questions to those living offgrid with battery/inverter...

[mobile_bob]

systems.

i have spent years reading all about batteries, charging them efficiently, inverters and their difference's
but to date i don't know anyone that is actually living with a battery inverter system as their sole source
of power, no matter how they are charged (genset, solar, wind, hydro, diy nuke etc)

If ever there was a moderator that walks the walk, it is you John 

can you tell us a bit about life with batteries and inverters?
what batteries do you use?  how has living with them been? are you happy with them?
what manufacture? etc etc.

i want the skinny on this deal, so tell us all about it.

i think i have a pretty good idea based on research what works and what doesn't, but...

i am not so sure i trust anything i have read without first getting some confirmation from those that
live it, not just write about what they sell.

call me skeptical, but statements like "my abc inverter is the best ever made, it is the most efficient, blah blah blah"
or my favorite  "i know it is doing what it is supposed to be doing because the green light is on"
(maybe the st head needs to have the light changed from red to green?)

There are many of us thinking of moving offgrid, several more that are thinking of building inverter generator sets, back up systems
etc. and learning from someone such as yourself the lessons you have learned is a valuable resource that needs to be tapped, so

tag your it buddy!



bob g

[JohnF]

I'm sure I'll miss something out here, so bear with me.

First, a bit of history will explain why my system is set up as it is - I originally intended to run 24/7/365 on the engines, my way of thinking was that I could install a 6/1-5kw combo for around $2400, but batteries and inverters were going to cost in the region of $10k.

I started my adventure doing just that, IIRC using a 12/2 and a 6/1 Lister. It soon became apparent that 2 engines, under these circumstances, was not enough (Mr. Murphy has a cot in my gensheds) so I looked for another solution.  Back to the battery idea.  Meanwhile, my neighbour (about 1/2 mile away, but he is the nearest I had) had been given a Magnum inverter for Christmas.  He was also going off grid (did it a few months before me) and bought 1400ah of Rolls-Surette batteries.  After he had it all installed I had a look and decided that it was a good idea - at least in the Summer I could drop back onto batteries a night and it would be quieter (damn frogs around here could deafen anyone!).

So I followed his lead, but started with a pair of used fork lift batteries which probably only were good for about 800 a/h.  For reason not yet fully understood, I configured these in a 12 volt array and bought a Magnum 5000 12 volt inverter (note to self - get OUT of the box every now and again!).  The good thing about this inverter is that it is rated to output a true 240 volts, so I could run my well pump and other stuff on it.  Unfortunately it turned out that the circuit boards could not handle the power, and both Ernie (my neighbour) and I suffered from broken inverters.  They were sent back to the manufacturer, who did fix and replace as necessary, but after it happened a couple of times I was no longer comfortable with it and the company willingly provided a full refund. After that I decided to go whole hog into the battery/inverter thing and bought 12 x 2 volt Rolls Surettes and set them up in a pair of parallel 12 volt strings, total battery capacity is around 3000 a/h.  (Excellent batteries if a bit costly, around $500 per battery plus shipping) I also bought a pair of Xantrex 24/12 inverters and stacked them - again this gives me a true 240 volts at the distribution panel.  There are some other additions that I was persuaded to put in by the installer (I'm no Tesla!) who told me that because the generators put out 240 volts and each inverter could only take 120 that I should put in a pair of 240/120 transformers - supposedly to balance the outputs and inputs better.

Sounded good to me (I'm no Hertz either!) so that is what was installed.  I did make a mistake however, and it is one I have not fixed yet, more through fear of letting smoke loose (no Edison either!) and charring myself than anything else.  The output from my engines first goes through the inverters before it gets to the house.  It seems that this is a major limiting factor - no matter what sized engine I use the inverters will only pass through 4800 watts on a continuous basis (up to 9600 for 5 minutes).  This has resulted in me not being able to use some of my large machines because the draw pops the fuse in the inverter.  What I need to do is to re-configure the 'lectrik string (No Joule either!) so that it goes to the house first then back to the inverters.  OH well, it is not a big deal, I'll get around to it eventually.

Because I am off-grid I wanted a fully-redundant system.  For that reason I put in the two 12 volt battery banks (if one string fails I can run on the other) and two inverters - even if only on 120 volts.  Additionally, I now have a total of 4 engines ready to run ( 2 x 6/1's, 1 x 10/1 and a 28hp 295AG).  I have everything set up so that it is impossible for more than one engine to supply power to the inverters and house at the same time.  To do that I use three double throw switches - the first two have one engine going into each input terminal.  The output from these two switches goes to the third inputs and the output from that goes to the inverters.  A bit complicated, but it works.

That's about it for now, fire away with questions (just remember - no Bill Rogers!).

[WGB]

Boy I'm glad Bob started this thread!
Hope this isn't a thread drift!
I do have many battery questions.
First I would like to ask you about your inverters.
I was looking hard at the Magnum line of inverters.
Also looked at all of them, Xantrex look good and has the 240 capability, large wattage, but made in China.
I really like Outback, but they seem to be a pain and expensive to get 240 with high wattage!
Apollo looks promising, but still new kids on the block, not the company but in this market.
http://apollosolar.com/Products/Inverters/TrueSineWaveOffGridInverter/tabid/80/Default.aspx
How much load did you have on the inverter with and the without the pump load?
How long ago did you have the board problems?
What did the company say was the issue?
I have tons of questions.
I'll what to see what Bob asks.

[JohnF]

"First I would like to ask you about your inverters.
I was looking hard at the Magnum line of inverters."

The company is good to deal with, although I think they were getting a little fed up with me in the end.  However, they did fix the inverters at no charge (except for shipping, of course) and in the end provided me with a full refund.  That is pretty good service, I was just uncomfortable with relying on them.

"Also looked at all of them, Xantrex look good and has the 240 capability, large wattage, but made in China.
I really like Outback, but they seem to be a pain and expensive to get 240 with high wattage!
Apollo looks promising, but still new kids on the block, not the company but in this market.
http://apollosolar.com/Products/Inverters/TrueSineWaveOffGridInverter/tabid/80/Default.aspx"

I just looked at the Xantrex, my installer recommended them.   They are dated but pretty bulletproof.

"How much load did you have on the inverter with and the without the pump load?
How long ago did you have the board problems?
What did the company say was the issue?"

Don't really know about the load.  However, before putting in the inverters I was happily running the whole house on a 6/1, so I would guess not much more than 3kw went through the inverter.  Board problems were about 2-3 years ago, the company could well have addressed this problem by now, it had become well known.  In the first instance the company blamed operator error, i.e. a backfeed through the inverter when switching from mains power to genny, and this could well have happened the first time.  However on subsequent occurrences they claimed the same thing BUT, I was off grid by then and had nothing to back feed.  We parted on reasonable terms, agreeing to disagree about the cause.  Of course I was at a disadvantage (see earlier references to me being an electrical idiot) and couldn't get them to see my point of view.

[WGB]

Thanks John.

[mobile_bob]

Thanks for the info John, it really nice to get some feedback or input from someone that
is doing rather than haveing some other agenda that is not alway clear.

As for your  batteries, you mention the rolls/surrette 2 volt cells, are these the 5000 series?
the really big bad boys of the line?

Have you had any issues with any of the batteries?

i am seriously thinking the rolls surrette 5000 series is likely to be the battery of choice for my system
they offer them as dry charged and shipped without electrolyte and am thinking this is the way i will
get them, that way i don't have to worry about maintaining them until i am ready to put them into use.

also there is this ongoing debate about 12 volt systems being dreadful and folks "must" have 48 volt systems
apparently this "must have" philosophy has been lost on you. do you feel as though your system is really
much worse than it would be had you gone with 24 or 48 volts?

personally i have always thought that 12volts is workable provided one keeps his cable runs large and short as possible
so as not to suffer high losses in transmission associated with 12 volts at very high amperage. Is your system setup in
a nice tight configuration where transmission losses are minimal?

your system has always fascinated me, just wish we lived closer, i would really like to take a look at how you have it all set up.

bob g

[WGB]

I just got back from a 6 day 10 to 12 hours a day wind turbine workshop.
The consensus from all the instructors and PHD that ran the workshop was get golf cart batteries, used batteries, used fork-truck batteries, etc., cheap is the key word.
Because you'll trash your first set! 
Of course they're not dealing with folks of you guys caliber!

JohnF are there some pics of your set up somewhere?

Thanks

[Cornelius]

Mobile_bob:
I just bought 2x S-530 (6V, 530Ah) from the 4000 series from Rolls; the little brothers to the 5000 series. Since i've just bought them, i have no experience with them yet, but i really like the specs and the look/feel... I'm going to hook them up to my solar panels (310W), and use them to light up my 1st floor and power my workshop...
I will know more on how they perform in a while... 

[JohnF]

I'll have to try and get pics, don't know why I don't have any of the install when it was clean and purdy.....My batteries are the 5000 series, big suckers about 30" tall.  As for 12 volt vs 24 vs 48, with me it really doesn't make that much difference (unless I put in solar later) my 12 volt runs are only 5 feet or so.  IIRC I decided to go with the 12 volt system so I could use the 2 volt batteries in two strings, just makes for swapping out a battery easy if needed.

[Jedon]

I got a used system from someone who was waiting a couple years to get hooked up to the grid.
2 Xantrex SW+ 5548's ( 5500W at 48V ) paired so I have 11KW and 220V. I have never even used 1/2 that much!
The inverters came with a set of Trojan L-16H 6V 420Ah batteries, 2 strings of 8 to make 48V so 16 batteries ( 120lbs each so fun to move... )

http://picasaweb.google.com/jedon13/XantrexSWPlus5548SAndTrojanL16HS#

I have a Lister SR2 12HP air cooled with a Lima 5400W generator head and the Metro Lister CS 6/1 with 5KW ST-5 generator head, I have these on a transfer panel so only one at a time.
http://picasaweb.google.com/jedon13/MetroLister61#
http://picasaweb.google.com/jedon13/ListerSR2#

I'm interested in that transformer idea since the inverters each have one leg of the 220V and they don't draw evenly which distresses the generators, especially the ST-5 which groans when you load only one leg.

I have 784W of solar panels which keep the fridge ( huge 26cf 1.2KW/day ) going as well as communications and computers etc during the day running.
Planning on 240W of hydro next year ( pelton wheel, 100ft head, 20+ gpm )
I run one of the generators when I get home from work ( 6:30pm ) and shut it off when I go to bed ( 11pm ).

[Mad_Labs]

Hi All,

Well, this is my first post to these forums. I was directed here by Bob, we met on another AP forums. Hi Bob! Late to this thread but figured I'd post anway.

Anyway, I have been living off the grid since June and am now looking down the barrel of my first winter. I *think* I'm just about ready. Summer was easy, let's hope winter goes OK too. Obviously I only have very  limited experience. Also, my system is borne od poverty, the reason I am living off grid is that with the economy I can no longer afford my rental place and the mortgage on my property. I live in Northern CA, about 5 miles outside the teaming metropolis of Albion, population 399.

I have 10 Sams Club golf cart batteries that I bought in June. This adds up to ~1200aH. At first I was using cheapie inverters, AIMS brand. I had some problems with them, involving grounding issues, that blew a couple. Now I have a Trace sw2512, gifted to me by a friend that upgraded his system to 48V. For charging I have a 4500 watt gas powered gen and a lawnmower running an alternator. For a long time all I had was the alt charger and it worked great. I upgraded my alt and have been running into some trouble that I haven't had the time to sort out yet. I have 2 little solar panels that give me about 70 watts in full sun. Lucky for me I have great sun exposure, but still they only give me a fraction of my power.

My usual power consumption is between 50-80aH/day. Sometimes higher and if I am away the fridge uses about 30aH/day. Of course when using tools and so on it goes higher. With my battery bank I can go several days between charges. I have gone away for a week and the batteries were still fine when I returned.

Domicile-wise, I am living in a 35' trailer. I am still using the incandescent lights but am going to switch over to LED over the winter. I have sattelite internet.

Bob, you asked how happy. I'll say very! I love living out here and providing my own power. We had a storm that took out the local mains power and I didn't notice a thing!

Jonathan

[mobile_bob]

Jonathon:

good to see you made it over here, hopefully you will find this place helpful

bob g

[Henry W]

Hello Jonathan,

Welcome aboard!

There is lots of knowledge from many of the members in this group. If you need help with anything just let us know. We will do our best to help.

Henry

[WGB]

Hi Jon!

[Mad_Labs]

Hmmm, posted this last night and it disapeared. I'll try again...

First, let me say that I beta test Parallax products from time to time. I don't get paid, they were very supportive of my hydrogen fuel cell robot project and I love their stuff.

Bruce, you are right, there are no analog inputs on the Propeller. This was a design choice, the why's of which are too OT for here. At first I was resistant, but now I see why and agree. I2C is easily done with the Propeller and can use the same pins as the eeprom or any other pins. The extrenal eeprom was another interesting choice, again this is not the place to discuss that.

The really fantastic thing about the Prop is the 8 cores linked by the hub. This makes the Prop totally deterministic and truly able to walk and chew gum at the same time. At my last house I had a Prop:

Getting time from a GPS
Broadcasting the time locally via RF
Displaying the time with Nixie tubes
Running my solar/wood/propane heated hot tub
Displaying the hot tub temp. on Nixie tubes
Gathering weather data
averaging and parsing  and doing math on the data
Logging all data to a thumb drive
Activating watering valves in the garden
Displaying data on a VGA monitor
Accepting user input (menus etc) with a mouse

So easy to make it do all those things at once. You set up a core to read your ADC and so on. Now you know how many samples a second you are getting no matter what. The user can interface, change settings, scroll through screens, whatever, and the data rate remains the same. No interupts! You can directly hook a monitor, keyboard and mouse to the Prop.

Bob, the support for the Prop is booming and the object exchange is getting big. The Prop is a little harder to program than a Stamp, but not much. And so much more powerful, and it makes many tasks much simpler than with a Stamp. For an example:

I do mini-sumobots with students quite often. Using a Stamp or PIC, it is a race to read the sensors, run the servos and make decisions. Students find it hard to add their ideas to the long loop that is the program without upsetting the timing.

Enter the Prop. We set up a core to read the sensors, another to run the servos. Now we can have a core just making decisions, very easy for students to understand and program.

Anyway, as you cann see, I'm a fanboy. So take this with whatever size grain of salt suits you.

Jonathan