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I wish to connect four 250w panels to a battery bank. Each panel is rated at 15A, yet my MPPT* regulator warns against exceeding 30A.

Could I add a second regulator, running two panels to each, but all connected to the same bank? Or is there a better alternative?

At present, I have four Neuton Power NPN200 12V 200Amp batteries, three 200w 12v panels, this 12V/24V 30A MPPT charge controller and this 600W Giandel pure sine wave inverter.

These are the new panels, which I have four of and would like to use in place of my old three.

* Maximum Power Point Tracking

  • 2
    This may be an appropriate question for posting on the Electrical Engineering Stack Exchange site electronics.stackexchange.com – Highly Irregular May 2 '16 at 9:11
  • Ah cheers, thanks for the heads up, this is my first post on here, scoping the community knowledge/support. – livin_amuk May 2 '16 at 9:30
  • I think this is appropriate for sustainable living. Also, there's a renewable energy SE in area 51, please follow that. :) – Henry Aug 24 '16 at 23:23
  • Also, you probably don't need another controller, check out my answer below. – Henry Aug 24 '16 at 23:26
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I have 1100 amp hour 24V battery bank with 2 solar controllers connected, each from a separate bank of solar panels. Works fine.

  • Interesting. Are the two panel arrays identical? And are the charge controllers? – livin_amuk May 3 '16 at 4:50
  • No. Different panels and regulators. When I started with solar 16 years ago, purchased Plasmatronics PL60, which works with 12/24/48V and had many features, but will only control 60 amps which worked well with initial 12V setup of 4 125W 12V panels. As I could afford added more of same panels until 16 125W 12V panels wired as pairs to give 24V. I have now added 6 250W 24V panels and a different brand controller as separate system, but still charging common 1100 amp hour 24V battery bank. In new future want to add another 4 250W 24V panels to have max of 100amp on this newest controller. – ozhank May 3 '16 at 21:49
  • So in that case I'll need to get a new 24v inverter. Can you recommend one? It almost seems like it's worth skipping a 24v system and going straight to 48v, to save money in the long run because in the end this is what we're all aiming for right? What are your thoughts? – livin_amuk May 4 '16 at 2:58
  • I have stayed with 24V as relatively easy to get LED lights, fridge/freezers/washers etc and other truck based devices to operate. I also have a 24V DC alternator for emergency battery charging. I would try buying one manufactured in your country, as likely to be able to get parts/repairs/warranty support, whereas imported ones can be difficult to get repaired (as I found out). I started with 12/24V inverter for hourse, which I have rebuilt with all new capacitors: selectronic.com.au/inverter/se22.html. Also have a Selectronic WM1700 for the workshop – ozhank May 4 '16 at 8:41
  • It would be useful to edit this answer to incorporate the additional details in the discussion underneath. – LShaver Aug 25 '16 at 1:18
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You probably don't need another controller.

If you connect your panels in series - i.e. one string - you won't exceed 15A.

You could connect them as 2 strings of 2 and that would be 30A in total.

Only if you connect them all in parallel will you exceed 30A.

You should check out the maximum input voltage of your MPPT. If the combined VOC of your panels does not exceed that maximum you should be able to run them all in series at 15A. (So take the VOC of one panel and multiply by 4.)

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