how do you build an offgrid system gradually? i'm poor

notarichman said:

i like your panel mount, but it is only good for 4 panels. i will have 12 panels in series and hope to have them tilt up and down only.

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It holds four panels in portrait, but can handle six in landscape. I just used four because I've sort of standardized on 120VDC for my solar inputs.

notarichman said:

i can have 528voc which is within the 600voc of the schneider controller. with 5 in series the voc is 220voc, which is within the 250voc of some controllers.

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What are your winter lows like? For high voltage strings, it is critical to remember that the voltage goes up as the temperature goes down. At freezing, a string that was 528 at room temperature will be 528Voc X 1.12 = 591Voc. At a colder -40 it's 528Voc X 1.25 = 660Voc

notarichman said:

I do have a midnight KID controller that i could use on the 4 315w panels -- 4 x 33.6voc = 134.4voc and the KID is 150voc. so i could use both controllers.

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Again, at freezing, that 134Voc is going to be 134Voc X 1.12 = 150Voc.

I like using Midnight's string calculator to accurately predict what my winter low voltage will be.

notarichman said:

like your panel mount, but it is only good for 4 panels. i will have 12 panels in series and hope to have them tilt up and down only.

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Modify his ideas to your needs

Rednecktek said:

OK, got a quick minute while the boss isn't looking. A couple more thoughts for you.

I would suggest skipping the AIO's and going for a component system for a couple of reasons. First, the standby draw on AIO's is notoriously bad and since you're on a budget you really need to maximize every watt hour. As an example my camp system will be 24v based and a 3Kw AIO (for simplicity because my nephews are jocks) and I'll have 6 of the 120Ah batteries in there. Of those batteries, 1/3 of them are JUST going to power the standby draw of the AIO while I'm up there. Going with components allows you to cherry pick your inverters and SCC to get the most out of every watt both in standby draw AND efficiency.

Secondly, since you're going to be building the system up gradually going for a component based system will make it easier to grow in the future as you'll be able to add SCC's or increase the inverter size much easier if you don't have to throw out the entire $1000 AIO when you want to make a big change.

Yes, AIO's are super simple, but they're really best for a Set-It-And-Forget-It type system.


Is there any reason you couldn't just turn the system off when you leave? Are there loads you'll need to have on all the time? How about just securing the breakers to the non-essential stuff and leave the fridge on? A good quality shunt can probably do all that and will be much cheaper than a SCC or something that will do the same thing. I think you'll have to fork out $RealMoney for the ability to do that. Affordable and Online Control are pretty mutually exclusive.

Winter is always the hardest on solar systems since you usually don't get krap for usable light and systems have a hard time keeping up depending on where you live. Definitely hit up PVWatts and the JRC solar map and see what you have to work with. You can check out my How Low Can You Go thread and see what kind of info you're going to get. The JRC site is really good for throwing in battery size and panel size and seeing how well you system will hold up.

Now is the time to do all the doodling and number crunching BEFORE you spend anything on parts that you might not be able to use.


I could do a really nice system in 8 months of pay if it weren't for those pesky cats and wife and house all wanting money.

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you have lots of questions! this reply should answer most of them.
i have 4 ea. 315w solar panels and 4ea. 245w panels - all used. will buy 4 more 245w next month. total will be close to 3kw.
i have a schneider inverter 5600w that i bought used for $500. currently, i am using a 1500w inverter for my beginner system.
i have a midnight KID mppt which only handles 150v and 30a.
i have 8 LFP batteries used hospital cart style 12v 40ah. I pick up 4 290ah 12v LFP batteries on may 2nd -- paid $1050 for them.
next month i buy the charger for them - 48v.
so far i've found several mppt's that will handle 250v pv and 2 that will handle 600v pv. i want to buy a 600v version to handle lots
of solar panels in series parallel eventually so i might as well buy it just once and save for it.
same for solar panels...an acquaintance is selling me the used 245w panels and has about 60 of them that he will sell me for $110 each.
yes, i have room for them. i live in north idaho. the webpage i found showing sun hours claims 3.5 hours of sun average. during the
winter i get about 4.5 if the sky is clear. but mostly the sky is cloudy. right now april 28th, i'm getting about 8 hours of sun when not
cloudy. i bought a killawatt and am checking the one circuit breaker for use normally. later i will turn off all but the fridge on that circuit
to measure it's power over a day. my computer gear and tv are the only other items on that circuit and the tv takes 20 to 30watts.
during the winter i will have my batteries in boxes with a very small heating pad inside to keep them somewhat warm. that will take WATTS.
there is plenty of room for all the equipment including if i buy more batteries eventually. i will buy a battery switch to choose set 1, set 2,
both, or off. that way i will be able to use/charge however i want. pushes/shoves...i will run just the fridge during the winter and battery
warmers, put the battery switch to my best set and leave to visit my sister. i may crack open the kitchen window to let a little cold air inside
for keeping the fridge running at a minimum. i don't have to worry about pipes freezing.
i have a good shunt, T class fuse, 2dc circuit breakers, but i think i need 2 more breakers.
another local guy has 365w panels for about $260 each, but it would be cheaper for me to buy 8 245watt panels than the 365w panels.
thanks for your advice/help. now i need to figure out whether i can hook up my little generator 1700w to my system when i'm home to charge
batteries and run the inverter without blowing up something.

I'm getting poorer! I bought two used 100ah 48v rack batteries @ a little over $4200 on my credit card. so i now have 3 loans to pay off.
plus my other credit card. however, as soon as i get the batteries I get to start wiring everything.

notarichman said:

I'm getting poorer! I bought two used 100ah 48v rack batteries @ a little over $4200 on my credit card. so i now have 3 loans to pay off.
plus my other credit card. however, as soon as i get the batteries I get to start wiring everything.

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You could have bought Costco's 210Ah golf-cart battery for 99$ each. Times 8 that would have been 800$ plus tax & core. Even at only 50%, that's 105Ah for 800$ instead of 4200$ Throw in a couple of dollars more for a couple of gallons of distilled water. Need to add it only every 2-3 months.

EG4 server rack batteries are $1500 brand new.

"mppt appears to cost $3000 including taxes and shipping."

Wow, that is a lot for a MPPT solar controller? You can get good controllers from $200 and up. And good pure sine wave inverters $600 and up.

GLC said:

"mppt appears to cost $3000 including taxes and shipping."

Wow, that is a lot for a MPPT solar controller? You can get good controllers from $200 and up. And good pure sine wave inverters $600 and up.

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Perhaps there's confusion between a controller, and an AiO? Most top of the top MPPT controllers are around 1400-1500$?

notarichman said:

I have some parts and am buying more in the next 8 days. i want to be able to power my kitchen when the power goes out...six times per year average,
usually 2 or 3 days, but one time for 9 days. i have totaled the max. watts I would need if using everything and the usual load; 4000 and 2500 respectfully.
350 ah per day should cover one day IMO. but for 3 days = 1050 ah would be better. especially in the winter (electric base board heat). i'm poor, so i'm going to have to buy major pieces like an mppt, solar panels, and batteries a little each month. i found 400 w solar panels @ 48 v for $229 each and think that i'll need
at least 4; 2 series/2 parallel. mppt appears to cost $3000 including taxes and shipping. 12v LFP Batteries could cost me $550 to ?? and i'd need 4 or $1500 for a set or a rack battery set for ??? All these big expenses total up to at least 8 months for me to buy. so my idea is to buy parts that i can use to grow my system as i can afford the parts and have a good 4kw system when finished instead of buying little system now, have to buy again later and have the small system which i can't use. i don't need blue tooth, but really want wifi monitoring and controlling. I usually spend 3 weeks new years and xmas out of town and want to be able to monitor the system and shut off the batteries if they go too low.
so what parts go together to make my intended system? thanks for your help.

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-DIY batteries (if you have the acknowledged).
-Inverters that can be added in parallel
-Cheap used Solar panels

notarichman said:

I'm getting poorer! I bought two used 100ah 48v rack batteries @ a little over $4200 on my credit card. so i now have 3 loans to pay off.
plus my other credit card. however, as soon as i get the batteries I get to start wiring everything.

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Not being mean, but used batteries should be way less than that. $3000 would replace my entire system snd then some. If you shop like that we can see why you’re poor! I’m not a rich man either but somehow I pulled off living off grid.

notarichman said:

I'm getting poorer! I bought two used 100ah 48v rack batteries @ a little over $4200 on my credit card. so i now have 3 loans to pay off.
plus my other credit card. however, as soon as i get the batteries I get to start wiring everything.

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Ouch! They better be top shelf and at LEAST have low temp protection considering N. Idaho gets cold for months on end. My property is right across the state line from you-abouts and it has ruled out LFP for me completely.

I think you got robbed dude unless there was a LOT more stuff in the boxes.

i did make a couple of mistakes buying equipment without doing quite enough research first.
my main mistake was buying a grid tie inverter that is used and old. i had never heard of a grid tie inverter. it won't work with
batteries. it just uses solar panels and ties into the grid. I don't want to deal with getting permission from the grid supplier
to feed into it. so now i have to buy an inverter that puts out about 5kw and runs on 48v batteries.
i will keep the grid tie inverter in case i eventually want to use it. OR maybe I'll sell to someone close by Spokane. It weighs about 70 lbs.
wouldn't want to ship it.

notarichman said:

i did make a couple of mistakes buying equipment without doing quite enough research first.

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Not uncommon, you should see my spare parts bin. Aaahhh, "Tuition"!

At least you can do the research. When I started trying to play with solar there wasn't much to work with for off-grid and it didn't start really becoming "available" to us working stiffs until the 100w panels got down below $200 a pop.

Fortunately 5Kw 48v inverters are readily available from pretty much everyone out there nowadays. You've got options, now you just need to decide if you need 120v or split-phase 240v and what brand you want.

Rednecktek said:

Not uncommon, you should see my spare parts bin. Aaahhh, "Tuition"!

At least you can do the research. When I started trying to play with solar there wasn't much to work with for off-grid and it didn't start really becoming "available" to us working stiffs until the 100w panels got down below $200 a pop.

Fortunately 5Kw 48v inverters are readily available from pretty much everyone out there nowadays. You've got options, now you just need to decide if you need 120v or split-phase 240v and what brand you want.

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i've been finding occasional 230w solar panels for $100. I don't need 240vac for now. when and if i ever need it; I will buy another 5kw inverter like the first one...probably the EG4LL 6500. They are about $1299 plus shipping and sales tax. but i owe about $12,000 and will have to pay it off 1st.
That will take me 4 to 6 months. I have a samlex 1500w inverter that I will use until then. ..and limit my critical loads to match it. I'd like to buy
2 more 315w panels to match the 4 I have. Meanwhile I'm buying 4 each 230w panels and put them 2s2p in series with the 315w panels. not totally efficient, but my math says they will produce more power.

notarichman said:

i've been finding occasional 230w solar panels for $100.

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SanTan has them a lot cheaper...