Whats the best Solar charge controller??

[Gotwind Ben]

I've been doing a bit of research into the better solar charge controllers.
I think I have found a good one by German company stecasolar.

http://www.stecasolar.com/index.php?Steca_Solsum_en

They come with a very impressive array of features
Does anyone know of a better product?

Product features

* Shunt controller
* Voltage regulation
* Automatic detection of voltage
* PWM control
* Multistage charging technology
* Load disconnection depending on voltage
* Automatic load reconnection
* Temperature compensation
* Common positive grounding or negative grounding on one terminal
* Monthly maintenance charge

Electronic protection functions

* Overcharge protection
* Deep discharge protection
* Reverse polarity protection of load and module
* Reverse polarity protection by internal fuse
* Automatic electronic fuse
* Short circuit protection of load and module
* Overvoltage protection at module input
* Open circuit protection without battery
* Reverse current protection at night
* Overtemperature and overload protection
* Battery overvoltage shutdown

Series controllers are generally considered superior to shunt type for solar.
The shunt type have a diode loss which can have some impact in lower lighting levels, or with longer (undersized) wire runs.

I am not convinced 3-stage is necessary for solar in smaller systems. Accurate control is more important.
Not sure 3-stage will help a smaller system with a battery big enough for a reliable system.
Pretty sure if the system is balance out well, there won't often be enough sun to do an automatic monthly maintenance charge. It almost needs to be done manually with most smaller systems.

The Steca's look improved from a few years ago. Most people were not very impressed with them before.

I like the way MorningStar does it. No problems with them to speak of.

LVDs, in my opinion, cause more trouble than they are worth for most end users.
G-

[Gotwind Ben]

Thanks Ghurd,
So for my small 55 watt panel into a 12v 110 A/h battery this series controller would be probably the best at around £30 ($55)?
http://www.morningstarcorp.com/en/sun-guard

I think so, yes.

It does the same thing as its SS-x big brothers right down to PWM and temp comp, though optimized for SLA.

I don't see any real difference between the SG-4 and SS-6/10/20 in day to day use, even with the SS-x set to flooded.
The SS-x green LED just means it is connected and day light (SG-4 has no LED- I put 0 faith in blinky LEDs that claim to be giving any accurate information about the true SoC anyway).

Where a shunt controller requires a diode with 0.7V (or MORE) drop between the PV and battery, a MorningStar sometimes will not have a measurable 0.01V forward voltage drop (because mosfets are Great!).

Full Disclosure. I am a licensed dealer and installer, and I sell and recommend the SG-4 for panels under 60W.
That said, I can sell and install anything I want, and go back and fix it free later, and MorningStar's wholesale distribution system does Not leave as much profit for the retailer as many other brands.
Meaning I sell it because I actually believe in it. :o
G-

Edited to change capital 4 ($) to regular 4.

[Gotwind Ben]

After a bit more thought and Ghurds advice.
I think the standard series solar charge controller is better in most situations.
Low voltage disconnect (LVD), I agree would be a pain in the rear for the end user.
also;
There is no limit on the current being drawn from the battery compared to the shunt type either, the shunt types limit this and cost more for higher amperages.

I will have to install extenal fuses from the panel (for safety in my application) and on the positive cable close to the battery - not a big problem.

No problems Ghurd, you being a licensed dealer and installer for the morningstar range - It doesn't effect me here, I appreciate your input.

A good article here
http://www.reuk.co.uk/Solar-Charge-Controller.htm

Thanks Ben.

A good indication of the dealer's profit margin is how many are available on ebay compared to the online stores.
And I see none are available on ebay UK. At this time.
I figure most retailers offer them to sell panels, without the added costs of tech support when an inferior controller is not quite working.

Morning Star?
http://medieval.stormthecastle.com/armorypages/morningstar.htm

[Gotwind Ben]

Just ordered the Morningstar SunGuard SG-4 here in the U.K
http://www.alternativeenergystore.co.uk ... roller.htm

The price in U.K. pounds is the same as the dollar price (26). So someone is making some money somewhere along the line :roll:

Fair enough I suppose - shipping e.t.c

Looks like a relay based controller.
Pos Input on the left, Pos Output on the right, and the Common is grounded.
They beat the battery into submission and show their age with use.
Sometimes they are used to beat the generator into submission.
:mrgreen:

[Gotwind Ben]

Thank you Ghurd - I got the humour ;)