Solar charge controller selection help needed

[skripo]

I am looking to put in a solar system that will produce about 30 amps per day. I choose a semi-flexible 135 watt panel made by Sunpower which meets my capacity needs.

My only problem is choosing the charge controller. My original choice was a 20 AMP Suntracer MPPT (yes it is a REAL MPPT) with the remote panel.

My only issue is that I want to use the see consumption and use the low voltage battery disconnect, unfortunately my converter is 55 AMPs. If I want a 55 AMP or more charge controller the cost goes up obscenely.

Realistically, what is the maximum draw I can see from 12V lights, heater fan, and other 12V loads. I know it is hard to estimate but what is typical?

Also, does the converter ever supply 55 amps for battery charging?

Thank you.

[westend]

The MS Sunsaver MPPT-15 would work with the two modules but it will clip output to 15 amps. I use the same controller with a 235W 24V nominal panel on a 12 V system.
The 200W PV rating is nominal in that the controller will handle additional current and the voltage input limit is 70V. It won't output anymore than 15 amps.
Edit: Looked up the output of the modules you've bought. Max current of 5.45A and SCV of 24V. You will be hard pressed to get those modules to deliver more than 15A of output to a battery. You do mention that you may buy another module so the bigger Tracer is going to be the better controller for your plans.
Let us know how the controller works for you, there aren't many MPPT controllers in this range at that price point.

[skripo]

smkettner wrote:

skripo wrote:
My 135 watt panel is 24 Volts and I may add another. I already own a new Net Solar 30 amp that was for another project.

I also wanted the ability to program my own charge profile because my AGM battery is slightly different than the stock ones you usually see.

Morningstar SunSaver MPPT will work perfect with one or two of these panels.
Programming can even self adjust absorption time for storage vs in-use.

http://www.morningstarcorp.com/products/sunsaver-mppt/

https://www.solarblvd.com/product_info.php?cPath=6_46_228&products_id=2000

I think you need to recheck your numbers. This model you referenced only handles 200 watts with a 12v battery so it's only good enough for one 135 watt 24v panel.

For the same price, I got a 40 Amp controller AND a remote display. I fail to see how this is a better buy.

[time2roll]

skripo wrote:
My 135 watt panel is 24 Volts and I may add another. I already own a new Net Solar 30 amp that was for another project.

I also wanted the ability to program my own charge profile because my AGM battery is slightly different than the stock ones you usually see.

Morningstar SunSaver MPPT will work perfect with one or two of these panels.
Programming can even self adjust absorption time for storage vs in-use.

http://www.morningstarcorp.com/products/sunsaver-mppt/

https://www.solarblvd.com/product_info.php?cPath=6_46_228&products_id=2000

[JiminDenver]

There is a PWM controller that will knock down a 24v panel to 12v, man that's a lot of lost power. It was the least expensive option to at least try my panel until the Eco-w came out. Rogue was the American option and $325 was a lot to play with $50 panel when I didn't know if it was for us.

[ewarnerusa]

With the TS-45, I believe the array voltage must match the battery voltage. So it can't take 48V array input and use it to charge a 12V system.

From my manual.
• Do not connect a solar input greater than a nominal 48V array for battery
charging. Never exceed a Voc (open-circuit voltage) of 125V.
• Charge only 12, 24, or 48 volt lead-acid batteries when using the standard
battery charging programs in the TriStar.
• Verify the nominal charging voltage is the same as the nominal
battery voltage.

[westend]

Any PWM charger will handle nominal 24V modules (as long as the input rating is not exceeded). A user will be giving up some power, though. IIRC, my MX Solar module's rated output is 8 amps at 36 V. I can get 15 amps if conditions are right. That is a fairly large gain in power harvested using MPPT.

I shouldn't have recommended the Bogart controller. Had a senior moment and forgot that the modules in question, here, are nominal 24 V. The Tracer will be a good fit with those modules.

[Chandalen]

Almot:

Unless I'm missing something the TS-45 by Morningstar is a PWM controller that can handle 12/24 and 48 v arrays and 12v batteries.

This cant be the only controller that does this.

There really is NO (-/+ 5% )advantage to an MPPT controller for systems less than 400w. This is of course debatable.

An MPPT would allow for significant array upgrade, but I can have ~800w on my TS-45 at 12v.

[skripo]

Believe me, I am in full agreement.

[Almot]

Tracer BN has nice features. How well they are built, I don't know. Maybe, - well enough. They now have a lot of innovations of their own. I'm merely trying not to help the enemy. Watch this if you have time. Last 15 minutes, from minute 41.00

[skripo]

Almot wrote:
as much as I prefer things not assembled in China...

I understand the sentiment but the EP Solar Tracer series seem very well built and are getting good reviews.

[Almot]

Yes, with 24V panels you need MPPT, no matter if it's one panel or more.

Yes, 20A MPPT is good up to about 300W.

Well, as much as I prefer things not assembled in China, Bogart controller with Bogart battery monitor makes sense only if you buy both. Bogart SC-2030 controller is essentially an add-on to their battery monitor, as a standalone controller it wouldn't be fully functional. But this is besides the point here, since it's PWM.

[westend]

If you want a better charge controller and need monitoring, the Bogart controllers and monitors are highly regarded. These are built by an independent and assembled in the USA by folks that wish to make good electronics.

I'd also give a look at the Morningstar products. I have the MPPT-15 and it has more monitoring function than I need. Their larger MPPT controllers use the same software so I'd assume they have the same functionality.

[skripo]

Almot wrote:
Have just noticed that the OP ordered not just a 40A controller, but an MPPT one. Cost about $260.

I'm usually the one who tells not to buy el-cheapo stuff for long-term projects, but 40A MPPT for 135W single 12V panel doesn't make sense.

A good PWM controller, with remote display and temp probe, like Xantrex C35, would cost about 2 times less. And it would likely result in higher daily output as well. MPPT becomes less efficient when input voltage is getting close to 12V.

The reason I had originally selected MPPT is my understanding that PWM could only be used when the panel and battery voltages where the same, or similar.

In my case, the panel is sending 25-29 volts going to a 12V battery. I also saw that MPPT controllers are also more efficient at lower and higher operating temperatures. I was also planning on adding 1 or 2 more 135 watt panels once I assess baseline performance.

I was also told that a 20 AMP controller would be at the limit for 2 135 watt panels. I tried to buy a 30 but EPsolar does not make one in the new Tracer series. I guess there is no significant price reduction for a 30 amp using their design.

Is this correct? If not I can always exchange it, I bought it locally.

[Almot]

What you'll get with this controller is normally called "adjustable setpoints". All MPPT have this feature. I wouldn't know what the heck "to program the charge profile" is :). Adjustable setpoints are important, to help your AGM last longer. Though 99% SOC is more important yet.

Now, with adding more panels - in future - in order to calculate the wire gauge, you should know the total wattage, voltage and current from the panels. I would use maximum parameters that this controller is designed for, i.e. 520W. Off the top of my head (and other heads here that have 500-700W array), a 10 gauge cable from panels to controller should be enough. In most RVs this length is waay more than 5ft, but #10 gauge will be alright up to 15-20ft.
To use MC4 connectors you will need to buy a double length of MC4 cable, obviously.

[skripo]

My 135 watt panel is 24 Volts and I may add another. I already own a new Net Solar 30 amp that was for another project.

I also wanted the ability to program my own charge profile because my AGM battery is slightly different than the stock ones you usually see.