I'm getting ready to increase my system to 12 panels, from the 3 panels I am using now.  My question is, what the voltage limit of the Harbor Freight Panels. I would like to tie 4 sets, of  3 panels in series for a a 48-50 volt system.  I don't want to spend a fortune on wire. I would be using a MPPT Controller, to charge my 12 volt battery bank. Any comments would be appreciated. 

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It's not an issue for the Panels but the limit of the charge controller. you need to remember that the HF panels have 2 voltage metrics

Open Circuit Voltage (V) 23.57

Maximum Power Voltage (V) 17.5

Open circuit is the max voltage the panel can produce at perfect sun and cold temperature with no load (just a meter to gauge the voltage). Max power is the maximum the panel can produce at perfect sun and cold temp with a load (charge controller). Even though they get called 12v panels that's because they have a high enough voltage to charge a 12v battery (14+v to get a good charge). In your scenario you would have

OV  4*23.57v = 94.28v

MV 4*17.5v = 70v

Now they probably will not get their max and most definitely not get the Open voltage but you should base your MPPT charge controller choice and design on what could possibly happen so as to avoid damage. Also you need to put a fuse or breaker between panel banks that you plan on connecting in parallel (4panels in one bank in series combined to another 4 panel bank in series you should put a fuse that covers the max amps rounded up to the nearest fuse or breaker size). As always refer to the MPPT charge controller manual for breaker/fuse sizes and other safety guidelines.

I recently connected 2 sets of 3 panels in series to a new MidNite 150 MPPT charge controller.

OV 3*22.8v = 68.4V 10.66amp

MV 3*18.3v = 54.9V 10.66amp

I usually see about 50-54v which is good based on the angel I have the panels and location. I have a 15amp breaker between the panels and charge controller (in a square D breaker box with 2 15a breakers acting as a combiner box).

This allowed me to use 10/2 electrical wire from Home Depot which is much cheaper.

Thank you for the info, I had planned on doing the same panel configuration as you used, but with 4 sets of 3. I had hoped to use a Rogue controller if the Max input voltage from the panels would be OK. I have 1 set of panels that I setup last year, and 3 more in boxes ready to hook up as soon as I can purchase a controller. You mentioned that I should fuse between panel groups, but do I need to also use diodes also?  

The panels I have already have diodes in them but I wouldn't use them since the MPPT charge controller prevents any back feeding from the batteries. The Breakers protect both the charge controller and panels from any surge.

I have the Rogue Charge controller Myself, And to be Honest I would be afraid to go above 60 volt.

I have seen open voltages as high as 45 volts for my system running 2 panels in series. So doing a 3 in series

would be kinda of chancy. Added note though. For those who are patient , There will be new version of the Rogue charge controller sometime in the future. For high Voltages,.And Higher Amps.

Got a rogue ran 5 sets of 3 HF to a combiner box.....good thing I seen this Question.

New to this just thought I could add panels until I got near 30amp.

Was gonna run the 8 wire with the 30 and 40 amp fuses today....but now I see this is probably not possible.

Use was gonna be for 4 lights with switch and 1 outlet for 1 room.

3 lights w/switch and outlet for room 2.

Is there anyway to do this? .....or do I have to use a HF regulator for some of the sets?

Will have four 6 volt golf batts 230ah

Any suggestions? The war dept.{wife} thinks I have gone nuts.




Trying to figure out what you think is not possible. If you Tied 3 panels in series, It possible you could damage the Rogue . Now 2 Panels in series is just fine with 8 Gauge wire, You can can do 400 to 500 watts in panels easy at 24 volt. Because the panels will put out around 34 volt average tied in series, And you can use 8 gauge up to around 60 feet in distance with that type of wattage. Don't confuse yourself.  You can Use the HF regulator as a power distribution just hook up to the batteries only.  But your limited to 4 amps as that is there design.

I think I am probably over reading something.Or tryin to cram all the variables in. I guess almost anything is possible....just don't want flames nor smoke. IHow can I use the most panels for the rouge...I have mounted 5 kits =15 single panels and wired to combiner box buss bar all + on one bar and all - or the other.  What if I just use 2  6vgolf batts? Should I start over and do a series wiring but then I will only use 6 of my 15 panels is that correct? { a good problem I suppose} then run the other panels to different CC. I definately am cornfusing myself ...Don't think I ever read this much in my whole life....THanks a ton.

You can use two panels in series.  This would give you a spare panel.  The Rogue is limited to 60 volts input.  If you go over this. the Rogue might let out the magic smoke.  This is not a good thing.  I have each kit of three panels wired in parallel.  Then, I have two of these kits wired into series.  This could be done with two panels instead of the whole kit.  Wire the gold batteries into series to make a large 12 volt battery.  The Rogue will take either a 12 volt or 24 volt panel configuration and apply the current into the 12 volt battery.  Check the charge setting for your type of battery.  The Rogue can be programmed for each level of charge.  You will love what you see when you get it all up and running!

have 12 panels in paralell to bus bar in combiner box reads 23 volt.....when I add the other two panels that are run in series shows 47 volt until I hook them to the buss bar then it just shows 23 volt.

Should nt it show 60 something using volt meter   Need Help 

When you added the series to the same combiner it drops to the lowest voltage which is the parallel group. you need to series them all (2pair at a time) or parallel them all. So with 12 panels you would have 6 sets of 2 in series. You then add the 6 sets to the bus bar giving you 47v

OK great that crossed my mind....but needed a little reassurance...than

  If I put 7 sets of two on the buss bar it will still be about 47v.

Will this still stay under my 60 volt max. input on my CC, with this many panels 14.

Thanks ....when I keep it simple in my head im ok......then i keep reading and reading......focus gets confused.

I am running the hf sets in series to achieve enough volts to charge a 24 volt battery bank.  I am using the Rogue.  I talked with Marc, the person who made the Rogue, to make sure this configuration would work.  I have always asked him before I try anything new to make sure I do not damage this fine charge controller.  This configuration works fine with the Rogue.  Just make sure you only tie 2 into series.  Tying 3 into series will overload the Rogue's max voltage.  This will make the magic smoke appear.  The number of panels into the Rogue is not an issue, as long as the voltage is kept below the max of 60 volts.  The Rogue will only put out 30 amps.  If you have too many panels wired into it, you are wasting solar power that cannot be converted with the Rogue.  On page 13 of the Rogue manual, it stated the following maximum watts input:

12 volt pv/12 volt battery - 432 watts

24 volt pv/12 volt battery - 432 watts

24 volt pv/24 volt battery - 864 watts

This is a rule of thumb.  Other factors include the time of day. shading, temperature, wire size.  I have 655 watts @ 24 volts wired into 24 volt batteries.  I have seen up to 649 peek watts, 105.2 Ah, and 2.80 kwH from this set up. 


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