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Solar and batteries, my .02

Started by Klunker, December 05, 2018, 01:06:07 PM

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Klunker

We have a new home that we added 10KW of solar to along with a battery backup system.
We moved in last Oct.
Its been roughly a year now.
Here is my .02 on the whole state of solar.

Our home is all electric which includes a 900 sq ft work shop that has an electric boiler that heats the slab to approx 45 degrees all winter. I didn't have it running all last fall/early winter.

We heat with wood and use approx 3 cords/winter.
Home is just me and my Wife.

We are still grid tied. We paid $850 for last years power.
Rates are .13/kwh, plus other flat charges / month that run a total of approx $19/month.
We get paid .04/kwh for any power returned over what we use.
So to get a "free" month we'd have to generate approx 475kwh more than we take off the grid.
We took approx 7200kwh from the grid and sent back approx 2400kwh.

Currently we have our battery charging/usage set up so that the battery is theoretically never used except for a power outage. We had 2 outages in the last year. One lasted only about 1-2 hrs but the last one lasted 27 hrs.

In the last outage the power went out in Aug. at about 5pm. We ran off battery till about 8pm the following day. Over night out battery got knocked down to about 50% charge. I disconnected the water softener, the iron filter and I dropped the temp on the electric air sourced heat pump water heater from 125 to 110. Power was running a small freezer and a refrigerator and what ever phantom loads we had.
The following morning once the sun hit the panels it took about 3 hrs to charge the battery up to 100% around 10-11 in the morning. At that point I told the wife that if we didn't use what we generated we would be loosing it so run anything that she might need to now.

This whole years has shown me the following.
If we wanted to be off grid we would have to do the following.
1) increase the size of our battery bank drastically. Now we have one 48v bank of batteries. Assuming that we can last 1 day with the batteries we have now at a very minimal draw I'd say we would have to increase it about 10 times at a minimum. Much beyond that and its get to be a problem with the amount of time it takes to recharge the entire bank. You'd have to increase the amount of panels jsut to charge the batteries when the get beat down. And you'd need that ability for the winter when there are days with zero generation.

I'm sure its been said before but as I see it solar is not going to be really viable until battery storage gets increased dramatically. It should really be looked at how much battery power do I need to run my house/day then you'd have to multiply that by how ever many ays you want to be able to without generation. You better be willing and able to clean panels off in the winter. I have one person I know that went approx a month with zero generation one winter. His setup would of required him getting up on top of a 2 story house to clean panels.

Me I'd think a bout 1 week worth of power without generation would do.


Hilltop366

Times may have changed some but 20 years ago I looked into building off grid and one thing that stood out was that it was more cost effective to reduce your usage with super efficient (super expensive too) appliances and water pumps as well as using other sources for high demand loads like heating, hot water than to try and supply and store enough electricity to run a typical house.

I was looking at wind and solar at the time after costing it all out I payed $7000 to run the grid power to the house.

Doing a quick calculation it looks like I am still ahead $15000 to $20000 for grid power versus off grid after being in the house for 17 years.

Don P

It can be done but isn't particularly cheap. I consider grid tied systems to be environmentally philanthropic, but a good thing and the way solar should be done. You are helping with peak demand and helping to eventually harden the grid. Batteries are still pretty stone age but provide backup if you can afford it. I don't like my generator but it is probably cheaper backup, as long as the fuel holds out. During the aftermath of the Durecho a few years back I could hear whole house and portable generators fire up and then went to check on a friend, he didn't realize the power was out till he went out the next morning and heard generators running. His solar and backup had switched automatically.

Ianab

It's still horrible expensive to get a fully electric house "off grid". Like Hilltop says, you need to reduce the loading to the most efficient essentials, and find a different energy source for the high load things like heating, hot water, and most cooking. 

Now if you switch those things to direct solar / wood burning / propane etc then the electrical load from your house becomes so much less. 

Then have an emergency backup plan like a small generator, so you can keep the lights on if you do get a week of cloudy weather. 

If you are able to run a small wind turbine and/or micro hydro as well? Even better. If the suns not shining, chances are it's raining or windy, and if your power draw is only in the hundreds of watts, small generators can help. 

People like to slag off wind generators, mostly because "the wind isn't always blowing". But they work here as the largest power source is hydro power. So when the wind blows, you can "bank" water in the hydro lakes. When the wind stops, you have the hydro reserves on hand. 
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

mike_belben

In my opinion its much cheaper to run a small generator in conjunction with an affordable panel and battery setup than to try for all solar.   Especially in conventional stick frame structures with low mass and poor layout for solar gain in winter and shade in summer.  

If you really want to be a watt miser and dont have deep pockets or a buddy in the grant department, you almost need to build an entire property from scratch, which can easily be a lifes work.  
Praise The Lord

maple flats

I have 2 solar systems. My original, at my sugarhouse just needed a new battery bank. The old one (10 yrs old on a 7 yr rated bank) died. I now have a set of Prius batteries coming today. Then I will need to reprogram the charge controller. That is actually a dual system, 1480 watts on battery back up (as well as grid tied) and 4840 watts just grid tied. My meter is net metered. Before the battery bank died 2 months ago, I typically got credits sent to my home bill totaling $350-450 per year. The only months I ever pay a bill for my sugarhouse electric is Jan and Feb, by March the sun is high enough and the days long enough that running the sugarhouse and the vacuum pump ball day and often all night, does not result in a bill, I still get a credit.
My second system is totally off grid at my home, even though the house is grid tied. There I just have 1720 WATTS solar, charging 4 large Rolls batteries. The solar just runs 2 sump pumps and our entertainment center plus some key lights. Those batteries are only 1 yr old and should last about 12-15 with proper care.
For sure, batteries are the costly part of solar. You just need to decide if you want or need electric during a grid outage. If no batteries, your solar shut down when it detects the grid is out. With those expensive batteries you can have the power during an outage.
My hope is that the Prius batteries are worth it. I am just building a single 48V bank.
logging small time for years but just learning how,  2012 36 HP Mahindra tractor, 3point log arch, 8000# class excavator, lifts 2500# and sets logs on mill precisely where needed, Woodland Mills HM130Max , maple syrup a hobby that consumes my time. looking to learn blacksmithing.

Klunker

Quote from: Hilltop366 on December 05, 2018, 04:48:46 PM
Times may have changed some but 20 years ago I looked into building off grid and one thing that stood out was that it was more cost effective to reduce your usage with super efficient (super expensive too) appliances and water pumps as well as using other sources for high demand loads like heating, hot water than to try and supply and store enough electricity to run a typical house.

I was looking at wind and solar at the time after costing it all out I payed $7000 to run the grid power to the house.

Doing a quick calculation it looks like I am still ahead $15000 to $20000 for grid power versus off grid after being in the house for 17 years.
I'm all for reducing use, and in fact I think it should be #1 on the list. However my wife is not willing to reduce her "lifestyle".
 
I'm sure we could reduce our usage considerably.
When we built we bought a air source heat pump water heater, heating uses no power, all of our lights in the house are LED.
Wife saw a show on "This Ole House" about a house being net neutral. She asked if we were net neutral. I thought maybe if we ditched the 3 TV's.

Klunker

Quote from: Don P on December 05, 2018, 10:22:05 PM
It can be done but isn't particularly cheap. I consider grid tied systems to be environmentally philanthropic, but a good thing and the way solar should be done. You are helping with peak demand and helping to eventually harden the grid. Batteries are still pretty stone age but provide backup if you can afford it. I don't like my generator but it is probably cheaper backup, as long as the fuel holds out. During the aftermath of the Durecho a few years back I could hear whole house and portable generators fire up and then went to check on a friend, he didn't realize the power was out till he went out the next morning and heard generators running. His solar and backup had switched automatically.
We were going to go "behind the grid" originally but our Solar installer got threatened by the power co and told no more.
So we either had to go off grid or grid tied. My wife was afraid to cut the cord and was not willing to adjust if she had to.
Didn't like the generator idea. Had to add another fuel.
We have the same issue, when the power goes out battery kicks in immediately. Only way we knew on the 27 hr outage wife was watching TV and it flickered. She made a comment about it and I checked power supply.
I'm thinking about adding something to the system so a light/buzzer goes off to tell one when the grid is down.

Klunker

Quote from: Ianab on December 06, 2018, 12:16:19 AM
It's still horrible expensive to get a fully electric house "off grid". Like Hilltop says, you need to reduce the loading to the most efficient essentials, and find a different energy source for the high load things like heating, hot water, and most cooking.

Now if you switch those things to direct solar / wood burning / propane etc then the electrical load from your house becomes so much less.

Then have an emergency backup plan like a small generator, so you can keep the lights on if you do get a week of cloudy weather.

If you are able to run a small wind turbine and/or micro hydro as well? Even better. If the suns not shining, chances are it's raining or windy, and if your power draw is only in the hundreds of watts, small generators can help.

People like to slag off wind generators, mostly because "the wind isn't always blowing". But they work here as the largest power source is hydro power. So when the wind blows, you can "bank" water in the hydro lakes. When the wind stops, you have the hydro reserves on hand.
We do heat with wood, and in fact our wood heat has an oven in it. Tho it would require adjustments to lifestyle to do it. Right now its possible. I thought about using our wood heat for heating water also. Maybe should of done it. Time was against us when we built, decisions had to be made and the window closed.
We have thought about a small wind turbine, he have a good location for it. But at the cost of the whole setup we could most likely add several banks of batteries and be in the same place.

Klunker

Quote from: mike_belben on December 06, 2018, 01:20:48 AM
In my opinion its much cheaper to run a small generator in conjunction with an affordable panel and battery setup than to try for all solar.   Especially in conventional stick frame structures with low mass and poor layout for solar gain in winter and shade in summer.  

If you really want to be a watt miser and dont have deep pockets or a buddy in the grant department, you almost need to build an entire property from scratch, which can easily be a lifes work.  
Our house is very energy efficient. 8" Neopor SIP panels with 1" of foam on the outside of that, triple pane windows, 6" of foam on basement walls, 4" under basement slab. 1 ACH. We built taking advantage of southern exposure, lots more windows on that side.
We heat using thermal mass, masonry heater.
We looked at solar gain, but again on days when its cloudy, nothing.
Our house should of been smaller, but when married you make concessions.

Klunker

Yes, lots of electric loads.
Water pump, septic lift pump, water softener, iron filter and water heater.
Those are just the beginning.
Then we have a fridge and a separate freezer.
Lots of power required just to keep our heads above water.

My wife was the big driver on going solar, she is likes the Independence she feels we have if the grid goes out.

When we ran the power in it cost us 12K. I mentioned that we could add at least 2 more banks of batteries at that cost.



beav

I have been off grid for twenty years now. I built the house, a saltbox, with Windows facing south, roof to the north etc. The hemlocks and pines here became my house.
Panels were expensive back then, and batteries less so. Anyway I have done fine with .7 kw of panels. Solar hot water, wood heat etc. I even recently got rid of the propane fridge, with wikkid efficient new electric one. One less bill!
However I will never have or spend more on batteries than to assure about 3 or 4 days of autonomy. By then the generator gets fired up and charges my batteries in a couple of hours.
I would never hook up to the grid. I like it too much the way it is. Booting the meter reader? Priceless!!
In twenty years I have saved 6000$ in hookup fees alone (roughly) , spent probably 4000 on batteries so im not too far in the weeds
Ymmv

maple flats

To me, a total electric house on Solar is crazy. Eliminate as many electric draws as you can. The batteries are the weak link.
I know, I just had to replace a 48V Trojan bank. I only have 1 circuit on my battery back-up and that is pretty much just insurance (I use it to run a back up heater in a well insulated small room where my Reverse osmosis is for my maple operation. In the 6 years since I ran grid power I have never had a power outage. That room is normally heated using a direct vented propane wall furnace. The back up only buys peace of mind.
logging small time for years but just learning how,  2012 36 HP Mahindra tractor, 3point log arch, 8000# class excavator, lifts 2500# and sets logs on mill precisely where needed, Woodland Mills HM130Max , maple syrup a hobby that consumes my time. looking to learn blacksmithing.

beav

Maple flats the prius battery conversion sounds very interesting. Are you engineering this? I would be very  grateful if you posted this procedure here.
If I only had a tesla i bet I could go a month on all that juice sitting in the driveway. Forget driving it. Well maybe if i got a neck brace i could take it..

jenkinswt

I'm new here so, Hello! Anyways I've been reading all over this forum and love it. I've lived off grid for several years now, by choice. I suspect I'm saving some money but I mostly do it because I enjoy it. We started small and keep adding as we can afford.

We use propane to cook with but have plans to change that at some point. I have a wood boiler in a pole building which actually wastes a little electricity and firewood but it seems worth it to us. I have a 50's Jacobs wind generator and about 4700 watts of solar. Our house is older and drafty but if you walked inside you wouldn't know we lived off grid. There's televisions, normal large fridge, microwave, coffee maker, well pump, kids playing nintendo, lol. We also check our charge controller on the computer a lot instead of walking outside. I'm not trying to make this sound easy because I've probably invested too much time reading on how to do things or looking for a good deal on batteries, etc. 

I do get people that look at my setup and say wow I bet those batteries, etc. cost a fortune to buy all the time then they hop in a nice vehicle with a large monthly payment and don't think twice about it. Sorry to ramble on my first post here!


mike_belben

Praise The Lord

maple flats

I will be re-programing the charge controller. I just need to get better educated on what the Prius batteries want. I have so far found that they do not want a float charge. Have not yet read if the want Absorb, MPPT and Bulk charges. Obviously they will need at least 1 of those, I'm still in discovery mode. My time now however is focused on the 2019 maple syrup season. There won't be much effort into the solar until I either get a break during the maple season or it will be after the season. I now have the panels that run the battery back up shut off, my inverter will not take energy from the CC without going thru the battery bank, which is completely dead. I stand to loose a lot more money if I'm not ready for the maple season than I would without that portion of my solar input being shut down. If I do ever need it, I do have 3 generators (a 5.5 kw gas, a 6KW diesel and a 15KW gas) that can run that emergency heat for my reverse osmosis.
logging small time for years but just learning how,  2012 36 HP Mahindra tractor, 3point log arch, 8000# class excavator, lifts 2500# and sets logs on mill precisely where needed, Woodland Mills HM130Max , maple syrup a hobby that consumes my time. looking to learn blacksmithing.

reelman65

This is a great thread.  Thanks for taking the time to record your experiences 
75 Acres of hardwoods that i want to try to optimize for HW growth, health and habitat. Also interested in creating a few small stands of fruit/nut trees and sample of different native species

maple flats

After I bought that Prius battery bank it proved to be a poor choice (not enough AH). I then got 16 cells LiFePo4 batteries for a 48V bank. That worked perfectly for 5 months, then things went horribly wrong. I had  a BMS (battery management system) that said it would shut down before it got to freezing because those batteries should not be charged when frozen. It did not shut down and the batteries were ruined, $2400 wasted.Right now I'm thinking I should just get a grid tied inverter for that 1480 watt array, since I've never had a power outage and besides my regular heat is propane which needs no electric. I still have 4840 watts strictly grid tied, the 1480 watts is setting idle until I get a new inverter. My XW6048 can't be programmed to be strictly grid, it is battery first then grid after the batteries are fully charged. No decisions made yet.
logging small time for years but just learning how,  2012 36 HP Mahindra tractor, 3point log arch, 8000# class excavator, lifts 2500# and sets logs on mill precisely where needed, Woodland Mills HM130Max , maple syrup a hobby that consumes my time. looking to learn blacksmithing.

peakbagger

I have three arrays, my original 19 year old array lost its string inverter and finding a replacement string inverter was not going to happen as it was only 660 watts and the string voltage was not going to be high enough for a new string inverter. I ended up buying used Enphase microinverters off of Ebay and a used length of trunk cable. The trunk cable is terminated at a breaker. When I installed the array I had spare wire so I ran the panel wires individually to a junction box in my basement so it was easy to tie in the inverters in the basement in the middle of the winter. I could move them out to the back of the panels like a standard microinverter setup but the temps and climate are a lot nicer in my basement. Nice option for what was an "orphan" array plus I got some shading protection as each panel has its own MPPT. 

Depending on the wattage of the panels you may be able to get a dual or quad panel microinverter but I stuck with Enphase as there are lots of them on the used market. 

Klunker

Mapleflats, we just had another power outage last week. 3 hours without power.
Not a big deal, if we didn't have the batteries not much would of been different.

Happened at night. Our grid supply alarm went off to advise us.

I think we get about 2-3 power outages/year. Usually a couple of hours only.

We had issues with our solar system. I noticed that when our panels were partially covered by snow we would get zero output. We had approx 40% open and clear but still no power generation.

Turns out the system was setup improperly in the beginning. Grounding issues. While working on it the Tech was on the phone with the mfg. The Tech changed the way it was grounded as advised by the Mfg. When he turned the power back on the wiring from the panels started to melt the insulation which quickly tuned to smoke and fire. At this point the Tech was smart enough to run to the disconnect for the solar panels and shut them off. Ended up replacing the Breaker box that is fed from the panels and a big chunk of wiring.

Now we have more production, looks like our power from the grid will be about 1/3 less.

We still have maybe 6 years or more on our existing lead acid batteries before replacement. I'm hoping there is something much better out there then.

nativewolf

1 or even 2 powerwalls would do wonders for you, sorry to hear about the install issues.
Liking Walnut

maple flats

Klunker, I can tell you one thing from experience. LiFePo4 batteries are a great choice but only with a few must haves. 1st, the battery management system (BMS) must have a shut down capability to prevent trying to charge the batteries when below freezing. My big mistake was believing a Chinese manufacturer and not testing it. I complained with no success (China). Or the battery bank must be in a space that does not freeze. In my case my battery bank was in my unheated sugarhouse and I did not go to the sugarhouse for 6 days in which time the solar panels were covered with snow and I had a heat pad to keep the batteries warm. The batteries were in an insulated box. My problem turned out to be stupidity, I connected the 65 watt heat pad directly to the battery bank and thus it did not shut down when the bank got to the low voltage setting. Hind sight is 20/20. I should have built a shelf and placed the battery bank in my tiny heated room (2.5' x 5.5' x6' with 3" foam insulation), but that would have required running the heavy battery cables about 45' and being that long I'd have needed bigger cable, instead of 4/0 they would have needed to be 350MCL to minimize voltage drop. I now know two things, placing the battery bank in the heated space and paying the cost for the heavier cable would have been cheaper than wasting $2500 on what ended up being scrap batteries.
I'm still thinking about how to start up that portion of my electric system. I have a XW6048 inverter (6000 watts @ 48V) which when purchased 12 yrs ago cost $3400. It's a good inverter for battery only or battery+ grid tie net metered, but will not grid tie without a 48V battery bank. As I see it now I have to decide, do I want to go back to a Trojan 48V 240 AH lead acid bank and have the monthly servicing (my last bank worked for 10.5 years) or do I want to buy a different inverter and sell the XW6048 one? Inverters are less expensive now and being that array is only 1480 rated watts, I could get a 2000 watt or maybe even a 1500 watt grid tie inverter and forget the battery back up, since that was only a back up for a propane heater to keep my reverse osmosis machine from freezing and since I use a propane wall furnace to heat it which needs no electric and the fact that in the 8 years since I added the grid connection I have never had a power outage. I need to make a decision in the next month or 2.
logging small time for years but just learning how,  2012 36 HP Mahindra tractor, 3point log arch, 8000# class excavator, lifts 2500# and sets logs on mill precisely where needed, Woodland Mills HM130Max , maple syrup a hobby that consumes my time. looking to learn blacksmithing.

scsmith42

Klunker, it seems to me that if you simply add a generator / battery charger combination to your existing setup, you can minimize additional cost yet extend your time off grid.

Run the generator in the late afternoons to fully charge up the battery bank before bed, and then run off the batteries overnight, and part of the next day until you need to fire up the generator and recharge.

If you're able to buy a propane generator, you will have the most maintenance free system possible.  The problem with gasoline and diesel generators (I have ten here on the farm) is that the fuel will go bad in you don't keep it somewhat fresh, and the filters on the diesel units will clog up in the winter time.
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

maple flats

At my sugarhouse I had a diesel generator to supplement my solar. I used that for 3 years, I never had any filter clogging or starting issues. I do use a product called Power Service year round, it gets added to my large tank at every fuel delivery. For the first year using that generator I used Stanadyne diesel fuel additive, no issue then either, but I switched to the Power Service only because it was easier to get locally.
logging small time for years but just learning how,  2012 36 HP Mahindra tractor, 3point log arch, 8000# class excavator, lifts 2500# and sets logs on mill precisely where needed, Woodland Mills HM130Max , maple syrup a hobby that consumes my time. looking to learn blacksmithing.

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