100mm! – that’s all it would have taken, just 100mm and there would have been no grief whatsoever! Even 50mm, or in fact 25mm, would have made life so much simpler! Grrrrr!

After swearing and cursing for 10 minutes I felt better! I had just discovered, when I started to install the cigarette lighter sockets into the portable energy box (let’s just call it PEB – I know it’s not a great acronym but…), that I didn’t have quite enough room for the push on connector on the rear of the socket. In the words of Agent 86, “Missed it by that much”. Up until then, things had been going reasonably well.

It’s taken longer than anticipated to wire up the unit as the space was a bit tighter than I would have liked (I’m blaming it on the size wood I had available rather than any underestimation of the dimensions required 🙂 ) and I used larger guage cables than was really necessary. But I can guarantee that voltage drop won’t be an issue in this system. The battery cables connecting the two batteries together are the original 50mm cables that came with the batteries, and other odd and ends, from the decommissioned PABX and are intended for  far higher currents than I will be subjecting them to.

The problem with the sockets had me stumped for a while as I had already made the cutouts for them, otherwise I could have bought a double socket assembly intended for under the dash and is surface mounted. However, after a bit of thinking and fiddling around and I was able to use a terminal socket to join the connector with about 5mm clearance. Phew!

After quite a bit of time the front panel was wired up including the combo plug and screw (banana plug) terminals for the regulator controlled lights. A quick test confirmed all the connections were good. I cleaned up the batteries and installed them in the box and wired them up. Those heavy cables were a bit of a struggle in the tight space but all the cables were finally connected. Now for the big test.

I flicked the circuit breaker and up came the controller lights and all the voltages checked out. I connected a 12V light and the inverter and everthing worked fine. Huzzah!

I still have to make the final termination for the PV and possibly put a cover on the front to help protect the exposed components but the unit is now functional. As a final test, I temporarily connected the PV inputs to my bench power supply, which I can set to mimic a 80W PV panel, and switched on the circuit breakers. The charge light came on the regulator started delivering 5A to the batteries and they were slowly climbing above 13V. I left it on for several hours and the batteries were charging well. I switched off the unit for the night and I will check the battery condition in the morning and then give them another few hours of charge.

I will install the final set of terminations over the weekend, tidy up the last tiny things on the box and run some more tests.

Overall I am very happy with the unit and it will be a nice addition to my set of sustainablility tools.

Last week, after I returned from Timor, I was a bit tired but still fired up enough to start work on my updated portable energy box to replace the small, now inoperative, one I built some time ago (see this post for details). Then I got sick! Damn bug got hold of me and wouldn’t let go for three or four days. Anyway, I finally got around to it on the weekend and made the box ready for the batteries and the electronics.

I used some timber that I had lying around for the box, but I did purchase some circuit breakers to use in an existing four way fuse box. I have also purchased a couple of other items including some cigarette lighter sockets and electrical plugs to use as connection points for various items such as lights and an inverter.

I toyed with the idea of mounting some wheels and a handle to move it around because it will be a bit heavy with two 38Ah batteries but decided to focus on the electrical side for now. I can always move it with my trolley when I need to. I had to focus on a few other things this week but I painted the box last night and now that it has two coats the box is ready for wiring up. I will wire the box up tomorrow.

The complete unit will have 76Ah of batteries, a 6A regulator that will accomodate around 80W of PV panels and a controlled output for lights, connections for a mains powered charger, two 12V cigarette lighter sockets (which will enable me to connect my small 150W inverter and other automotive gadgets) and one set of generic output terminals to connect other 12V equipment or a bigger charger.

Once it’s finished, I’ll provide some details on the testing and operation.