Author Topic: Jumped in with both feet...360 watts of solar! (Read 7938 times)

Striider · « **on:** January 23, 2009, 04:32:27 PM »

So I have been lurking here and absorbing as much information as I can from you folks, and man, what a great resource this forum is. Thanks!

I figure I should introduce myself properly so here goes.

I have a 900 square foot A-frame getaway cabin on 5 acres WAY off the grid in central Colorado near Hartsel. It was quite a fix-er-upper, but we are enjoying the heck out of the process and it is shaping up quite nicely. Lately it has become apparent that the correct way to go out there is a solar/wind combo so after researching for awhile, the right deal came along on three new 120 watt 24v solar panels. These are on the way, and I am trying to get a pair of 12v sealed AGM 100AH batteries to start with as well. Planning to mount the panels on the roof, as it is around 45 degrees and faces south. Also planning to keep the batteries inside the cabin in a closet sort of thing to keep the temperature as stable as possible since I am not there all the time and the heat is provided by a wood stove only.

I realize I still need to find a charge controller that will handle 15 amps at 24v, and would love to find one that can dump the excess load to a water heater. Do you guys have any suggestions? I tried a search and didn't find a whole lot, so any help would be appreciated.

Thanks!

ghurd · « **Reply #1 on:** January 23, 2009, 10:23:11 AM »

I think you will be happier with 2 pairs of 6V golf cart batteries than 2 AGMs.

The 360W will not heat much water. TS-45 or TS-60 will do it. Then heating elements, etc. It gets expensive compared to the heat it can make.

MorningStar SS-20 24V will handle the power. And total cost will be a couple hundered $ cheaper than a water heating system.

G-

kurt · « **Reply #2 on:** January 23, 2009, 10:31:12 AM »

only thing with the cart batteries is you will have to be sure to vent them to the outside.. but they are allot cheaper per amp hour than agm and allot more tolerant of abuse.

Lowhead · « **Reply #3 on:** January 23, 2009, 10:56:01 AM »

I'd be worried about bursting the water heater if the place isn't always heated and you had few cloudy days.

Low head

scottsAI · « **Reply #4 on:** January 23, 2009, 12:51:54 PM »

Welcome Striider.

Checkout www.builditsolar.com

Cheap solar heating, keep temperature without cutting wood or as supplemental heat.

You will be surprised at how cheap current designs are, if the roof needs replacing, incremental cost becomes cheap! to install solar. If solar good enough for electric then slam dunk for heating.

Golf cart batteries are about a third the cost of AGM, can handle freezing temperature if kept charged.

My battery (8 golf cart) is on the ground (patio stones) with an insulated cover box outside (MI).

Have fun,

Scott Beversdorf

independent · « **Reply #5 on:** January 23, 2009, 02:19:10 PM »

I use a Ghurd controller with 170w of panels. It dumps into an absorbtion fridge. Works really well, not that I'd recommend it for 360w. You could dump into resistors available at ghurd.info while you think of what you want to do with the excess amps and make yourself up a controller while you are at it. Can't beat the price for the controler (IMO)--$12.50!

Ungrounded Lightning Rod · « **Reply #6 on:** January 23, 2009, 02:54:16 PM »

I'd do a thermal panel to heat the water, too. Thermal panels can be homebrewed cheaply.

luv2weld · « **Reply #7 on:** January 24, 2009, 07:32:40 AM »

Howdy neighbor!!!!

Our 911 address is Hartsel, although we are about 20 miles

from there. We are still in Park county and that is the closest

town, so it's our address. We are actually on the south

end of Kaufman ridge.

Glad to see someone close by on here.

I would also be concerned with freezing things up, if you use a

water heater dump load. I know you don't want to waste any power,

so maybe you should do like independant suggested and use a ghurd

controller and dump to a resistive load and use it as an air heater.

You won't get any heat to speak of, but you won't cook your batteries.

That way you can save your money for the controller for your wind generator.

Are you building your own wind genny??? If so, how far along are you??

Ralph

Striider · « **Reply #8 on:** January 24, 2009, 09:20:28 AM »

Thanks folks for all the great ideas and feedback. I am now re-strategerizing my battery plans and will build a Ghurd controller, as I am a semi-handy guy who loves to solder. How would I heat air with a dump load? Just a water heater element or something? Also, I remembered that one of my long lost friends sells forklifts, so I am reaching out to him now to see what I can scrounge up in the way of used megabatteries. Iluvtoweld - that is very cool that you live so close. We are 6 miles south of Hartsel overlooking the valley and Antero. Maybe you could give me a tour of your setup some time for ideas? The wind generator is still in the idea stage, and all I have procured so far is an old treadmill motor to start with. Would like to build something larger like the 10 footer on this site, but I have cold feet so far. My email address is striider at comcast dot net. Heading into Lake George for 1/2 cord of firewood, will chk forums later

Thanks all, will keep you posted on progress.

vtpeaknik · « **Reply #9 on:** January 24, 2009, 10:22:18 AM »

You may also consider the BZ MPPT500 charge controller - right size for your system and will give you 20-30% more power from the same panels thanks to MPPT, especially when the panels are cold and your batteries are empty, i.e., when you need it most. You can get one for less than $200 if you look around. On the other hand, if you are thinking of enlarging your system over time (adding more panels) then you may want to go straight to a bigger MPPT controller, e.g. from Outback ($500 or more).

ghurd · « **Reply #10 on:** January 24, 2009, 03:14:05 PM »

Power resistors are the best way to heat air.

Weater heater elements will burn up in air, and a ghurd controller isn't perfectly suited to many water heater elements.

Ghurd has power resistors. Cheap!

(plug myself in the 3rd person?)

A single ghurd controller can handle the solar and treadmill windmill.

Simply add more power fets and power resistors.

Watch out for Ralph... He's liable to help you make a neat system.

G-

luv2weld · « **Reply #11 on:** January 25, 2009, 07:36:07 AM »

Hey!!! I resemble that remark!!!

Thanks for the vote of confidence.

It's nice to have friends.

Ralph

luv2weld · « **Reply #12 on:** January 25, 2009, 07:56:52 AM »

Eric,

You are welcome anytime. And no need to go to Lake George to

buy wood. I have a sawmill and give away the slabs so

people can use them for firewood or whatever they want. It might

be a little farther drive to find me, but the price for the wood is right.

But "cold feet"??? It's time to warm them puppies up!!!!!

You'll find some really nice wind generators on here. And tons of

ideas to incorporate into whatever you're doing. Also, like scottsAI

said, take a look at this link for several days reading.

http://www.builditsolar.com/

To look at someones files, click on User Info in the gray

box at the top of their message. Then scroll down and click on

view ***'s files.

Time to start building!!!!

Ralph

Striider · « **Reply #13 on:** January 28, 2009, 03:33:36 AM »

Ralph - That is a great offer and much appreciated for the wood Ralph! I will bring my small trailer when I come to visit. Should be in about 2 weeks, depending on how long it takes to put up the solar panels when I get back out there. I will be in touch via email.

For now, I am totaly into the solar project, but plan to attack the wind project at some point.

Ghurd and I have been talking ALOT, and thanks Ghurd so much for the advice and pointers along the way. Your tolerance of my noobie questions has been amazing

An update: The solar panels should be here Thursday, but I will be unable to go install them until the next weekend. Ghurd and others in this thread have talked me into a MPPT controller for a number of reasons.

24 volt hardware is expensive and most reasonably priced inverters and such have high idle current draw.
MPPT controller will allow me to get the most out of my relatively small bank of panels in a few ways. I will be hooking them in series to the MPPT and charging a 12 volt battery bank. This makes inverters affordable, more efficient, and my initial battery investment reasonably priced.
I found a factory refurbished (brand new looking) Outback MX-60 on craigslist for $325. So my savings here on the price of the controller, and going to 12 volt pretty much paid for another set of batteries and a small inverter to get started.
Decided to go with golf cart batteries, as they really seem to be the best betfor me at this point and easily expandable.

Striider · « **Reply #14 on:** January 29, 2009, 06:00:27 PM »

Well good news, bad news.

The panels were delivered today, but they were damaged pretty badly in frieght. The outer casing was fine, but internally, most of the cells have cracked or lost many pieces. Those pieces are floating around in the casings. It was packed semi-well, but not as well as I would have packed them myself, so really this falls on UPS and I have started a claim. Hopefully, I will get to keep them and try to salvage some cells and re-use the cases. On the plus side, he really overbuilt the cases - they are awesome! Anyway, I may end up shipping them back, it depends on what the inspector says. They were insured.

Assuming I get a refund, I am back to square one possibly...and thinking I should start looking at 12 volt panels this time since I have decided to go with a 12 volt battery bank/inverter. With the Outback MX60, does it really matter which voltage per panel I use to send into it as long as it is 24v or more in series? Time for more learning and research!

Eric

http://www.otherpower.com/images/scimages/12186/_Strider1_my_pictures_digital_cam_Damaged_package_IMG_6268sml.jpg

Airstream · « **Reply #15 on:** January 29, 2009, 06:21:24 PM »

Files link bug strikes again...

Striider · « **Reply #16 on:** January 29, 2009, 06:27:27 PM »

Yup- couldn't get that sucker to link!

luv2weld · « **Reply #17 on:** January 30, 2009, 08:57:18 AM »

Eric,

I am sick when I look at that!!!!!

What a huge disappointment. I sure hope you're not in a hurry.

Filing a claim can take a while.

Ralph

Striider · « **Reply #18 on:** February 06, 2009, 11:09:34 PM »

I figured the sun will still be there when I am ready to harness it

Hey, I measured the output today in bright sunlight of all 3 panels, and they are still 32-36 volts. I think the wattage varied quite a bit, but am unsure if I set my voltmeter correctly to measure that. How do I measure the output correctly?

Striider · « **Reply #19 on:** March 05, 2009, 04:17:34 AM »

OK here is the latest. UPS, after much haggling, FINALLY paid the claim and I got to keep these panels! So I basically got 3 panels for $150 since the guy is refunding the entire $1000 of the claim money to me. This frees up money for me to buy the battery I wanted...a forkilift battery. As I stated before, they are all still putting out voltage, but I have no idea the wattage yet. I am assuming since some of the cells lost some surface area that I will lose a bit of the wattage.

I am going to be using an Outback MX60 with remote temperature sensor and stepping down to a 12 volt 510 AH refurbished warranteed forklift battery. I believe it is a Deka but am unsure yet of the model, but he said it will weigh roughly 500 lbs. Is $500 a good price for a battery like this? I will check the power output of the panels this weekend, barring bad weather of course and report in what the MX60 sees.

Wish me luck!

Airstream · « **Reply #20 on:** March 05, 2009, 10:50:50 AM »

That $500 may be purchasing warranty and the batteries are free, well okay, may be some division between battery cost and warrantying them for X months.. What are the details of the purchase?

Striider · « **Reply #21 on:** March 10, 2009, 04:53:27 PM »

Ok here are the details:

Battery model = DEKA 6-D85-13

AH
month warranty

Tested at 85 amps for 5 hours - each cell had to be 1.70 volts or higher to pass after the 5 hours.

Also specific gravity was tested

Airstream · « **Reply #22 on:** March 10, 2009, 10:38:12 PM »

Sorry to throw so much info 'late' in the process...

Those batteries sound too large for a beginning PV install, and just right if you can exercise them; you might find a gas or diesel generator is needed. Your battery is designed around a usage model of the 8-hour workday for discharge and 16-hours to cool/recover/recharge/cool, deka specs are listed as 6-hour discharge so add 15-20% to that capacity to compare other brands equivalent 20 hour rate (usual advertised rates).

If you get these batteries here is your bible for them:

http://www.eastpenn-deka.com/assets/base/0656.pdf

Those motive power batteries are meant to be worked hard, Deka says "Proper charging is essential for maximum battery life. In general, the proper charging rate for lead-acid batteries is any rate which doesn't produce temperature higher than 115°F (46°C), and any rate which doesn't cause excessive gassing."

A very interesting excerpt from Deka's PDF...

The charger delivers a "high" start rate of 20-23 amps per 100 A.H. of rated capacity. As the voltage rises to 2.37 volts @ 77°F (25°C) per cell, the gassing voltage of the battery is held constant until the charge rate tapers down to 4-5 amps per 100 A.H. This finish rate is held constant until the charger automatically shuts off. Charger start rates should not be more than 23 amps per 100 A.H. of rated capacity, and the finish rates not less that 4-5 amps per 100 A.H. @ 2.55 V.P.C.

The Outback MX-60 at 14.7V will produce around 50 amps with the maximum recommended NEC 750 watt solar array; if you have the 510AH bank the Dekka PDF calls for 100A minimum initial charging current, and enough charging time on their charge profile the electrolyte mixes thoroughly while the batteries are bubbling to avoid sulfation. Weekly equalizing will be very necessary, using solar alone may not make it.

I don't know your system specifics, but instead of the MPPT MX-60 why not a good used Xantrex RV series inverter/charger? They have built in 100/120/140A 3-stage chargers that you can attach a generator to for equalizing and sunless weeks; and take the money that would've gone to the MPPT and get another solar panel? Buying a 12V bank sure limits available resources once you get to such a large 500AH+ banks...

ghurd · « **Reply #23 on:** March 11, 2009, 08:17:06 AM »

I disagree. A lot.

Looks like a classic case of over-thinking the plumbing with the use of choice excerpts.

The excerpt sounds more related to "The Charger" than the batteries. And the need to get them back in service in less than 16 hours.

The 23A per 100AH sounds completely crazy to me.

The proper charging rate is "Any" rate that stays below 115F and with low gassing. 50A of PV into a 510AH bank is a waste of PV. The battery will be at regulation voltage in a very short time. After that the controller will stop most of the PV power from being stored. Meaning the 750W of PV puts out the same as maybe 200W of PV.

The plan is 360W of PV. Buy another 120W PV, then buy a non-MPPT for 480W of PV. Like a TS-45 for $200? Or the MPPT he has that should get 100W more output than the TS-45 for less cost than 100W more PV?

Not a very efficient use of funds.

Your MX-60 numbers make no sense. It works out to someone with a simple system and a pair of golf cart batteries needing 953W of solar.

Someone with a wally-world 110AH really needs 477W of solar?

I use a 550AH bank with 180W of solar, on a less efficient MPPT than the one he has. The batteries can get bubbling pretty good under the right conditions. The batteries are over 8 years old (110AH is unknown, but newer). Rarely get an equalization charge. Spend 4 months a year usually below 14V. Sometimes a month below 13V, even during charging. I am not saying it is good, because it is not.

The peak charging current is about 11% of that 23A / 100AH. They spend all summer fully charged and are used every day.

This is the snow belt where worst case 30 day average insolation is below 0.5H/D. The cost to keep the batteries above 'suggested voltages' is too great.

For us the batteries were the expendable part of the system, same as expecting the car driven to work will eventually need replaced.

G-

TomW · « **Reply #24 on:** March 11, 2009, 09:12:03 AM »

Striider;

My bank is Deka setup very similar but at 24 volts.

I posted a Diary over here on it:

http://www.fieldlines.com/story/2009/1/30/161351/147

I got a 5 year full replacement warranty. In writing. 6 months seems kind of short?

Just curios why yours would be 10% of what our dealer gave us? Maybe it is more "dealer" than "manufacturer" warranty?

Tom

Airstream · « **Reply #25 on:** March 11, 2009, 12:18:35 PM »

Gave some timely data, with full documentation, on one specific battery and got generic quickie-mart deep cycle batteries paraded around for comparison.

Deka listing electrolyte temperature corrections up to 130F / 54C should tell you that specific plate composition and weight is not very friendly to idle time and low usage, and especially unfriendly to cool temperatures and low charge cycles.

Deka is telling us their plate separator and plate insulation design requires the high current to ensure electrolyte mixing. At 130F consumer deep-cycle batteries will most likely have been permanently damaged.

The Deka battery can be an almost forever battery at 1200-1600 discharge cycles but it is engineered with brute force electric "healing" in mind....

ghurd · « **Reply #26 on:** March 11, 2009, 12:52:57 PM »

You are still saying he needs 1700W of solar, a MPPT controller, and a generator with RV inverter, to properly charge a $500 battery?

Or this vasty superior battery the lesser choice to a generic quickie-mart deep cycle battery?

Back when PVs retailed for $3/W, and copper and lead were cheap, a system cost about $10/W installed.

Nobody can tell me it is a good idea if it takes $17,000 to charge a $500 battery.

How old are your batteries?

Do they get much abuse?

How are they charged?

Striider · « **Reply #27 on:** March 11, 2009, 04:09:29 PM »

I am supposed to go pick up this battery tomorrow, and just talked to the guy. 5 years on a used battery? That sounds like a heck of a warranty, but I will press him to see if I can do better than 6 months. He was actually pretty pumped about his test results just now - he finished testing today and said the battery has 90%+ capacity. Normally they aim for 85% or better to resell.

Ghurd and others, thanks so much for the input, this is great! So yes, I got a deal on the MX-60 so I am kinda trying to use it if at all possible. Also already have a remote temperature sensor for the MX-60. I am also not above charging the battery with a generator occasionally if necessary, mine is Honda EU2000i which has a charger built in that puts out 15 amps if needed. I think that may work for "equalizing"? I am unclear on this equalizing procedure to be honest. Time for more research. Would be nice if the MX-60 had a built in charger, but alas, it does not from what I can gather after reading the manual 4 or 5 times.

Another factor here is that while I did get paid back for the first set of panels I bought, they seem to be pretty much toast as far as power output. I hooked a couple of them up through the MX-60 and into a small scooter battery I had laying around to try to see what kind of wattage the controller would see on a single panel at a time. One of them put out a whole 5 watts at 36 or so volts, but the other put out even less. Apparently the broken cells really affect output. I still have 1 panel to test, but not looking promising.

Also, today with my refund I ordered 2 195 watt panels from sunelec.com.

SUN HS-195 - 195 Watt Solar Panel

So I should have a full 390 watts to charge with now at 54 volts minus drop through the controller. Not sure how that affects my whole setup, but I bet you guys could tell me exactly lol. All right- off to the scrapyard for now!

TomW · « **Reply #28 on:** March 11, 2009, 04:14:10 PM »

Eric;

Sorry, my battery is new. I missed that part in the thread, I guess. My apologies. 5 years be great on a used one, tho.

Tom

Striider · « **Reply #29 on:** March 11, 2009, 07:15:40 PM »

No worries! Anyway, I am excited about getting my battery tomorrow. I am not excited about wrestling it into the cabin though, as I don't think mine comes apart as easily as the one you bought. Todd at the battery place suggested steel pipes to roll it on like ball bearings. It just so happens I have plenty of that laying around up there, and a nice sized floor jack and some chain to lift up the ends with to get the pipe under it.

Thanks for the link to the manual, I will print that out and perouse it later.

Airstream · « **Reply #30 on:** March 11, 2009, 08:28:07 PM »

One of the Editors here looked at the mangled thoughts woven into a near hecklers' response (*not from the original poster getting the information) and frankly stated "Don't even try, you can't win"... Thanks for the advice.

zeusmorg · « **Reply #31 on:** March 12, 2009, 06:51:02 AM »

One easy way to use your dumpload for heating air would be to salvage an old resistance heater, even a non-functioning one would probably have what you need. The heating elements in them are nichromme wire. just measure out the resistance required to match the dumpload, add a 12V dc fan.. and you're good to go!

RandomJoe · « **Reply #32 on:** March 12, 2009, 05:36:37 PM »

I am also not above charging the battery with a generator occasionally if necessary, mine is Honda EU2000i which has a charger built in that puts out 15 amps if needed.

I have an EU2000i as well. You will find it's MUCH more efficient to just get a 120VAC battery charger to run off the generator. That 12V output will only give you full power if you switch the generator to full speed ("Eco" setting off) and at that setting the 120V inverter can run a much beefier charger. For example, I bought a 55A charger for my batteries, it runs right around 1600VA (continuous-duty limit of the generator) at full amperage.

Also note that the DC output won't adjust the throttle in "Eco" mode, it's just a separate winding added on that doesn't have any connection with the "smarts" of the unit. It's also not a charger - it's simply a winding that is rectified. So no regulation on the output voltage.

And I'm not an equalizing expert - have yet to do it to my new setup - but if I understand what I've read correctly, you'd be very hard pressed to equalize a 510AH battery with just 15A. Especially if you still had any loads at all going, you'd just be power those directly. 15A is only 3% of the battery size, which is well under the usual recommended charge rates.

News:

Author Topic: Jumped in with both feet...360 watts of solar! (Read 7938 times)