Portable Power Supply

Some of you may know that I tinker around with solar power from time to time and that in fact my workshop is 'off-grid'. One of the features of a lifetime spent tinkering with stuff is a lot of spare bits lying around, so when a friend was looking for a lighting system for her allotment shed and summer house I thought I could come up with something quite easily.

I had a 86W panel and a small car battery knocking about (as you do - they were part of the evolution of my workshop solar power system), so I would not have to spend much money. I also had a simple panel controller, which essentially sense battery voltage & connects the panel if the voltage is below a set point and disconnects it when it goes above the set point - pretty basic; no MPPT here.

What I needed was something to unite it all into a simple portable unit. This came in the form of a bit of an old kitchen unit and some pine offcuts:

I used the little router to cut a slot at the back:

This accommodates the foot of the battery. I sized it to suit the largest battery I had, to 'future proof' it a little. You can see how the foot of the battery is trapped in the groove:

The other foot is trapped under this little bar, made from 3 mm cold rolled sheet and retained with two M6 wing nuts:

Here's the battery in place with the controller:

Here I've added a simple modified sine wave inverter. It gives 200 W at 220 VAC, so you can charge your phone from it.

Here it is with the wiring completed. The six terminals top left are for the solar panel and for two 12V outputs. Lower down, there is a higher current termination for main battery cable, voltage sensor and feed to the inverter.

The inverter provides 200W at 220 VAC - that's about an amp, which translates to about 20 A on the DC side; I can run a 60Ah battery for 36 minutes at that rate, assuming my maximum allowable discharge is 20% - with a deep cycle battery I could increase that, and the frame will carry larger batteries.

Power to Weight Data

I've been meaning to look at power to weight ratios for a while, mainly since the PO of my SQ4 delivered it to me saying 'I can't see myself using this, it's a big bike and way too heavy for me'. I thought I would look around at some modern bikes and see how heavy it really was, and whether I was going to be able to ride it into old age.

So the table shown here lists a few bikes of interest to me, with their fuelled-up weight in pounds, seat heights for some and power to weight ratios. Look at some of the older bikes & how they compare with some newer ones!

Here's the power to weight ratios charted. enjoy figuring that out, I will replace the chart with one that is easier to read!

Oil Pressure

So as I have mentioned previously, my plan was to spin the engine up on the big power drill. I've now done this using a 1/2" square driver with a hexagonal shank in the drill chuck, with the drill set to 2nd gear - slow speed, high torque. The drill drives the engine through the crankshaft nut under the oil pump.

I connected a short hose to trap any fluids coming out of the oil pressure gauge line and take them back to the oil tank. Because of course the timing cover is off, there is a lot of oil in the drip tray which comes from the rear main bearing. 

The plugs are out to reduce the torque required from the drill.

And here it is:

Evidence of oil emerging from the return line. When the drill is running, you can see this pouring out, and you can see it at all eight rockers as well. Its noticeable that the inlet rockers get a lot more oil than the exhaust rockers - Ariel should have adjusted the size of the oil holes (smaller in the inlet rockers) to increase the feed to the exhaust rockers.

After a few minutes on the power drill, the bike is noticeably easier to kick over. Next I refitted the rocker cover studs and I put the tank and the oil pressure gauge back on and ran the test again looking for measurable oil pressure.

At maybe 250 rpm on the drill I am getting something like 25 psi.

Off Grid

Some while ago I promised to tell you about a little off-grid electrical project. Take a look at this...