Offgrid Electric Car | Hacker News Reader

Offgrid Electric Car

joeyh.name

29 pointsakkartik9 comments

Awsome! And a real incentive to close the loop on my off grid house and shop, and add transportation. I am thinking about getting a car to go with the truck I will keep, but realise is just more vehicle than I need 50% of the time, so upgrading my solar array, and adding charging equipment for a car is looking good. I can attest to the simple facts of how reliable solar pv is, and that the ROI is amazing. The intangible part is that I just dont consider costs around electricity or home (wood) heating, which I realise has given me that bit of margin when I am running close to the edge.....ie: certain bills and stresses, just never add to the pile. I have also built and run a whole bio diesel truck and plant.There are local farmers who have gone all in, and are raising crops that are pressed for oil, which is then used in diesel powered equipment, the left over "cake" fed to livestock, some have gone even further and built methan digesters that convert manure, into well, methane, which fuels generator motors. Little islands that are operating successfully, providing employment, and selling goods and services, off the grid. Technicaly challenging, but profitable and insulated from other bumps in the economy.

This article is great: hard data from someone who is actually doing it.

The way solar panel prices are going, my suspicion is that the most economical way to get a reliable home system is to massively over specify the solar array so it puts out a decent amount of power on the worst possible day. The electronics would be sized to account for your maximum usage, even if that means dumping energy when the array output exceeds what you need. A battery would be sized to simply last overnight, on the assumption that the oversized solar array will be able to fully recharge it the next day whatever the weather. It would only be worth upgrading the electronics/battery if a buyer/money earner could be found for the excess capacity. I need to do the numbers to see if this hypothesis is true.

As someone who lives on grid, but barely... in that I lose power many times per year and have had week+ outage's.

I believe you are mostly right with the addition of * shift power consumption to summer months. * wood heat in the winter and electric air conditioning in the summer. * electric-expensive hobbies in the summer (e.g. welding) * with low winter consumption, multi day battery operation becomes feasible * small dual fuel generator and a propane tank to recharge the battery bank in emergencies and extended outages with little solar production

Why are the panels vertical? If indeed they are.

The panels have gotten cheap enough that the they are a small portion of final price. Mounting and investors becoming dominating.

So if you can mount them for cheap, you can get a cheaper system overall even if you need more panels to get the same total system output.

Plus cleaning panels on your roof when it snows it a huge problem.

So you're saying it's cheaper to e.g. buy 2x 100 Watt panels and mount them vertically, than 1x 100 Watt panel + extra hardware to tilt it to it's optimum orientation?

Vertical orientation is better for winter. This is an off grid setup he doesn’t care how much power he can have at noon in July. He already has plenty then. Vertical gives more power in the morning when the battery is low and he actually bends it

I don't have the exact break point but if you optimize for winter then you want a steeper angle. Especially further up north.

This guy compared different orientations:

https://www.youtube.com/watch?v=5AVO1IyfA9M

His conclusion is the vertical generate about 70% of optimal incline cells. The charge profile has two peaks, one in the morning, one in the evening. I can imagine using the vertical orientation for a fence. It would definitely keep them cleaner too.

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