Solar question

[Stargazer]

A friend is building a small offgrid house.  She (and I) have basic knowledge but here is my question.

The house is wired all AC.  It has a breaker box that has a separate cable that will plug into her generator to power the AC through the breaker box.

The solar array (Renogy panels totaling 1600W, I think) is mounted about 10 ft from the house near the breaker box.  The four large lithium ion batteries will be on the inside of the wall where the breaker box is installed.  I don't know battery size.  She says the generator will be wired to charge the batteries  She bought this in a system from a company who told her it would power her needs.  

The licensed electrician she has hired to put it all together has never done solar but is willing to try.  This makes me nervous.  So, in simple terms, how will the sequence go?  The solar panels wired to the controller wired to the batteries wired to the inverter wired to the breaker box?  The generator somehow wired to charge batteries when needed?  How does that go?  Does the generator charge through the controller so she doesn't kill her batteries?

I don't need details like wire size etc.  Just the sequence.  Have searched online but too much detail for me.

Thanks!

 

[B and C]

Your electrician should have all the info (s)he needs provided in the kit. Hopefully (s)he is a licensed electrician. Setting the solar controller and the batter charger is probably the biggest unknown to her/him.

Your sequence sounds right. The generator probably has an autostart feature to start and power a seperate battery charger, not the solar charge controller. The generator may have the charger built into it. Too many unknowns for me to answer any further. The genny may run on a schedule or there is an amps in/out counter or a voltage sense somewhere to tell the genny to run.

 

[Stargazer]

Got it, thanks!

Didn't know that about gens. Hers is a portable and will be used for backup only, I am told. We are in Western CO where lots of sun but may be days of clouds in winter. It will be interesting to see how this all goes.

 

[B and C]

I also saw where there is a box that everything ties into and includes the solar charge controller:

It is all going to depend on what equipment you have.

Edit to add: another look:

 

[RVTravel]

Licensed and bonded electrician.

 

[highdesertranger]

I believe you need some type of transfer switch that switches over to what power source is being utilized. in grid tie systems this is built into the inverter. if the electrician she hired doesn't know how to do this I would find one that does. highdesertranger

 

[B and C]

Or the generator could be configured to just charge the batteries. The transfer switch is the best option but there will be a short power outage when the power switches (each way). This is all dependant on what hardware and generator is there.

 

[Stargazer]

Ok.  I think I'm getting this.  I never had solar in my vans or RVs so know only the basics from reading here.  The electrician is licensed and has many years of experience, just not with solar.  He is also a friend of the state electrical inspector who has said he will be glad to act as advisor if needed.  This is a very rural community and help is scarce and frequently unreliable.  Therefore, my concern.  When I ask her questions, her response is "I don't know, that's his job."  Which heightens my concern.

HDR:  you mention grid tie.  Not sure what that means but she is not hooked up to local supplier at all.  Propane for heat, cooking, hot water.  Electric will be for lights, small fridge, ceiling fan, and the ignitors for propane appliances.  So not much demand.  She is on municipal water as wells are not allowed here.  County code inspectors are involved.  Not sure if that's good news or not...

I have been helping her with light work like trims inside (a little putty will fill up that nasty crack) and today we finished mounting the six solar panels on a pole frame which we put together yesterday.  It was fun, like a giant puzzle, and it feels very solid.  Next is hooking it all up.  She is so trusting.  Me, I'm the crusty one who questions everybody, lol.

This is a fun project and I will get some real first hand knowledge.  So thanks to all you smart ones out there!

 

[highdesertranger]

yes grid tie means connected to the grid(local electrical supplier). I still believe you need a transfer switch or else you will be back feeding the inverter when the generator is running.

with these questions I am not trying to put anybody down or be disrespectful but,

if nobody on this job knows what they are doing who is buying the equipment?
who did the calculations for aiming the solar array?
what type of inverter was purchased?
what generator?
is there a auto start on the generator if the batteries get low?
are the batteries in a heated space?
will this cabin be lived in 4 seasons?
many more issues to be dealt with.

there's a lot more to this then plugging in an extension cord. I still say get someone that knows what they are doing.

highdesertranger

 

[Stargazer]

HDR,

You have such a way with words.  Bingo!

She purchased the solar equipment from a "good company" on line.

She established the array angles etc based on charts online.  When the poles had been set in concrete, I took one look and a discussion and recalculations were done.  It is currently set (by my eyeballing it)at about 50-55 degrees, due south.  We are at approx 31 degr lat.

Inverter type: whatever the solar company sent.

Generator:  I don't know.  She asked the solar company what to get and got that.

Batteries: still in original boxes, unopened in her garage.  Don't know how long they've been there but at least four to six months.  They will be installed in her bedroom.  When I ask about them all she says is "they're lithium".

Cabin will be her permanent full time home.  She is living (camping) in it now.

Yes to your last statements.  You have zeroed in on my concerns.  I am happy to help all I can with an extra pair of hands and a little muscle.  But lack of knowledge is a scary thing, especially in regards to electrical systems.

 

[B and C]

I would hope that a licensed electrician would know where to look for help. Probably on a forum just like this for electricians. A licensed electrician will know when they are over their head and get some help, somewhere. I think it is safe to bet that they won't leave it in a state where it is a fire or shock hazard.

It's a shame your friend doesn't disclose what she has. Hard to help when you are blind, you become a told person and not an informed person. It is her life and cabin at stake, not your's.

 

[Stargazer]

Brian,

She doesn't disclose because she doesn't know, or at least that's what she says.

 

[Trebor English]

In Florida, where I am, barbers must be licensed by the state.  If I get a bad haircut the state of Florida will not fix it.  The licensing thing is, in my opinion, a way for people in the business to keep new people from competing.  I have not seen the word "competent" used in this thread.  That is a different word from "licensed." 

Electricians can be like physicians.  You do not want a pediatric cardiologist if you are like me, over 70 with high blood sugar.  If you are an infant with a messed up ticker you don't want an geriatric endocrinologist.  You would probably want an experienced pediatric cardiologist.  "Experienced" is another different word.

 

[Stargazer]

Trebor,

You noticed that...

Goodnight, Dick.

 

[DLTooley]

It sounds like you are asking the right questions.

Charging batteries while there is also a load could damage the batteries. There’s a fair chance the stuff you’ve bought is smart enough to do that, but to be safe just disconnect the house while you are charging if you have any uncertainty. This isn’t a big deal if done only occasionally. If your battery kit also provides you info on loads and inputs use that info to educate yourself. If not, you might consider an upgrade.

As always, fuse.

 

[wayne49]

Do you have a reference for the following statement? "Charging batteries while there is also a load could damage the batteries."

https://www.quora.com/Is-it-possible-to-charge-and-discharge-a-battery-at-the-same-time

"Coming back to your question the battery can not be charging or discharging at the same time. If a load is connected to the battery while charging the charger powers the load along with charging the battery. As the battery gets fully charged the charging current drops to zero. After that the current through the battery reverses and discharges through the load. This discharges the battery so it gets charged from the charger. Actually the systems stops at a point of equilibrium where there is no battery current involved. The charger powers the load as long as connected and the battery does not drain or charge."