NEED BIG help choosing Charge Controller/controllers please?

[Bigmotoxer]

Hello guys. I need help here finding the right charge controller or controllers please.
Here is the run down(keep in mind I DO have fuse, fuses, breakers installed in all necessary locations). Ok, I have a 30' Toy Hauler/RV. The RV has (8)eight 250 watt panels on roof(38voc @ 8.75A), I ran #8 THWN-2 straight down to combiner box(parallel)...[ "Insert CC here" ]....Ok, so after CC will be charging 12 volt battery bank(1,200 a.h.), then Xantrex 2000watt inverter. And before we get on the subject, yes, I know this is alot of output amperage. I know I could go up in voltage to drop inversely proportioned amperage down but I need this system to be 12 volt....because the RV lighting, pumps, etc are already 12 volt, appliance are 12 volt, etc.
So here's the big question= do I use one big CC like Midnight classic 150, or do I split it up and use two CC together on one battery bank like the Xantrex mppt60-150 ? ...Or will either of these even work the way I'm seeing it? ...I'm exhausted, my brain is fried, help please.

[paulcheung]

8 250 watts panels are 166 amps to 12 volt battery bank, you need 2 Midnite Classic 150 wire the panels 2 in series. if you use any other CC you need three of them. Classic 150 can give you 96 amps each. others 80 amps Max.

[Bigmotoxer]

8 250 watts panels are 166 amps to 12 volt battery bank, you need 2 Midnite Classic 150 wire the panels 2 in series. if you use any other CC you need three of them. Classic 150 can give you 96 amps each. others 80 amps Max.

Thanks Paul ...#1... Should I split the panels in half sending 1000watts to each CC?...or send all 8 panels/2000watts to both CC?
#2... when you say "wire panels 2 in series" do you mean 2 panels in series x 4, which is 4 pairs/strings, which is 8 panels total?
#3... I had 4 panels in parallel(38v/26A/1000watts input)connected to intronics mppt charge controller before I got these other 4 panels, and at full sun my charging/output amps was only 50A(when technically it should have been 80)not sure why, maybe some serious loss somewhere.
#4...Dang. 2 midnite controllers? Dang. Big money but if this is what I have to do to stay 12v I will. Oh, and I've never owned a midnite before but I've been reading they are good ,but that also they are a PAIN to set-up, usually consisting of, and ending with a phone call to tech support @Midnite headquarters. I sure hope they're not that difficult to setup for one's specific needs.
#5 Anyone else with a 2 cent?
#6 Thanks Paul

[lkruper]

8 250 watts panels are 166 amps to 12 volt battery bank, you need 2 Midnite Classic 150 wire the panels 2 in series. if you use any other CC you need three of them. Classic 150 can give you 96 amps each. others 80 amps Max.

The only way I know how to estimate the amperage of panels with an MPPT controller is to divide the panel voltage by 12 and multiply by the amps. But I get a higher number than you do. Is your number a real world number taking inefficiencies into consideration, or do you have a different way to calculate this?

[paulcheung]

The only way I know how to estimate the amperage of panels with an MPPT controller is to divide the panel voltage by 12 and multiply by the amps. But I get a higher number than you do. Is your number a real world number taking inefficiencies into consideration, or do you have a different way to calculate this?

38 volts is VOC, you don't get that with load. 2000 watts /12 =166.66amps.

[paulcheung]

Thanks Paul ...#1... Should I split the panels in half sending 1000watts to each CC?...or send all 8 panels/2000watts to both CC?
#2... when you say "wire panels 2 in series" do you mean 2 panels in series x 4, which is 4 pairs/strings, which is 8 panels total?

#6 Thanks Paul

Your are welcomed.
You connect 2 panels in a series and 2 strings into one CC. 4 panels per controller. All those 60 to 80 amps quality controllers are about the same price, the Midnite Classic give you 96amps Max. others give you 80amps max. you don't really want to operate you CC in Maximum current all the times.

[Mike90250]

The only way I know how to estimate the amperage of panels with an MPPT controller is to divide the panel voltage by 12 and multiply by the amps. But I get a higher number than you do. Is your number a real world number taking inefficiencies into consideration, or do you have a different way to calculate this?

It's much simpler to work with the wattage #'s 8*250 = 2000w divided by 14 charging volts = 143A
so you have to split that over 2 different charge controllers, 4 panels per controller. 4 parallel panels will need a combiner box with 4 DC breakers. (total need for 2 combiner boxes & 8 breakers)

In a shared RV interior, I would use the morningstar MPPT 60 controllers, they are silent and don't have turbo fans running. You do need to provide for air flow over their heatsinks, you can't stuff them into the back of a closet, they need cooling air. (I have both the midnight and morningstar controllers side by side)

With panels flat on the RV roof, you will seldom, if ever, see full power. The major brands of MPPT are all very robust and will limit power to a safe amount.

The batteries I see as an issue, unless you already have 2V cells wired up. There is not going to be any good way to wire 10 parallel 12V batteries decently in an RV, unless you make a dedicated battery room with proper buss bars. See this http://www.smartgauge.co.uk/batt_con.html article on how to manage parallel batteries, which should all have their own fuse going to the buss.

[Bigmotoxer]

Thanks guys. For a few reasons though the fan noise wouldn't be an issue(motocross rig and it's loud where we're at anyway). Couple questions tho please. #1 I have read where the Midnite is complicated to set up and get dialed in? #2 If I have a 12v system and the panels are 38voc(24-28v delivered) wouldn't it be better to run panels in parallel?...Example= 2 in series would double the voltage(76voc)Then CC has to transform that voltage all the way down to 12v...Maybe I'm wrong but seems like the less voltage/watt/amp transformed the less wasted etc(better efficiency). Anyway I ran the 1000 watt array with intronics 75amp controller, at it height(Florida, mid-day, summer, HOT) I received 50amps to battery bank. So I'm confident that a 60amp x 2 controller/controllers will work great. But since the cost is nearly the same I think it'd be in my best interests to get the Midnite x2.....but still scared of the programming horror stories that I've heard?

[Bigmotoxer]

Ok that's it I'm going 24v. With 1 midnite CC. Last thing if anyone knows best-bang-for-the-buck on 24v 3000w pure sine inverter please let me know because I'm about to order something. Thanks guys.

[Bigmotoxer]

What??!

Wow WHAT IS THAT THING?!!---> http://www.ebay.com/itm/HVA-440-amp-...3D291196716116

[thastinger]

You planning to run the roof top AC from this inverter?
Since you don't need an inverter to also be a charger, look into the Cotek line of inverters, not cheap but have a UL listing. How are you doing the equipment grounding?

[Bigmotoxer]

You planning to run the roof top AC from this inverter?
Since you don't need an inverter to also be a charger, look into the Cotek line of inverters, not cheap but have a UL listing. How are you doing the equipment grounding?

I seen Cotek, looks good, about the same price as Go Power. Seems to be quality and pricey too. I just found that wind/solar CC on eBay(in the link I posted) I like it but I need to know more about it.

[thastinger]

I believe Samlex/Go Power/Cotek are the same company but AFAIK, only Cotek carries the UL, may not be a concern to you though as your system will not have to be inspected.

Mind my asking why you decided to do solar for your hauler? I ask because we also have a toy hauler and use it for racing as well but it doesn't have a single panel on it, just too easy to pull out the Yamaha 3000ISEB and let it run. Less maintenance, less cost and you may find less noise if you mount the CC and inverter inside the living compartment (the fans do make some noise).

[Bigmotoxer]

I believe Samlex/Go Power/Cotek are the same company but AFAIK, only Cotek carries the UL, may not be a concern to you though as your system will not have to be inspected.

Mind my asking why you decided to do solar for your hauler? I ask because we also have a toy hauler and use it for racing as well but it doesn't have a single panel on it, just too easy to pull out the Yamaha 3000ISEB and let it run. Less maintenance, less cost and you may find less noise if you mount the CC and inverter inside the living compartment (the fans do make some noise).

Hi. 30' hauler(15'living, shower etc and 15' bikes, work bench). Built this toyhauler from my old camper(sink, oven, water heater, beds, etc). I also have Yamaha 3000. I'm an electrical contractor and just got locked in with UMA solar distributor and Crown battery distributors, ...despite being a master electrician this will be my first solar system and figured "I'm goin all out on this system"(easy access to equipment, fuses, fuse blocks, panels and conductors etc etc) to be both useful for me away from power grid and as a demo for potential customers. So getting better educated on DC theory and solar in general was all I was lacking. And in general it's just cool lol.

[Mike90250]

ebay HVA 440 amp 10,000 watt charge controller 12/24/48 volt

Run away, fast.




Yikes - an air conditioner !! The compressor starting surges will be your big issue..
Find someone with the fancy clamp on PEAK HOLD AC AMP meter and see what the starting load is.. That's what your inverter has to be able to supply for 5 seconds while the compressor spins up. The batteries and wires must also be able to sustain that load too. 24Vdc gets you to some better gear, that can handle real life surges. But my recommendation would be, since you don't NEED 12V anymore, go all the way to 48V. You can use 8, cheep, 6V-200a golf cart batteries in series, simplifying the battery bank issues for 12 / 24V where you will need parallel. less issue with OOOO cables & crimpers needed