Looking for the right solar controller

[iFred]

I just purchased 650 single solar cells to make panels with.

Looks like I would produce about 600 watts or so on good days.

I know nothing of solar, so this will be a neat experiment.

I figure I can make about 10-15 panels w/36 cells per panel.

I am going to require a solar charge controler in the nabourhood of about 45 amps. I"ll be hooking the cells up as 12vdc.

Any ideas on the type of charge contoller, pro's con's and otherwise.

From what I understand and have read there is different charge methods such as PMW or was that PMS??? LOL.. and what is up with these new ones that offer more power from what you have?

In any case, Suggestions please.

Thanks in advance!!

Fred.

[TomW]

fred;

I'll pass on my ideas which will not suit everyone or work for everyone.

I have 300 watts of solar and 1500 AH of 12 volt trojan 105s. When I first put together the system I bought a Trace C-60 controller. I have found it to be completely unnecessary for my system and wish I had bought another pair of batteries. In fact, I believe it costs power running thru it. I seldom see it limiting the incoming as I balance usage fairly naturally. My system gets used daily so it never overcharges the batteries and even if it would the 18 - 20 amps I get would never hurt the batteries I have now and with an aditional 225 ah of an extra pair certainly never would.

In retrospect I should have passed on the Trace and got more storage and had change left over. I am here a lot and it is a regularly used system so the controller seems redundant. In an unattended system or with a smallish battery to panel ratio it might be necessary, however.

Oh well, at least it can be setup as a charge controller, load or dump load controller too so I will likely rig it for that when the time comes that I have excess from wind.

Cheers.

TomW

[windstuffnow]

  iFred,

    This is my first year with solar panels also.  I started out with 3 115w panels and found them to be a bit lacking for my needs and ended up finding a good deal on some used 77 watt photowatt panels and bought the 4.  This seemed to be sufficient while I rebuilt my wind system.

    Anyway, I bought a C60 controller (Xantrex/Trace) which works very well so far. I added a second C60 to use as a diversion controller which also works very nice.  Sunelectric sells them for 148.00.  Your pretty handy with electronics, you could build a quick shunt regulator which would work fine.  I made some up a long time ago using the schematics form homepower.com ( search downloads for shunt regulator).  I used these for 4 years with no problems with the wind systems.  Cost around 5 bux to make them up...  I'm not any good at making perf boards so I used an experimentors board and built 2 of them to dump 30 amps.

    I may change the controller for the solar to a diversion controller, haven't decided yet, they seem to work ok as a pair so far.  we'll see...

    My system only has 8 T105's (880 Ah) and between the solar and wind they would easily cook without the control.  Today was P cloudy but fairly breezy, pushing between 32 and 40 amps all day long... gotta love them turbines, by 2pm all was charged to 14.6v and was lighting my heater off and on.  Now and then the sun would peek through and I'd see peaks of 70amps on my trimetric.

    I've been thinking toward future additions and sized everything a bit larger than I needed (ie: wire, controllers etc.)  This way if I want to add more panels or toss up more turbines then things won't have to be changed or added to real soon.

HaveFun

Windstuff Ed

   

[ghurd]

I still like the basic Morningstars.

Temp. compensated, true PWM, easy, reliable, cheap, and etc.  The De-Sulfator concept is based on these patents. An expensive knock-off of the cheap original. Some wholesale companies quit suppling them for a while because of the B.S. Check Sandia labs. True PWM puts more power into a battery at the end of the average day. Less gassing and water use too. Why spend $150 for a doo-hicky copy if the original does more for less money?

Battery temp is important. Thats why you get a temp chart with the floating ball turkey baster battey testers. Check with the battery manufacturers. Try to get a Trace temp. probe for the cost of a complete Morningstar for a small system. A SG-4 can be had for $30, if you pick it up I'll give it to you for $25, temp comp. and all (how much is a Trace temp probe again?)

Pro's and con's? Check the Sandia labs papers. May have to dig deep. True PWM is much better. It's in there.

Trackers offer 'up to 30% more', by following the sun. The gain would be offset by that same money in more panels in most places, in most systems. Simple enough with a calculator. BTW, some major companies no longer handle tracker BS because they just don't work like claimed.

Max Power Point has some good points. Mostly with water pumps, given what it does and what it costs. It can put a few extra amps into a 12v battery when the supply is at 9v. For solar, this only happens a few minutes per average day (without constant drain, like a stalled, shorted pump motor).

Rated watts divided by 17v should give about peak amps for a factory PV module.

Get your PV panels to about 20-22v open circuit (for a 12v system). Get a controller rated for at least that much (Isc and Voc). Make sure it is for that much continuous (fine print BS). Check the warrenty. Check the failure rate. Call tech support to see if they can speak anything close to English, and if they are even still in bussiness.

Make the panels first. I'd go with 38 cells if possible(there is a reason they are surplus).

Big job. Look for at charge control systems when they are done.

[iFred]

I'm pretty good with electronics, Yep. Let me ask this question then. If you could build such a controller, what would you include into the design?

I figure; shunt load diversion, pulse width modulated desulfator, 12vdc reglator and over/under load protection for the batts... Anything else i'm missing?

Thanks!

Fred.

[windstuffnow]

   I looked at the morning star units.  The 30 amp units were $25 more than the C60's. I've had a good luck with their other products and the C60's were the lowest priced units in the amp range I needed. If iFred makes the 600 watts he's expecting from the solar plus his wind turbines he's gonna need something that will handle some juice.

Have Fun

Windstuff Ed

[windstuffnow]

  Bulk, float and equalize.... works for me.

Have Fun

Windstuff Ed

[booner]

Hi there i have a Morningstar Tristar and there great you can also do data logging with them, It will handle 60 Amps no probs not the cheapest on the market but very good !

[iFred]

Here is basically the stats.

I purchased the cells from Ebay. I bought 13 pounds worth.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5917781955

I have purchased 650 individual cells. Each cell puts out 1.36w. 3.02a .45v

I figure 36 cells gives me 18v at 3.02amps. So that each panel would put out about 48.96 watts at peak. Figuring that won't happen, I figure 3/4 of that power on a nice day. If all goes well and I don't break anything, I figure this would give me 13 panels at 636 watts. Including breakage and all I still figure on 550-600 watts.

Now add on top of that multiple wind turbines putting out at least 3-8 kw a day with some nice wind. I pretty much figured that I would keep things on the power side separated wind for wind and solar for solar and then combine later.

Any idea's on how I can calculate for the amount of batts I should need to handle this power??

AS far as load is concerned. I have 2 computers and several FLA lights and that's about it. The computers drain less then 200 watts each (watt meter says 160-180), the lights are less then 60w for all of them. 15 and 25w each.

In the winter i figure I can take the extra diverted power and dump to heaters and to an electric hot water heater.

Any Suggestions???

THANKS AGAIN for the help!

Fred.

[ghurd]

  Must have been the 30 amp with the fancy meter. That one costs about the same ($1 more) as the 60 amp without the fancy meter.

[ghurd]

I've done some more thinking on this. If the solar is sized about right for the loads, there isn't much usable dump load. That goes out the window when all those spinning magnets enter the picture.

Trace does have a HUGE advantage given the dump load mode. If I read it right.

My understanding is that it is built in to the C60. The Morningstar "can be used" to control diversion loads, but not at the same time as it is regulating the battery.

So, you need 2! (for a typical system)

Maybe it takes 2 C60's also? Like Ed did.

There were some nice load diverter plans on this site in the last month or 2.

Has to less than the $175 for the 2nd controller.

600 watts of solar is pretty serious. I bet everyone will be surprised how consistant the output is. Even in the winter (unless you are in a crappy place for solar, like here) it should make about 2kw a day!

When it's Snowin' and Blowin' 600 watts of solar is a lot to lose. When the wind filled the battery last night, the 600 watts of solar will do nothing. Having the controller just shut it off seems like a huge waste.

I think you are talking about a lot of battery.

Check 'solar insolation' for your area. I'll say it is 5 hours, meaning the out put will be 5 times the peak amps, or 300 amp hours per day. The peak out put, say 60 amps, will only happen around noon when it's a great day.

The max current most people want to put into a battery is about C/10 rate. For T-105s its around 20 amps. 3 pairs is 60 amps at C/10, and thats just to keep them from boiling when the sun is out. Throw in the wind power...

Holy Cow!  You need more loads!

G-

[TomW]

G-;



My understanding is that it is built in to the C60. The Morningstar "can be used" to control diversion loads, but not at the same time as it is regulating the battery.

My Trace C60 can, indeed, be used as either a charge controller, diversion controller [dump load control] or load control. However, with mine [3 years old] it can only perform one function at a time.

T

[ibedonc]

did you see this that I posted the other day

http://focus.ti.com/lit/an/slua055/slua055.pdf

also my SCC3 I built works for me  and can do 70 amps with it

I am going to try one from the ti site