Best Low-Cost Charge Controller?

[Feral Cement]

I've found lots of "best bang for buck" discussions re: solar panels, and lots of discussion re: CC's but no value comparison. I just bought a 145W DM Solar panel for $160 (including shipping!) and need a low-cost/high quality CC to keep my twin Group 31's happy and healthy. Do any of these look like a good choice? Got a better idea in the $<50 range?

http://www.amazon.com/Solar-Power-Controller-Digital-Display/dp/B008BQHQSY/ref=sr_1_40?s=lawn-garden&ie=UTF8&qid=1341061433&sr=1-40&keywords=charge+controller
http://www.solarblvd.com/Charge-Controllers-PWM-Charge-Controllers-Morningstar-Charge-Controllers/c6_48_100/p622/Morningstar-SK-12,-12A,-12V,-SunKeeper-Controller/product_info.html
http://www.solarblvd.com/Charge-Controllers-PWM-Charge-Controllers-Morningstar-Charge-Controllers/c6_48_100/p191/Morningstar-Sunsaver-SS-10-10A,-12V-Pwm-Charge-Controller/product_info.html
http://www.amazon.com/Solar-Battery-Charge-Controller-Regulator/dp/B008BQPYF6/ref=sr_1_66?s=lawn-garden&ie=UTF8&qid=1341065602&sr=1-66&keywords=charge+controller
http://www.amazon.com/SunSaver-SS-10-Morningstar-Charge-Controller/dp/B006H9VP3O/ref=sr_1_123?s=lawn-garden&ie=UTF8&qid=1341066110&sr=1-123&keywords=charge+controller
http://www.amazon.com/Morningstar-SunSaver-SS-10L-12V-Charge-Controller/dp/B003T7TBXI/ref=sr_1_143?s=lawn-garden&ie=UTF8&qid=1341066541&sr=1-143&keywords=charge+controller
If I missed the perfect CF thread on this subject, please provide a link. I looked and did not see one. Thanks!
John

[sailorchic34]

I've got the 4th one on your list with 11 amps connected to it. I checked the mosfets and they had the capacity for 11 amps and more. Heat being the main issue). BTW thats 11 amps actual solar output (230watts connected, 60-65% of rated panel eff., which is about all you really get) Been working for almost 2 years.

The wire connectors are a bit weak, so don't over torque the screws. but it works well.

[Pblais]

I would agree with Sailorchic34. We have two 85 watt panels on a Morningstar SunSaver 20. Just now saw 9.4 amps and that is about as good as I've seen it perform. We did have another controller for an afternoon that was not as good. The Morningstar's seem a little better made than the others.

This one lacks a lot of fancy features and displays but it does what it is supposed to do. I also have a battery monitor so the display was less important.

[Captain Bill]

I won't pretend to be qualified to to tell which is best, but I'll pass along my experiences with 2. I formerly owned a Xantrex C40 which performed pretty well and gave me 10 years of service before I lost it to a nearby lightning strike. My 300 watt array regularly produced 15-17 amps at mid-day in June. I replaced it with a Bluesky 2512ix with a IPN-ProRemote because I wanted MPPT and better monitoring. When I got the Bluesky I was shocked to find out that the battery and PV connectors were only sized to accept 10AWG wire. Nobody that I know uses wire that small on their arrays. Even the documentation that comes in the box reccomends sizes as large as 4awg. So the first thing I had to do was put some 10 gauge pigtails on my 6awg PV and battery wires. The pigtails are only 6 inches long and may or may not be causing my problem, but I have yet to see more than 12.5 amps out of the Bluesky. I am working with bluesky tech support now trying to find out why I'm loosing 30% with their MPPT controller rather than gaining 30% like their advertising.

[mbianka]

[QUOTE=Feral Cement;980780]I've found lots of "best bang for buck" discussions re: solar panels, and lots of discussion re: CC's but no value comparison. I just bought a 145W DM Solar panel for $160 (including shipping!) and need a low-cost/high quality CC to keep my twin Group 31's happy and healthy. Do any of these look like a good choice? Got a better idea in the $<50 range?

I've been using two Morningstar Pro Star controllers on board for years. One is for the 12 volt house bank (two 75 watt 12 volt solar panels) and the other 48 volt (two 60 watt 48 volts panels) for the electric propulsion bank. Have not had to touch them since the install. The 48 volt has the meter installed. The 12 volt I put in analog current meter in the solar loop. Personally I would go with the one with the meter. Helps give a quick voltage and current check in the same package. Also a back up for other meters you may have.

Also use a Morningstar sunlight controller for my house LED lighting system. IMO you can't go wrong with the Morningstar controller products.

[foggysail]

Originally Posted by sailorchic34

I've got the 4th one on your list with 11 amps connected to it. I checked the mosfets and they had the capacity for 11 amps and more. Heat being the main issue). BTW thats 11 amps actual solar output (230watts connected, 60-65% of rated panel eff., which is about all you really get) Been working for almost 2 years.

The wire connectors are a bit weak, so don't over torque the screws. but it works well.

OK Chic, you got me. You measured 11 amps from the panel rated at what voltage? You quoted 230 watts connected so that leaves me to do a lot of guessing. How many amperes were being stuffed into your battery bank and at what voltage?

But I know you're technically sound so I must be missing something.

Foggy

[sailorchic34]

Oh sorry, the panels (one 130 and one 100 watt) are rated for 230 watts, which of course you never get (like epa gas millage). So its 11 amps, well 10.8ish anyway at 13.8. So say 149 watts into the batteries. The controller goes from bulk to absorption at that point, so the amps hr's decrease a bit due to PWM.

One note, there is quite a bit of noise on the hf when the thing starts the pwm. I have a bypass switch to bypass the controller when I need to listen to HF in the day. It also works as the poor girls equalizer (which ties the battery direct to the panels.

[foggysail]

Thanks Chic--

Foggy

[Mr B]

Get an MPPT one, They are more efficient Than the PWM ones,

[noelex 77]

Originally Posted by Captain Bill

I won't pretend to be qualified to to tell which is best, but I'll pass along my experiences with 2. I formerly owned a Xantrex C40 which performed pretty well and gave me 10 years of service before I lost it to a nearby lightning strike. My 300 watt array regularly produced 15-17 amps at mid-day in June. I replaced it with a Bluesky 2512ix with a IPN-ProRemote because I wanted MPPT and better monitoring. When I got the Bluesky I was shocked to find out that the battery and PV connectors were only sized to accept 10AWG wire. Nobody that I know uses wire that small on their arrays. Even the documentation that comes in the box reccomends sizes as large as 4awg. So the first thing I had to do was put some 10 gauge pigtails on my 6awg PV and battery wires. The pigtails are only 6 inches long and may or may not be causing my problem, but I have yet to see more than 12.5 amps out of the Bluesky. I am working with bluesky tech support now trying to find out why I'm loosing 30% with their MPPT controller rather than gaining 30% like their advertising.

12.5 A from 300w as a maximum result is very poor. I have recorded almost double that from 330w (as a short term peak) For much of the day I get well above 20A.

The short 10 gauge is not the problem a total length of 1 m would only have a voltage drop of 0.08 v consuming about 0.3w. The connections between the thicker and thinner wire will also have some resistance, but the total effect is still negligible. I agree it is very annoying, increases installation time, and introduces unessasary points of failure all because Bluesky wanted to save a few cents on smaller connectors.

Some of the cheap MPPT regulators are very poor and the results can be worse than a simpler non MPPT. I have never been a big fan of Bluesky their MPPT conversion seems very poor especially for a medium priced regulator, but assuming you have had some occasions when the panels have been shade free in full strong sun and your batteries have been flat enough to accept a high current I think your results are so poor there must be a problem somewhere.

[Feral Cement]

Sailorchic & Pblais -- the fourth one on the list is not a Morningstar as far as I can tell (though #3 and #5 are). Please clarify which one you have and like, or which one to stay away from. Also, they are all 10A, except for the Sunkleeper, which is 12A. Chic, are you getting 11A thru a 10A CC?

Thanks to everyone for their insights!

John

[Feral Cement]

And can ANYone explain why a 20A unit is MORE than twice as expensive as the 10A unit? One case, one set of connectors, etc.

Would a second CC for a future/second 145W panel be a good idea or a bad idea?

[Pblais]

Sailorchic & Pblais -- the fourth one on the list is not a Morningstar as far as I can tell (though #3 and #5 are)

I had trouble counting but I said a Morningstar Sunsaver 20 was what I had. That part I had correct.

And can ANY one explain why a 20A unit is MORE than twice as expensive as the 10A unit?

More amps takes more control. At low acceptance there is some heat to disapate and that takes better components than a 10 amp controller.

[sailorchic34]

I have the el cheapy "non-morningstar" model. Paid something like $18 from amazon 2 years ago. As to why 20 amps costs more then 10. Well for a pwm, the control circuits and logic are about the same, though you have more power or higher rated fets, better heat sinks, larger circuit traces and filters, etc. Plus more profit too...

Oddly enough the more or less generic power transistors in the el cheapy have a max amp rating of about 40 amps, but that's intermittent and not continous rating. The poor or lack of a heat sink and the "TO" case design pretty much limit it to about 11-12 amps continuous before the junction temp starts running away.

Having seen a bluesky mppt unit work in Florida, it did increase output by 10 percent. However I feel that with the price of panels being low now, it makes more sense to just buy another panel and use a pwm controller. Btw, the MPPT controllers are also PWM with an extra dc to dc converter which adds some loss to the system during standby ("Night").

I felt that a low standby power rating was more important then the high priced mppt higher standby usage. The bluesky units use 2 amps in 12 hours just idling. My el cheapy uses 0.75 amps for the same time. With a 100 watt panel being available for $160 ish including shipping, why spend $200 for mppt.

The extra panel proves more power for less money. When panels for $800-$1000 each, mppt made sense. Now a days, it makes somewhat less so. Well from an engineering perspective anyway...

[Feral Cement]

Sailorchic, in spite of the margin for error based on the size of the components, I'm thinking the el cheapo CC won't handle two 145's for a total of 290 watts, right? At $160 each for 145W, I'll probably get another panel ASAP. That's gonna require a mo bigger CC, right?