I need a free OG consultant

[TVLocationScout]

Hello,

I am homeless/off-grid and living in a cargo container in the Mojave Desert. I have acquired 10 each Jinko panels that range in wattage but are around 315-350 watts each. That is my starting point. I need to know what to buy next starting with combiner boxes and then the charge controller and then an inverter and so on and so on. I know I want the system it to be a 24 volt system. I know I will probably be starting with lead acid batteries. I have been using a couple of small panels from harbor freight for a couple of years. I am hoping that someone will help me design and be willing to let me contact them later on when I have questions.

My budget is near zero now but it could grow. I need to know how to wire it up with the combiners, and what size and type I need. Then I need to know what size of charge controller to buy, given which configuration the panels eventually are strung together. I’m pretty resourceful when it comes to acquiring things cheaply but what I need is a couple of options that I can switch to if my budget increases. Basically, I need help. I am homeless and have lived in a cargo container for the last four years. If someone is willing to provide me with the opportunity to call them a few times for additional advice, I will be able to make it through another Mojave Desert summer.

Thanks
Sincerely
Andy G

 

[AntronX]

Here is cheap setup for you. Hookup all 10 panels in parallel, no combiner. Connect direct to 2 x 12V batteries in series - no charge controller needed but you have to monitor battery voltage and disconnect panels when batteries get to 30 - 32V. Use power during daytime so batteries don't get full. I don't think batteries will last a long time with this kind of abuse so you may want to get a bunch of cheap PWM controllers.

 

[TVLocationScout]

I

Here is cheap setup for you. Hookup all 10 panels in parallel, no combiner. Connect direct to 2 x 12V batteries in series - no charge controller needed but you have to monitor battery voltage and disconnect panels when batteries get to 30 - 32V. Use power during daytime so batteries don't get full. I don't think batteries will last a long time with this kind of abuse so you may want to get a bunch of cheap PWM controllers.

Thanks for this tip. Not sure if I want to go without the controller though. Mainly because I think the cost of it would outweigh the shortened battery lifespan. But it would work in the meantime.

 

[OffGridForGood]

My budget is near zero now but it could grow.

I need to know what to buy next starting with combiner boxes and then the charge controller and then an inverter

PV - check
L-A battery - check
Connect as @AntronX noted, and be the manual SCC - to get started and be able to charge your phone to reach the forum - check
Next as you can afford cheap $30 PWM SCC to automate the charging of the batteries
Next add some small 24v DC items like lights or what ever you need in the connex
Next small inverter you can switch on and off manually just when you need some AC power
Next expand the battery system, one day get LFP when you can (you have a few years to reach this before your LA battery degrades.
Now you have a plan, and can work towards it.
When you have questions, post them here, and some of the 100,000+ members will help you out!

 

[wpns]

Not sure you need a specific consultant, the folks here have a wide range of knowledge and can help out any time.

I like the 'manual charge controller' thing, as long as you use golf cart LA batteries that can be topped off, you aren't going to destroy your batteries with the occasional overcharge, just consider it an equalizing charge. 8*)

Hint: LA batteries should be topped off with distilled water _AFTER_ being fully charged, as the electrolyte expands as the battery charges, and you want the electrolyte at the bottom of the fill ring at it's maximum point. Golf cart batteries properly maintained will give 5 years service, so just take care of them and they'll take care of you.

https://www.amazon.com/Battery-Indicator-Stacking-Monitor-Lithium/dp/B0BYMBJLMY is an example of a battery meter that's pretty cheap (and probably inaccurate, but you can mentally calibrate it for your current set of batteries). [My wife's golf cart has (8) Trojan T-105 batteries, and I got the 'high capacity battery' Curtis meter, and she just knows she can't go below 50% on the meter.] Yeah, there are better meters, and coulomb-counting ones with shunts and all that, but I'm trying to stay closer to your Zero Budget requirement.

There's a wealth of knowledge here and at https://batteryuniversity.com/articles

If you have a cheap DVM and/or battery tester or https://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html you can scrounge batteries at golf cart maintenance/refurb places and assemble a pack that'll be useful.

Why 24V? I'd think 12V would give you a wider set of available (automotive) devices.

Post the exact specs on your panels, and someone can help you optimize strings and a SCC to harvest closer to the 3KW that your panels can produce, and then you've got 15KWHR/day to play with...

Watch the video by Will about installing an AC split (and how to save money, and you can drill down to AC splits that'll run off solar panels directly, no battery, no charge controller, no nothing.

In fact, watch all the videos by Will at https://www.youtube.com/c/WillProwse 8*)

 

[AntronX]

Why 24V? I'd think 12V would give you a wider set of available (automotive) devices.

24V is better match for 315w 60 - 72cell solar panel voltage without requiring more expensive MPPT controller vs. PWM.

 

[Rednecktek]

You've got over 3kw of panel there, on a 24v system you're looking at 125a of charge controller at 24v. You're never going to find a cheap option for getting that much power into your battery.

Considering that dollar per usable watt, LFP is cheaper than lead acid. Lead acids only get to use 50% of their capacity so you need 200ah of lead to get the same usable power as a 100ah LFP. Considering you probably don't need low temp protection, you can get the cheapest LFP batteries and save money.
I.E. you'd need 4 WallyWorld 100ah deep cycle batteries at $125ea or $500 in batteries compared to $320 for LFP of the same capacity and 10x the life span by getting 2 of the 100ah LFP's.

Even the cheapest MPPT controller will turn solar DC into battery DC, no need for $$Victron$$ moneys on this. Whether you go 12v or 24v or 48v, you're going to need a few SCC's playing together.

 

[Daddy Tanuki]

You've got over 3kw of panel there, on a 24v system you're looking at 125a of charge controller at 24v. You're never going to find a cheap option for getting that much power into your battery.

Considering that dollar per usable watt, LFP is cheaper than lead acid. Lead acids only get to use 50% of their capacity so you need 200ah of lead to get the same usable power as a 100ah LFP. Considering you probably don't need low temp protection, you can get the cheapest LFP batteries and save money.
I.E. you'd need 4 WallyWorld 100ah deep cycle batteries at $125ea or $500 in batteries compared to $320 for LFP of the same capacity and 10x the life span by getting 2 of the 100ah LFP's.

Even the cheapest MPPT controller will turn solar DC into battery DC, no need for $$Victron$$ moneys on this. Whether you go 12v or 24v or 48v, you're going to need a few SCC's playing together.

yep i would go 48 with one good SCC. that and a samlex inverter, I use Magnum inverters, but Samlex are pretty good and reasonably priced.

 

[Pi Curio]

What are your power requirements? That is, what devices do you plan to run on this system?

Your panel's specs?

What is the lowest temperature you see in your area year-round?

If you were to sell some of these panels, how much money would you be able to get per panel?


As you can see, we don't have much information to go by at this point.

Yet depending on your power requirements it might be possible to design a small 48V LiFePO4 system that could give you enough power with limited duration. At the same time, keep the cost for components, tools, and wiring at a minimum, and enable you to do future system expansions in all aspects of the system in increments.

 

[DIYrich]

Will occasionally gives away free stuff. If you can make it to Las Vegas, he might have some spare stuff that would be useful.

 

[Daddy Tanuki]

Will occasionally gives away free stuff. If you can make it to Las Vegas, he might have some spare stuff that would be useful.

shit I have a bunch of stuff I would give for the USPS postal ride. if you are going to go 12 volt i have inverters, and chargers from well known brand names. i have nothing to spare onf the 48 volt front where I currently live, but yeah. leftovers from my first couple of installs and systems.. if the OP cannot pay shipping, then any member willing to pay from a military postal address (FPO-AP) to the OP can help assure this. We improvise, we adapt and we overcome.

 

[OffGridForGood]

Will occasionally gives away free stuff. If you can make it to Las Vegas, he might have some spare stuff that would be useful.

yeah, if you are good with some budget LFP packs, missing their cases...seems he would have quite a few of these from past testing!!

I agree with everything RNT says - get some entry level LFP - can always grow the system in the future. And all the Free OG advice you can handle is right here on the forum.

 

[Mattb4]

Hello,

I am homeless/off-grid and living in a cargo container in the Mojave Desert. I have acquired 10 each Jinko panels that range in wattage but are around 315-350 watts each. That is my starting point. I need to know what to buy next starting with combiner boxes and then the charge controller and then an inverter and so on and so on....

Before you buy anything (or acquire) next I would suggest you get a firm grasp of how the electrical specifications of each item affects the next item. You have 10 non wattage matched solar panels. You really need to know the specifications of each to be able to plan how they might be connected. The SCC (Solar charge controller) has requirements that must be met for proper operation which will dictate the need for combiner boxes and possible branch connectors and fuses.

A quick analogy for you. Your car runs on unleaded gas. If you fill it with diesel you will not get far.

When a person can not afford to hire others than they need to become an expert themselves by doing the study and research. Thankfully much of it is free for the learning.

 

[Norwasian]

The EPEVER charge controllers can automatically adapt to 12/24/36/48 volt systems, and they are not that expensive. I'm planning to buy two of them for my 48-volt setup just to have two separate MPPTs from them, in addition to the inverter's own MPPT. You could use them for a 24-volt system, and upgrade later to 48-volt without needing new charge controllers. That said, you will need a separate inverter if you plan to convert to AC.

Though less efficient, PWMs are much cheaper than MPPTs, and may be more reliable, especially in hot climates. Aside from efficiency, the principal caveat with using a PWM charge controller is that the panel voltage must more nearly match the battery voltage, at least a few volts higher, but not a whole lot higher as the PWM will just pulse the full panels' voltage through to the battery in bursts.