What was your biggest mistake on your first system?

[metalheaddoc]

So we beginners can learn from our more experienced members, can you share your biggest mistakes when you were building your first system?

 

[BentleyJ]

I'm going to have to go with not planning ahead far enough. After we had our 20 year leased solar system installed back in 2011, I started thinking about improving the system over time. First upgrading the 100A main panel to 200A with 42 breakers. Then after a couple of years I wanted to add batteries and an AC coupled back-up inverter with gen input. End result is that all the upgrades work very well, we have 6KW of solar, whole house back-up, with about 13KWh of LFP batteries, a dual fuel generator that plugs directly into the secondary inverter input. The system can provide Peak Load Shave for Time of Use metering Etc. Here is what we DON'T have. Extra space to add a second, stackable back up inverter and more batteries. Not to mention the dual fuel generator cable has to be manually plugged in because I didn't install an extra UG conduit with we completely landscaped the backyard and side yards a few years ago

 

[rmaddy]

Mine was not starting sooner.

If I may, I'll offer advice on how to avoid making any mistakes - plan, plan, and plan some more, before buying anything. Work out your realistic needs with an energy audit. Plan a system. Post it all on this forum for lots of feedback. Work out every component, wire, connector, fuse, etc. before buying any parts. Don't cheap out on poor quality parts. Saving a few dollars on a cheap breaker isn't worth burning down your house/van/RV, for example.

I did the above and after 9 months of living full-time in my solar powered trailer, I can say I wouldn't change a thing in my electrical system.

 

[robby]

Mine was designing my first system plan based on conversations with SMA sales people and then Impulse buying a Sunny Boy Inverter. Then weeks later finding out that the sales people had told me a bunch of rubbish and that I would need twice as much equipment as first proposed and then another week later when pressed to put it in writing that all of this extra equipment would indeed allow me to create a Micro Grid, they backed out and would not confirm in writing that it would work.
Luckily I was able to return the Sunny Boy but I wasted a good six weeks of time on planning.
This almost went even worst when I almost bought the LG battery that was part of the planned system.

Lessons learned: Do not impulse buy anything solar and do not assume that sales people actually know how the equipment works.

 

[chrisski]

For my RV install, it was not planning the roof top panel placement to fit as much as I could up there.

There's things I may do differently this time like either use an All in One or Inverter / charger, but I am glad I did not wait.

 

[Rocketman]

My first biggest mistake goes back 20+ years.

I was adding a 100w solar panel to my 5th wheel RV. This is back when solar stuff was really expensive (but it was cheaper than replacing RV batteries every two years - in the long run).

Anyway I hooked up the SCC (solar charge controller) to the battery, then got on the roof to hook up the solar panel.

Got down and I could smell something burning. The SCC had a quarter-size burn hole in it. It had burned away the plastic type covering underneath and scorched the plywood underneath.

All because I confused that houses have a black hot wire and white neutral and vehicles have a ground black wire - I had switched and wired the SCC backwards. Yes, I realize I was lucky/blessed that I only destroyed the SCC and not the RV and house (and neighbors house).

 

[toms]

Biggest mistake i see is not looking at what others have done. Find as many systems as possible with similar requirements to yours and look at what has been working long term.

I see too many people following youtube advice of others who have barely any experience - then are disappointed when their system fails early.

 

[pollenface]

I was really clueless to begin with.

I went threw 3 controllers in the bin because I unknowingly connected them to the PV first and they overcharged my 12v battery.

I killed 2x 170ah AGM, 2x 85ah AGM, 2x 50ah Lifepo4 within 18 months with el-cheapo single stage PWM regulators (14.6/29.2v ALL DAY LONG).

Someone I know just connected the solar panel straight to the battery without a charge controller and left it like that for MONTHS.

 

[Substrate]

My biggest was trying to manually "compensate" for a long run of thin cable's voltage drop.

While my battery specs said the terminals wanted to see 14.4v CV, when I measured the cable prior to setup, I did a dc measurement with another battery and saw a little less than a whole volt drop at the other end.

No problem - I'll just manually compensate by setting my charge-controller's CV a whole volt higher! Brilliant! Spun the propeller on my hat. So I set the controller to 15.4v instead of 14.4.

Things were working - at first. Seemed normal through the bulk phase, and even got into absorb phase hanging around 14.4v eventually. I'm cheating the laws of physics and getting away with it! Why is everyone harping on the proper cable size all the time? Just compensate!

Then the solar gods got angry. Once the battery had charged up so much, where the current was so small that voltage drop was no longer an issue, I fried that little agm at 15.4v.
I heard kind of a whine. Like that little voice from the classi sci-fi movie "The Fly", asking for someone to kill me... kill me...

It was my agm gassing out. Learned not to try and cheat physics.

 

[Nobodybusiness]

So we beginners can learn from our more experienced members, can you share your biggest mistakes when you were building your first system?

Biggest mistake IMHO is not knowing what you want to do with it, What is is supposed to provide, What is your motivation for doing it?

It’s hard to go from running a Fridge to a whole house.
Totally different set of problems and equipment.

Please do not buy anything before you do the rest.

There is a steep learning curve for DIY even if you have electrical background.

Determine from the outset what you want it to do and how much it needs to provide ( Energy Audit).
Determine if you have enough space to do that.

A Good solar system for a house with battery Backup isnt cheap even if you do all the work yourself.
If Just saving money is the thought process then you may be disappointed.

Learn, Learn , Learn about every Manufacture. What their strengths are, faults. Ask everyone about their “Real world” system not the one on paper.
Just because some solar installer or Guy next door tells you this is the bees knees doesn’t mean it is.
Unfortunately people lie and some outright just don’t know or worse yet think they know.

You will also need to know how to maintain it after it’s installed.

If you just want to call someone at 3:00 am then it’s gonna cost you.


The industry isn’t mature enough yet to just grab someone off the street and have them build you one or even take their advice about building one yourself.

Me personally is was more about energy independence.
When everyone else’s power is out we still have it.

If they decide to raise rates then we don’t care.

If they decide you are not complying with their latest set of ridiculous laws and threaten your public service, Ect.

This is what is comes down too.

Why are you doing it? What do you want it to do for you? How much are you willing to Spend?
How much are you willing to learn?
How much are you willing to do yourself?

Most of the regrets people have is from not thoroughly answering those questions.

 

[Rennit]

I wish I would have bought more batteries. When I planned and developed my system, I planned on using my batteries for backup only, but instead I'm using them daily to offset grid usage at night. I went with 15kwh of batteries which won't 100% offset my night time usage. I wish I had at least 30kwh minimum, and that's only enough to keep me off grid at night. I have a big power hungry house, 2000 to 2600kwh a month is pretty average usage depending on the time of year, so you can image how little 15kwh of batteries goes towards that.

 

[Rednecktek]

I'd have to say that my 2 biggest mistakes, and 1 I'm still dealing with today, were:

1: Not knowing where to find the information to learn, doing everything by trial and error. I didn't know about this site until after I was fighting with my 2nd small system and failing.

2: Thinking that the math for solar meant anything in the PNW where we have no sun.

 

[robby]

I wish I would have bought more batteries. When I planned and developed my system, I planned on using my batteries for backup only, but instead I'm using them daily to offset grid usage at night. I went with 15kwh of batteries which won't 100% offset my night time usage. I wish I had at least 30kwh minimum, and that's only enough to keep me off grid at night. I have a big power hungry house, 2000 to 2600kwh a month is pretty average usage depending on the time of year, so you can image how little 15kwh of batteries goes towards that.

Did you plan the PV and inverter size to fully power the house? I was shooting for a 50% reduction on my bill using 16KWh of batteries but I put in enough panels and a big enough inverter to go off grid.
Batteries are expensive but addictive. Adding one more pack bought me up to 21KWh and a 75% reduction in the bill.
If you have the $ then the return on adding more packs is not linear, the lower draw rate makes all of them run a bit longer. Two more 5kwh packs and it’s bye bye utility co for me.

 

[12VoltInstalls]

Oddly I can’t think of a single ‘mistake.’
I bought a 200W “kit” intending to scale up over time. I did.
If any poor choices were made it was not jumping to 800W or 1kW of panels with electric fridge sooner.

I’m not bragging or whatever about no mistakes. I made sure what I was doing was going to work before I bought so there wasn’t anything to go wrong.

Hmm. Except MC4s! Mixing brands and/or buying cheap ones was a definite mistake.

 

[Johnson]

Worrying too much. It took me a week to top balance my battery, if I had to do it again, I would hook it up to a BMS and charge, I would only top balance if I don't get within 80% of the capacity. The BMS will balance the battery over time.

Oh and remeber that the white terminal on the Chinese battery is the negative and the black positive. (Fried my circuit breaker but everything else was fine)

 

[Rennit]

Did you plan the PV and inverter size to fully power the house? I was shooting for a 50% reduction on my bill using 16KWh of batteries but I put in enough panels and a big enough inverter to go off grid.
Batteries are expensive but addictive. Adding one more pack bought me up to 21KWh and a 75% reduction in the bill.
If you have the $ then the return on adding more packs is not linear, the lower draw rate makes all of them run a bit longer. Two more 5kwh packs and it’s bye bye utility co for me.

I was aiming for a 70% reduction on my bill and I think I got that, but now that I'm here I want more powah! Of course lol.

I have 12kw of panels with a sol-ark 12k and 15kwh of battery backup. I did not know the 12k sol-ark will only put out 9kw ac max until I already had all the parts here, ready to install, but discharging the batteries at night kind of offsets that since the 12k will produce 9kw ac and charge the batteries at 3kw for a total of 12k so I just set my batteries to charge at 3kw that way I'm not losing any output to the grid. I have seen output on my 12k of up to 11.9kw. It regularly gets up to 11kw assuming it's not a cloudy day.

I would probably need to add 1 more 12k inverter to 100% power my entire house, mainly for the surge of my 5 ton geothermal hvac unit but I also have 2 50 gallon hybrid electric water heaters, but the power draw for those is dependent on the outside temperature to be efficient. In hybrid mode they draw about 600 watts but the ambient temperature needs to be above 60F ideally. Less than that and you really need to run them like a regular electric water heater. I haven't really done the math but I would probably need to add more panels to my array and go with at least 60kwh of batteries for 100% off grid, assuming I wont the lottery and was suddenly able to afford the extra cost lol

 

[BentleyJ]

I would probably need to add 1 more 12k inverter to 100% power my entire house, mainly for the surge of my 5 ton geothermal hvac unit

Consider installing a soft starter on your 5 ton compressor. Something like a Hyper Engineering SS1B08-16SN (230V, 60/50Hz, 08-16 FLA)

 

[robby]

I was aiming for a 70% reduction on my bill and I think I got that, but now that I'm here I want more powah! Of course lol.

I have 12kw of panels with a sol-ark 12k and 15kwh of battery backup. I did not know the 12k sol-ark will only put out 9kw ac max until I already had all the parts here, ready to install, but discharging the batteries at night kind of offsets that since the 12k will produce 9kw ac and charge the batteries at 3kw for a total of 12k so I just set my batteries to charge at 3kw that way I'm not losing any output to the grid. I have seen output on my 12k of up to 11.9kw. It regularly gets up to 11kw assuming it's not a cloudy day.

I would probably need to add 1 more 12k inverter to 100% power my entire house, mainly for the surge of my 5 ton geothermal hvac unit but I also have 2 50 gallon hybrid electric water heaters, but the power draw for those is dependent on the outside temperature to be efficient. In hybrid mode they draw about 600 watts but the ambient temperature needs to be above 60F ideally. Less than that and you really need to run them like a regular electric water heater. I haven't really done the math but I would probably need to add more panels to my array and go with at least 60kwh of batteries for 100% off grid, assuming I wont the lottery and was suddenly able to afford the extra cost lol

You have two good options to get there.
1) You could sell the 12K and probably recover 75% of your money and then buy a 15K unit.
2) Since you will need more panels you could add MicroInverters to your system and then divert more of the Sol-Ark 12K power to battery charging in the day and let the Micros pick up the slack.

 

[Rennit]

You have two good options to get there.
1) You could sell the 12K and probably recover 75% of your money and then buy a 15K unit.
2) Since you will need more panels you could add MicroInverters to your system and then divert more of the Sol-Ark 12K power to battery charging in the day and let the Micros pick up the slack.

That's a really good idea but I'm tapped out of funds for now. My electric rates are pretty low anyways, like less than .10 cents. I mainly wanted to be more self sustainable and I have a backup gas generator if it comes to that.

 

[DerpsyDoodler]

I'd have paid more attention to squeezing every drop of solar i could out of my RV roof.