Noobie solar system for charging construction batteries

[eppich8479]

Im in the process of buying an old abandoned house that will need a lot of work. Electricity was probably added after its original construction. Its going to get all new wiring so i dont even want to connect power to it.

I will need power for my tools. I even have a dewalt power station so i can power big tools. I just need something that can give me maybe 1000Wh a day to charge batteries. And storage capacity isnt a big deal. With all these sales going on right now whats the best bang for my buck? Because once the house is built and ready for power i wont have much use for the system.

I see these small all in one ecoflow systems on sale but the solar panels are like 1000$, 400w at 12v. Then you see the commercial grade panels for like $250-300 and they are 400w at 48v. This is whats killing me trying to decide.

 

[Solarcabin Channel]

1000Wh is 83Ah so a 200 watt panel, 100Ah LFP battery, 30 amp MPPT controller and inverter should work as long as you get decent sun.

That is probably cheaper than a power station.

Added: That is basically one of my recharging stations I use all the time for charging the ebike and recharging gadgets and tools and runs a 12 volt fridge. Also used to recharge my electric mower. I use a 200Ah battery because that system doesn't need to charge stuff every day.

After you get the house built you might want to expand that system and you can add panels and batteries to run all kinds of appliances and reduce your power bill and have an emergency system for a blackout.

 

[Madco]

I feel your pain - trying to help me elderly parents with a similar need!

I your case, why not just put together a small system? If you only want to charge hand tool batteries, the inverter will be small. At 1kWh/day usage, you will only need a couple, if not one, panel on the order of 400W.

 

[Hedges]

"Tools" - only charging batteries? If so a cheap AIO (batteries optional) and whatever used PV panels you can get locally.

Midnight DIY is a Chinese inverter rebranded and supported by Midnight. Plenty of Chinese named ones too.

Midnite Solar DIY Series Inverters

NEW from Midnite Solar - the DIY Series off-grid inverter/chargers. Affordable and simple, with excellent surge capability for demanding loads of off-grid cabins or homes.

www.altestore.com

Or get a 12V inverter, PV panel(s) & SCC, and hook it up to your car's battery. Can run engine on cloudy days.




Or do you need to run a skillsaw, a compressor? In that case, need to determine max running current, also starting surge. And get a fairly capable inverter. Starting current is typically 5x running current. Induction motors are more difficult than brush type. Tell us the current and we can recommend some expensive name brands, maybe people here will have experience with what the GroWatts and EG4 inverters can run. We've seen people start skillsaws and large angle grinders with cheap inverters, so long as a battery is attached.

Here's my favorite. Requires 48V battery (at least 4x car batteries in series) and separate charge controller. It should start any motor that has standard 120V 15A plug.

SMA Sunny Island SI 5048U 5kW Inverter 60 Hz | eBay

<p>SMA Sunny Island SI 5048U 5kW Inverter 60 Hz. </p><br /><p>Used but works well.</p><br /><p>Warehouse overstock.</p>

www.ebay.com

Some cheap inverters may do the trick. If they give a surge rating, must be for a couple seconds, not just 30 milliseconds.


Think about the future. How much is grid power? Does it make sense to have PV pick up some of the load? How about a backup system for critical loads? For furnace fan? If so, you could get something expandable now.

 

[eppich8479]

Or do you need to run a skillsaw, a compressor? In that case, need to determine max running current, also starting surge

This is why i mentioned the dewalt power station. It will charge 4x batteries, OR turn 4x20v into 110v 1800w peak. I can slow charge batteries all day and plug a table saw or microwave into this thing.

But i also have dewalts 60v tools and you cant tell the power difference between 60v battery and 110v wall power. They are heavy, but i love them.

Think about the future. How much is grid power?

This! This is why i dont spend $2000+ on a system because while it would do a great job durring building it would be challenging to make it work once my power needs hit full house size. And i dont want to drop +5000 for a true expandable system that might get rained on, stolen, or just damage during construction.

 

[Hedges]

Table Saw? What kind of table saw can you start with 1800W peak inverter?

If a battery powered circular saw (BLDC, VFD feeding 3-phase motor) does the work you need then you're OK.

some cheap AIO will do it. One guy got a Chinese inverter, fed the PV input from his Bolt EV battery, and that would start smaller tools. 4x automotive batteries for 48V bank it and started large ones.

Here's something in the moderate price range. Based on specs I think it would start any 120V 15A tools. It could serve as critical loads backup in the future.

EG4 3kW Off-Grid Inverter | 3000EHV-48 | 3000W Output | 5000W PV Input | 500 VOC Input

Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL

signaturesolar.com

You should be able to find PV panels used around $0.20/W, $200 for 1000W about 5 to 7 m^2. Expect around 4 kWh harvested in a summer day; how much of that you an use depends on battery size or how often you draw power. I think EG4 5kW lithium battery is about $1200. Four junkyard 12V car batteries maybe $100 (not good for cycling more than maybe 10%, but gives starting surge.)

Or as I said earlier, build a 12V system around your car battery.

You're just remodeling, not cutting all the lumber and plywood for a full house. Will have to see how compressor for roofing nailer works out.
Maybe something small does all you need.

I've been meaning to make a pickup truck mounted system.

 

[eppich8479]

Table Saw? What kind of table saw can you start with 1800W peak inverter?

This guy.

10" Jobsite Table Saw 32 - 1/2" (82.5cm) Rip Capacity, and a Rolling Stand | DEWALT

The DWE7491RS 10" Jobsite Table Saw 32 - 1/2" Rip Capacity, and a Rolling Stand has a 15 Amp motor and 32-1/2" rip capacity to allow cutting of large and hardwood materials. Features tool-free ...

www.dewalt.com

You're just remodeling, not cutting all the lumber and plywood for a full house. Will have to see how compressor for roofing nailer works out.

Dewalt makes all sorts of battery nailers and i have 6 different nailers of theirs. They work by spinning up a mass of weight and the grabbing it with a clutch bearing to drive a hammer. Works pretty well.

But im pretty sure the power station would work for at least 20 minutes with 9Ah batteries. Enough to pump up, and then i would have to swap batteries twice during the day.

 

[Hedges]

"15 amp Motor"

Try it, with a power station, before you buy them.

If it is brush type, might be able to arrange a soft-start. Dimmer switch, step-down transformer, maybe just a diode.

 

[eppich8479]

"15 amp Motor"

Try it, with a power station, before you buy them.

If it is brush type, might be able to arrange a soft-start. Dimmer switch, step-down transformer, maybe just a diode.

I already know it works. And its 3600w peak, 1800w continuous. I made a mistake

 

[hwy17]

If you're gonna be staying somewhere with power then I would think some combination of EG4 battery, EG4 charger, and Victron Phoenix inverter would be the cheapest. Lots of cost and complexity and uncertainty added to try and make it solar when you could just charge and travel.

Table saw adds a big surge requirement though that complicates it.

And then you compare that all to the fact that a $150 two stroke generator could do all of it. They don't crap out and beep like a lifepo4 battery or inverter on an inductive load they just droop way down to double digit volts and recover.

 

[Q-Dog]

I don't have any of these things so can't speak to their reliability.
3 or 4 of these panels: https://www.ebay.com/itm/124447507823?hash=item1cf9a6456f:g:1f0AAOSwnlZlPxen
connected to 1 of these: https://windandsolar.com/24-volt-pure-sine-suntaqe/
You should be able to charge your tool batteries as long as you have sun.

 

[eppich8479]

I don't have any of these things so can't speak to their reliability.
3 or 4 of these panels: https://www.ebay.com/itm/124447507823?hash=item1cf9a6456f:g:1f0AAOSwnlZlPxen
connected to 1 of these: https://windandsolar.com/24-volt-pure-sine-suntaqe/
You should be able to charge your tool batteries as long as you have sun.

The panels are 12v and you are suggesting 24v inverter. Can you series 2x and parallel 2x? I have a cheapy 400w car inverter. I could just hook it up to 4 panels in parallel?

 

[50ShadesOfDirt]

You are in "construction phase", and who knows what tool will be needed at what stage of construction ... compressors, table saws, etc. ... plus a raft of charging stations for battery packs. Also, this is a house, so even if on-grid, sooner or later you'll want "backup power", as the grid will occasionally (or frequently) go down on you.

Thus, put in a generator now ... site fuel of propane (with site tank), and a Westinghouse wgen9500df (autostart, remote fob, auto-choke, smart port for ATS, about $1000), and you've got power for any situation during any phase of construction. Later, you've got a smart backup power system, capable of being automated with ATS & such.

Don't want this fuel generator running all the time? Put in place an inverter and battery-bank (about $2000), and now the fuel generator runs about 4 hours per day, instead of continuously for utilization periods. You also have the start of solar equipment system ...

Hope this helps ...

 

[Q-Dog]

The panels are 12v and you are suggesting 24v inverter. Can you series 2x and parallel 2x? I have a cheapy 400w car inverter. I could just hook it up to 4 panels in parallel?

Did you look at the suntaqe page? It is power without batteries. Watch the video. Their custom box interfaces with a 24volt inverter. It's not a solution I would do, but if all you want to do is charge batteries, it could work.