My Scratch Pad

[lighthunter]

Hi Steve!  I liked your freezer fridge mod you did a while back. Thats a pretty cool idea. Are you happy with the results now? I imagine it eliminates a fair bit of battery bank and doesnt deteriorate (like batteries do). Might it make sense to do it in a non portable setting as well like a walk-in cooler? (with xtra peak solar of course).

Cheers,
LH

[MadScientist267]

LH -

Indeed. It's one of my better creations of all time really... a lot of thought, time, and effort went into making it what it is, and it works absolutely beautifully...

Link to the (way overdue but finally posted) update on it...

http://www.anotherpower.com/board/index.php/topic,928.msg11589.html#msg11589

I'm in the process now of adding the final magic trick to the software that controls it... will post that update as well when I get it finished.

Nutshell, I'm adding Pload and Peltier demand to it to fine tune it's awareness of what's available to the batteries... So say if I need to run the laptop but the sky is sketchy, it'll favor the battery over the ice core and shut down the compressor until conditions are once again favorable.

The Peltier part has to be done separate because the classic can't "see" it's participation in the mix (high power mode is sourced at the PV combiner and has it's own controller). With summer heat, the fridge tends to dig into the battery further than it should at the end of the day because it's unaware of this additional load...

To answer the question about larger scale walk-in type stuff... I would imagine it's entirely plausible to pull it off... But, that comes with a "warning" of sorts LOL...

Thermodynamics is an insanely complex thing, and I have only begun to understand a tiny fraction of it's wonder, behavior, and propensity for practical jokes (which are apparently hilarious to *at least one* entity somewhere)... Smaller spaces are easier to gain control of, react quicker to input, and likewise, provide feedback as to how one screwed up on the last judgement call

With enough patience, the right phase change material, layout, software, insulation, and finger sized holes in one's scalp, I'd say it's certainly doable. That list by the way being nowhere near exhaustive... The bigger the stakes, the less sanity one will walk away with. That much I can say with absolute certainty

Till next time...

[lighthunter]

Thankyou for your reply & recommendation! very interesting!  I would think most folk with RE have peak excess at times and the obvious one is to heat water but storing ice is also just as valuable yet I hardly ever notice anyone considering it as you have. Mostly surplus solar happens when nobody is around to use it. For that reason is why I have built my setup to run all the cooling appliances first, then heat water and make distilled water (Oz says is waste hes lots more creative with RO. In the winter i get the extra heat from the distillers tho. Anyway, I just love your idea and it makes so muh sense when batterys are a large part of an RE system, when you can store without a battery i say its a winner!! In all my travels running into R&D / proto people you have got to be the most detailed individual Ive run across, you certainly have thought out every variable in the equation. In your application i suppose efficiency has bigger rewards with limited panel size. Good work and thanks for sharing it! some day (hopefully this summer) when I get the wind gen up I will have need of more load and that might be the ticket. Might even be a place for two stage compressor with a more dense capacity working fluid. Havent thought about it much but a cyrogenic type comes to mind. Something that doesnt disappear at STP and exhibits phase change at a cooler temp than 32 so as to maintain a controlled temp at 0F rather than 40. Maybe there isnt one in that category, just thinking of possibilities!

Have a great Eve!
LH

[MadScientist267]

G-Forces... ugh

[bj]

Take it that you had issues with movement versus object mass.
Don't know what size your chassis is, (2, 3, 5 ton)  but I know the only
time my two ton rides smoothly is when it has 4400 litres of water on it. 

[rossw]

I know the only time my two ton rides smoothly is when it has 4400 litres of water on it. 

Wow, overloaded much? (That's almost 4.5 tonnes on board!)
I know my tandem trailer bounces like mad until it gets around half a tonne in it... then it's sweet.

[dang]

4400 Pounds = 1,995.84 Liters     4400 liters = 9,700 Pounds 

[bj]

  It's licensed for 3920 KG  (based on tire size) so overloaded a bit.  More and the
overload springs are too flat, less and the water sloshes too much.  The "sweet" spot.

[MadScientist267]

---------------

Bj/Ross - on the classic - yes, I didn't realize it at the time but the plastic in that "hanger" isn't just superficial. Not the greatest design, but I'm not holding that against the folks at midnite... I'm probably one of the rarer cases of use in a hostile mobile environment. That said:

Guys at midnite: "We're out there... Something to keep in mind for the future!"

I would have reinforced it from the git-go but didn't realize it at the time of installation. Gonna be fun getting it down if/when the time comes.

[solarnewbee]

Hey there Mad!

I've racked my brain in what little free time I have and came to the conclusion that my brain doesn't wrap around these things as well as yours does. So,,,,I relented and purchased a Relat BMS system on Alibaba. Just under $975 it covers each lfp cell and monitors impedance of the cells and reports can be tailored for web software use.

website if you're interested what it does:  http://relat.en.alibaba.com/?spm=a2700.7803228.0.0.0Qedow

I am going to charge forth (even if I blow a brain fuse) with raspberry/arduino monitoring temps etc on my PJ and take action.

I am always captivated by your projects and techniques so thanks for sharing.

SN

[MadScientist267]

SN - I'm glad to see it's useful to someone... What I've got here is something somewhere between insatiable curiosity and necessity... attempting to coexist LOL - I've made my self-imposed quota if even one crazy nut like me finds the key to a magic trick buried in the mess of postings I've got going here

For the battery management - indeed. Lithium isn't like lead acid at all once you get past the ideas that 1, they both have terminal voltages, 2, they are DC, and 3, they store energy. I think they both will pass current as well...

[Flooded] Lead acid is incredibly forgiving compared to lithium. I haven't seen a case yet (except maybe where only a small single cell is involved, eg yard lights etc) where a good battery management system isn't absolutely crucial to the continued health of a bank, pack, group, flock, school, pride, clusterpfft of lithium cells... regardless of what you want to call them LOL... and in a few cases, outright safety

One day I hope to take the plunge myself into a "real" lithium bank... until then, I'm watching just like you (except lucky you gets to be another [apparently to be satisfied] guinea pig for LFP). So far I've heard good things, just gotta do 'em right

Rock on dude, I have a lot of fun doing this stuff even if it does have some really whack moments... I rest easier knowing what I design can't be any more insane than I am for building it LOL

Steve

[MadScientist267]

Anybody hear a sox fan?

[bj]

  Over the years I've used those fans for a lot of different things.
  That's a new one for me though.
  Impressive.

[MadScientist267]

Hehe Yeah they're pretty handy for sure. Not so sure tho that the entire project would have been possible without the advent of the brushless DC motor. Or at least not anywhere near as practical anyway

They're indeed holding the socks open but the one on the right isn't dark due to moisture. Zoom in on that and you'll make the same discovery I did a couple days ago... At some point the phone's camera got in to an argument with the sun and lost apparently.

Only thing I can place any bets on as to when it happened is "probably mid day"... shrug

[MadScientist267]