This is a discussion on Our off-grid system & life within the Alternative Energy (Wind, Solar, Hydro etc) forums, part of the Off-Grid Lifestyle category; Mountaingirl. Click on my my nickname “chiefster23” and view my previous posts. Back in March 2017, the thread is titled ‘my solar project’ I also ...
Mountaingirl. Click on my my nickname “chiefster23” and view my previous posts. Back in March 2017, the thread is titled ‘my solar project’
I also have a Honda genny but it’s only a 2000watt. I also bought an army surplus 3kw diesel genny that I can run on my furnace fuel oil. I would love to have a remote location and a setup like yours, but I am too old to go back into debt and start a project like yours. Keep us posted.
One down side to some areas deep water. My second sons well is 400 feet. On this place it can be 10 two 90 depending where you want one and a sand point will work in some parts of the land. I could not ever see us living in town. I remind myself that family settled this area and for a generation had no electric, another generation had darn little. They did well. Just a different life than what most live today.
New life as a house husband, major shift in duties.
Karl Marx said, "Destroy their culture, rewrite their history. Ruin their art and literature, and defame their heroes, by offering fabrications to scandalize that which they considered good.
After reading this Obama said I am on it.
Yes, it does pretty well. Actually, I think I could power up more if I had a bigger battery bank. Maybe that will be a future project.
MountainGirl, If I may make a suggestion about "balancing" your system...
It's great that you rarely go below 90% SOC to maximize battery life. I'm assuming that you're using a hydrometer occasionally to verify the SOC meter. We tend to drop to about 80 - 84% SOC most evenings (more electronics including a teenager and a mini-split) but we have more panels so it works.
The thing is while it's best to not cycle the batteries too deeply often it's better if they drop down to about 80% occasionally to give the electrolyte a good stir with a hard charge. But from what I've read in your OP considering the 77% panel/controller efficiency factor most solar professionals assume when designing a system you can only recharge those batteries at about a C/25 rate which is way to gentle (slow) to maintain battery health. A general rule of thumb is for a weekend cabin a C/20 charge rate is considered the bare minimum(C/13 is much better) for healthy batteries and a C/10 rate is better for a system that is cycled daily. With those Rolls you can safely charge them at up to a C/8 rate.
This means that you may want to conceder either doubling your panels or pulling one string out of that battery bank. (I understand that pulling a string of batteries at this point is not a realistic option.) In an effort to help make your batteries cycle a bit more you may want to at least double your panels and maybe once a week turn the panels off for a day so the batteries cycle a little deeper, but you still need more panels. In your case you are way over on the batteries.
Go to this site and you will learn a lot. Recent Discussions ? northernarizona-windandsun
It would be a shame to lose that $7500 battery bank in only 6 years.
I've been running some solar for about 8 years and designed and installed the system my home runs on as I type tonight over 2 years ago.
18 (and adding more) SW285 panels
Conext 80-600 controller (working on adding Conext 60-150)
Schneider 6848 XW+ inverter (more inverter than needed but I've seen it peak at over 9200 watts, well, microwave, clothes washer, ect all kicked in at once while the mini-split was heating).
16 Crown 395 amp/hr 6v batteries
Conext battery monitor @MountainGirl
Last edited by 8301; 10-31-2017 at 06:57 PM.
I do like the setup but only 8 acres, seriously?? Must have a lot of neighbors/friends close by. Are they on the same page or a liability?? Envy not hardly, you'll burn up those few pine trees the first hard winter. Hows the garden going??
Last edited by Chipper; 10-31-2017 at 08:24 PM.
I'm listing below some of the components we have (copied from a pdf I'd saved of the bid); and we live up here 24/7 - rather than it just being a week-end cabin.
Schneider Conext SW 4024 4000 watt Off-Grid Inverter/Charger 120/240VAC
SW System Control Panel
Trimetric 2030-A Meter kit w/500amp shunt
FM-80 Charger Controller MPPT
MNPV3 combiner box
15 amp 150v dc Single Pole DIN
Delta LA602DC Lightning Arrester
Delta LA302R AC Lightning Arrester
80 amp 125VDC panel mount ¼ stud
You are right that re-configuring the battery bank is not really an option, and, sadly we cannot add more panels. There is no more room up there - and we had to soldier them in a row to keep the array height down (high winds).
Thanks again, your input is very much appreciated.
When drilling in SC we hit wet sand at about 55' and went down to 90' (hitting the bedrock) which gave us water year round,,, sand and seashell coming up all the way.
Lot to cover so I'm just going to hit the high points.
Battery maintance is almost as much art as science, lots of opinions out there.
If you are running sixteen 6v batteries with a SW 4024 then you are running four strings of batteries. Almost impossible to keep four strings balanced. The fact that you haven't noticed this means you guys aren't using a SG (specific gravity) meter and instead are totally relying on your battery monitor. Battery monitors drift off within a few weeks of being reset and should only be used as a rough estimate. Get a SG meter and use it, many types out there but this is the one I use. https://www.solar-electric.com/catal...t/?q=Hydrovolt Always rinse a SG meter out with water before storing to avoid buildup inside. A clamp meter that can read DC current will also help you see problems with uneven current flow in the battery cables.
After testing all cells (full charge should show a SG of about 1.277) look to see if there if the maximum variance between all cells is more than .020. If not then you don't need to EQ (equalize). EQing is hard on the cells, you're basically making them shed metal, so you only EQ when needed. Automatically EQing monthly with a well maintained battery bank usually isn't needed. Maybe every 3 months or whenever you see the cells too far out of balance (more than about .020). Unfortunaly with your running 4 strings of batteries (especially with such a soft absorb amperage) makes me suspect that you are going to find that the batteries are out of balance unless your frequent EQing has forced them back inline. But many EQing cycles are only one hour, sometimes you may need 3 or more hours to get things straight or reasonably close.
To properly EQ fully charge batteries using Absorb (SG around 1.277). If batteries are badly out of balance (some cells not getting above about 1.255 using absorb) EQ and check SGs every 30 minutes or hour. Continue EQing until the weaker cells stop rising. This may take several hours. If the batteries are older or have been damaged from chronic under charging don't wear out the stronger cells by EQing too often or long. Rolls batteries have a wonderful warranty but ONLY if you have documented their SG readings occasionally. Great warranty but hard to get a warrant claim approved. Be sure to review the Rolls charging suggestions.
By having a SG meter you can adjust your absorb time to assure fully charged batteries while minimizing battery heating.
part two is next post. @MountainGirl