Wednesday, July 27, 2016

Article on savings by the first Australian to install Tesla Powerwall could easily mislead.

When I read some articles in the news media I really can't believe them. The following article is one example.

If you read this article the implication is the savings were made all because of the Tesla Powerwall. A massive 90% saving. However dig a little deeper and if I'm reading the information provided by the person through their own site and other news sites, a different story starts to appear.

Yes the person has made savings. Whilst I don't know how many kWh per day the $660 bill was for, the bill was for 91 days and a rough estimate would indicate around 24-25kWh per day. The person has now reduced their usage through knowledge to 13.7209kWh per day. That's roughly a 43% reduction.

Reducing electricity usage isn't a saving that can be attributed to the Tesla Powerwall. The same or better can be achieved using a $25 power meter device and reading the energy ratings on devices. Power companies now provide sites providing information down to the hour on your usage. Knowledge that doesn't need any outlay.

This is all very rough, but I think you get the picture. If we reduce the electricity usage by 43% (first removing the daily service charge) the equivalent bill for the same usage would be roughly $326 compared to the post Powerwall bill of $50.39. Yes an excellent saving, but not quite as much. That's a saving of roughly $92 per month, and if we assume usage is the same every month, a yearly saving of  roughly $1,100.

The set-up cost for the person for their system was $15,990. The payback period is thus around 14.5 years.

The person also mentioned they could have put the money into their mortgage for an interest saving of $750, which people often forget is also tax free. Put the same money into the mortgage over 14.5 years and the benefit would be around $31,000 tax free.

The problem here is not unusual. People only think about reducing usage after they've made a large investment. I nearly did the same. Instead I worked on reducing my usage first. My normal electricity usage was around 13-14kWh per day. It's now 5-6kWh per day. No solar. No large outlay. With discounts, once you're using the level of electricity grid connected solar no longer makes financial sense.

If you have mortgage or other debt, it really may be worth considering paying down the debt before making purchases like this that have payback periods that are near or longer than the life expectancy of the equipment. With electricity usage, first reduce your usage as best you can and only then look at the payback on investing.

The article in the newspaper really made me interested again in the Tesla Powerwall, but once I go through the numbers and research further, what's being said simply doesn't add up. Good unbiased knowledge can only help you make better and more informed decisions.

Kelvin Eldridge
Electricity Cost Calculator

Tuesday, July 26, 2016

Share My Location web app is now live.

Hot off the press the Share My Location web app is now live. Those of you who know me, know I write web apps for myself and make them available for others. I figure if they help me then perhaps they'll help others as well.

Share My Location enables you to share your location with someone else. Not just your current location, but your location as you're moving. You may in a car, on public transport, or just walking, but now you can share your location with someone else.

Yes there are apps that do this, but most only work for one device. Share My Location doesn't need to be installed and works across multiple platforms. Now obviously if you're sharing your location it's best if you have a GPS enabled device, but the person you're sharing with can be on any computer or mobile device.

No identifying information is requested. No sign up. You just visit the site,, click the Share On button, click on the link to send an email and you and the other person (or people) can see your location and follow your journey. Great for letting people know where you are. Great for meeting up with people. Great for helping people.

I write the web apps because over time it's what I wanted on a number of occasions. Now I have what I want and I'd be fairly sure others have probably been in the same situation.


Kelvin Eldridge

Friday, July 22, 2016

Petrol prices in Melbourne spiking at the moment.

It's been interesting watching the latest petrol price hike in Melbourne. There's usually up to 4 days before the new higher price moves across the market. Normally I see the price hike on the second of the four days and alert everyone using the Petrol Price Melbourne site  This time I noticed the price hike very early since I'm now recording prices in the area.

Two things became apparent. The trend on the site can go in any direction on the first day. Whilst some prices are spiking, others are still going down. It is really weird to watch part of the market going down whilst another part is having a massive price hike of around thirty cents per litre.

The second was I felt the colour coding for the markers on the maps which help people locate lower priced petrol wasn't particularly good. My initial approach was 21 coloured markers at set price intervals, but unfortunately this approach didn't make it easy to distinguish the cheaper prices as the prices move down. This is because the market has a small spread of prices (4-6 cents) so the markers all look very similar.

I decided to change the markers to indicate one cent differences. This is very good when prices are going down. When prices are going down the range of prices is usually between 6-10 cents, so the coloured markers can be easily distinguished. When the price spikes the average moves towards the middle so is everything lumped into red (expensive) and green (cheap). When this occurs you may need to check individual markers or use the cheapest page to find the cheapest petrol. When the price peaks the new peak becomes the average which will show as yellow. As prices drop the range increases and the range of coloured markers again increases.

I hope this new colour coding scheme makes it easier for people to find cheaper petrol and save money on their petrol purchases.

Kelvin Eldridge

Wednesday, July 13, 2016

Petrol Prices Melbourne - Now showing average, maximum, minimum and trend.

The main page of Petrol Prices Melbourne now shows the average, maximum, minimum unleaded submitted petrol prices, along with the trend from yesterday. This is a good way to know roughly the price petrol will cost. Petrol Prices Melbourne 

Kelvin Eldridge