Solar Power question

[dogmush]

I'm considering getting a 12V fridge for my camping rig.  Going to a fridge over a cooler will allow me to bring my food in a much smaller box (no need for 4 days worth of ice), and I find I need the room in the back of the truck for my new dog, who is larger than the adoption ad implied.

If I run a fridge, I want to upgrade my electrical instead of just running it all off the F-150's single crank battery.  There are computer issues that make it complicated to add a second battery to the truck for more capacity, so that has me looking at the overlanding/camping power stations, as well as ways to charge them without running the engine.

I have this roughly 23"x53" spot on the roof unused:


So I figure I can get a 100w panel there pretty easy.

For the power station, the 1000w(ish) stations all seem to be like a grand and have more crap than I need.  For example: Jackery 1000 I have no interest in the inverter, as I don't need AC much, and have one in the truck already anyway.  So I should be able to do this myself, right?

A panel
A charge controller
A Battery
and a box to hold it all

That's all I really need, right?  anyone that has put panels on a vehicle have any gotchas I need to look for?  How much cooling does the charge controller need? This will all be mounted on the outside of the truck, with just a power cable going into the cab for the fridge.  I also noticed that Renogy has a bluetooth module for the charge controller.  I already have a tablet in the truck running GaiaGPS for nav, so I monitor the whole thing from there, which would be handy.

Thoughts?  Ideas?

[Ben]

Thoughts?  Ideas?

Yeah, here's a thought or idea: Don't just drop "I got a new dog" on us in the middle of a solar power topic without starting another thread about the new member of the family!

 

[Brad Johnson]

How about one of the ready-made power pack setups like Jackery? 

In all seriousness, somthing like that should be more than plenty to run a small camp fridge and the integrated solar charging options make it easy. Can be spendy, but considering what you'd have in seperately-purchased components, it's not all that much more.

Brad

[bedlamite]

Have you put a Kill-A-Watt meter on the fridge? Some of them take more power.

I'd consider more battery. For the same price, you could get a pair of 29DC batteries from Mal-Wart and have a lot more reserve capacity.

The PWM controller is fine for a one panel system, and you're about at the limit. If you ever upgrade, a MPPT charge controller is the way to go. I set up my parents trailer with an EPEver 4215BN and 400 watts of panels a few years ago, and it runs everything they need. All their previous PWM controller did was get hot with 150w of panels and they had to run the generator when they weren't plugged in. This was running a fridge, on demand water pump, a couple LED lights, and the fan and controller for the propane heating system.

[dogmush]

I don't have the fridge yet, but online reviews lead me to believe it draws between 30 (eco mode) and 55 (max cooling) watts when the compressor  is running. Testing shows it'll run 35-40hrs on a 1000Wh battery.

Due to packaging, weight, and physical size, I'm not going to do this project with lead acid batteries. I'll look at the other controllers. I'd like the ability to add more panels later if I want.

[Bogie]

Consider buying some used bike/scooter lithium batteries... They're still good - it is just the bikes/scooters weren't...

[Jim147]

Start up watts and if it has automatic defrost will push the load way up.

[dogmush]

The fridge is designed for this application.

I'm more trying to build a reliable and non-incendiary charger and storage solution.

[Nick1911]

{quote author=dogmush link=topic=65872.msg1335805#msg1335805 date=1640983377]
I don't have the fridge yet, but online reviews lead me to believe it draws between 30 (eco mode) and 55 (max cooling) watts when the compressor  is running. Testing shows it'll run 35-40hrs on a 1000Wh battery.

Due to packaging, weight, and physical size, I'm not going to do this project with lead acid batteries. I'll look at the other controllers. I'd like the ability to add more panels later if I want.
[/quote]

So for a 24 hours day of use, you'd need 720Wh ish.

The amount of power per day you can get out of a solar panel, roughtly, is about 3x the nameplate wattage in Wh.  A 100 watt panel could be expected to provide 300Wh per day.  Of course, it depends on solar irradiance, panel angle, etc.  For your use case, I would want 250-300 watts of panel.

Thoughts?  Ideas?

Its not a bad idea.  Consider second hand panels that are no longer listed for grid tie as an economical option.
Pick your conductor sizes for ampacity, and fuse everything!
Your in a high vibration environment - use stranded wire and grommets.

[bedlamite]

Consider second hand panels that are no longer listed for grid tie as an economical option.

https://santansolar.com/

[French G.]

Do you give yourself the option to charge off of the vehicle when riding?

[dogmush]

Do you give yourself the option to charge off of the vehicle when riding?

I was thinking about it, but that complicates the setup.

[tokugawa]

I was thinking about it, but that complicates the setup.

The return is impressive, though. Reliable power and lots of it.

[Bogie]

You're probably going to want something that you can pick up, put in a sunny place, and then hook up. Going to be several panels.
 
As for batteries...

https://www.oreillyauto.com/detail/c/marine/battery-accessories/batteries---commercial/f78a23ef17b7/super-start-marine-battery-group-size-31/ssb2/31dcm

I have one of these out at the lake. 185 reserve capacity, 100 amp hours. Weighs in about 60 pounds. Ran an LED shop light off a small inverter for 4-5 nights at Knob Creek, but was in need of a charge after that...  If we do the Oklahoma shoot, I'm buying another one for the stereo.

If you're using computer equipment, you're either going to want something that can charge/run off 12 volt, or get a pure sine wave inverter. Those are pricey, but won't fry your chippies...

Thing is, the big lead acid batteries are a hassle - this guy has been doing DIY powerwall, etc., etc., stuff... With surplus/used battery packs, which are made up of basically what we use as flashlight batteries.

https://youtu.be/kIAMUnVxbq4

Testing

https://youtu.be/WvYlfZCOacE

[Bogie]

Or... a lot of folks are using small generators. The little Hondas, the knockoffs from China Fright, and the little 1000 watt things from China Fright. Easily portable fuel is a plus...

[dogmush]

Yeah, no.  This will be permanently affixed to the truck. Small and light is good on the batteries,  lead acid is out.  There are a number of prepackaged "solar generators " that do exactly what I want with a couple panels, a lithium  battery, and some fancy electronics,  but you pay quite a bit for that packaging.  I'm trying to see what it will take to make one, minus the fancy packaging and inverter.

REF: https://www.jackery.com/products/jackery-solar-generator-1500-jackery-1500-4-x-solarsaga-100w

I don't  need that much power though. I figure I need about 500Wh a day of generation, and storage.

[RocketMan]

Futurlec has an assortment of solar power charge controllers available.  Not very expensive.  I've done a little business with them over the years.

https://www.futurlec.com/solar-charge-controller.shtml

[dogmush]

Thanks, I'll look at them.

What is the difference  between pwm and mpg as far as charging control?  I'm familiar with PWM as a dc motor speed control.

[Nick1911]

If you're using computer equipment, you're either going to want something that can charge/run off 12 volt, or get a pure sine wave inverter. Those are pricey, but won't fry your chippies...

I think this is false.  Why would a switched mode power supply - whose input stage immediately knocks the AC to high voltage DC with a rectifier and filtering cap care one lick about waveform? 

[bedlamite]

Thanks, I'll look at them.

What is the difference  between pwm and mpg as far as charging control?  I'm familiar with PWM as a dc motor speed control.

MPPT is about 95-98% efficient, PWM is about 70%

[Bogie]

Okay. Go ahead. Plug your stuff into a square-wave inverter.

I know that stuff as simple as photo lights will go zappy pretty rapidly.

The Jackery things seem to be basically a battery packaged with a charge controller and an inverter.

I figure a charge controller to work a LI battery would be a bit more complicated, but you can get panels from China Fright at a fairly decent price. I think we sell LI deep cycles, but haven't even seen one in going on five years there. Just did a quickie price check - $1,250 for a 31 series that is equivalent to the one I have at the lake, but which weighs half the amount. Also seems to have better cycle longevity.

If the fridge is running off straight 12 volt, probably no problem, but a lot of gear hates the squarez...

This brand has good reviews... https://www.xantrex.com/power-products/power-inverters/prosine.aspx

I still have a couple of 110/120 to 12 volt transformers around here... Not wall-warts, but big industrial things, about the size of a couple of boot boxes. They'll put out some 12v juice, but they like their 20amp outlets...

[Nick1911]

Okay. Go ahead. Plug your stuff into a square-wave inverter.

Oh, I do.  And it works fine.  Heck, I recently started running my workshop LED lights off 170VDC.  Works fine, I'm not doing anything that the internal bits aren't doing already.  I take your snark to mean you have no valid technical argument to back your claim?  As someone that doesn't like to be lied to, I suggest you look further into that.  I think you'll find these are lies which premium UPC and inverter companies use to convince grandma she needs that to protect her "sensitive electronics", when the fridge compressor is by far more frequency and waveform sensitive.

[bedlamite]

Oh, I do.  And it works fine.

^This. With the vast majority of electronics it works fine.

[Bogie]

Okay - I'll try to forget about smoking a Schumacher battery charger that I was running off a generator - luckily was mostly done with that shoot... The strobes didn't like that sort of thing either. When I was doing a lot of the cell tower testing, they tried running some of the 110 stuff off a truck stop inverter, and... that wasn't good. Went to the pure sine wave stuff...

[Bogie]

Battery-wise, in the Sprinter, had the starter battery, and a pair of yellowtop Optimas, isolated and wired for 12 volts - still managed to kill at least one alternator with load tho... If I was doing that again today, I wouldn't use the Optimas - quality has gone downhill. I probably wouldn't go with AGM either. The battery banks constructed of the LI batteries look really interesting. The yellowtops would run some lights and a Webasto diesel furnace for about 12 hours or so. Wouldn't even dream of running an AC with it. I don't know how it would hold up with one of the chip fridge coolers either.
 
Weight wise, it is hard to beat the small generators. The Hondas are pricey, but they're quiet, and pretty efficient.
 
The "solar generators" I have seen seem to be woefully underpowered, and marketed to the same people who want pocket telephones with big buttons...