Which MPPT solar charge controller do I need?

[EarthWays]

Hello everyone.

I am installing a solar panel system to power my polytunnel

I have 2 solar panels that are:
Ubbink 240 with tech spec: 37V (VOC); 8.7A (ISO); 28.9v (Vmpp); 8.3A (Impp)
I understand that I need a MPPT solar charge controller.


Can you please recommend me an affordable one that suits my requirements?

I understand already that I will need a 40A one as the generous SunKing has pointed out:
To figure out the amps need you need to know the battery voltage and panel wattage in which you will operate at.

Amps = Panel Wattage / Battery Voltage.

All we know is you have 480 watts of panels.

AT 12 volts = 40 amps
AT 24 volts = 20 amps

What about my 37V peak output of my panels? Could anyone link me to an example of a charge controller that would suit me?

Thanks very much
Ludwig

[Wy_White_Wolf]

Wire the 2 panels in series.

http://www.solartown.com/store/product/morningstar-tristar-ts-mppt-45-charge-controller/

WWW

[jimindenver]

Unfortunately MPPT and affordable don't seem to go hand in hand unless you give up features or buy untested. The TS-MPPT-45 is probably the least expensive way I have found to run my two 245w panels. Until I decide I have been using twin 20a MPPT controllers.

[Sunking]

Amps = Panel Wattage / Battery Voltage.

All we know is you have 480 watts of panels.

AT 12 volts = 40 amps
AT 24 volts = 20 amps

What about my 37V peak output of my panels? Could anyone link me to an example of a charge controller that would suit me?

Thanks very much
Ludwig

You need a controller which can input at least 75 volts, because you want to wire your panels in series.

[EarthWays]

$400 dollar is a bit much for my budget, how to proceed?

$400 is a bit much for me.

Jimdenver, I don't care about features if they don't contribute much to functionality. Is there anything cheaper on the market?

What is the advantage of wiring in series?

[PNjunction]

My 2c for what it's worth:

Going for the cheapest in the long run costs you at least double down the road. When it fails, you end up purchasing yet another cheap replacement. OR, you are finally convinced to go with quality, but you add what you've already spent on top of that.

Buying quality up front in the long run is cheaper. Not to mention the usual perks like customer/products support, better warrantee's, etc.

Maybe something in the EPsolar (or rebadge) could get your feet wet at low cost. You've got the specs, but think about the above.

[Wy_White_Wolf]

$400 is a bit much for me.

Jimdenver, I don't care about features if they don't contribute much to functionality. Is there anything cheaper on the market?

What is the advantage of wiring in series?

The charge controller has a max 150V input. Wiring them in series allows you to get more in the range of it's design and allows you to run smaller wiring and fuses.

You will be able to find cheaper ones on Fleabay, but will also get what you pay for. Morningstar is a quality mid-level charge controller.

WWW

[jimindenver]

$400 is a bit much for me.

Jimdenver, I don't care about features if they don't contribute much to functionality. Is there anything cheaper on the market?

What is the advantage of wiring in series?

I can't say I dispute what the others are saying. There are lower cost controllers that are at least functional but like in the case of the Eco-worthy 20a MPPT controllers I use, you lose features and capabilities. The VOC is limited to 42v meaning I can't combine a pair of 12v panels in series. The temperature sensor is built into the unit and there is no option for it to be remote or is there a voltage sense line. You can set the various voltage set points but no automatic equalization. it does have a digital display but again, no where to plug in a remote. So for $102 shipped, it is functional but also limited.

Tracer has come out with a line of MPPT and has a 40a. I have heard from a few that the unit is functional but the remote display is inaccurate. I would have to check on remote sensors but I do know it has a high VOC limit. There are other 40a controllers on ebay but each time I think they might be worth taking a chance on, I see something that makes it unacceptable. One wont have a remote sensor or display, another requires 40v to work or is limited in battery that can be used.

Without remote sensors, I wont use the Eco-worthys in a install. The batteries will see well below freezing to over 100 f and I'd rather bring them home if they wont be taken care of properly. Eventually I'll break down and get a respectable controller, selling the older panels and 20a controllers to fund it.

Will your install be flat or tilted? Mounting flat may mean a 30a controller might do with only a small amount of clipping at mid day.

[paulcheung]

The Tracer 4210 is a midrange MPPT charge controller, it cost about 260 with the display on amazon. The maximum input volt is 100 volts and 40 amps at 12 or 24 volts. it is functional but it doesn't has the manual adjustable charge voltage, the reading is quit accurate, atleast mine does. The problem is the input voltage limit and the 40 amps limit also the most important for me is not be able to manual set the charge voltage.

Cheers.

[jimindenver]

And there it is, functional but limited. Fine if you can use it within the limitations but it's not a good all around choice. There are a number of people I know using the controller I do but Like me, they are seasonal campers with a single 24v panel per controller.

I talked to the guy selling a 40a and 60a MPPT controller out of Canada. Specs didn't look bad but I think I would have to wait on the remote display for the 40a.

[Beanyboy57]

My 2c for what it's worth:

Going for the cheapest in the long run costs you at least double down the road. When it fails, you end up purchasing yet another cheap replacement. OR, you are finally convinced to go with quality, but you add what you've already spent on top of that.

Buying quality up front in the long run is cheaper. Not to mention the usual perks like customer/products support, better warrantee's, etc.

Maybe something in the EPsolar (or rebadge) could get your feet wet at low cost. You've got the specs, but think about the above.

I totally agree. I bought cheap Chinese MPPT CC to begin with, almost ruined my battery bank, then I chose quality Victron components and have had satisfaction every since. Pay now and reap the benefits in the long term!