diy solar

diy solar

new to all this help lmao

Jtech1586

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Sep 11, 2020
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hey so i just started the idea of biulding a tiny home which is a 12 foot trailer after grabbing a watt tester and testing my top watts used per hour not including my back up electric fireplace is around 250-350watts this is what ive been looking at but might change my mind depending on your guys help

products im looking to use

batterys :
Power Safe SBS170F 12 Volt Solar battery's ?(100$ each used company went under cuz of covid)

solar panels : are 300 watt hhv solar tech panels x2 (125$ each used )

charge controller :
Renogy Rover 40 Amp 12V/24V DC Input MPPT Solar Charge Controller(brand new 200$)

and a inverter of course now that added up is 741 amp hours of battery on 600watts of panels but from what i was reading i NEED a mppt charge controller on any solar panel over 100watts or useing a pwm on a 300watt panel will basically make it run as a 100watt panel (yes my system will be 12 volts)

or other idea would be to run

the same batterys 4-6 100watt panels to stay with the 12volt panels and a pwm controller. useing a pwm controller is much cheaper but still seem to work fine for 100 watt panels batterys will still cost me the same and 100watt panels well there all over and seem work work around the same ish 70-85watts per panel

so what do you guys think it the better way to go about this? they both will end up costing me about the same either way
 
It really depends on the panel specs. i think a PWM controller will allow the panel voltage to drop to battery voltage which could result in the panel not producing full watts. If you had 100 watt 12v nominal panels which would actually be around 15 volts you could get full power but if you have 40 volt panels you probably wont get full power and a MPPT would be better for sure.

All that said bite the bullet and get the MPPT it will make life so much easier down the road.
 
so then yea probly best to just get the 600 watt panels 300 each and spend the extra for the mppt now i got 2 mppt charge controllers one 20amp for 109 or 1 40 amp for 189 for 600 watts i guess i need the 40amp? since i dont think 20amp will be enough over like 450watts right?
 
thank you so much nice to have a place to finally ask and get some answers .. 3 days ago i knew jack really now my brains melted with all the info about solar lol

if i wasnt limited to like 30sqft of space i would deffinitly go with 18v 100-150watt panels next time to keep it simple
 
Keep in mind, to recharge 740ish Ah (over 9.4KWh) is going to take over 15hours with the full 600 watts... and panels rarely put out full rating much of the day...
Also, 40 amps isn’t enough to handle the full 600 watts... it will be close though. At 14.8V, it’s 40.5 Amps, but many charge at 14.2V, so, 42.3A
 
I am unfamiliar with your panels, and if they're used they might put out to specs, but I doubt a brand new panel will put out 300 watts for $125. If new, I recommend looking at the dimensions and compare the surface size to a reputable company and the watts per surface size would be pretty similar. I recently found a 200 watt panel for a cheap price that put out twice the power per area a reputable company. I used Renogy for the company. That seemed too good to be true, so when I posted that here, there's heaps of panels that don't live up to specs being hawked from E-Bay.

For the battery, figure out the amp hours it will provide and if it meets your needs. Amp Hours X volts = watt hours. Also, with the lead batteries you don't want to discharge below 50% and you want to keep a reserve for cloudy days, so perhaps 75%.

When you say electric fireplace, if it puts off heats, peak watts is important to size the inverter. Some appliances that surge may require an inverter 3X the size of their rated watts.

As far as companies going under or close out sales, you're at the mercy that the equipment delivered to you is fine with no issues.
 
this is the panel specs there not 100% new and yes i know they will take along time to charge the ful amp hours but cuz its going on a off grid home im thinking at a full charge i would have days befor running out of power also might not use both batterys yet seeing as there 361amp hours each 40amp is legit like the best i can find for a mppt with out spending way more then my budget can go right now so it will have to do still better then running a pwm controller on it lmao
 

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its a 12 foot travel trailer with a tv computer fridge and water pump already tested the tv and comp running under 100% load on the computer is 165watts the fridge i was looking at has a run of 90watts surge of 200 but they dont run 24/7 so water pump is tiny and will barly be on along with 6 3watt led lights

as for the fireplace its 1250 watts peak its only for emerg tho since i also have a wood stove in the lil trailer plus if all goes well i'll be traveling from ontario canada to bc canada where winters are not even winter lol

my logic was if i used say 350watts per hour for 24 hours how much battery bank would i need lol incase i got stranded plus i wanted a lil more overhead watt wise in case i add things like cell phone reception extenders and shit
 
I know they will take along time to charge the ful amp hours but cuz its going on a off grid home
At which latitude are you intend to run that solar system? How many consecutive muggy days will you expect having to deal with?
How many power do you need overnight?
be aware that on an average rainy day a 600W peak solar installation might deliver only 30 Watt during a few hours around noon time and nothing else...

Just to give you an idea: I have expected to run just a WiFi router that draws only 6 Watt out of a 100W solar panel and a 100Ah battery.
That is just not enough to pass the winter. After three rainy days following a week of mid cloudy days, I was out of power.

P.S. most of the 12V solar panels are designed to get the MPP around 14V anyhow, so as long as you have matching panels, a PWM regulator will not be worse...
 
my logic was if i used say 350watts per hour for 24 hours how much battery bank would i need lol incase i got stranded plus i wanted a lil more overhead watt wise in case i add things like cell phone reception extenders and shit
You will need A LOT of batteries and half a yard of solar panels, if you want to run on rainy days as well.
If you only use the trailer on sunny days only, and be sure to operate in a 100% shadeless environment, then 3 KW solar would be OK.
 
Just curious about the fridge and computer, for a small space those seem to consume most of your watts. Have you looked at any changes there to reduce your consumption? Also, have you considered something like a propane heater as backup instead of electric, I assume that is there in case you don't have a supply of wood available to use with your wood burning stove?
 
where i will be moving to only gets to about 10cat its coldest so really im not worryed to much about heat its just a redundent back up to the wood as for power its a off grid home but can also charge off my car which is slow but its power along with a few other lil tricks to creat energy

i understand rainy days and all that lowwr power and if im am somewhere that has a power hook up im 100% able to hook up to that also i do have propain and use it mainly for hot water and showers but can be used for heat to

and yes the comp and fridge deffinitl;y use the most power 100% when testing the computer during a stress test and the tv on it only ran 150watts total the fridge says 90watts when i looked at it and even then fridges dont run all the time its on and off also might be something i actually put on a timer so it only runs when i allow it a few times a day specially if im gone with shity weather for days on end

as for the 48v panels and bucking down totally thought thats what the point of buying a mppt controller was for over the pwm is to deal with hgiher voltage panels and there output or am i wrong?

i biuld alot of custom computers for a living and i to was very saprised as 150 watts under a load test for the comp which puts it through way more then i ever will as a daily user what killed me was the brightness on my tv i useally sit at 10 but at 100 it added 100WATTS!! to the total power useage lol thats crazy when running the fireplace tv and computer under load is was 1330watts tho again the fireplace is part of the tv unit and there strickly for emerg


anymore questions or opinions? love all the input you guys are awsome hope im covering the points

edit the batterys im useing are 3500amp batterys

https://www.canadabatterysystems.com/products/view/33-enersys-powersafe-sbs-170f-12v x2
 
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anyone got any insight on these? saw some in videos look just like it


info on the side of the charge controller itself .. the 300 watt panels i was gunna get are gone now so got offered some 240watt watt panels cheaper and run 39voc so wouldnt tht match this all in 1? and a 800 watt pure sine inverter would cover my needs 100% cept for the stupid electric fireplace which at this point i dont care what u guys think?
 

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anyone got any insight on these? saw some in videos look just like it


info on the side of the charge controller itself .. the 300 watt panels i was gunna get are gone now so got offered some 240watt watt panels cheaper and run 39voc so wouldnt tht match this all in 1? and a 800 watt pure sine inverter would cover my needs 100% cept for the stupid electric fireplace which at this point i dont care what u guys think?
I'm skeptical it will be very good.
 
I'm skeptical it will be very good.
i normally would agree tho looks identical to the one prowes uses in his videos they even have a 24v version all the same kinda think it could be the one for my question is im im correct by these numbers technically they will accent the 240watt panel? or should i just go back to the idea of 150watt 18v panels insted?
 
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