2 panels off CL - now what?!

[ohmslaw]

Just bought two used (but not used outside) Panasonic panels 325w (VBHN325SA17) for $300 on CL and wondering how to set them up as cheaply as possible. They are just lying on the ground for now.

I may get other panels in the future. Looking to power something during the day but at 600w max I’ll be limited. Was thinking of a DIY storage heater, heating up a bunch of bricks somehow. I’m relatively handy electronics wise but also trying not to burn down my home Could just use it to power an oil heater we have here but the min power requirement of the oil heater is 800w I think.

I am looking for the cheapest option to get some useful power out of these pups!

So I posted this question on reddit and only got one response - someone was going on about my Voc was too high 69.6V “Those have Voc of 69.7V which makes them un-useable except with the bigger all-in-one solar power banks“ What you talking about Willis? I was under the impression a higher voltage would be better?

I see my options are some cheap micro inverters or string them together with a sting inverter. Not sure what’s the min voltage a string inverter can accept? (This on looks like a good price VEVOR 1200W MPPT Waterproof Solar Grid Tie Inverter) I assume I can then take that directly to my appliance. I’m also open to RTFM-ing if there is a good up to date book out there!

Here are the panel specs:
Model Number VBHN325SA17
STC Rating 325.0
PTC Rating 306.8
Open Circuit Voltage (V) 69.6
Short Circuit Current (A) 6.03
Maximum Power Voltage (Vpm) 57.6V
Maximum Power Current (Ipm) 5.65A
Open Circuit Voltage (Voc) 69.6V
Short Circuit Current (Isc) 6.03A
Maximum System Voltage (Voc):600V

 

[MisterSandals]

How about heating a barrel of water to warm your garage or shed or ??

6 Inch DC Submersible Water Heater Element

6 Inch 12 Volt and 24 Volt DC Water Heater Element from Missouri Wind and Solar. Use your solar panels, batteries, wind turbines, hydroelectric power to heat water and other liquids.

windandsolar.com

Several discussions...

Search results for query: heating element

diysolarforum.com

 

[Rednecktek]

Micro inverters and string inverters are for grid tie systems and require permits and inspections and tons of hoops. Avoid it if you can for a starter systems. If you get one of those "plug in the wall micro inverters" you might get the power company SWAT team banging down your door if it doesn't catch on fire first. (I kid... kinda)

When it comes to heating of any kind, the general response is "Anything But Solar!" because of the inverter and battery requirements involved. To put it in perspective, your bog standard electric heater wants 1500w which means your standard 100ah 12v LFP battery lasts about 45 minutes.

The VoC on those is high but not unusable. Even the most basic mid-tier MPPT can take 100v and 150v is not uncommon. I'd stick to parallel just to be safe as PVInput limits are a HARD limit.

Fortunately with that high a VoC you can use it on pretty much any size system, 12v (60a), 24v (30a), or 48v (15a) MPPT controllers are all available, and AIO's are a simple way to get started.

 

[Hedges]

Here's one of Will's links, for an AIO that I think would fit:

PIP-1012LV-MS – 12V 120VAC 1000W AC output, 500W Max 40A Mppt Solar Input – Watts247 Wholesale

watts247.com

 

[Mattb4]

600w peak over the average 5 hour sun day is ~3kWh to do something with. Enough to power a modest refrigerator. Runs some LED lights in the evening, watch TV charge your phone. If you go the cheap AIO route to a battery you would lose maybe half of that production to power the AIO but it would still likely power the refrigerator. Or you could go separate component route of panel/SCC/battery/inverter.

At 69.6Voc likely you will need to run panels in parallel unless you have one for the higher voltage SCC/AIO units.

 

[Rednecktek]

Here's one of Will's links, for an AIO that I think would fit:

PIP-1012LV-MS – 12V 120VAC 1000W AC output, 500W Max 40A Mppt Solar Input – Watts247 Wholesale

watts247.com

I have one of those, very handy starter AIO, if a bit limited.

 

[Rednecktek]

If you go the cheap AIO route to a battery you would lose maybe half of that production to power the AIO but

Depending on the AIO. As a rough estimate figure 1% of your rating per hour. I.E a 3Kw AIO will want about 30w per hour. A 1kw calls for 10-ish watts per hour. A 6kw might want 60w-ish per hour. It is just something to figure into when calculating loads.

 

[WindWizard]

If you want to go super cheap then just hook them in series and then wire them to a socket and then plug this immersion heater or one like it. It should be able to heat some water for you.

If the oil heater is electric then it may work. You would need to plug it in and see if it works.

Amazon.com

www.amazon.com

 

[Hedges]

The particular inverter I linked, data sheet says 15W (5W in standby). 15W x 24 = ~ 360 Wh, 12% of the estimated 3kWh production of the panels.

Yes, you can go direct to heat, perhaps more efficiently (depends on how far of Vmp the load operates.)
But some electric loads may be more useful.

I thought this would not be much of a way to save money, but ... $400 to process 3kWh/day, amortized over 5 years the inverter costs $0.073/kWh. Cheaper after that the longer it lasts. I expect panels to work for decades, inverter will vary with quality (and abuse) but many runs for years.

I have one of those, very handy starter AIO, if a bit limited.

You can spend more upfront, or cut your teeth on this and get another for bigger things.

 

[Liam M]

My 1st system I put together in 2020 was the MPP 1012 in the link, 600w solar on a manual tracker, 460ah FLA.
I added a 3000w inverter.
Ran all the small loads (charging laptops, phones, etc) on the 1012, and switched on the 3kw inverter to run microwave, water kettle, toaster, blender and more when needed. Even ran the washer and gas dryer in summer.

 

[ohmslaw]

Thanks for all the great suggestions. Heating water is a great idea. Kids always complaining about how cold the pool is in summer! Might take some time though! I know I overpaid for the panels vs a crate of them you can get for $40 each in AZ I heard + shipping.

Here in CO we get a shite ton of sun so I need to put these buggers to work ASAP! I saw the the thread about an oil heater and DC - if I wire this pup up Delonghi electric oil heater Model TRD0715T (following the guidance about arcing) and put it on it's lowest setting 800w I curious if this would work. I know the power is more than the panels so how do solar panels handle excess current? Probably not good idea.

Any suggestions on books / Courses? (To decode all the MPPs, FLA and AOIs!)
Also a good place to buy all the wire, connectors, breakers? Not that I'll need a lot of them.

A few folks on reddit said I wasted my money - told them I could also make a nice table out of the panels - cheeky buggers!
Thanks again

 

[Liam M]

Thanks for all the great suggestions. Heating water is a great idea. Kids always complaining about how cold the pool is in summer! Might take some time though! I know I overpaid for the panels vs a crate of them you can get for $40 each in AZ I heard + shipping.

Here in CO we get a shite ton of sun so I need to put these buggers to work ASAP! I saw the the thread about an oil heater and DC - if I wire this pup up Delonghi electric oil heater Model TRD0715T (following the guidance about arcing) and put it on it's lowest setting 800w I curious if this would work. I know the power is more than the panels so how do solar panels handle excess current? Probably not good idea.

Any suggestions on books / Courses? (To decode all the MPPs, FLA and AOIs!)
Also a good place to buy all the wire, connectors, breakers? Not that I'll need a lot of them.

A few folks on reddit said I wasted my money - told them I could also make a nice table out of the panels - cheeky buggers!
Thanks again

In the context of this thread, MPP = MPPSolar, makers of the 1012LV-MS, which is a 1kW 12v AIO (all in one - solar charge controller, inverter + in one case). This AIO would play well with your 2 panels in parallel, it has a VOC max of 102v as I recall.
FLA = flooded lead acid batteries, I bought mine 4 yrs ago when Lifepo4 was still expensive, no longer the case.
Will’s book and website mobilesolarpower helped me get started in learning the basics 4 yrs ago, and the website has lists of solar components like wire etc, with handy affiliate links for ordering.

 

[ohmslaw]

Ok will check out Will's website and assume you mean this book - https://www.mobile-solarpower.com/the-book.html
I order a solid state relay for my first project! Measured the oil heater resistance and lowest setting is 20 Ohms so current wise I should be ok.

CGELE Solid State Relay SSR-25DD with Heat Sink DC to DC Input 3-32VDC To Output 5-240VDC 25A Single Phase $11​

This also looks like it may work

Cadet 2F500-1W Baseboard Heater, 4.2 A, 120 V, 500 W, 1710 Btu, 50 sq-ft Heating Area, White​