Solar panel controller

[cjdock]

I have a windmill up and working. It's a 6'3 diameter and working good (with the help of the folks on this board!) I bought some cheap HF solar panels. It's the 45watt kit. It came with a charge controller and some 12vdc lights. I have 4 t-105 trojan batteries...I need more that's for sure. I'm also using an over charge device to prevent overcharging. My question is; do I need to hook the solar panels to the controller it came with or can I just go straight to the batteries? I have read somewhere that a diode may be needed to prevent voltage going to the panels? Or should I just use this controller? Should I turn the controller off every night when the sun goes down as well? It has lights that are on as long as the controller is on, that seems like a waste of electricty at night.

I've had my windmill up for the last 2 days, of course there has been no wind at all!!

[terramir]

I have a cheap charge controller from fry's and when I tested the current and voltage at night measuring from the controller circuit to the solar panel not from the battery side (you could fry your multimeter) I get less than a volt and less than 1mA of current flowing in the negative direction not enough to harm the solar panels or really waste much 0.6 mA x 1V = 0.6 mW considering my newly moved to the roof panels provide a little less than 1/2 kw a day during the dark hours losing about 6mW during the dark hours don't seem much to worry about, now you might want to run these tests on your equipment first before deciding use the 10 A setting   in-line in darkness first to check if there is major current flowing (remember to do it on the solar panel side.

However I do see one concern here if your windmill is on the same input line as your panel during a windy night you might be heating your solarpanel and frying it in the process you might want to keep those on seperate charge controllers or different charge controller (depending on your controller) input lines.

My .02

terramir

[iFred]

You don't need a controller but its nice to have one. It provides an internal diode so that at night the current from your batteries won't go into the panels, basically considered a loss. Another reason to use a controller is for maintaining the batteries and their life span, batteries have four distinct charging cycles composed of bulk charge, PMW Absorption, float & equalize. Some of the better controllers have this built in, some of the cheaper ones don't. Again, the central reason for these cycles is only to increase the lifespan and output of the batteries. Hope this helps.

[Slingshot]

I saw this earlier this week and almost bought it, because they had a 20% off (expired 4/19) that would have brought the price down from $199 to $159.  That's only $3.53 a watt for the ENTIRE SYSTEM, which in our local store included the three panels, a mounting frame, the controller, and two 12-V fixtures with CF lamps installed.  Incredible bargain if the panels are any good.  Keep us updated on how it works out, I may buy it next time it goes on special.

Was there any documentation to indicate whether the controller could handle additional panels added later?

[cjdock]

That is the price I got the kit for. (under 170 out the door)

The doc's didn't say if more could be added. We have had a lot of sun but I don't know how much they have put into the batteries. I'm not running anything off the batteries yet and my voltage is only 12.4 - 12.6. How high should my batteries reach with nothing taking power from them? I realize that 45w isn't much.

[AbyssUnderground]

Sealed lead acid batteries can reach 13.20v when fully charged. Mine is sitting here now at 12.97v with no load. Its had no charge today because its been dull and completely overcast all day. Im not sure if you are using sealed lead acid's or other types.

[Nil]

I actually have the same HF setup. I've had them for a little over a month and they seam to be ok. I don't remember exactly off hand but I've seen the amp-meter reading a tad over 3 amps into the batteries on sunny days.

I've measured the draw at night using an analog meter and could detect a faint draw, just enough to light the LEDs it seems. I should check it on the panel side...

I myself don't plug in the light until I need them, that is inconvenient at times but the 4 watts they provide each isn't too useful to do work by anyway.

Once the batteries reach roughly 13.5v the controller starts making an annoying buzz, and shuts off the charging. I'm charging some big NiCads so I popped the cover on the controller and bumped it to 15v by playing with rheostats. Now my inverter doesn't come on until I bring the battery volts down to just under 15v, so I need to adjust the controller again.

Anyway I think it would be safe to leave the controller on, since it regulates itself be prepared for the buzzer to come on at full charge (what the controller deems to be). And the lights can be unplugged until needed.

I'm in need of tackling a windmill project like yours now.

Have fun.

[cjdock]

Thanks for the info about the buzzing from the controller, I had no idea what that was.  I'm so bummed, 3 days and no wind for the windmill! It has been sunny but it doesn't seem to add much to the batteries. They went from 12.06 volts to around 12.5 volts but it's been a few days...now that I have these solar panels I do see the need for a sun tracker set-up.

They are calling for 20mph winds tomorrow :}

[(unknown)]

I purchased the HF system and I have been very pleased with it. I did have a prolem with the charge controller (only putting out 2.3 volts) but after I returned it and got another unit, it worked great! The buzzing was a bit intrusive, but my buzzer broke. ;-) Now, the charge light goes out and no buzzer.

I have noticed that when this happens, the controller does indeed disconnect the solar panels at 14.5 volts. Once the voltage drops back to 13.5 volts, the charge light comes back on and the solar panels start charging again. (you can see this by monitoring the panel voltage. It will be the same as the battery voltage until the controller disconnects them and then the voltage goes to around 25 volts - same as open voltage)

For the price, this system works great! (I got the 20% off the website price of 199.99) By the way, the price in most HF stores is 299.99. If you print out the website page, they will honor the website price at your local HF store. If you sign up for email notifications, they will send you coupons for % off. That is how I got 20% off the website price of 199.99. Mine cost 160.00 plus tax. That is 140.00 off the in store price!

I was tempted to see if I could replace the pezo busser with a small relay to use for a dump load. Then I believe I could hook up my newly made windmill directly to my batteries. The charge controller for the pv's would monitor the voltage and would turn on the dump load when the voltage reached 14.5 volts. (when the buzzer would normally start buzzing.

Does anyone think this would cause a problem? I believe it would utilize the monitoring circuit already in the pv charge controller. I might have to use two relays. One circuit board (low power draw relay) to drive a larger relay with the dump load on it. I believe the small relay would raw the same current as the pezo buzzer so it should not hinder the performance of the existing circuit.

Thanks for the great info and I hope I can help someone as well.

Paul

[cjdock]

I ended up taking my charge controller out and just putting in a box that has a kill switch, amp meter, and a voltmeter. The most I've ever had was a bit over 2 amps....don't know why I can't hit 3 amps..maybe I should test each panel individually to see if one is not working. I don't have a diode in line with the positive side at this point. Do you think that causes a drain in the day when the panel is making power? At night I flip the kill switch to make sure the panels won't drain the batteries.

[ghurd]

The 2A makes me wonder if one panel is bad or not properly connected. I would check each.

What angle are the panels compared to your latitude?  The should be the same or close.

They should be facing the equator.

Panels will not drain in the daylight.

The controller automatically does what the switch does.  If you are not happy with the ICP controller, try a Morningstar SG-4.

G-

[cjdock]

I just checked each panel and they are all very consistant to each other with current and voltage, bummer...I was hoping to find a bad connection or something. They are set up on the frame the kit came with so they are sitting at equal angles. I have taken them off the mounting bracket and then laid them on the roof with wood underneath them to get the best angle towards the sun that I could. I then check my amp meter to see the change from the stock position to the ideal best position, and I did this in perfectly clear direct sunlight and still the best is about 2.1 amps total.

 When I did this test described above, I did leave the panels connected to the batteries. I wonder how the rating of the panels is taken meaning, if you took the floating voltage of the panel output which is 22volt right now form my panels, and mutliplied it by 2, thats basically 45watts.....it's a cloudy day today so I don't know how much higher the floating voltage goes up with good sunlight. But, you guys say you get 3 amps from the panels and that's probably with them connected to your batteries..

Mine just suck I guess.

[ghurd]

The controller could be kicking on?  I do not know what controller you have, or if you are still using it.

Each panel should be making the same current into a low battery (12.4V or so).

If all 3 panels are the same output, seperately, into a low battery, then the panels are OK.

The problem is humidity, less than perfect angle, etc.

A 15W panel (of that type) should put about 1A into a low battery.

"...22volt right now form my panels, and mutliplied it by 2, thats basically 45watts..."

That is not correct for rating panels.

"...it's a cloudy day today..."

That is the problem.

Check each panel into a battery when it is sunny at noon. Each should be about 1A.

All 3 panels, when sunny at noon, should put 3A into a low battery.

Amps go down with a high battery, a wrong angle, time away from noon, and angle away from perfect.

G-

[ghurd]

(amps go down even more with clouds)

[(unknown)]

Hey guys, it is me again. I would put your charge controller back on, and then put your amp meter inline with the positive from the panels. Also, you can put your volt meter across the battery. The charge controller will keep the panels from over-charging your batteries.

By the way, I did de-solder the bad buzzer from the board and I soldered two wires in place. Those wires I hooked to a 5-volt pc-board relay. The n/o contacts I soldered wires to and brought them out of the charge controller. Now, here is the part I like. I then opened my power inverter and I soldered 2 wires to the on/off switch. I brought those wires out and connected them to the wires from the relay. (The power inverter was disconnected from the battery!)

Now I have a dump load. Well sort of. When my batteries reach 14.5 volts, the relay is energized and it turns on my power inverter that has my shop lights connected to it. (all my lights are low power twist lights - 7 lights x 100 watt each but they only use 23 watts each. When the inverter is on, then I am pulling about 160 watts plus what the inverter uses. My windmill can put out about 200 watts and it is directly connected to the batteries so that should cover it.

This was a easy modification to the HF solar controller to make it compatable with a wind/solar system. Since the solar controller monitors the battery voltage and starts the buzzer/relay when it is to high, it was easy. The circuit was already there to turn on a relay for a small dump load or to drive a larger relay for a bigger dump load. I will monitor the system for a few days and let you know the results.

As for the output of the panels, mine are at 37 degrees (verified by angle meter purchased from HF) and the are pointed due south. I am in Kentucky and that is how they are supposed to be pointed here. You need to check your latitude and then compute your pv angle here: http://www.wattsun.com/resources/calculators/photovoltaic_tilt.html

Hope this helps.

Paul

[cjdock]

The only thing I haven't tried in your list is each panel seperate with a load of a low battery on them. The humidity has been low, I did try perfect, direct sunlight with the panels at the best angle, at noon. I went to the link listed in the other post, 20 degrees is the ideal angle for my location (MI) right now and that makes sence, almost flat on the roof at noon. (very slightly pitched porch roof facing south)

 Cool idea for the dump load relay. I have a set-up already in place, it just reads the battery voltage and if it gets over 14.2 then a big relay flips and some car headlights come on. As far as using the controller, I don't see the benifit for me, I already controll the overcharge issue. It seems like a load loss with it's lights and circuitry plus I like my accurate volt and amp meter! I know that I could still use them with the conroller.

Thanks folks for your continued thoughts and ideas, I thought this posting was dead!

[(unknown)]

I am glad this thred is not dead. I have gotten some usefull info from it.

As far as the HF controller, it does have 2 other nice features.

1. You can run your dc stuff from the controller. It supplies 12-volts, 9-volts, 6-volts and 3-volts to run anything up to 4 amps total load.
   
2. It also provides under-voltage protection for the batteries for any load you have connected to it. If your batteries go under a certain voltage, it disconnects whatever is connected to it from the batteries until the voltage is restord.
   
   

The power draw of the controller is very little. It is just enough to run a couple of led's and the monitoring citcuit. (remember, this unit is made to be effecient)

Well, thanks again and good luck to everyone.

Paul

[ghurd]

Some of my earlier comments were about a different controller than it seems many of you got from HF.

G-

[cjdock]

I like the idea of using my controller to power my 2 routers, cable modem and switch...I'll make sure it totals no more than 4 amps like you said. Then I can keep my inverter off unless I need it! I bought a 3000w, 6000w surge inverter...it's a cheap one so it's probably not efficient at all. I though I could produce more power than I'm producing. I could have got away with a 1k inverter. That would have been the better route I think, a high efficient, pure sinewave 1k inverter instead of what I have. If I add another windmill and more panels...and more batteries then I'll be able to use this hugh inverter...