New Member / Howdy

Txflyboy

Joining up because I'm planning a 5KW installation at our old farm place.

I have the panel's bought. 24 215W Evergreen panels. And that's it so far.

I'm meeting with a solar 'expert' this week to discuss the installation. He tell's me what he's done at his home is a grid tie with an inverter that you can add batteries to later. That's what I'm thinking of doing, but I may dive in head first and do it all.

Anyway, hello everyone and I'm looking forward to your expertise and my learning curve.

Txflyboy

Re: New Member / Howdy

hmmmmm, 30 looks and not even a hello.

You folks don't like Texans or something?

icarus

Re: New Member / Howdy

Welcome to the forum. Don't worry, folks here keep odd hours!

One quick question. Why would you want to "add batteries" later? Battery back up solar comes at about twice the price per KW at about half the efficiency, leading to power costs that are ~ 4 times as expensive as grid tie.

For emergency back up, a well sized efficient generator is usually a much more cost effective choice for back up power for relatively short term, rare outages. Unless your grid is very unreliable consider spending the money you would spend on the batteries to buy more PV, and buy a good genny.

Your 5 kw of PV might yield ( in a battery based system) ~ 9 kwh/day net/net out the inverter. The batteries might cost ~ $3000 and need to be replaced every 5-10 years. The same $3k might buy another 600 watts of PV and instalation, and or a good Honda EU 2000 generator that will power much of your needs regardless of the length of an outage.

Once again, welcome to the forum. There are some very sharp folks here (present company not included!) who have forgotten more about PV and it's varios derivations than most of us will know. Don't hesitate to ask as many questions as possible before you commit to buying anything. The single biggest pitfall of PV is,, "ready, fire, aim!"

Tony

Txflyboy

Re: New Member / Howdy

icarus wrote: »

Welcome to the forum. Don't worry, folks here keep odd hours!

One quick question. Why would you want to "add batteries" later? Battery back up solar comes at about twice the price per KW at about half the efficiency, leading to power costs that are ~ 4 times as expensive as grid tie.

For emergency back up, a well sized efficient generator is usually a much more cost effective choice for back up power for relatively short term, rare outages. Unless your grid is very unreliable consider spending the money you would spend on the batteries to buy more PV, and buy a good genny.

Your 5 kw of PV might yield ( in a battery based system) ~ 9 kwh/day net/net out the inverter. The batteries might cost ~ $3000 and need to be replaced every 5-10 years. The same $3k might buy another 600 watts of PV and instalation, and or a good Honda EU 2000 generator that will power much of your needs regardless of the length of an outage.

Once again, welcome to the forum. There are some very sharp folks here (present company not included!) who have forgotten more about PV and it's varios derivations than most of us will know. Don't hesitate to ask as many questions as possible before you commit to buying anything. The single biggest pitfall of PV is,, "ready, fire, aim!"

Tony

Thanks Tony. I had not thought of it that way. But I'm a total noob to solar.

Good points. I have a 7kw diesel portable generator. I'll talk more in depth with the installer when I see him later this week.

Most likely, I'll probably end up going with just a grid tie installation. Everyone I've talked to say that is the best return on the money. Being an older farmer, I don't like batteries. They always let you down at some point.

I impulsively got into the solar business when I bought the panel's on a special sale for ~$.78cents/watt.

BB.

Re: New Member / Howdy

Sunelect had a really nice sale on the Evergreen panels.

If you go with Grid Tied Power--Make sure the panels you have are labeled and have the UL/CSAus/TUV or other approved NRTL LISTING Mark. Having LISTED panels is (almost always) a requirement for Grid Tied systems.

Also, we tend not be a "chatty" forum (no Cafe). We try to keep to the point of questions/information posted (hey--what to do expect from a forum populated mostly with guys ).

Now--ask a question, and I will post really long answers that require two or three posts to get around the 5,000 character limit :roll:.

Welcome to the forums.

-Bill

Txflyboy

Re: New Member / Howdy

Thanks Bill, I'll check those labels.

niel

Re: New Member / Howdy

there are times when battery backup is good to have like if the outage goes on for a long time and is widespread. your local service station will not pump the fuel needed for your generator if they have no power so a solar backed system could recharge allowing some consumption without the availability of fossil fuels. also a battery backup would switch in nearly instantaneously avoiding possible damage to some appliances and preventing a hard shutdown of your pc. this does not mean because you may have a few things that may need backed up for fast switching that everything would need to be placed onto it (whole house) as this is not the case as only those circuits handling those items would possibly need the fast switchover.

i'm not saying you need the battery backup either, but i am saying there are times one may wish to have it even if on a smaller scale. it can be added later if you wish after seeing a need for it. straight gt systems are useless in an outage as they need the grid to work. also, some people can't or won't run a generator at night due to noise.

techntrek

Re: New Member / Howdy

Welcome, txflyboy. Love your avatar image. One advantage of combining a battery backup with a genset is - like a hybrid car - you will increase the overall efficiency of your genset. Gensets are most efficient when run close to a full load, but most homes only use a few hundred watts baseline 75% of the day. Plus as Neil mentioned, some (like me) don't want to run a genset at night. I added a battery backup for all of these reasons, and did it cheap by buying a used large UPS which tend to be very cheap on Ebay. Now during a long outage I use the battery overnight and during the day when I'm at work, taking care of the baseline. When the genset is running it gets the additional load of charging the batteries which increases its efficiency.

Txflyboy

Re: New Member / Howdy

I wish this forum had a thanks button. Wow. You guy's have been doing this a while I can see by your post's. Thanks.

I checked those label's and they're UL listed panel's from Evergreen. I'm good to go. The model #'s I wrote down are out in the truck. I will post them later.

I'm really thinking of going ahead and getting some battery power just like ya'll mentioned. I want a critical load center that the batts would be on. The rest of the house would have to be gennied. I have tractor's, so I'm thinking of getting a larger P.T.O. generator in the 15KW range?

I guess that's my next question. Would a 15KW genny be adequate for a 5KW solar setup with only critical load on the batts on about a 2000 sq.ft. house? I'm thinking of installing on demand propane water heater's. Central Heat is electric (bummer) but I plan to install stoves cuz we have wood. Main thing is A/C down here. If it's hot, I would have to run the genny at night or maybe get one very efficient 110 window unit's. 8)

niel

Re: New Member / Howdy

i don't know for you will need to size up the ac loads you have deemed vital for solar backup. you not only need to know the max wattage at one time, but also the duration of the use over the time of at least 1 day. some appliances may need to be estimated if they are hardwired, but you can use an ac power monitor such as a killawatt meter to check some plugin items. this should at least represent the average usage or you can plan for a worst case usage for this is up to you.

the max wattage at one time determines the wattage of the inverter. for example, you wouldn't want to draw 1000w from a 600w inverter as this just doesn't work. going with that same example of 1000w draw may also warrant an inverter capable of much more headroom not only for not running the inverter at hard max, but also for unexpected high bumps in power needs and the possible future expansion of the loads. you may also need to up this rating due to power factor placing extra stress on the inverter from inductive loads like fans, motors, compressors, etc.

the duration gives us the watthours or kilowatt hours required so that a sizing for the battery bank and all solar charging equipment can be determined.