Anyone have experience with Renogy vs WindyNation PWM solar charge controllers?

**Amy@altE** · 12-12-2014, 04:45 PM

If you have 250W panels, I would say they are not 12V panels. Are they 20V or 24V? 60 cells (squares) or 72? What is the model so we can check the specs.

**overtak3n** · 12-12-2014, 06:10 PM

Here are the specs:

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http://www.civicsolar.com/sites/default/files/documents/jinko-solar-jkm-p-60-datasheet-156848.pdf

Looks like they are indeed higher than 12 volts. Also, looks like they are 60 cell solar panels.
Looks like it's either 30V at max power or 37V open circuit, I'm not sure which one I should be looking at. Let me know.

If that is the case, I'm not sure if those solar charge controllers would still work. Let me know what's possible.

Thanks!

**jimindenver** · 12-12-2014, 06:16 PM

What voltage is the battery to be charged. If it is 12v you will need a MPPT controller to convert down the voltage. The least expensive for one of the panels would be $102 for a Eco-worthy 20a MPPT, functional but limited.

**Amy@altE** · 12-12-2014, 06:18 PM

Yup, those are 60 cell, 20V nominal panels. You cannot use a PWM, you have to use MPPT. Go to YouTube and search for altE Store, watch my video on PWM vs MPPT. If you use PWM, you will lose around half of your panels power. Big waste. I get this call pretty much every day, people get a great deal on the panels, but have to spend more money on the charge controller.

You need at least a 35A MPPT charge controller. Blue Sky makes a 40A SB3024iL. You'd have to wire the panels in parallel. Or MorningStar's TS-MPPT-45, you could wire the panels in series or parallel. We are talking $350 - $400 range.

**Amy@altE** · 12-12-2014, 06:20 PM

Originally posted by jimindenver

What voltage is the battery to be charged. If it is 12v you will need a MPPT controller to convert down the voltage. The least expensive for one of the panels would be $102 for a Eco-worthy 20a MPPT, functional but limited.

20A is not big enough for 2 panels. He needs at least 35A. 20V / 12V x 8.23A x 2 x 1.25 = 34.29A.

Amy

PS I just re-read and see you said for one panel. Yes, I agree, that will work for 1.

**jimindenver** · 12-12-2014, 06:26 PM

Both panels flat would be ok with a TS-MPPT-45, Rogue or other 30a controllers but you are looking at the $400 range and nice controllers. I have used multiple smaller controllers, one per panel, it worked out well because I could combine the for 34a or separate them to keep multiple banks up.

**overtak3n** · 12-12-2014, 06:35 PM

Should I be looking at the 30V max power rating or the 36V open circuit rating of the panels?

As for the controller:
Is a PWM controller not suggested because I can't charge a 12V battery with 30+V panels so it won't work?
Or is it that I can charge the battery but there will be a lot of power loss so it would be inefficient?
Which of the above two is correct?

This is for a small project, for a school competition, so spending hundreds on a MPPT charge controller would be out of the budget.

Thanks for all the help!

**Bucho** · 12-12-2014, 07:28 PM

Originally posted by overtak3n

We were given two solar panels 250 watts each. At 30-37V and 30A, I think wiring the solar panels in parallel to charge the battery together would require at least 40-50A charge controller so I'm probably only going to use 1 solar panel to charge the battery unless someone can recommend a charge controller that can handle both panels and is affordable (at most about $100).

Thanks!

So I don't see where your getting the 30A from also can you tell us what you're using for batteries?

**overtak3n** · 12-12-2014, 07:56 PM

We haven't decided on batteries yet. Thinking of using a deep cycle battery like this:

http://www.amazon.com/gp/product/B006T07BC0/ref=olp_product_details?ie=UTF8&me=

Sorry for he confusion. I assumed the controller can handle 30A, at 12V that's 360 watts. For two 250 watt panels, that's not enough.
Also, I modified the original post to fix the voltage but forgot to modify the rest of the post. Edited the post again.

Thanks.

**russ** · 12-13-2014, 03:45 AM

Originally posted by overtak3n

We haven't decided on batteries yet. Thinking of using a deep cycle battery like this:

Deep cycle? Not at all - those are standard batteries.

**overtak3n** · 12-13-2014, 04:01 AM

Or this:

AtBatt - Not Found

http://www.atbatt.com/csb-battery-evh12150-12v-15ah-extended-deep-cycle-battery.asp

Find batteries, battery chargers and power supplies for your device. AtBatt's easy to use Battery Select Technology ensures you the perfect power match

**jimindenver** · 12-13-2014, 12:40 PM

That battery weighs 9.8 lbs, not much storage there. With a 15 Ah capacity you will only get 7 and a half before it needs to be recharged. We had a 35 Ah gel cell that we used to keep cell phones and Mp3 players charged. It also powered a small portable DVD player or two small personal fans. With such limited use it would go a week to 10 days before needing to be recharged. The last trip we used it we replaced the portable DVD player with a TV/DVD combo that pulled 65w. That didn't sound like much but watch a movie or two and the battery needed to be recharged. After that we went to the full size systems and the gel cell is somewhere in the garage.

**Bucho** · 12-13-2014, 01:05 PM

Originally posted by overtak3n

Sorry for he confusion. I assumed the controller can handle 30A, at 12V that's 360 watts. For two 250 watt panels, that's not enough.
Also, I modified the original post to fix the voltage but forgot to modify the rest of the post. Edited the post again.
Thanks.

With PWM controllers Amps in = Amps out.

So those 250w panels have a Vmp of 30.4v and an Imp of 8.23a that's where the 250w comes from: 30.4 x 8.23 = 250.192

This means that if you put them in parallel you get 8.23 x 2 = 16.46

So you should be able to use a 20amp charge controller. It's only when we start talking about MPPT that watts in and watts out comes up.

**Bucho** · 12-13-2014, 01:12 PM

Originally posted by overtak3n

We haven't decided on batteries yet. Thinking of using a deep cycle battery like this:

http://www.amazon.com/gp/product/B006T07BC0/ref=olp_product_details?ie=UTF8&me=

Thanks.

Glad I asked about batteries you can only charge batteries so quickly. Those batteries are way too small for your solar panels.

Anyone have experience with Renogy vs WindyNation PWM solar charge controllers?

Anyone have experience with Renogy vs WindyNation PWM solar charge controllers?

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