Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Show HN: $200 Solar Self-Sufficiency Without Your Landlord Noticing

medium.com

Post reply on HN
Print view View original

81–90 of 192 posts

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#81

Post by cjonas »

AnimalMuppet wrote: post #57
grecy wrote: post #33

I built a very similar system into my Jeep-house. I have two 100W panels on the pop-top roof, a charge controller and a dedicated solar battery (isolated from the engine-starting battery) that runs my fridge, water pump, UV treatment lamp, interior lights, air compressor and charges all my electronics (laptop, kindle, cameras, etc.) directly from 12V DC. I can leave the Jeep parked without running the engine for days…

A question: How much did the solar aspects of your rig cost? And a comment: You might want the ability to tap your solar battery to start the Jeep, if you're going to leave it parked that long.

I have a setup on my van and it was about 700$:

100w panel: 100$ Mppt Charge controller: 100$ 100ah batteries x2: 400$ dc breakers, fuses, wires: ~100$

My setup is enough to run a fan 24/7, multiple led light, charge phone & computers (~2x a day). Takes about two days of rainy weather before the system capacity drops below 50% DOC (which is where you should disconnect loads).

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#83

Post by accountyaccount »

Retric wrote: post #63
sitkack wrote: post #54

Please bolt the panel down, if wind picks it up and blows it off the roof it could easily kill someone.

I really doubt the wind is going to pick up a 2'x4' ~20lb panel like that when it's flat on a roof. Now if he had lifted an edge to try and get a better angle with the sun that would IMO be a much larger issue.

20lbs is nothing for a strong gust of wind on a roof.

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#84

Post by adrianmonk »

> Renters don’t need permission from their landlords to place things on their windowsill and rooftops if it’s not altering the building

This has never been the case in any apartment community I've lived in, ever. Every time I've looked into anything like this, the lease says I have to follow community rules, and those rules include stuff like pool hours and parking but also say I can't put foil in my windows, have a window AC unit, etc.

I'm sure there are some landlords who won't notice or won't care if you do this, but it's just not true in general that renters only need permission for things that alter the building.

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#85

Post by throwanem »

radiorental wrote: post #78
nettdata wrote: post #74

Earlier quoted context omitted.

It's called a battery isolator, and it's basically a monster diode from the alternator to the battery. Very common setup for RV's, etc. I had one set up in my Jeep so that it would charge the deep cycle marine battery for my fishing pontoon's electric motor... way, way faster than anything you plug into the wall.

I think you might mean solenoid?? It's controlled by the ignition. When the key is on / car running both batteries are in parallel. When the ignition is cut, the solenoid isolates a few circuits that are wired on the backup battery side of the solenoid. This is what I have in my vanagon. I run the radio, fridge, interior lights and some 12v / USB outlets. http://www.gowesty.com/product-details.php?id=2418

Both no doubt exist. A diode would let the secondary battery charge, but never let the engine draw on it; a solenoid-driven contactor would let the engine both charge and draw on the secondary battery, but only when the engine is running.

Combining both might not be the world's worst idea, depending on the design purpose. The diode alone would allow the secondary system to draw from the primary battery, potentially drawing it down far enough that it couldn't turn over the engine. The contactor would prevent that by completely isolating the two circuits while the engine is off; the diode would prevent the secondary battery being drawn down while the engine is on. If you need to draw from the secondary to turn the engine over or draw from the primary into your hotel load, you can short across the diode-contactor pair with one side of a set of jumper cables.

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#86

Post by arcaster »

mdb333 wrote: post #55

A couple nice things about SF on this topic: 1. Davis Stirling (Housing related laws) mandates that building associations cannot prohibit owners from installing solar panels. Basically, they have to work with you to find a way and can't just say no. 2. As of this year, SF is the first city to require that all new buildings (10 stories or less) have solar installed.

Another excuse to raise rent...

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#87

Post by lubujackson »

Cool. One caveat in SF (and elsewhere, I'm sure): since I work from home my electricity usage is way higher than the PG&E norm (which itself seems aspirationally low). Of course, PG&E uses this to charge me huge "overage" charges so using a solar panel to offset some of those charges might actually make this economically viable.

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#88

Post by 35bge57dtjku »

adrianmonk wrote: post #80
mchannon wrote: post #15

Far more cost-effective would have been to skip the battery and just put a cheap chinese pure-sine-wave grid-tie inverter to bridge between the wall outlet and the panel. It's simple- it has a 110V line cord and plugs into the outlet, sending current the opposite way of normal. Do a search on your favorite e-commerce site for "grid tie inverter" and you'll see what I mean. These cheap inverters have most of the same…

If you're going to break the law, isn't it easier to just tamper with the electric meter or run an extension cord to your next door neighbor's outlet?

Not if you want to avoid stealing.

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#89

Post by nikodunk »

adrianmonk wrote: post #84

> Renters don’t need permission from their landlords to place things on their windowsill and rooftops if it’s not altering the building This has never been the case in any apartment community I've lived in, ever. Every time I've looked into anything like this, the lease says I have to follow community rules, and those rules include stuff like pool hours and parking but also say I can't put foil in my windows, have a…

Good point. I'll clean up the language there. I've never lived in a non-ac unit and non-satellite dish place, but I probably have friends who do. How to work around that then? You could only use an ESCO (energy service company) on the east coast or cleanpowerSF for those scenarios.

Re: Show HN: $200 Solar Self-Sufficiency  Without Your Landlord Noticing

#90

Post by nikodunk »

matt_wulfeck wrote: post #67
xsmasher wrote: post #30

Earlier quoted context omitted.

Those calculations also assume he'll use all of the energy it produces, every day, with no loss; it's a back-of-envelope best-case calculation, at best.

If we're getting into the nitty-gritty, then let's also include energy cost inflation into the equation. These numbers are for PG&E which is roughly equivalent for SF: 2001: 0.10c kw/h 2017: 0.28c kw/h (as per my recent bill) That's an average of 10% increase in energy cost per year ! https://www.pge.com/tariffs/electric.shtml

Hahahaha that's an awesome point and not something I'd thought of.

But it seems that on your recent bill they're including the service fee in that – I'm only paying 14 I believe? Also, wasn't energy super expensive in 2001 due to deregulation? (I'd need to research this, not sure).

Post reply on HN