2 @295 watt panels in parallel

[Canine]

jimindenver, what I mean is if a newbie looks at an MPPT controller and sees it can put out a maximum of 40 amps, he/she may mistakenly think the input is 40 amps. A 3024i with 36 cell panels is rated to take a maximum of 32 amps worth of solar panels with a maximum output of 40 amps to the batteries. 40 amps of 36 cell panels would be too much. It can be easy to become confused when trying to juggle all this information.

With my setup I had mistakenly purchased one 3024i for two 285 watt panels. When I realized my mistake and told that to Blue Sky Energy, they said it could eventually burn up the controller despite the voltage being within spec (2 panels in parallel, 39.2 VOC with 47.6 volt max input on the CC. With 60 cell panels and a 12 volt battery bank, the maximum amp input goes down to a measly 12 amps! I was running 19.04 amps.). With one controller it did clip off excess power. When I smartened up and put two controllers on it, my power production became amazing. I grunt like a gorilla every time it's sunny.

I could have written that better in my previous comment.

Blue Sky makes controllers for the RV industry so their controllers are smaller than other manufacturers. Now that we are seeing more interest in solar, cheaper prices, and higher wattage and/or voltage panels, more powerful controllers are needed. Am glad Blue Sky has networked controllers so they can handle most of the extra power we see nowadays, but it is kinda spendy buying the extra controllers, wire, fuses, etc. Price notwithstanding, two controllers are much better than one. It's like having the Doublemint Twins in a charge controller.

 

[frater secessus]

It is true that many brands and sources at the cheaper end of the market flat-out lie wrt their specs, even claim MPPT falsely etc.

Cheap Chinese junk off eBay is a roll of the dice, unless a specific listing is recommended by someone with knowledge you trust that's verified its performance with an ammeter.

I suggest onlookers make decisions based on facts, reviews, and experience rather than fearmongering or bias.





Someday I'm going to turn this FUD into a drinking game. 

Or I could just start posting it myself to save time.

 

[frater secessus]

It is true that many brands and sources at the cheaper end of the market flat-out lie wrt their specs, even claim MPPT falsely etc.

Cheap Chinese junk off eBay is a roll of the dice, unless a specific listing is recommended by someone with knowledge you trust that's verified its performance with an ammeter.

That should be your signature block.

 

[MotorVation]

Okey dokey. Based on everything I've read I'm going to go ahead and buy the two panels.

A few weeks ago Home Depot had 180 watt Grape mono panels (China) on sale for 180.00 each and I wouldn't have to pay shipping. I was going to buy 3 of them. Well, I waited too long, they sold out and I was left sitting here feeling like a dope.

The price on the 2@ 295 watt mono panels with freight comes out to about 545.00. They're engineered and made in Germany and have an excellent warranty. Northern Arizona Wind and Sun (the seller) has a good reputation so I feel confident about dealing with them. (Thanks, Bob Wells for mentioning them. I checked out their site and that's how I discovered the 295 watt panels). I'm concerned about the possible upcoming 30% tariff on imported solar so I'm gonna get while the gettin's good.

Why so much solar? I'm a night owl. Most of my power usage is going to happen after the sun goes down. I'm online most of the night and stream a LOT. Connectivity is another topic I've already started working on. (Thanks Jim).  I'm also going to have a TV on all night. I have a sleep disorder aside from being partly nocturnal. I wake up every couple hours and get back to sleep by watching documentary's etc. I'm also going to be running a 12 volt compressor fridge, roof fan and led lighting along with the laptop, phone, hotspot(s) etc.

My battery bank is going to be 470 ah FLA and based on the solar usage calculators I've tried, I'm going to need it especially with a couple/few cloudy days in a row. I feel better about over-paneling than the one watt of solar to one ah of battery because of the reasons above. I'm going to attempt to fully charge the bank as often as possible to extend the life of the batteries.

I think I'm going to call the seller tomorrow to find out what kind of cables/connectors I need to parallel them and then run to the controller so I don't have to pay extra shipping on them.

I'm going to deal with the controller issue later on. I have plenty of time to get that sorted out.

I'll let you know how it goes.
Thanks again.......

 

[akrvbob]

I had a friend with a van just like yours and he mounted 2 Kyocera 315 watt panels on it and still had room for a Fantastic Fan. But, he had to mount them sideways so they hung over a bit.

But it worked out good, so hopefully you will have enough room as well.

 

[jimindenver]

Xantrex C40, cheaper because PWM, lose a bit of efficiency.

But very robust, been around forever, have "diversion" load capability built-in (frater's opportunity), and quite adjustable charge setpoints.

https://www.altestore.com/store/cha...40-solar-charge-controller-40a-122448v-p2070/

Being PWM the loses on a 24 volt bank would be barely acceptable. On a 12 volt bank it would be a crying shame with these two big panels to get a third of the power available straight off the panel and not even a quarter possible with a MPPT controller. Nice controller for what it is but a horrible match up for these panels.

 

[MotorVation]

I had a friend with a van just like yours and he mounted 2 Kyocera 315 watt panels on it and still had room for a Fantastic Fan. But, he had to mount them sideways so they hung over a bit.

But it worked out good, so hopefully you will have enough room as well.

I just went ahead and ordered the panels five minutes ago before I chickened out. I measured the top of the van and there's enough room to mount them in line (butted up against each other they'll cover 130 inches lengthwise) but they will cover the factory indent for AC or a fan. I was hoping to avoid that but it is what it is. They're MAY be enough room for a fan behind them but it's iffy as the roof isn't totally flat all the way to the rear and the upper brake light is there so it may be impossible to get a tight seal. We'll see. I'm pretty sure I'll have to start another post down the road some for some mounting ideas. Sideways may have to be an option.
Thanks again Bob

 

[John61CT]

Being PWM the loses on a 24 volt bank would be barely acceptable. On a 12 volt bank it would be a crying shame with these two big panels to get a third of the power available straight off the panel and not even a quarter possible with a MPPT controller. Nice controller for what it is but a horrible match up for these panels.

All true, I must have brain-farted the fact these panels are higher-voltage.

 

[frater secessus]

Why so much solar? I'm a night owl. Most of my power usage is going to happen after the sun goes down. I'm online most of the night and stream a LOT. ... I'm also going to have a TV on all night. I have a sleep disorder aside from being partly nocturnal. I wake up every couple hours and get back to sleep by watching documentary's etc. I'm also going to be running a 12 volt compressor fridge, roof fan and led lighting along with the laptop, phone, hotspot(s) etc.

That's a really interesting use case.  Thank you for sharing the underlying issues;  it could very well help other folks who stop by later.

 

[MotorVation]

That's a really interesting use case.  Thank you for sharing the underlying issues;  it could very well help other folks who stop by later.

I've always been mostly nocturnal. I used to stuff paper in the cracks around my bedroom door when I was a kid so my parents couldn't see my light on. I used to read all night back then and had to get up for school with very little sleep. Having enough power at night to do what I normally do is important so I can feel at home in the van. Getting enough sleep is paramount to my health.

Thanks again everyone. I expected and welcomed varied opinions. My takeaway is that now I know that one way or other the panels will work. I didn't know that for sure before I asked...

 

[jimindenver]

My mother said I didn't sleep as a child, some nights I didn't. It depended on if the book I was reading was too good to put down. Now I stay up to 3 AM often and Max wakes me at dawn.

 

[MotorVation]

My mother said I didn't sleep as a child, some nights I didn't. It depended on if the book I was reading was too good to put down. Now I stay up to 3 AM often and Max wakes me at dawn.

I feel ya. It's usually 4:30 am for me now. Last night 5:30 am because I was fired up about the solar panels.

When I was a kid I read the works of Mark Twain on those long nights. Huck Finn had a damn good story to tell. I was envious. Now I'm about to embark on my own journey. At 63 I'm an old fart but I'm chomping at the bit to get this van adventure rollin'
Better late than never.........

 

[MotorVation]

I'm seriously considering this Solar Epic 40A MPPT controller. It's the same as the Renogy Commander. I don't mean it's similar, it's the same exact unit from the same manufacturer with a different sticker on the case. From what I've read, the firmware on the Renogy has been changed a bit so that the MT-50 that Renogy sells is only compatible with their unit. The MT-50 that's included in this package isn't compatible with the Renogy. Other than that they're identical. I can get all four pieces for $194.39 shipped with a 10% off coupon applied to my Amazon shopping cart. From what I've read, this controller will handle the two 295 watt panels I ordered.
Good reviews also.

I realize that there are better controllers out there but I really don't want to spend 500 or so bucks on one right now. I'm more concerned with getting everything I need to hit the road together and installed in the van by this coming November. (I'm working right now to save money for all this but when I do drive away my income is going to be limited until I figure out what it is I want (or need) to do next).

I'll post two links.

The first one is for the Solar Epic 40A MPPT and the accessories that come with it on the Amazon site.
The second will be the pdf for the two panels I bought with all the specs. Mine are the ones at the bottom of the chart. (the 295 watt) (wired in parallel)
Thanks again............

https://www.amazon.com/gp/product/B07429RK43/ref=ox_sc_act_title_1?smid=A2P9F29Y7BYBUO&psc=1
https://www.amazon.com/gp/product/B07429RK43/ref=ox_sc_act_title_1?smid=A2P9F29Y7BYBUO&psc=1
https://www.amazon.com/gp/product/B07429RK43/ref=ox_sc_act_title_1?smid=A2P9F29Y7BYBUO&psc=1https://www.solar-electric.com/lib/wind-sun/AXITEC_AXI_blackpremium_60c_260W-290W.pdfhttps://www.solar-electric.com/lib/wind-sun/AXITEC_AXI_premium_60c_270W-295W.pdf

 

[Canine]

The two panels will be 590 watts, but the charge controller is rated to handle only 520 watts with a 12 volt battery bank. Do you have a 12 volt or 24 volt battery bank? If you have a 24 volt battery bank, then those panels look like they will work. I didn't see anything about amp limit; this would be something to look further into if you have a 24 volt battery bank.

 

[jimindenver]

Controller says over paneling is ok as long as it is not over three times rated limit. Mounted flat the panels will rarely over panel by much unless you are using big loads mid day, mid summer.

 

[John61CT]

Personally I'd stick to my Victron reco in #11. More recent design and electronics, likely a bit more efficient, maybe quite a bit at the higher Voc with those panels.

Plus not overpanelled, so capture all the peak output.

Plus superior partial shade handling, each panel getting its own dedicated MPPT optimization.

#1 brand in the marine market, Dutch engineering and QC oversight, five-year worldwide unconditional warranty, so likely better build quality, more robust for mobile use.

That specific vendor, Alan @ Bay Marine also gives great personal support, even if you don't buy from him!

But that Tracer unit's likely to be just fine too...

 

[MotorVation]

Controller says over paneling is ok as long as it is not over three times rated limit. Mounted flat the panels will rarely over panel by much unless you are using big loads mid day, mid summer.

@Canine, I didn't get the batteries yet but yes, it's going to be a 4@ 235 6v, 12v bank w/470ah FLA. They do warn not to over voltage (the controller) but I won't be anywhere near the 150v the controller is rated.

Jim, you're right. I'm going to mount them flat and the easiest way possible at first. I may change it around someday but I don't think it'll be necessary at first to fully charge my bank..

I didn't think to check the warranty before I posted but I went back to Amazon and asked the seller to post it. (Amazon said to contact the seller for warranty info). There's always the 30 day Amazon return policy but I doubt the system will be running that soon. It may be a deal breaker depending on the seller response..

 

[MotorVation]

Personally I'd stick to my Victron reco in #11. More recent design and electronics, likely a bit more efficient, maybe quite a bit at the higher Voc with those panels.

Plus not overpanelled, so capture all the peak output.
But that Tracer unit's likely to be just fine too...

John,
The Victron looks good but I would have to buy two of them. I understand that it would actually be better to do it that way but I'm trying to keep the cost down

Thanks...

 

[John61CT]

Yes, 2 units with shipping is ~$323

 

[Canine]

MotorVation, I wasn't referencing volts, I was referencing watts. I meant that the controller is rated for only 520 watts which means 590 watts of panels is too much. Sometimes it depends on how many volts the battery bank is, but in your case, it doesn't matter, so we can ignore the volts of the battery bank. However, jimindenver said overpaneling is OK as long as you don't have more than 1560 watts of panels.

What overpaneling means is when the panels are at full sun and making the most power, you won't be able to use 70 watts of power from the panels- you would only be able to utilize 520 watts (590 watts from the panels minus the 520 watt limit of the charge controller). That's the bad news. The good news is at least you won't be burning up your controller by having too many watts of panels. If you want to get the most out of your panels, you will need a larger controller. Or better yet get two controllers. Or better yet get two controllers that are networked together.