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

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

#71

Post by Washuu »

mod wrote: post #61
AnimalMuppet wrote: post #57

Earlier quoted context omitted.

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.

Wouldn't tapping the other battery be a simple matter of a pair of jumper cables? I mean, I guess it'd be nice to have wired in, but I can't imagine the time-savings would ever catch up to the initial amount of work.

On TJ and older Wrangler the tray on the opposite side battery tray is empty. People will run dual battery setups that way. There are even options for all Wrangler models to put dual batteries in the stock location. $100 to $200 on a TJ Wrangler.

The cost and amount of work to do it is minimal.

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

#72

Post by dchuk »

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…

I can't remember how I did it specifically, but I believe there's a way to wire up a second battery to your alternator where it only charges it, and your vehicle will never draw from it. Could be a way to keep it topped off while cruising around.

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

#73

Post by k__ »

cjonas wrote: post #64

Obvious Problems: 1: You're not using a pure sine wave inverter so right off the back you are losing significant efficiency (Most the things you're charging use DC power anyways so it would be better to just get a nice DC charger). 2: If you are discharging your battery past 50%, you're going to significant reduce it's life span.

I asked this myself too.

Aren't most electric devices used today DC?

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

#74

Post by nettdata »

dchuk wrote: post #72
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…

I can't remember how I did it specifically, but I believe there's a way to wire up a second battery to your alternator where it only charges it, and your vehicle will never draw from it. Could be a way to keep it topped off while cruising around.

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.

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

#75

Post by diafygi »

I work in solar, and your panel really, really, REALLY needs to be secured from wind. Luckily, they make ballast mounts that don't require screwing into the roof[1][2].

[1]: http://www.orionsolarracking.com/commercial-roof-mount/balla... [2]: https://www.civicsolar.com/products/racking-mounting/applica...

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

#77

Post by serf »

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.

"Really doubt" is probably a poor level of confidence with regards to a decision that may or may not kill someone.

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

#78

Post by radiorental »

nettdata wrote: post #74
dchuk wrote: post #72

Earlier quoted context omitted.

I can't remember how I did it specifically, but I believe there's a way to wire up a second battery to your alternator where it only charges it, and your vehicle will never draw from it. Could be a way to keep it topped off while cruising around.

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

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

#79

Post by cjonas »

k__ wrote: post #73
cjonas wrote: post #64

Obvious Problems: 1: You're not using a pure sine wave inverter so right off the back you are losing significant efficiency (Most the things you're charging use DC power anyways so it would be better to just get a nice DC charger). 2: If you are discharging your battery past 50%, you're going to significant reduce it's life span.

I asked this myself too. Aren't most electric devices used today DC?

Everything that runs off a battery is DC.

However, for the past 4 months, I've been charging all my devices off solar/battery (working-travel vacation in a van). I have run into some issues with certain devices not accepting charge. I think it has more to do with the device charges themselves than the power source.

For example, my girlfriends Motorola Droid Turbo won't charge at all anymore off the 2.1 amp usb chargers. My S7 has no problems. Her cheap windows laptop will also sometimes refuse charge temporarily. Battery voltage is reliably between 12.3-13.0, which makes me think it's an issue with the chargers themselves.

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

#80

Post by adrianmonk »

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?
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