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A hike around Lake Walyungup

July 05, 2020 — BarryK

The State of Western Australia is in a fortunate situation, as it is coronavirus-free. The only cases are those of returning international travellers, and they get isolated for two weeks. As far as the rest of Australia is concerned, unfortunately, Victoria has let the country down, with many new cases every day -- which was caused by incompetent isolation of returning international travellers -- it was mostly the security guards, apparently, who were responsible for spreading the virus from the isolation-hotels to the wider community.

Anyway, here in WA, we have had competent handling of the crisis, and we are just about back to normal. I am getting around on public transport and going to favourite restaurants. Today, went for a hike, before some lunch and shopping...

While considering where to hike in the Rockingham-Warnbro area of WA, I stumbled across "metrotrekker" Marc's website:

https://www.metrotrekker.com/search?country=All_Countries&city=All_Cities

Marc hikes in metropolitan, or outer-metropolitan, areas, accessable at each terminus by public transport. He has hiked in Europe, Japan, Singapore and Australia. I wanted to walk around Lake Walyungup, and found that he has done that:

https://www.metrotrekker.com/australia-perth-hiking-a-walk-on-lake-walyungup

I drove there, but if you come by public transport from Perth, take the Mandurah Line and get off at Warnbro Station. This is about 37 minutes train journey. Walk East from the station, along Safety Bay Road, not far, and you will see a parking spot on the right, and a very small one on the left. On the south side, there is an entry gate to the lake:

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...the time is about 10.00am, on Sunday, July 5, 2020 (mid-winter), and there were several cars parked, so other hikers were encountered.

What's so special about this lake? Nothing in particular. Perth is located on a coastal sandplain, so that is the kind of terrain, sand and limestone. South of Perth City, the suburbs have sprawled right down to Mandurah and beyond, and there is a metro train line that terminates at Mandurah, running through Rockingham and Warnbro.

There is a military base on Garden Island, close to the coast just north of Rockingham, and they used Lake Walyungup for target practise, and I saw the warning:

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No longer of course! As to footpaths, there are some, but it is mostly a huge expanse of flat sand and limestone:

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...there isn't much water, and the ground is firm, as it is limestone sprinkled with sand.

Google map shows lots of water, but it is in actuality much less. I walked south, on the west side of the lake, then cut across east, and walked back on the east side of the lake. It seems that there are two bodies of water, so walking south from the entrance, one can walk east across the land that separates the two bodies.

I then walked north along the east side of the lake, and took a photo to prove that there is still some water here:

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I ambled about a bit, and the walk took about 2 hours. If someone walked closer to the water, the walk around it and back to the car park, would be about 1.5 hours, maybe less.

A pleasant walk, no spectacular scenic features, but of interest to observe the type of terrain and plants.

Stealing Marc's map of where he walked:

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...in my case, I walked down the west side of the lake, until I saw that Lakeside Deli directly east, then walked across. I could not see any access to the deli, nothing easy anyway. Instead, I went back to my car and drove to the nearby Waikiki Shopping Centre and bought a Jesters pie and chips for lunch -- hey, there is a lot to be said in favour of urban trekking! 

Tags: nomad

Giandel 300W Pure Sine Wave inverter mini-review

May 26, 2020 — BarryK

I have owned a modified-sinewave 150W inverter for a very long time, probably about 15 years, and it has been taken on camping trips. However, has seen very little use, as it does not have enough grunt.

On a recent trip, I tried to use it to drive my LCD/LED TV (an old 55cm 1080p TV that I usually use as a monitor) and (not at the same time) my "big" laptop, without success. The TV for example, the power-LED just kept flickering on and off and the screen stayed dark -- it must be the startup current is too high. So, time for a higher-capacity inverter, and also one with "pure" sinewave output, more suited to driving electronic equipment.

Actually, I do have a DC-DC converter for my "big" laptop, 12V in, 18V out, that plugs into the cigarette lighter socket, and that works well. Also, the TV is capable of running directly off 12V -- it would be just a matter of making up a suitable cable.

So, there is no immediate need for an inverter, but I got the itch...

After some research, I settled on a 300W inverter. That suits the maximum current that my powerbox is designed to handle, and is enough for TV and laptop and something else running together. Or an electric drill.

Prices vary from AU$78 to over $350 -- for what seems like the same thing. At the top-end, there is this Redarc 350W inverter:

https://www.mygenerator.com.au/redarc-350w-12v-pure-sine-wave-inverter.html

...I studied the specs in a PDF, and the no-load input current is stated to be <0.9A. If the input voltage is 13V, then it is consuming <11.7 watts. Efficiency is stated as 89%. Redarc is an Australian company with local manufacturing, which these days is a rarity. It does mean more expensive than Chinese products, however the quality is top-notch.

https://www.redarc.com.au/australianmade

Fast forward to what I ended up purchasing, this Giandel 350W Pure Sine Wave inverter, for just AU$78.96, including delivery:

https://www.ebay.com.au/itm/Pure-Sine-Wave-Power-Inverter-300W-600W-12V-240V-USA-Transistors-Large-shell/331279407166

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Note, this does look like a generic Chinese product. I have seen other brands on eBay and YouTube that look the same.

Before ordering, I contacted the vendor and they confirmed that they ship by Australia Post -- some eBay vendors use Fastway Couriers (now renamed to Aramex), but after they lost my parcel earlier this year, and reading about them on productreview.com.au, I vowed never to buy from any eBay vendor that uses them.

So, the Giandel inverter came by Australia Post, and it came fast, very pleased.

Here it is, setup, running off the lithium powerbox, powering my big laptop:

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Now here is something very interesting: the online specifications state that the no-load input current is 1 ampere. However, I measured it: 13.3V input, at 0.47A. Only 0.47 amperes!

Most of the other 300W cheapies claim around 0.9A standby current. Except I did find one that claims <0.4A, the Elinz INTPW300:

https://www.ebay.com.au/itm/300W-600W-Pure-Sine-Wave-Power-Inverter-12V-240V-AUS-Plug-Car-Boat-Caravan/272368676006

The Elinz inverter claims over 90% efficiency, and something important, Australian "C-Tick" EMC compliance. I didn't give that much thought at time, but the importance became obvious later, when I tested the Giandel.

There is no C-Tick shown anywhere on the Giandel or the documentation, nor can I find it on their website, giandel.com.au -- except that it does state "Australian standard design". Which means that it is illegal to use in Australia, I think. It is probably one of those legal-grey areas.

Anyway, the importance of EMC became apparent to me when I powered up the laptop, and the USB mouse was very erratic. It would freeze momentarily, work a bit, freeze again.

I did some searching with google, and found that this interference from inverters is common with laptop touchpads, but I eventually found someone who had it happening with their USB mouse.

Look at the above photo, where the mouse cable is draped!

Simple solution, moved the cable further away, and less interference. At about 2 feet away, no interference. This is RF, high frequency radio waves.

There is an earth terminal on the back of the inverter, which might help if connected. If I had an "earth" to connect it to. What about when in a tent, could "earth" be a steel peg in the ground?

Anyway, the solution is just to keep the inverter away from sensitive electronic equipment. Probably in tent, have it on the floor.

The unit itself looks well made. Very heavy cast heatsink chassis, finned aluminium.

One very good thing -- the fan is intelligent, only comes on when the chassis reaches 40degC. So, runs silent, much appreciated.

I did consider buying the Elinz inverter. Their eBay page states that they use Australia Post:

https://www.ebay.com.au/itm/300W-600W-Pure-Sine-Wave-Power-Inverter-12V-240V-AUS-Plug-Car-Boat-Caravan/272368676006

But when I contacted them, they said that they use both Australia Post and Fastway Couriers, and a couple others. Although I was enquiring about the inverter, they did not specifically state which of those carriers would be used, so their loss, I went elsewhere. 

Regarding cabling, the Giandel unit came with two sets of cables, one with cigarette-lighter plug, the other with crocodile clips.

The cigarette-lighter socket will be fused, maybe 10A or 15A, hence the other cable set is required to obtain the full power that the inverter is capable of. My powerbox has an Anderson plug output, so I will use that to run the inverter -- the Anderson plug is rated up to 50A, but of course need to use heavy cable also. Anyway, my powerbox has a 30A circuit breaker, limiting power output to around 13x30, which is 390W, a good match for the inverter. Though of course the inverter is specified to handle surges up to 600W.

I loaded the Giandel inverter a bit more: ran the desktop PC playing a video, monitor (my LED TV), a pedestal fan, and a pedestal lamp. All up, was getting 12.8V at 12.5A, which is 159W. Could hardly feel any warmth on that massive heatsink. 

Tags: nomad

Koorda Native Flora Reserve mini-review

May 19, 2020 — BarryK

Yay, we are allowed to drive in the Wheatbelt Region of WA! I went for a trip into the Wheatbelt and as it was too far for a comfortable one-day trip, looked for somewhere to park overnight. I used Google, typed in "campsites near Koorda" and got a few hits, including the Koorda Native Flora Reserve.

Koorda is a small town, about two hours drive from Perth:

https://en.wikipedia.org/wiki/Koorda,_Western_Australia

Google Maps also recognised the reserve and was able to direct me there. It is about 14km from Koorda. Had a Telstra signal all the way and also at the site. There is a sign at the entrance:

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A narrow track to get in, but a big open area to turn around at the "picnic area" if you have a caravan. Nice facilities, a covered table:

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Also, there are a couple of fire pits and a toilet. The toilet is on the horizon in the above photo, and needs special mention, as it is very clean and well maintained:

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...there is even soap on the basin!

A big plus point is that it is free. But I do like to give something back, and buy petrol and food in the local town.

Any negatives? Well, yes, the flies. These are annoying little critters, that try and get into the eyes. These "bush flies" are prevalent throughout the northern Wheatbelt and further north and inland. Just have to put up with them. As the evening gets cooler, they reduce. There is really only 2-3 months from mid-winter when they are very reduced during the day.

Anyway, apart from that pet peeve, it is a nice little spot, well worth an overnight stay if you are going that way. More links:

https://www.aircamp.com.au/campsite/koorda-native-flora-reserve

https://www.wheatbeltway.com.au/towns/?act=Koorda   

Tags: nomad

Ganga Mill Campground mini-review

May 13, 2020 — BarryK

Here in Western Australia, we have restrictions where we can drive. As I live in Perth, I am only allowed to go camping in the Perth-Peel Regions. Though, from Monday 18th May, this will be eased and driving will be allowed to the Wheatbelt, South West and Great Southern Regions. That is good, but most of the grey nomads would prefer to be able to drive north, toward warmer climate.

I checked out what DPAW campgrounds are in the Perth-Peel Regions, and also don't require pre-booking. Not much choice, in fact, no choice, only Nanga Mill and Nanga Townsite campgrounds are first-come-first-served, no booking. So, decided to get away for a couple of days.

If you live in Perth and just want a quick get-away for the weekend, it is a good choice, only about 1 hour and 30 minutes drive. You drive south from Perth, on the South Western Highway, through Byford, then before Pinjarra there is a turn-off to the left, to Dwellingup. Arrive Dwellingup, turn left at main street t-junction, go out of town, and Nanga Road is on the right.

Here is the DPAW page:

https://parks.dpaw.wa.gov.au/site/nanga-mill

Concession price is AU$8 one-time entry fee per car, and AU$7 per night, per person.

I have to admit, these days I prefer coastal camping, just find the ocean, beaches, etc., so much more interesting. But, thick bushland, tall trees, do have some attraction.

Tall trees, yes, nestled in a valley beside a stream -- very nice, but a problem for my solar panel. I chose the sunniest spot, and got sun from about 9.00am to 2.30pm -- either side of those times the sun was partly obscured by trees. Winter here, so the sunshine hours will be more in the other three seasons.

This is my camping spot, I am on the right:

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...doesn't look like many people camping there, but there were, lots of people, spread along the stream bank. Most of them were in more thickly-treed spots then mine.

It was interesting to observe the type of people there. More of the city get-away-for-a-few-days crowd, than holidayers and grey nomads. Consequently, some of the groups were "living it up" a bit more than I am accustomed to.

The group next to me, on left in above photo, had a radio running from arrival until late at night. On the other side, a fellow played "bongo drums".

The campsite does not have a camp kitchen, but does have open-air gas barbecues and fire pits. Many groups availed themselves of the latter, and there was a pall of smoke thoughout the campsite in the evening. I don't mind smoke though. Here is one of the barbecues and one of the bigger firepits:

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...the gas is free.

The campsite runs along a stream, which was no more than about 12 inches deep at the deepest, so paddling only:

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I didn't see them, but apparently some of the nearby campsites have places where you can swim.

So, what is there to do, apart from paddling in the stream? There are walking trails, various lengths, up to an 18km loop.

So, thumbs-up or thumbs-down? Personally, I would have preferred a covered kitchen area, and gas-ring stove would have been nice. I spotted one tap, with non-potable water. There are toilets, the deep-drop kind, and they were clean and didn't smell.

You have to bring your own wood, and bags are available in Dwellingup for $10. I have been to DPAW campsites that have wood available for free.

No phone signal, though there is a notice that Telstra intends to put a tower there. Radio reception on AM band had a lot of background hiss and only one station, 558KHz, was listenable. Nothing on FM.

Yeah, overall OK. Depends what you want. A weekend get-away with your friends, then ticks the boxes.  As a stop-over as you do the "big lap" around Australia, ticks the boxes also. After a few days, most people would be bored and would want to move on, I reckon -- but then, everyone is different, and some might like an extended stay, just going for long walks. Here is some feedback at TripAdvisor:

https://www.tripadvisor.com.au/Attraction_Review-g495055-d8009885-Reviews-Lane_Pool_Reserve-Dwellingup_Western_Australia.html

...some of the other campsites, that require pre-booking,  within Lane Pool Reserve look very interesting.

Tags: nomad

Coulometer error creep

May 04, 2020 — BarryK

I posted about installation and calibration of the coulometer, that displays battery state-of-charge (SoC):

https://bkhome.org/news/202004/installation-of-the-coulometer-lcd-display.html

I used the Amptron 15A LifePO4 mains-input battery charger to charge the battery to 100%, then set the coulometer to 100% and capacity 50AH.

There is however, a problem: a battery charge/discharge cycle is not 100% efficient, there is some loss as heat. The battery may be capable of supplying 50AH, however, it will require more than 50AH to charge it fully from empty.

Lead-acid technology battery are very inefficient, only about 70-80% efficient in the discharge/recharge cycle. LiFePO4 batteries are much more efficient, 90-92% round trip, see this document:

https://www.victronenergy.com/upload/documents/Datasheet-BMS-12-200-EN.pdf

The problem is that the heat loss is going to mean the coulometer will read incorrectly, becoming more incorrect with each discharge/recharge cycle. This is what will happen if we start with a coulometer reading of 100%, discharge to a reading of 20% SoC, then charge back up to a reading of 100%, then down to a reading of 20%, and so on:

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...this is showing the actual battery capacity (the values given are for illustration only). After some charge and discharge cycles, when the coulometer drops to reading 20%, the battery will actually have reached 0%.

This is bad news, however, the coulometer will self-correct every time the battery is charged to full. For example, I plugged in the Amptron mains-input LiFePO4 12V 15A charger, and plotted voltage, current and state-of-charge (latter as read by the coulometer):

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The coulometer has reached a reading of 100% before the mains charger has finished charging. As you can see above, the coulometer is reading 100% at 29 minutes, and the charger keeps going and turned itself off at about 31.5 minutes.

Note, after about a minute, the charger turned back on momentarily, then did so again after about another minute. I didn't catch the voltage/current readings, it was a very short duration.

Reaching 100% reading on the coulometer before the charging completes is a correction mechanism, however, a problem is that this self-correction is only going to happen if the battery is charged to full, or nearly full.

We really need another mechanism for the coulometer to self-correct. I don't see how we can use the charging voltage, however, the coulometer could be set to read 0% if the battery voltage drops below a certain value. This web page is a good read, and has some information on discharge voltage:

https://www.solacity.com/how-to-keep-lifepo4-lithium-ion-batteries-happy/

...that link has a graph of battery voltage while discharging, though it must be recognized that this is dependent on the discharge current. The graph is reproduced here:

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The Battery Management System (BMS) built-in to the battery will automatically disconnect the output if the voltage falls below a certain value -- from a bit of reading, this seems to be in the range of 2.5 to 2.8 volts per cell, which will be 10.0 to 11.2 volts for a 12 volt battery.

My Amptron 50AH battery has a BMS that turns the battery off at 10.0 volts.

The coulometer setup allows entry of a minimum voltage, below which the % charge will immediately drop to 0%. So, how about 11.2V?

OK, I have done that, have programmed 11.2V as the 0% limit in the coulometer. This will give an automatic correction when discharging the battery. The battery will be down at around 5% actual charge to trigger this.

Discharging a LifePO4 battery to 5% SoC will reduce the lifetime, but this should be a correction factor that is only triggered occasionally. Hopefully. Even if it is triggered often, I will still expect to get about 2,000 cycles, and even if I cycle the battery every day, it is going to last several years. 

One more point to make about coulometer setup: does a battery rated at "50AH" actually deliver 50AH? If not, then the capacity entry in the coulometer will have to be adjusted accordingly.

It should be noted that the "error creep" that I have reported in this post is a known problem, and it occurs on many devices, such as mobile phones and electric scooters. 

Tags: nomad

Powerbox front-page in nomad section

May 03, 2020 — BarryK

I have created a front-page for the lithium powerbox project, in the "nomad" section of my website:

https://bkhome.org/nomad/barrys-lithium-powerbox.html

The nomad section is a gradual accumulation of documents for and about "nomads", especially "grey nomads" -- these are people who have chosen an alternative lifestyle on-the-road, periodically or permanent. Here is the front-page to the "nomad" section:

https://bkhome.org/nomad/

Ha ha, I am in lockdown, as are all the grey nomads in Australia, but restrictions are easing. 

Tags: nomad

Powerbox circuit diagram updated

May 03, 2020 — BarryK

As the "protected +bus" has been added, and the binding-posts are not shown in the original circuit diagram, I have updated the diagram:

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The earlier blog post has been edited and the latest Dia and SVG files posted:

https://bkhome.org/news/202004/powerbox-fuse-redesign.html 

Tags: nomad