tesa's Off Grid System

Started by tesa, January 30, 2009, 05:57:51 PM

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MountainDon

Quotei sort of thought the lights werent too bad, when you consider a normal house and how many
40-60 watt bulbs they might employ, so i thought my 4 36 watters were ok

For comparisons sake we use 23 watt CFL's in most places, both the house and the cabin. One of those gives out as much light (lumens) as an incandescent 100 watt lamp. Not sure what the lumens are from 36 watts worth of 12 volt RV lighting, but it's bound to be less than the 23 watt CFL. Incandescents turn a lot of the electrical energy into heat; CFL's do not. Neither do LED's.


Quote
it draws 84 watts and for 12 hours, thats a biggie, so i'm willing to look outside the box

That water pump wouldn't be working for 12 hours a day. The typical RV water pump only draws power when a faucet is opened. The circuit may be turned on, but until a faucet is opened the only draw will be the pilot light on the switch (if there is one). I've never metered the actual run time on our RV water pump, but my best guess is that it is under an hour per day for certain. More than likely a quarter hour at the most, probably less most days.



RV furnaces suck watts too, but only when the fan is running.


A big disadvantage of those MK batteries is their capacity; 26 amp-hours. With all ten in parallel that gives 260 amp hours total capacity. That's slightly more than two regular 6 volt golf cart batteries in series.

They should not be used in the same battery bank, with batteries of a different type like wet cell golf cart or L-16.

Just because something has been done and has not failed, doesn't mean it is good design.

tesa

great news about the water pump, thats gonna make my new numbers look that much better!!

daniel spoke at length with the friend that gave them to us, and actually, he can not confirm
that they haven't been used, so i'm gonna recant my "brand new" claim

also, he said when he called the company (MK) they said the main problem
with them, for our useage, would be that they don't accept a trickle type charge
which wouldn't be ideal for us

i guess i might try to put them up on craigs list for free, since we really can't
confirm they are in fact new

i'm also searching for a local recycling place we can take them   :(

i feel so much better than i did just 24 hours ago, i'm gonna re-run the numbers
based on the new info on the pump, and try again

i went to the sams club website and found lots of battery choices

and i know of several golf cart places in houston on my list to call tomorrow for pricing

tesa
"building a house requires thousands of decisions based on a million bits of information"-charlie wing


hnash53

Tesa,

Here is a link to a fellow that sells Lots of batteries for off grid use.  I purchased 16 12V AGM batteries for $800 from him.  They are super batteries.  They each weigh 100lbs.  But do they ever hold a charge. 

Each one is rated at 120 amp-hours.  Since they are absorbent glass matt batteries, you can mount them in any position (Why anyone would mount them other than straight up, I can't imagine).  They are non-spillable and as long as you use a charge controller they should last a long long time as long as you don't drain them below 50% of their capacity.

The batteries I got were from a data center in Denver.  They were used as a battery back up for the data center.  The seller is quite knowledgable and communicates well.  Ask him any questions and he'll respond.

Here's the link:
http://stores.shop.ebay.com/SolarEnergyQuest__W0QQ_armrsZ1

Copy and paste into your browser.

Best wishes,

Hal

tesa

great, thanks for the link, will do!

after some research, daniel thought flooded batteries would better suit our needs,
as i'm only just now beginning to understand the battery thing

after some poking around, i found some 6v 232 ah flooded for $140 each and
the site is offering free shipping

we've been investigating the pros and cons of each type of battery (flooded, gell, etc)

we thought flooded would better suit our needs, as the sealed have less
life span?

am i on the right track with that?

tesa
"building a house requires thousands of decisions based on a million bits of information"-charlie wing

hnash53

As to lifespan, I really can't say.  You might ask the fellow selling these kinds of batteries.  He himself has a cabin at about 11,000 feet in Colorado and uses these batteries there.

My experience so far with them has been great.  As I've researched things myself, I always find pros and cons, people "insisting" on this type of battery, others "insisting" on another.  Gel batteries are maintenance free...no adding of water, specific gravity tests...all of that.  Yes you might trade a bit of longevity for maintenance free.

After educating yourself, then trust yourself and your decisions....something I am learning to do myself!!

Best.

Hal


MountainDon

Quote from: hnash53 on February 05, 2009, 09:42:56 AM
Gel batteries are maintenance free...

Just remember Gel does not mean AGM. There are both and there s a difference. Neither will leak fluid, both can be mounted in any position. However, a Gel cell requires a different charge rate than AGM or flooded cell. AGM and flooded cell can use the standard type of battery chargers. Gel cells also do not "like" high discharge rates, however they excel at low rates of discharge. AGM are a much better choice than Gels for alternative power systems. It  is commonplace to find AGM's referred to as Gel cells. If in doubt check and see what the manufacturer calls them.

Just because something has been done and has not failed, doesn't mean it is good design.

Mike 870

I thought this was a good write up on AGM batteries. There are also some other FAQ type explanations on there that I thought were good.  http://www.windsun.com/Batteries/AgmTech.htm

tesa

i went to that very site when reading up

i just re-read the article, just to make sure i understand

i sort of do, but i'm relying on daniel choosing, since he'll be
the one takin' care of the "babies"

i think he thinks flooded will last longer, and be a better investment, but i know
this is a big decission, so he's taking a day off from reading websites, and
gonna hit the research again tomorrow, as we have plans tonight


also, in my travels today, i stopped at a few auto zone type places, and looked
at LED lights, i think i'm gonna lay low on those, i really don't think our lighting
load is too bad, i still think 3 36 watt lights isn't too bad, i do respect that
the LED's are less watts, but none the less, i think we should be able
to manage

however, if someone really thinks 3 36 watts is too much, then i'll reconsider

but for now, i'm good

on another note, i've been looking at inverters, we have a very small ac load compared to
our dc load (benifit of the RV) i added up everything we might ever run (like the sewing maching,
and our cd player) and only came up with 361 watts, so i looked at a 600 sine wave
inverter for around 250, i think, off the top of my head

tesa
"building a house requires thousands of decisions based on a million bits of information"-charlie wing

MountainDon

Just a quick note as I'm short on time right now...

You will need a good battery charger as well. For maximum battery life it needs to be able to put out 15.5 to 16 volts, on a 12 v system, in order to perform a proper equalization charge. Good inverters, like Outback, have a multi-stage charger built in to them. They are user programmable for the charging voltages, within a certain range.

So, if you are looking at a good pure sine wave inverter, without charger, you need to address the charger/equalization issue. Many RV's do not come with a charger that can do that.

There may be other inverter/chargers out there that can do the proper equaliztion voltages. I have not looked at them all in close detail.

I began my inverter/charger search with operating temperature range being important. I wanted one whose specs said it could be used down to minus segree F temps. Many are not rated for below freezing or below zero, so I didn't look any further. Outbacks inverter/chargers are approved for down to -60 degrees F.

Just because something has been done and has not failed, doesn't mean it is good design.


glenn kangiser

No air compressor, table saw, skill saw, microwave, washer, drier?

BTW, tesa -- my son and GF have been to Burning Man a couple of times. d* 

They may have powered a few of those lights...  [waiting]
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.

tesa

i did see the outback inverters

and i knew we'd need a charger

i'm tryin' to keep my research to just a few things at a time, least i get overwhelmed

but thats next on the list

daniel plans to use the power tools with the generator, and i'm gonna give up
the microwave, no washer or dryer

we actually don't use the microwave too much, the odd bag of popcorn, or maby
a quick warm up of cold pizza

i know people, mostly bachelors who use the thing every day, but we really don't

i think what i'm gonna really miss the most is the toaster, we use that by far
more than the microwave

i have this thing for toasted bread with honey and butter, but at 800 watts, i'm
gonna give it up

prolly won't see you all again till monday, busy weekend

have a great weekend!!

tesa
"building a house requires thousands of decisions based on a million bits of information"-charlie wing


glenn kangiser

tesa, keep in mind that while it is 800 watts, it is only used for a few minutes so its effect on the batteries is not so bad if you have a big enough inverter.

Ultimately up to you but I would caution you against getting too small an inverter to start off with because I wasted a lot of money getting a square wave (modified sine- Trace) then decided nothing but sine would work and went for 4000 watts to start - a Trace 4024 which had the built in charger.  I don't know what capability it has for equalization programming as I use a welder for equalization and haven't checked it out.

Just wanted to throw this in to think about - adding to the confusion.  The Outback I know is one of the better ones.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.

MountainDon

We used to have one of those camp stove top toasters. I like my toast to be toasty on the outside, but not dried all the way through. It tended to dry the bread out too much for my likes, but others may vary. Cheap enough to be worth a try.

However, as Glenn stated, the toaster doesn't run for long periods. Given good batteries and an inverter that will handle, say 1000-1100 watts continuous, you could retain the toaster.

The inverter election deserves a lot of thought. I wanted to retain the use of my 1100 watt Exeltach pure sine wave inverter, but in the end decided it was not the way to go for us.
Just because something has been done and has not failed, doesn't mean it is good design.


tesa

good morning!

waiting on a call back from the "parts on sale" people

hopefully, they can help with some of my general questions, and their website doesn't list
prices on their solar panels

found a Samlex America 600 watt pure sine inverter for $259, but i don't think it has a
charger, so it might be better to go with the outback which include the charger

its my understanding this helps equalize the batteries?

i'm not really clear on what the darn thing actually does   d*

i also believe we're gonna go with a ground mounted array, after some surveying of the location for
the house, i don't think it will be the best place for panels, i dont want to cut down every tree, for
gosh sake, so i'm thinking the panels themselves will be about 80-100 feet from the house, but for
the rv, they'll be right next to us, tryin' to think ahead a bit

to do list for today

continue resarching batteries,
get pricing on the panels, and inverter

and try to understand this charger business

last night, i tossed and turned all night dreaming of rainwater harvesting, and roofs

tesa
"building a house requires thousands of decisions based on a million bits of information"-charlie wing

glenn kangiser

The charger is for when you are hooked to the generator to charge the batteries in low sun or no sun conditions.  The ability to equalize built into that charger will help bring low cells up to the same specific gravity as the rest  preventing you from having to buy new batteries every couple of years.  A normal charger as in automotive will not do that.

I would stick with Outback rather than some unknown as that is their specialty.  It could save you from buying one that won't work and having to spend the money again in the future.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.

MountainDon

Remember, IF you go with AGM batteries you can likely forgo the equalization charge... depending on battery manufacturers recommendations.   ???  Can't say definitively if that's a good thing or bad.
Just because something has been done and has not failed, doesn't mean it is good design.

tesa

well, heres our quote from "parts on sale"

2 suntech stp 210 watt panels $839 each
mppt500 charge controller $195
mc4-10 solar connector cable $13
breaker box $25
2 pv array breakers $12
tfb150 fuse block $45
bc3-2/0 connector cable for fuse block $18
ugm84 ground mount $216

total of $2,214.00
shipping is $329

the quote included a 1000 watt inverter, which we really only wanted 600, i didn't want to
oversize the inverter too much our ac load is 310 watts apx.

so this quote doesn't include an inverter, as we're still searching/researching

also, i'm still looking at batteries, and daniel might be leaning towards the AGM batteries

based on prelem research, i thought they were a bit higher priced, but you get what you
pay for, and i don't think he wants to babysit the batteires too much

thoughts?

tesa
"building a house requires thousands of decisions based on a million bits of information"-charlie wing

glenn kangiser

You will find little difference in standby  power use  on the inverter but may really like having the added capacity.   I have 8000 watts of inverter power but seldom use them hard.

They seem to have lowered their price since we bought from them.  $4.00 per watt is cheap.  they were prompt and great to deal with - also sent a wire diagram with the system.

We have the mppt 500 controller and it works fine.  Note that it does not have equalization built in but if you equalize with the charger on the inverter it is not a problem. 

As an after thought ask them how you are going to equalize your batteries - if the inverter charger will do it or if it has one.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.

tesa

ok, don't think we can use the 600 watt inverter, as its only 115 vac, and we need 120 vac

so i guess we're buying a 1000 watt inverter

the samlex s-1012a is an inverter/charger $579 sold on their website (parts on sale) so maby
they can include that in our package

will send them an e-mail and ask them about the equilization

so if i buy an inverter with a charger, than i don't have to buy a seperate charger, am i correct?

tesa



"building a house requires thousands of decisions based on a million bits of information"-charlie wing


tesa

interesting development

daniel says the rv's CONVERTER actually has a battery charger

he says its a built in three stage charger

i wonder if that would work as a charger?

oh, and regarding the parts on sale people, they were so helpful today

answered all my questions, were very friendly, didn't make me feel like an idiot, and
i got the quote back in less than 4 hours

tesa
"building a house requires thousands of decisions based on a million bits of information"-charlie wing

Mike 870

I have heard some people say they prefer a seperate inverter and charger so that if one fails they only have to replace the one.  I'm not off grid though so you may want to stick with the experts on here.

MountainDon

#47
115, 120 VAC; basically no difference in use.

samlex s-1012a  does not have a equalization setting. It tops out at an absorption rate of 14.5 v in the 12 V model.

The Samlex efficiency is 85% in inverter mode; not as high as top line inverters which are around 92%.

An indicator of whether or not an inverter is top line is the weight of the unit. The 2000 watt Samlex weighs about 23 lbs. The top line, like Outback weigh in at about 67 lbs. 

The Xantrex Truecharge 2 battery chargers are one of the few that have equalization mode. 40 amps for about $300+ IIRC. Do a Google. There may be other brands as well.


About the RV converter/charger. Your RV converter may be suitable for charging your solar system battery bank and there's a good chance it is not. Many converter/chargers that come with the RV are unsuitable for use with more than the single battery that come with many RV's. Check the specs and see what the charger output is; how many amps. Many of these are a poor compromise, they don't have a high enough output to rapidly charge the batteries, yet the output is too high for a trickle or maintenance charge. The converter/charger that came with our RV puts out 6 to 10 amps; I replaced it with one that can put out up to 55 amps.

The maximum charge rate is determined by the batteries; how many or total amp-hour capacity. If running a generator to charge it's a waste of gasoline to charge at low rates. Add up the total of the amp-hours for the batteries. In our RV that's 440 amp-hours. Using the C/8 formula, 440/8 = 55 amps, bang on the nose. You don't have to be that close, mine just worked out that way. That's the MAX rate, less is fine, just takes longer. You can see if I relied on the built in RV controller/charger it would take much longer for the generator to charge the batteries.

When you go to equalize the batteries you first have to bring them to full charge, then set the equalization process in process. Every month is ideal, many folks do it every 3 months, if they remember. So, if your solar panels are able to bring the batteries up on a great sunny day, the generator may not need many hours of running. But if it's been cloudy for a while them the genset will have to do all the work.


Just because something has been done and has not failed, doesn't mean it is good design.

MountainDon

Quote from: Mike 870 on February 09, 2009, 10:31:09 PM
I have heard some people say they prefer a separate inverter and charger so that if one fails they only have to replace the one. 

Here's my take on it.

1. Starting off with a top line unit means it is less likely that you will have a failure. Not impossible, just less likely.  Glenn has Trace (discontinued, now Xantrex) I believe; good quality units. He's probably made sparks fly more than once and they still work.  :o

2. Combination Inverter/Chargers automatically switch the inverter off when generator power is applied to the genset input. This protects components that are connected to the battery bank from possible over voltage conditions.

In some separate inverter, separate charger systems it could be possible for the charger to be putting power into the batteries at the same time the inverter or other DC equipment is connected to the batteries. If the charger is placed in equalization mode it will be placing a voltage 15.5 to 16 VDC  on the batteries. THe rated input range voltage on that Samlex inverter is 10 to 15 volts. Some units will turn off if the input voltage is too high. Some may not. I have no idea what that one does.

So separate devices could work. It depends on how you set it up and how faithful you are to doing things in the correct sequence if the system doesn't look after those details automatically.
Just because something has been done and has not failed, doesn't mean it is good design.

MountainDon



Inverter Trivia:

Trace inverters were recognized as one of the best. Trace got bought out and became Xantrex. Some believe Xantrex quality was not up to the old Trace. Outback was started after Trace became Xantrex. The founders of Outback were disgruntled Trace engineers.
Just because something has been done and has not failed, doesn't mean it is good design.