Thursday, February 6, 2020

Internal Power Reticulation

The 12 Volt systems might be XT60

The 5 Volt might be best done as 10Pcs Dual USB Output 6-24V To 5.2V 3A DC-DC Step Down Power Charger Module Converter

The 19.5 Volt

I have a raw 26.X volt system derived from two sets of lead acid in series.
This system is rough and unbalanced and will require refinement.

One leg relies on the AGM UPS batteries and the bulk of the solar panels. This system also supplies all the 12 volts for everything.

The other leg is a spare car battery which was used for starting the petrol genset before I got rid of it. There is a single solar panel spare which I manually switch in to charge it and MUST remember to disconnect it.

Bangood  DC-DC CC CV Buck Converter Board Step Down Power Supply Module 7-32V to 0.8-28V 12A 
A decent set of speakers will finish the job nicely. Wireless speakers would be cool.

Wednesday, February 5, 2020


Penguins always lend a jolly tone to proceedings and this spot goes to emphasize this point.

The Penguins are nesting and they make a sound between a turkey and a very robust frog. Sounds like a call and response. A train comes along a few times a day and blows its horn as it rattles along the tracks. Not much more you can ask for really.

Fuel Starvation.

An intermittent fault finally needed reckoning with.

All rather dreary, but I found a workshop where they let you work with thier guy on tools as a T/A. Sort of thing you find out bush. Its good to know exactly what got done.

We went from the fuel filler to the injector block and steam cleaned, blew compressed air, replaced hoses and filters. ~touch wood~ no more fuel feed issues hence forth. Really good bloke I got to work with. Very Tasmanian. At "smoko" they all smoked. Outstanding workmanship from the welding and fab team. 

From Fuel Cap to injector block, all flushed and inspected. Apart from a slightly perished and kinked hose, no real "smoking gun" was found.

These guys had a really distinctive accent. Boss is on the right. Other chap was my colleague (offsider - actually he did most of it.) Very interesting CV - off shore Oil and Gas. Very Old SKool the pair of them.

Early indications are that the fault is fixed.

Tuesday, February 4, 2020

Battery Storage System

*Build a backup Rasberry Pi controller relay board.
*Source 12 x Second Hand ex Telstra 2 volt cells. 70 x 180 x 350. These will fit nicely.

UXL220-2FR Spec Sheet

These are a premium UPS battery with a design life of 15 years. They are AGM design apparently but are no where designated as "deep cycle". They have a maximum charge rate of .1C and , possibly more diagnostic , are able to be mounted either vertically or horizontally. This must mean that the electrolyte has a tenous role in the duty cycle. The batteries are available at 60 bucks for a 500 odd dollar list price battery apparently ex Telco, in the original packaging and with no witness marks on the terminals.

At first blush this suggests these batteries must be over provisioned and nursed in an Off Grid role.

The brutal question could be ; these batteries will last 15 years of doing nothing in a Godfather UPS role. However if you were to make them do something Off Grid wise and the battery was being pulled off the Manufacturer Spec Sheet (have not yet found and cycling vs life contention let alone specs). You might make inroads into the design life but the cost benefit puts them in front of purpose batteries such as the Century C105 type industrial deep cycle purchased Retail and new.

At very least this suggests some "hard stops". My first limit  would be charge rate. Anecdotally I have heard of systems comprising this product just collapsing early in service. I can only conclude overcharging would be the failure mechanism.

My next guess is ; treated gently on depth of discharge. Clearly an Off Grid battery that cannot withstand any meaningfull depth of cycle is no battery at all.

Is it better to buy twice as many as you need and treat the aggregate more gently in an "Off the Reservation " role? Dont rightly know.

The charge controller is the epsolar tracer 4210A.

Tuesday, January 28, 2020

Seven segment display clock using Neon indicators.

Looking for a project to learn KiCad.

I love the color of neon and this design will use 5 per arm.

5 x 7 x 6 = 210.

I think I have 400 of them in a bag someplace.  Will use 6 latching BCD to seven segment ICs
CD74HC4511E . CD to Seven-Segment Decoder / Driver / Latch, HC Family, 7 Output, 10 mA, 4.5 V to 5.5 V, DIP-16
and discrete transistors to provide the high voltage drive.

The driver transistors are 20 bucks per hundred. The ripple counters are about ten bucks. I already have some high voltage power supplies.

DC-DC Boost Converter 8~32V to 45~390V High Voltage Charging Booster

I should see plenty of change out of a hundred bucks.

It will use 4 BCD GPIOs and 6 clock signals ...oops forgot the decimal points. Make that 11 output pins on the Arduino. Or I could go really agricultural and use an Arduino Mega with its 54 pins and drive each segment directly.

The challenging bit will be programming the Arduino. Deriving a timing reference and laying out the PCB in KiCAD.

I was trying to think of some artistic way of mounting the neons. Perhaps a copper wire trellis? Nothing seemed interesting. Just regular PCB makes sense and isn't getting too clever clever.