Hey guys, what would be the cheapest way to store 15kwh of solar

>>1224229
unironically the tesla powerwall

I live on a boat and currently am using two sealed 4d gel cells and two deep cycle wet cells for a theoretical total ~4kwh.

Lead acid looks cheaper at first but they have a discharge limit of 80% before cycle count degrades meaning you'd have to buy a lot more of them to get your full 14kwh discharge. They are also more lossy when charging, discharging, and lose more power the faster you discharge them.

Good 18650s when not buying by the pallet are very spencive. Buying lots of dead laptop batteries to rip open and salvage good cells is time consuming. $5,500 will get you a new 14kwh powerwall from tesla.

When my gel cells go that's what I'm going to do. That or buy battery modules from one of their cars. The weight savings alone would be worth it for me.

>>1224238
Ripping open laptop batteries and testing them may be time consuming but if you don't value your time too much, or have downtime at certain random times through out the week, it's a great project. I can't wait to get started. Breaking and rebuilding things makes me happy, even if it gets repetitive. If it serves a useful purpose or saves me money then I just enjoy it more. Used laptop batteries are cheaaaaaap

>>1224238

Use deep cycle lead acid batteries, not reused car ones.

>>1224229
A couple hundred thousand gallons on a hill.

>>1224229
Telco lead acid or AGMs.

Keeps the voltage steady at 12 DC across 98% of the discharge curve, and you can stack them.

Cons:you need deep pockets.

Don't use lithium ion cells for solar. It's so bad for the world and they are only good for 300 cycles or so

>>1224435
10 year warranty on the power wall with 70% energy retention at 10 years. and lets be honest, in 10 years we'll have something with double or triple the capacity for the same price so OP will upgrade anyway.

Buy a used Nissan Leaf or Chevy Volt battery pack (~20kwh) and break the modules down to 48v or whatever your system runs on. They can be had for ~2,200usd shipped to your door via car-part/lkq/etc.

The Volt batteries have provisions for water cooling - but are otherwise very similar in dimensions/price.

There aren't many (if any) solar charge controllers that support lithium chemistries out of the box - but as long as you can adjust the high/low voltage thresholds you'll be fine.

Downside: possible fire, upside: no outgassing/topping off with water maintence

>>1224229

Flywheels.

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>>1224229
Get yourself Electric Car Power-Pack.
Toyota Prius Hybrid has 2,3KWh Lithium Ion
BMW i3 33.4KWh Li-PO
prius you looking for 200 - 500 $ for BMW .. 5k$ ++

>>1224507

is this a troll post or a great post?

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>>1224876
Not trolling. Nissan Leaf/Chevy Volt modules are the best price per kwh for lithium.

I've put them in golf carts, scooters, kayaks w/ trolling motors - but haven't gotten around to putting them in a solar config yet. Hopefully later this year. The only scary part is dealing with 400+VDC when first opening the battery case. You really just need some gloves and a 10mm extension covered in heatshrink to take the whole thing apart. Maybe 2hrs top.

pic related what remains of my Leaf stash

>>1224507
You fail at charging lithium batteries.
Read stuff you lead-acid lover.

>>1224238
Boat-anon, I keep reading on CF about those LiFePo4's, expensive but a real game changer.

>>1224229
Check out HBPowerwall on youtube. He uses recycled 18650s in huge series.

>>1224237
or buy a scrapped Tesla car for salvage. The battery cells are literally the same but there's a bit of work to do to rearrange those battery cells into a power wall.

Pump water uphill, or use fuel cells if you don't mind blowing up
http://www.siei.org/mainpage.html

Overall:
Lead Acid and Lithium are actually starting to be comparably priced at that scale if you're willing to do the effort of rearranging cells from a Leaf power pack or such.
I'm really considering soon switching to Lithium because we get a lot of cloudy days in a row sometimes, and if I'm using my solar setup heavily for AC or something, my lead acid bank might not make it to full each day, and that's not great for the batteries. :(
Lithium's less picky about being fully charged every day. No 'sulfation' to worry about as I understand.

>>1224237
This is completely false in most cases, and also doesn't work if it's off-grid.
Tesla says that their powerwall system can't be completely off-grid, or you void the warranty.
(Also, good luck GETTING a Tesla Powerwall if you haven't already ordered, as I understand it.)

But...
>>1225221
Yea, this basically.
Or
>>1224507
Chevy Volt and Nissan Leaf power modules do tend to be pretty cheap.

>>1224404
Man, those Telco backup batteries make me hard. Seriously some of the best lead acid storage you can buy.

>>1225279
>pump water
This OP. With a good centrifugal pump/motor set up your losses will be MAX 60% with no degradation over time and it's pretty easy to get up to 80%
potential kinetic energy best energy

LG chem resu, LG sell a 48v and a 400v model depending on what is better for your use case.

Since this seems to be the designated solar thread I might as well shitpost here.

I am sick of paying for my mortgage so I am renting the house and going touring the country in a caravan. Whatever I buy will no way be ready to live in long term so I will be retrofitting a bunch of this shit.

Powerwise I will probably be running a 12v fridge, 4g modem, laptop a few hours a day, some LED lights and a 12v slow cooker. Heating and oven/range will be done on gas/240 if at a powered site.

If I stack my roof with 1000w of solar panels and a 300w wind turbine running back to ~500ah of 12v agm batteries, will that have me pretty much covered?

I live in New Zealand and hopefully will be touring up north so there is heaps of sun and wind. I have done a few calculations and this seems about right. Is there anyone with actual experience living off panels/turbines that could let me know if I am in the ballpark?

>>1224326
He means Tesla car batteries you silly cunt

>>1225093
I don't really want bleeding edge tech on my boat. Need something that can take quartering seas which is why I've been looking a lot at the car modules. They're impact tolerant and grouped into really conveniently shaped bricks that I could squeeze in the back of lockers or under cabins where the space is otherwise wasted. The best of all is each module has its own self contained plastic housing to contain splosions.

>>1226192
Unless caravan means something different here then where you're at I doubt you'd be able to get 1000w of solar on the roof. 300w panels are 77"x40". I could see you getting two of them on the roof... Maybe a third sideways. Don't expect them to put out 300w mounted flat to the roof. They really do need to be angled to the sun and track it to get the rated numbers. I normally only see ~220-250w out of my 315w panels because of it.

Be very very careful buying a 300w wind turbine. Anything under $400 usd is probably shit. Also they can be very noisy. Not the good relaxing noisy either. It's hard to explain. I had on one my radar pole and took it down because it's choppy whispy sound. Check youtube to get an idea.

500ah is close to what I run. My two gel cells are rated around 180ah each. I do have a couple other deep cycle bats that add another 100ah plus a standard wet cell for the engine that I never really use. The trick is to not go under 80% charge. Get a decent $2-300 MPPT charger and you shouldn't have power problems. Something to think about would be forgetting the solar and getting an inverting genset instead. It would be a lot cheaper even factoring fuel.

What are you doing for water/toilet/washing?

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>>1226230
When I say caravan I don't mean some poxy little caravan. Something like pic related. I was probably going to pick up a set of motorised rails that I can adjust the angle on too.

As far as toilet goes I'm hoping to retrofit a composting one in otherwise black waste and pumpouts which is pretty gay but it's just what it is. Washing will be by hand unless we are at a park and water is just from a tank.

How is living on a boat? It was an option I really wanted to do but the money for a decent sized catamaram is just not there and two dogs and a gf in a monohull is going to get uncomfortable real quick.

>>1226267
Oh you're going full on RV. That's so much better than what I thought you meant. Awesome.

I sailed with a guy which had a composting head. Life is a bit different with one. You don't put any toilet paper down them. He had a trash can next to the head which you tossed 'used' toilet paper into. Also you had to pee sitting down because they have a 'urine trap' in the front that just goes to a bottle you have to empty. It was a bit ... too much for me.

Boat life is awesome to sucky almost totally depending on the weather. As long as you're not in a hurry and can ride out unfavorable winds at harbor things are generally great. A week ago I had to harbor hop with rear quartering seas (thank god for dramamine).

I have a 38 foot fix keel boat. I wouldn't trade her for a multihull. Cat's have to be babied when sailed. Have to be ready to reef at a moments notice because if a blow comes on a cat and you're not ready you're going to lose your sail, mast, or even possible flip it. On my monohull I got 6000lb's of lead in the keel holding me up and the ability to heel. Worse thing a blow does is heel my boat more than normal and overpower the rudder turning her into the wind. Yeah it's a bit scary but blows aren't really predictable things. After I get the sails set and the auto-pilot working I can go below and watch a movie, make some food, read a book or (gasp) sleep.

You should look at 40-50ft center cockpit monohulls if you want space. A 43ft center cockpit makes my 38ft aft cockpit feel like a hatchback :(

>>1226287
Would you say an MPPT controller is necessary or would I be better spending the savings on a PWM controller to buy another 100ah or so of battery life?

>>1224919
Hey, can you please point me to where you buy these?

>>1226311
Would depend on your usage i guess. If you're going to be a heavy user at nights I can see where that would make sense (as long as you have enough panels to recover). It's a bit the opposite for me. I like having a surplus of power late day. It lets me run the watermaker off the panels with fully charged batteries. Also what power I use for cooking (microwave) is also mostly from the panels. Lastly I only have so much physical space for panels so I need to get every last watt out of them.

Remember though with a PWM controller the more discharged your batteries the less power you get from the panels.

>>1225988
This sounds like a really cool idea, storing water uphill and pushing a 12v generator going down, but all I can find is these 10w micro ones which don't look up to the job really. Am I looking for the wrong thing?

>>1226311
>>1226519
In a full time residence? Not likely.


The case where I'd recommend larger batteries and a PWM controller instead of MPPT, would be a 'weekend house' sort of thing.

Sure, if you have all week to let your batteries charge up, and then use them over the weekend, and then let them charge back up all week... you can get away with PWM and having a larger bank. You can also even decrease your array size if you feel like it in a lot of cases.

I can't really see getting a cheap PWM for much of any reason, especially since you're still talking about limited space for panels on a large caravan... you need the watts per sqft you can squeeze out of the panels.
Cheap MPPT controllers (as long as they're actually MPPT) are still better than pricey PWM controllers in most cases.

>>1224327
I came to post this. It is the only viable option that meets the OP's criteria of "cheapest way", providing that he has access to a pond or lake in the first place.

>>1224229
in the long run: nickel iron batteries. they dont die. never of ever

>>1226287
if you have the propane, get an incinerator toilet, the only things you have to have are proper ventilation/extinguishers, a small can to throw the ash, paper liners(to prevent shit sticking to the drop shoot), 12 volts, propane, and to remember to "FLUSH" only once a day or so. Shit and paper and piss ALL will be reduced to ash. Sprinkle that shit in the trash.

>>1228100
Get a LARGE AIR TANK, and an electric air compressor, off shoot extra energy during the day/night/wind into said tank.
Now you have all your AIR TOOLS POWERED, vacuum powered, compression air-conditioner powered, and direct/alternator power covered.

>>1230640
Fuck me that is a good idea. I love the idea of using it for air tools while building a house.

Newfag solar question. How many panels in series can I hook up? Do panels have different series amperage rates? I assume for example I can't hook up 5kw of panels together, they would have to be several parallel rows and that where a 48v MPPT controller is used right? Since it can take that (12vx4) 48v of power and make it all 12v.

>>1224229
Don't bother with lithium its a fucking MEME. he price is 5 times that of lead with cycle life you can achieve with lead. The only real advantage is has is no sulfation and efficiency and charge time. Biggest issue is price which is made worse by the need for a bms. Very prone to early failure. When the bms goes the whole pack will be ruined, even with stable lifepo4 batteries.
Look up a company called sbs industries. They sell tubular lead acid fork truck cells that are rared for 3250 cycles at 50% DOD. Just keep the cycles shallow, with daily charges and monthly equalizes and you won't have issue. I paid 1900 for 1070 AH 12 volt cells. They charge at a 10% rate. You would need a fuck huge 150 KWh battery bank for that. 15 KW of solar is pretty impractical. 5 kw would more than cover a modern home. Also look into outback powers enercell nano carbon batteries. Pretty much fixes the sulfation problem and they charge at 30%, costs more than the fork truck cell though. A little more sensitive than a flooded cell being AGM. Flooded batteries are more forgiving and repairable. The nano cell has less cycle life but can get pretty close. I think like 2500+ at 50%.
I can't recommend any battery that needs more than 60 AMPs going in at any voltage. 90 tops at higher voltages. Finding a controller that can handle that brings it down to a handful and at 12 volts the wire size is usually to big for most controllers. 48 volt 600-900 AH tops for a battery. So 40 KWH of storage.

>>1231614
so about 7 years for those batteries to lose usefulness,
is there anything diy or otherwise that works better for energy storage anons??
Air tanks work, BUT have limited usage/Large construction/cleaning/etc usages
Water tanks, both pumping to higher elevation and pushing a large mass upwards to drop and power a turbine have lots of mechanical wear and tear/seasonal issues.
Converting electricity into hydrogen/oxygen just uses up converters/storage of these not long/efficient
heating salt/water and using said heat later not that efficient/ very corrosive
dynamos and flywheels breakdown overtime too.

Solar during the day,
wind during the day, mainly the early morning and evenings,
generators and furnaces during the night(fuel dependent)

Do we go MAD MAX and turn pig flatulence and shit into methane power??

>>1226287
I'm slightly insane and want a really big boat, something with a crane and a cargo hold
could you point me to something matching that? most of what I find searching classifieds is yachts and I don't want no shitty yacht

>>1224229
668kg of marraging steel as a flywheel, or 6.35m^3 of mylar as a capacitor.

In all seriousness, deep-cycle lead-acids are probably the way to go if you can get them cheaper than stopping by your local Prius scrapyard. Where I live every single taxi is a hybrid, so I can imagine a growing market in cheap used lithium ion cells soon, thanks subsidies.

>>1225988
Top keks are on top for a reason. I bet i can hit 90 without even trying

>>1226230
Bonus with most 18650s feom electric cars is they have some sort of coating that turns into fire resistant foam when your cell explodes.

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>>1226317
Find your local salvage yard, get a quote, then lowball them an offer. In the USA, 'pull a part' and 'LKQ' are the big recyclers.

>>1232332
>big boat, something with a crane and a cargo hold
Me too anon. Me too.
I take it you've already seen 'SV Seeker' on YT?

>18650s feom electric cars is they have some sort of coating that turns into fire resistant foam when your cell explodes.
What? They are just metal cylinders filled with a rolled up goop filled mylar wrapper.

>>1232335
Are flywheels doable? Or are they just too inefficient?

>>1232644
They're lossier than chemical storage right now.

Hey, how do you get Pb wet cells back to holding a charge after going completely dry? I have one that'll charge but not hold a charge. It goes flat after a day.

>>1232335
Calcium copper titanate caps when? I'm actually tempted to buy the ingredients and attempt to synthesise some just to measure its leakage current and breakdown voltage to see how viable it is over standard electrolytics.