3R Home and Barn Project

   / 3R Home and Barn Project #851  
Hey Rob,

Thanks for the update on the solar system. It's one of those things that I find interesting, but other then you, don't know anybody who's gone that route. Hearing your real world experiences with it is probably the most valuable information there is!!!

I really like the new section of decking in front. It's funny how I never thought of it, but looking at the pictures, the house really needed it to balance itself out. Now it looks finished to me, even though I thought it was awesome before and never thought about it before.

Hope that makes sense????

Eddie
 
   / 3R Home and Barn Project
  • Thread Starter
#852  
Thanks for your comments.
We really like the wrap around deck and it's true, it balances the look of it. More importantly, it really saves getting from one end to the other instead of either walking all the way around the back or down and up those stairs and ramp. It just made sense to do it now. Plus, there was no other place to get the fire wood up to the deck level, other than wheeling it up the ramp or carrying it the front stairs. When I saw what Larry did at his home in New Mexico, I thought that was a good idea so I stole his concept and made that removable gate on the new section. It allows a straight shot in with the tractor(s). I still have to build the custom pallets much like BillBill did, except with wheels on it. I also have to build the fire wood shed or rack somewhere in between the garage and barn. I have tons of wood already cut (4 years worth) but just piled up right now. I'll have to split and stack it once we get the wood shed done. Although we have central air and heating, our goal is to heat with the wood stove as much as possible.

It's funny you brought up adding acid to the batteries. The solar contractor says any batteries that were boiled down might have sulfated and need acid put in to rejuvenate them. That's why he's doing it now. It's supposed to be the method to bring them back ... I don't know?
But the first time we told him they were low, he told us before NOT to add distilled water but acid instead. We (Loretta) read up about the specific gravity and that it tells us the state of battery charge. We found out what you guys are saying. She questioned him about adding acid since we found out you should only add distilled water. So he agreed with us.:confused: Weird. That shows his ambivalence.
We have gotten several different answers from him for the same questions so we really don't know which answer is the correct one. It's like he either really doesn't know or he changes his mind. I know in my profession it's very hard to give a definitive answer because there are usually pros and cons, but there is a "best or better" way to do it and that's what I recommend.
His answers don't do that and we are doubly confused.

The solar panels are not directly connected to the batteries. They are connected to the inverters which control the charge to the batteries. It sets the system in "float" when the batteries say they are full...or when the inverters "think" they are fully charged. The problem is they were NOT really full, so they never got charged properly. That is one of the problems he was working on. Plus, there were only a few batteries that had good specific gravity readings and they were the ones boiled down. They appeared to be the only ones getting a full charge and not the others. He now says it's because of the way he set the system up while we were building the home and forgot to change it over. I will have to check this week if the changes he made really charges all the battery banks fully or not. I don't know enough about it to question him even, but some things are intuative. I know the system has the capacity to run our place if it was put together properly. On Loretta's solar forum where Bruce (Ravensroost) is also a poster, the guys did calculations to show what the system "should" be capable of doing once it's working correctly. They even included parasitic energy use of the inverters themselves. We hope the contractor gets it right this time. I wish I could get a straight, better answer from him so I understand what he's talking about. I can't wrap my mind around it yet.

What about my earlier questions? Hook them all (6 inverters) up together and have the generator feed both house and barn then? Also, was my thinking correct on the batteries needing to be charged up to provide a large load like the "starting the car" example?
 
   / 3R Home and Barn Project #853  
Rob, I only have a single Trace 4KW sinewave inverter, 2KW of panels, 8KW diesel genny for back up but have been using system at a weekend place for about 7 years now. The size of your system is way over my head and I only understand the basics of the multi-stack Outback inverters.

First maybe a little general info then I will try to answer some of your questions.

Each inverter can only supply 120 volts AC, so to get "normal" 230v AC you need a pair of inverters: one supplying leg 1 (L1) of 230v while the other inverter supplies leg #2 (L2), there is 120v between each leg and neutral same as in utility power.

There are at least three (or more ?) strategies that can be used for the layout:
1. All inverters on all the time basically in parallel supplying everything (Inverters use power even when they aren't doing anything, so this is less efficient)

2. Barn/shop inverter #1 for L1 and #2 for L2 on "auto" meaning the inverter(s) fire up when it senses a load. You will see issues with digital clocks dropping out and such. This would be the likely set up for intermittent usage at barn/shop.

3. The 4 house inverters can be connected so #1=L1 and #2=L2 and #3 & #4 come on in parallel to #1 & #2 in response to loads, or, they can be connected so all 4 are on at the same time disregarding load, or, #1 & #2 in auto with #3 & #4 coming on if the first 2 cannot handle the load which is how it sounds like they are set up.

When you are there full time, I am guessing you will probably end up with barn/shop on auto and the house #1 & #2 inverters on all the time with #3 & #4 coming on for heavy loads.

A functional hub is needed for all of the inverters and Mate to communicate, so when it was not working your system was crippled. Now that the hub has been replaced (?) you probably need to start over on your observations of what works the way you want it to and what does not

The inverters can use genny power to carry a load while they are also charging batts, can config how much AC power goes towards charging batts leaving balance for normal loads. You can config the inverters using Mate to set how much of each gets done as the inverters have very powerful batt chargers on board so if all 6 were on max batt charge, even your large 20KW genny could not handle the batt charging load load, thus the need to carefully select a strategy and config set points accordingly. (I believe each inverter can handle 60 AAC input: max of 30 to charger and max of 30 transferred to loads.)

If the genny is running and inverters are charging batts while you also have loads that need to run is when things need to be carefully considered and configured. Usually, the loads get priority and charging batts gets less of the genny output as the assumption is that the genny is going to run for at least 2 or 3 hrs or more and will eventually charge the batts.

You asked:
1. My question is, ... if the batteries are so low for the generator to kick on, will they have enough juice to power the barn/shop when there is a big draw from it?
==> Short answer is it depends. The inverters need to be wired and configured to do this and set so the chargers on the barn/shop inverters do not use all the genny power available to them for battery charging, some left for loads.

2. Will they be charging the batteries fast enough to do this? Yes or no? I'm thinking no. It's like when you try to use a battery charger on a car (dead or low battery) to start the car right away...there's just not enough juice built up in the battery to turn the motor over, right?
==> This is pretty much the whole deal: decide how long you will let the genny run to charge batts ($$$) and the excess capability can be used to run loads e.g shop and house A/C. Problem is, when you are not there or are just not running any big loads, the batts cannot charge any faster than they could with the loads as the system is not intelligent enough to dynamically change the set points (as far as I know).

3. Wouldn't it be better for the generator to also power the barn like it does the house? Could I attach 2 cables from the generator to the barn inverters like however the generator is hooked up to the house inverters?
==> I agree it would be better and am surprised it was not wired and configured this way. (See earlier note about hub, this may function as desired now, start over?)

4. Next question is, ... what if all 6 inverters were hooked up together. They supply both the house and barn/shop together making no differentiation. I presume that when the generator kicks on, it would also supply the barn like it does the house when it kicks on. Not only that, I would have all those inverters working together to supply a huge amp draw now. Am I asking the right questions? Does it make sense. I would like to know advantages and drawbacks. Also any suggestions for other methods."
==> The primary drawback is this is less efficient. It might also mean redoing the whole deal and you amy need a larger load cneter and perhaps new wiring. You may want to get as close to this set up as you can e.g. all inverters on all the time and wired/configured to pass AC thru to loads when genny is running so you get a good baseline for this method, then make changes one at a time and reevaluate usage and performance: change the barn/shop to auto, change house inverters #3 & #4 to respond to load (only), etc.

BTW, my understanding is that you NEVER add acid to batteries in use, only pure water. I would ask your installer what's up with that. I am guessing he is trying to save the batts that were sulfated, no clue if this works, just does not sound right to me. Yeah, it will bring the SG up but does it treat the root cause (sulfation) or just the symptom (SG low on some cells/batts)? Your installer will want to have another look see after he is able to do a good equalization on the batts. In addition, conventional wisdom is that it is very difficult to get maximum performance and life out of a battery plant having four parallel strings. This is because of the large DC amperages involved in and out and even a slight difference in resistance means a large difference in voltage so the strings are all out of balance which tends to mean one string is getting all of the charge and doing all the work and the rest are just taking up space. The best design is for all batteries to be in a single series string. For you would be 8 humongous batteries for 48 VDC.

All of this will take you awhile to get your arms around, you and Loretta have come a long ways, hang in there.....

Regards,
RavensRoost
 
   / 3R Home and Barn Project
  • Thread Starter
#854  
Wow, great post Bruce!
I actually understood what you said, I think.:)
I'll print this out and run it by the contractor. Thanks especially for the choices of inverter configuration. Your answer(s) will help me to ask the contractor how he has it set up now. I have some ideas of what it is we want to accomplish, and how to do it.

Your explanation of the generator providing load and charging the batteries with careful balance makes sense too. He has it split now, providing 10kW to charging the batteries and 10kW available for load. If I'm not mistaken, we never use more than the 10kW hrs the generator has for immediate power available to the house. In fact, we are well below that even if the air condition kicks on while the generator is running and charging the batteries. With the Mate, The TM500 and the Watt Plot, we know there is power available now.
That is why I wanted to have some of the generator power available for the barn/shop loads.

I am VERY curious about your battery answer.
I suspected exactly what you said about one string doing all the work.
In addition, conventional wisdom is that it is very difficult to get maximum performance and life out of a battery plant having four parallel strings. This is because of the large DC amperages involved in and out and even a slight difference in resistance means a large difference in voltage so the strings are all out of balance which tends to mean one string is getting all of the charge and doing all the work and the rest are just taking up space. The best design is for all batteries to be in a single series string. For you would be 8 humongous batteries for 48 VDC.
Aside from getting 8 huge 48v batteries, obviously ($$$) I am interested in getting the 16 we have now working to the best of their capability. How can we do that? Is "A single series string" the answer? What can we do to balance the resistance? Any way to check that?
Thanks again for taking the time to post such a resourceful and helpful comment Bruce.
 
   / 3R Home and Barn Project #855  
BTW, my understanding is that you NEVER add acid to batteries in use, only pure water. I would ask your installer what's up with that.

I have heard that too, but I don't buy it. I see that adding only water
is what you want to do when your loss of electrolyte is due to evaporating
off the water. This naturally occurs while charging, esp if the batteries get
hot.

But what happens when you lose electrolyte as when LIQUID comes out
of the vents? It is clear that you are losing more than water in that
case. This is exactly what would happen with many M/C batteries I
have owned. It was clear that I was losing battery acid and I needed to
replace it.
 
   / 3R Home and Barn Project #856  
As far as those battery operated sprinkler controllers, we bought some a couple years ago to irrigate the food plot where we camped. We must have gotten some crummy ones, even though they were expensive. We never got them to really work right and they leaked a lot. .:)

Well, I think the 'real' problem is that they were installed right where the sprinkler head was, and because of the way the connections were, they had to be upside down..... so when the sprinklers ran, the batteries got wet. :rolleyes:
 
   / 3R Home and Barn Project #857  
Well, you got me Brian.
I didn't think I'd have a yard, then it turned to hoping I wouldn't then it turned to Loretta WAS hoping to having a yard and the to now we ARE gonna have a yard. Know what I mean?:D

Hey, wait a second... I remember it the other way around!:eek:

However, the real truth is that we have to have a 100' defensible perimeter all the way around the house, so we have to do something that we can keep green and/or short. Also, because the land in front of the house (notice how I avoided the use of the word 'yard'), is sloped, we have to do something to keep it a) away from the house and b) eroding our leach field.... so 'terraces' seem to work best... and grass seems to grow the fastest.... ergo... a 'yard'.
 
   / 3R Home and Barn Project #858  
Thanks Dave,
I have worn out 2 pairs of new jeans in the knees already getting down to thank the Lord for my new workshop!:)

Oh, is THAT what you were getting on your knees for??? And all this time I thought you were begging me for a new gun.:D
 
   / 3R Home and Barn Project #859  
Rob the series parralle thing on the strings the equlise fuction is suppose to correct any un ballenced discharge the other thng that will help if possible is to wire load off oppisite corners of the bank.

tommu
 
   / 3R Home and Barn Project #860  
I have heard that too, but I don't buy it. I see that adding only water
is what you want to do when your loss of electrolyte is due to evaporating
off the water. This naturally occurs while charging, esp if the batteries get
hot.

But what happens when you lose electrolyte as when LIQUID comes out
of the vents? It is clear that you are losing more than water in that
case. This is exactly what would happen with many M/C batteries I
have owned. It was clear that I was losing battery acid and I needed to
replace it.

I've been trying and trying to research this also, and one of the things I have read is very similar to this.... when you overfill the batteries, you end up losing liquid out of the vents, and part of that liquid is the acid itself. The Surrette manual says to ONLY add distilled water - never acid, except when you are first installing the batteries. But then it also talks about never overfill, because if you overfill it causes loss of electrolyte.
 

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