OFF GRID POWER; various thoughts on...

[Squirl]

Actually you need a 60 amp charge controller.  Yes you are right that you have 11.23 amps coming in, but it when it converts the power out you have 50 amps at 12 volts.  So you need a charge controller that doesn't only hand the amps coming in, but the amps it is putting out after the conversion.  I'm actually disapointed in the Xantrex manuals that they don't lay this out.  I read the Xantrex, Outback, and Morningstar manuals.  You can see from the product manuals the maximum array size per controller at which battery bank voltage.
Here are morningstar's mppt:
http://www.morningstarcorp.com/en/tristar%20mppt

As you can see the maximun nominal for a 45 amp controller with a 12v battery can handle a 600 watt array, and the 60 amp maximum is 800 watts .

Here is the Flex60:
http://www.wholesalesolar.com/pdf.folder/controller%20pdf%20folder/flexmax60_specs.pdf

Page 2 has the specs for the 60 amp version.
12 VDC systems 750 Watts / 24 VDC systems 1500 Watts /
48 VDC systems 3000 Watts / 60 VDC Systems 3750 Watts

Again, the "system" size voltage is the battery bank voltage, not the solar panel voltage.

[OlJarhead]

Actually you need a 60 amp charge controller.  Yes you are right that you have 11.23 amps coming in, but it when it converts the power out you have 50 amps at 12 volts.  So you need a charge controller that doesn't only hand the amps coming in, but the amps it is putting out after the conversion.  I'm actually disapointed in the Xantrex manuals that they don't lay this out.  I read the Xantrex, Outback, and Morningstar manuals.  You can see from the product manuals the maximum array size per controller at which battery bank voltage.
Here are morningstar's mppt:
http://www.morningstarcorp.com/en/tristar%20mppt

As you can see the maximun nominal for a 45 amp controller with a 12v battery can handle a 600 watt array, and the 60 amp maximum is 800 watts .

Here is the Flex60:
http://www.wholesalesolar.com/pdf.folder/controller%20pdf%20folder/flexmax60_specs.pdf

Page 2 has the specs for the 60 amp version.
12 VDC systems 750 Watts / 24 VDC systems 1500 Watts /
48 VDC systems 3000 Watts / 60 VDC Systems 3750 Watts

Again, the "system" size voltage is the battery bank voltage, not the solar panel voltage.

Hey, I appreciate that!  I've been trying to grasp what I need and keep running into various questions but I think you just solved it.  So I need the bigger controllers (read:  spendy ones) that can take the power coming in from the panels and then convert it to the 12v battery bank and retain all the power that came in -- or as you said 60amps once converted to 12vdc.  DOH!  I guess I missed all that in the beginning when planning my system.

So I could use one of these: http://www.thesolarstore.com/charge-controllers-mppt-charge-controllers-morningstar-tristar-mppt-mppt-charge-controller-volt-wremote-sensor-mppt-p-451.html

Or one of these:  http://sunelec.com/index.php?main_page=product_info&cPath=22&products_id=35

Or the Outbacks you posted.

Now it's just a matter of which one has the best reputation I guess 

I hate to say it, but I'm kicking myself for not understanding this to start out but I get it now...and I'll be ordering very shortly!  I also understand now why I didn't seem to have the charging capacity to keep up with the silly heat tracer I was running!  Sheesh!  I should have been able to run that without an issue this winter but nearly drained the batteries in a week on it.  I've also noticed that the batteries haven't been fully charged very often when I've gotten to the cabin.

On a side note, when the Iota charger kicks on they do pick up pretty quickly but I don't like to run it if I don't have to as the whole idea is to have little use for the generator in the future....anyway, which controller do you recommend?

[Squirl]

I have seen many debates as to which charge controller was better the Xantrex, Outback, or Morningstar.  Most seem to agree that there is very little difference in performance.  I have not researched midnight solar.  They all seem to be priced around the same at around $500.   Most posts I read seemed to agree outback had the best customer service.  Others said they wouldn't know for morningstar, because they didn't need customer service.  If Xantrex told you you needed a 20 amp charge controller, I would start to question their customer service representatives.
Dave Sparks would have great insight into the better product.

[MountainDon]

Like Dave stated; nice thing about Outback or Xantrex is the ability to integrate as a system. Charge controller, inverter, a central control panel for monitoring and programming. You can even hook them up to a computer with the right software and record everything the system does. I appreciate having the Outback Mate inside the cabin, mounted on the wall at a nice easy to read height, rather than poking my head into the crowded enclosure where the CC and inverter are.  

Outback and Xantrex both have good reputations. Midnight is also good and has charge controllers with 200 and 250 volt maximums. Other than that I don't know much about them. They have been around for a few years too.

On the charge controller: note the difference the system voltage makes to the array wattage capacity; higher system volts makes for the ability to use a higher wattage array. That is one of the reasons I chose 24 volts for the battery system. And I believe one of the reasons Windpower chose to go 48 volts on the battery bank.

On the generator: Normally the only reason I run my generator is to "exercise" the engine. I do that once a month or so; probably more like six weeks on average. When I do that I may also run an equalization cycle, although that can be done with the PV array and charge controller if I have the right bright sunny day.

[Squirl]

I did notice that one of the savings between the morningstar and outback was that the morningstar does not have an integrate LCD display standard.  I did feel that this was a little deceptive because every picture they advertise has the LCD display in it, but it is not included.  I had to read the massive manual to find that out. You can buy one separately for $100, or you can buy a remote one for around $130.  It didn't matter to me because the morningstar stores twice as much data as the outback (200 days) and can be accessed by plugging a computer into it.  (I already have some extra cheap laptops).  Also the display doesn't matter if you were going to get a remote anyway.  I think the remote display for outback was $150.  I'm not really sure the necessity of the display because it just shows you the past performance.  So, it is what it is, and many of the less expensive controllers don't record this at all.

It took me a week of researching the different components and options to figure out the difference.  Don't feel bad for not getting it at first.

I understand the issue with the price.  It seems like if you want to have a panel array over 600 watts you have to go with the more expensive controller or up the battery voltage and get a more expensive inverter.  Seems like they get you either way.

[OlJarhead]

Thanks and Thanks.

I'll probably get the Morningstar or the Outback.  I found the Morningstar a little cheaper and can use a laptop to get the readings from it if I want -- truth is I have only a meter on my inverter right now and have to count lights to know what the battery bank voltage is!

I won't buy the Xantrex because 1.  They really didn't make it clear in their documentation in the beginning that it wouldn't do what I wanted.  2.  They advised me to get a different cheapo controller that wouldn't work either.

I've also decided not to buy from Sunelec now because they suggested the 10awg cable and running the panels in series and then sold me the C40 controller!  DOH! 

All in all, I'm not happy with Xantrex or Sunelec but also have to smack myself for not making absolutely certain that what I was getting was going to do what I thought it would....ahh lessons learned.

Now I just need to find good sources, check prices again and make a final decision on the Outback vs. Morningstar and I'll be set   probably buy tonight so I can have it ready for the next trip to the cabin -- then I'm going to do some work on the system too I'm thinking (need to clean up cabling and equalize since i haven't done it yet).

I have a ton of other projects but this one matters the most at the moment   Thanks again!

[MountainDon]

I think the remote display for outback was $150.  I'm not really sure the necessity of the display because it just shows you the past performance.  

The Outback Mate provides full control of an Outback charge controller or inverter(s). Everything from setting the charge points, time for different charge modes, turning on or off the EQ mode, present battery conditions, input voltages and amps, volts and amps into the batteries, etc.  If you have a compatible generator you can setup the auto start. The Mate is much more than a place to read past daily performance data, although it does that too.

The only thing I found slightly annoying is that a Mate is required as an extra purchase in order to program the Outback inverters. But there's a reason for that too. Their inverters can be stacked, series and parallel to increase the AC voltage (240) or the AC wattage capacity. If the Mate was included with each inverter that would be a waste.

[OlJarhead]

Here is the response I got from Morningstar just now when I asked them if the 45amp MPPT controller would work:

Hi Erik,

The TSMPPT 45 can deliver up to 600W to a 12V battery bank. Using 615W will not damage the controller, the controller will simply limit the harvest to 600W.

This, however, will be significantly more than what you will get with the C40 in your present configuration. The C40 will only be able to deliver up to the short circuit current rating of the array (likely 12-13A) in full sunlight. The TSMPPT 45 can deliver 45A with this array (in full sunlight).


Regards,

Adam Kehlenbeck
MS Technical Support
www.morningstarcorp.com
support@morningstarcorp.com

I decided to re-ask the question with the 60amp MPPT controller in mind...at least I'm getting somewhere!

[Squirl]

That is a good thing to know.  I did not know they were required to program the inverters and generator auto start.

I know this may be a little off Erik's question, but Don do you use the equalization feature of the charge controller.  I have been meaning to ask this.  It seemed like another advantage that many of the less expensive controllers didn't have.  Does anyone have any opinions on this feature?

[MountainDon]

Yes Squirl. I normally use the equalization feature in the FM60 CC when I equalize. What works well for us is if I'm thinking about equalizing I hope for a sunny morning and afternoon on a day that we drive up to the cabin. By the the time we get there (11 AM or so) the system will have run through a short re-bulk charge and will be in absorb already. (Because there's been no use for a day or longer). I check the fluid levels in the batteries and if good use the Mate to initiate the equalization charge. It can be programmed to equalize for a predetermined length of time and the system would then go into float.

I sometimes use the equalize settings from the inverter/charger if I want to exercise the generator. The cool thing is I could most likely do away with the generator altogether. This winter at Christmas we spent several days up there and three of them were partly cloudy to very cloudy. We were in  no danger of withdrawing too much power from the batteries. I did run the generator on the third day but only because it had not been run since October.


I have discovered a variety of features, abilities, that the FM60 and the VFX3524M inverter/charger can do. I will never be sorry I spent the money for them.
http://eshop.thesolar.biz/retail/Items.aspx?code=OUTBACK_CC&key=cat

[OlJarhead]

Decided to go with the Morningstar 60amp MPPT controller.  Price was almost the same so it came down to the discussions here and their support which I interacted with a bit yesterday (I'll post their response to my question about the 45a vs the 60a controller but in a nutshell the 60a won't ever be near max so will always use the full 615watts - if enough sun etc - for charging unlike the 45a controller).

Hope to have it in a few days (got it from the place in Bend OR which isn't too far from me actually).  Then we'll see how that battery bank does!  I'm assuming I'll need bigger wire to the controller then with the C40 but I haven't tied it all up yet anyway so swapping should be easy and I'll keep the C40 for the well system I'm planning.  It might be overkill but ought to work fine with a 75watt panel and 12v deep cycle battery I'm thinking -- then I can plant those fruit trees!

Anyway, thanks again Don and Squirl for squaring me away!  Now I'll be able to hook up that freezer and abuse the system and see what the controller tells me it's doing

[OlJarhead]

http://www.thesolarstore.com/batteries-accessories-battery-accessories-desulfator-battery-life-saver-volt-desulfator-p-416.html
What the heck does this do and do they really work?  I'm curious.

I was perusing the store and well, I can see several things I want now!  Sheesh...I want a meter for the bank for a quick glance when not plugging in the laptop, those nifty caps looks like a good idea, the battery bank vent sounds like a good idea too and and and...sheesh I need to get back to work! hahahah  I worked 8:30am to 10:30pm yesterday and will likely pull long days for the next two weeks which always gets me wondering what new gadgets I can get for the cabin

[Dave Sparks]

No generators allowed at my place! So, yes the CC is used for EQ! In this industry you really need to know that most of it is dealer/installer driven. You can get decent advice from the manufactures and it can be spotty. The point is you really need to understand all that you are doing unless you can write lot's of checks.
I have huge respect for check writers!

[MountainDon]

I used less than 5 gallons of gas (heavy on the Stabil) in the last year.
Most of that was just to run it because it had not been run in a while.    
It was indispensable while building and pre solar system though.

[OlJarhead]

Help!  I was getting ready for my trip to the cabin and reading my new Controller manual to make sure I have the right cable for it (4awg sounds about right for 60amps over a short distance (2 feet)) and saw that I needed a 75 amp breaker and NOT the 60amp breaker I have in there now.

So here is the question: what will happen if I continue to use this: "60 amp 150VDC with 1/4" stud terminals. Uses one small 3/4" breaker space. Midnite Part Number: MNEDC60 Same as: OBDC-60, OBB-60-150VDC-PNL"?

I assume it will pop if there is full sun and the batteries need max charging but otherwise will be fine until I can find a 70 amp breaker? And does anyone have a line on one?  I am having trouble finding a 75amp breaker of the same size etc...but that's 25% above the rating.

Thanks in advance.

[EDIT:  changed to 75amp breaker to meat the 125% rating]

[MountainDon]

http://www.midnitesolar.com/productPhoto.php?product_ID=197&productCatName=Breakers&productCat_ID=16

[OlJarhead]

http://www.midnitesolar.com/productPhoto.php?product_ID=197&productCatName=Breakers&productCat_ID=16

I found this one there: OBDC-80 though no 75amp ones...I'm thinking 80 would be ok?

[OlJarhead]

Did a little reading on the GC2's and it seems I can use the Trojan settings for the T-105's for my charging profile.  Listed here: http://www.trojanbattery.com/BatteryMaintenance/Charging.aspx

So that means I need to set the voltages to the following:
Absorption:  14.80v
Float: 13.20v
Equalize: 15.50v

They are currently set at (setting #5 for flooded cell):
Absorption:  14.60v
Float: 13.50v
Equalize: 15.30v

I can custom set those using their software to build a custom profile but will have to leave as is for the next 10 days -- hope I didn't goof that up too much.  The controller has only two flooded cell settings (in their canned settings) so I chose the lower of the two and left it.  What I'm wondering is if it will make much difference?

I'm also wondering if the controller's telling me that it was down to 0-30% charge has anything to do with these settings?  I'm looking to see if there are others I can change now, but the controller shows a min voltage of 12.62 for the day I saw the lights indicating 0-30% charge...I'm trying to figure that one out still.


This shows a min voltage of 12.62 which according to Trojan is only a 10% discharge or 90% charge....thoughts?

[MountainDon]

There is likely little effective difference between those charger settings.

I don't know or understand where the 0-30% and "lights" you refer to are coming from? 

On the low voltage reading.... don't forget that the voltage reading will drop lower faster when large loads are applied. If I microwave something for several minutes the instantaneous reading falls precipitously but then climbs back up to where it was. Also remember temperature effect. Hydrometers give most accurate readings for state of charge, and also require temperature corrections.

[OlJarhead]

There is likely little effective difference between those charger settings.

I don't know or understand where the 0-30% and "lights" you refer to are coming from? 

On the low voltage reading.... don't forget that the voltage reading will drop lower faster when large loads are applied. If I microwave something for several minutes the instantaneous reading falls precipitously but then climbs back up to where it was. Also remember temperature effect. Hydrometers give most accurate readings for state of charge, and also require temperature corrections.

Thanks Don,

On the controller are 3 lights:  Green, Yellow and Red.  In the book it says that if the Yellow and Red are on then the batteries at 0-30% of charge.  This confused me when I saw that the recorded lowest voltage was in the 90% range...maybe a glitch in the controller?

[MountainDon]

Could be.  A hydrometer reading would clinch it. I use the voltmeter as a handy quick indicator to what's happening, but the hydrometer never lies when corrected for electrolyte temperature.

[OlJarhead]

Could be.  A hydrometer reading would clinch it. I use the voltmeter as a handy quick indicator to what's happening, but the hydrometer never lies when corrected for electrolyte temperature.

I'm going to have to get one and a new Multimeter I think.  Just found some 6awg 90c wire (THHN) that I can use in my install instead of the 4awg stuff I installed.  I'm so NOT an electrician but the book says that as long as I use 90c wire I can use 6awg and I think it would make a cleaner install and since the controller isn't more then 2 feet from the battery bus I don't think the bigger wire will make a noticable difference (if any).  Now I just need to get some conduit so I can put all the wiring in conduit next trip out and then I might just be nearing that point in which I can be proud of the install!

[OlJarhead]

Here are the last two weeks of data from the controller.  I've noticed that the lights still indicate a low charge on the batteries when they shouldn't and I'll have to call Morningstar on that.  I think, actually, I just need to download their software and make some changes to the settings.

Meanwhile, thinks seem to be working nicely.

[PlainsMontanaPower]

So im new to these forums and fairly new too offgrid power so hello everyone.
id like to first say i really like your cabin setup and detailed build especially your power center mountainmandon.
i liked the box setup you built so much that i built one this last week at my cabin in montana. its not quite finished yet but its getting there im down to running a vent out the roof and putting all the equipment in there and some paint.

that said i have alot of questions lol

1. where can i find the copper bar material you used for your bus bars i love that its sooooo clean.

2. at what voltage should i get scared when batteries drop too ?? 11.7?

and many other question i have but first ill tell ya myt setup

we started our cabin 20 years ago and started with a very small solar panel and 2 batteries well when i brought my kids over a few years back they brought all there gadgets and almost killed the batteries so we ordered a new kyocera 130 watt panel a ts-45 morningstar controller and 2 more golfcart 6 volt batteries.....my dad hooked it all up............not good he got a lot of wrong information so as of last week we had a 80 watt panel and the 130watt panel hooked together in parrallel and then running 55 ft with 8 awg large strand wire to the morning star controller needeless to say as far as the controller was telling us we were never getting past a 35% soc even on a nice sunny day so yeah i figured the wire had a lot to do with that i called a few place like montana solar out of misoula very good guys and  arizona solar and wind which is who we bought most of our stuff from they both said to noit hook the 2 panels together and that it would make the 130 panel work like a 80 watt panel so now ive unhooked them im going to run 2 awg just for the 130 watt panel to the morning star  controller and then hook the 80 watt panel to our old mark 15 controller with the existing 8 awg and both in parrale to the batteris (4x 6 volt cart batteris is series-parralell) Does this sound right ? and what percentage of gain do you thjink ill get from this ?

right now i think the biggest problem is not enough voltage is going to the batteries to ever get them even close to topped off.

oh and also again love your power center ill have to post pics of the one i built very similar to yours  but not enough room for 3 seperate compartments so for the batteries i built a box over them in the big box and am running a vent just from the battery box throug the roof and the bigger room is also vented with eve roof vents.

any help here is greatly appreciated im so glad im found these froums so much great info my brain is going to burst lol

[MountainDon]

Copper from Storm Copper.  
http://www.stormcopper.com/Copper-Landing1.html?gclid=CIDi1bbQ76gCFcgZQgod2H8MCw

Here's a voltage vs state of charge chart

I would find 11.7 volts very worrisome..  We generally don't drop below 80%

Also note that a hydrometer is the best method to determine SOC.


If the panels are very mismatched as those two are you will be much better off with them having separate charge controllers. I did not take time to run the numbers but the change in wires should make for a better more efficient system.  There are a number of voltage drop calculators online. We have some links here for them someplace, but I have to run right now.