly and utterly bizarre. That means that unusually I will have to employ other methods.

Given that the charge controller does not regulate voltage output at all, I imagine a relay will be very useful there. It'll be a constant drain on power though. That would allow me to use the bus body as the negative for the battery and for the circuits. Indeed, lighter wiring could be used to power that relay. The downside is that I'm going to have to rethink some of my circuitry. The alternative would be to use a negative and a positive cable from the battery and just isolate the battery from the bodywork. That flies in the face of conventional vehicle wiring but if it's what must be done then it must be done.

I can hear it now. All those morons saying "shouldn't have bought Chinese crap". I ask the question - how do you know what's Chinese or not? How do you know whether something Chinese is good or bad? It's just not possible. If a company buys the electronics from China and assembles in the USA, is it American or is it Chinese? The Chinese can produce some darned good stuff. They can also produce some bloody awful stuff. In fact the vast majority of what they throw out on eBay tends to be the rejects and low quality stuff but a lot of it is still good enough to use. The exception being clothing - a Chinese XXXL will be Medium to the rest of us.

One of the easier things to do was to fix my batwing doors. Well, they're not actually saloon style batwing doors though this is what I'd have loved to have but they're in essence batwing doors. One of the doors was out of synch and needed a stabilizing screw and another screw tightened. Now though they no longer swing to the center and close automatically because the plastic bits have worn down in the past two years, they still look pretty darned good.

Looking at my pushbutton door controller, I found that it was possible to change the on period for the relay. I changed it from 5 seconds to 10 seconds so now when I open the door using the pushbutton, it will take just one operation. Similarly the wrong key entry alarm sounds for one minute after a wrong key entry. I was going to put a piezo buzzer under the hood but decided in the end that I might just as well connect to the vehicle horn.

I decided to run the door controller off the driving battery because if I run it off the door battery, it burns up door battery power at the rate of 30ma. In a day that would be 720ma. In 3.4 days that would drain my door batteries flat and that really wouldn't be helpful. At least I can disconnect the driving battery when I park. Now in an emergency such as my leaving my keys somewhere, I can just connect the bus battery and boom - I have power to the door lock. Of course, if I then go on to put a lock on my battery compartment then that gives rise to a new problem!

Thinking of locks, I'm thinking of putting locking latches on the fuel cap and the battery compartment on the basis that some people just are too dishonest. That being the case, it begins to look as though I will have to provide a totally different power source for my door lock controller. Perhaps just run it off the door battery as before but with a pushbutton switch to power it up while in use? That being the case, putting a wrong key alarm seems a bit pointless. Far better then to keep the wiring simple.

As can be seen here, it's just a few pairs of wires in use. That plus a power pushbutton should all work really well off my simple 8AA battery power supply. Having no permanent power drain, my emergency entry lock should work as required. Clearly a pushbutton door close switch will be needed inside. Then another thought is that if a 12V lithium battery were used to power just the unit itself and a relay then the 12v lithium battery could be just installed and forgotten about for a few years as with a momentary on button there would be no current drain and lithium batteries have a shelf life of about a decade. That could happily be installed inside the vehicle.

Thinking along the lines of specialty batteries, I realized eventually that my current setup using 8AA batteries is best. If I put - as I said - the momentary on switch to power the keypad when required, I can run the emergency unlocker from the ordinary lock batteries. Indeed, if I'm not likely to be accessing the lock for a long period, I could even replace the standard alkaline batteries with lithium AA or even go up to C or D cells. The current rechargeable AAs have been in use now for several months without having been recharge between whenever it was I last charged them and now. Sometimes just sitting, thinking about all the funky and complicated ways of doing things, it turns out the way I am doing them is still the simplest.

Having spent most of the day looking at and considering options, I'm not really convinced that putting the button control in the engine compartment is the right place. Similarly I'm convinced that underneath and inside any of the existing hatches is probably also the wrong place. I've been looking at other latches thinking that it might be possible to install a whole new door. I could simply label it DEF so that anybody looking would think that's for Diesel Emission Fluid instead of having a keypad concealed. Thinking further along the lines of the existing door lock, I'd probably be best keeping the existing arrangement but purely to prevent an accident that will never happen, I'll put a relay in that cuts power from the key lock side while the codepad lock is operating. I might as well run that straight off the solar battery.

I'm hoping that next weekend I will be less exhausted. The problem is I take my work very seriously and put 110% into what I'm doing. I do this with every job I do. That means that I tend to use the weekends recuperating.

For the moment I shall put the keypad controller on the back burner while I complete the final wiring. That involves getting under the bus on tarmac again to fit more cable attachments and also to extend any wires that are too short.

Finally, today I saw a video online of a driver who drove straight into a bus and had a head on collision. It is not known whether the driver fell asleep or whether he was on his cellphone. That driver is now dead. The driver of the bus had a hard job keeping the bus upright and ended up way off in the fields and the front of the bus is a mess but the occupants survived. I feel happier to have an old schoolbus because I feel they're better built. So, let that be your lesson for today - that text message, phonecall, facebook message - it could just put you into the next world.