Jump to content
Randyretired

Solar controller recommendation

Recommended Posts

I just purchased 4 solar panels and I am looking for a controller for these.

Pmax 1000V 265 W* (0%, +5%) 30.96 V 8.56 A 38.14 V 9.1 A 16.21% -0.33% /ºC +0.058% /ºC -0.43% /ºC

These will charge 6 GC2 6 volt batteries wired for 12 volts.  Originally I was looking at an Outback 80 amp controller but that controller is limited to 1,000 watts.  These panels are 1,060 watts. I was thinking of this https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F262594343468.

but I am open to suggestions.

Share this post


Link to post
Share on other sites

Don't worry about a specific wattage because you'll never see 100% efficiency and most times on the wattage side, that's just an estimate. The more important number to worry about is the input voltage. You want to make sure even if you add up the short circuit voltage, you stay under that. Of course arranging panels in series vs parallel can help vary the voltage or amps depending on how you wire them. 

I'm feeding 800w into the Victron 100/50 which is rated at 700w and no issues. In fact I've even seen more than 700w from it and 47amps charging. If you max out on watts, it will just bleed off the extra. 

I like the Victron controllers myself. 

The Victron 150/70. It looks like though you'd be slightly over 150v with the short circuit voltage if you went strictly series, so would probably need to go 2S2P panels or 4p panels. - https://www.amazon.com/Victron-SmartSolar-Charge-Controller-150V/dp/B07B4K62LN/ref=sr_1_fkmrnull_2?keywords=victron+smart+solar+150%2F70&qid=1549852630&s=gateway&sr=8-2-fkmrnull

There is the Victron 150/85 which gives you a bit better charging amps and more capacity although I really doubt you'll see the extra. You are still limited to the 150v though. 

 

Edited by BlueLghtning

Share this post


Link to post
Share on other sites

Looking at the numbers, say all your panels were actually producing 1060 watts (yeah right good luck with that as it depends on sun and angle and efficiency) and lets say you were charging those batteries at 13.6 volts, 1060/13.6 (typical absorption) = 78 amps while 1060/13.2 (typical float) = 80 amps so I would "consider" a 100 amp controller to allow for expansion, although an 80 will most likely get you by as seldom (If ever) will you pump full 80 charging amps due to all the losses and inefficiency.

Subject to how you wire the four panels it looks like a 150 volt max input rated voltage (may be less, depends on how you configure them) controller will suffice and many brands and models will accept that much input voltage (or 24 or 48 etc). It depends on your roof real estate and shading and mounting considerations but it would take an entire strictly series array to achieve near that 150 volt max.   

Of course you will most likely go with an MPPT unit.  

Ima thinkin an MPPT 80 minimum to 100 amp controller that accepts up to 150 input volts will suffice, with of course, smart 3/4 stage charging  and the ability to charge Lithium if ever needed.

Im NOT gonna recommend any particular brand, only the ratings as above. 

PS As a practical real world example when running my 950 watts of flat rooftop mounted panels and MPPT charge controller about the most  charging amps I've reached was 50 amps, NEVER 950/13.2 = 72 theoretical not allowing for loss and inefficiency, meaning an 80 amp 150 volt unit may well suffice for you BUT NO WARRANTY CHECK WITH THE VENDOR NOT ME !!!!!!!!!!!!!

John T

Share this post


Link to post
Share on other sites
14 hours ago, BlueLghtning said:

Don't worry about a specific wattage because you'll never see 100% efficiency...

If you max out on watts, it will just bleed off the extra.

That's the important takeaway, IMO.  For the geeks among us, MPPT controllers handle this scenario by moving Vpanel to a powerpoint where less power is produced.  Normally toward Voc. 

For non-geeks, this is my attempt to flesh out the concept

Don't try this with PWM!

Share this post


Link to post
Share on other sites
39 minutes ago, frater jason said:

That's the important takeaway, IMO.  For the geeks among us, MPPT controllers handle this scenario by moving Vpanel to a powerpoint where less power is produced.  Normally toward Voc. 

For non-geeks, this is my attempt to flesh out the concept

Don't try this with PWM!

Good read, thanks for sharing! 

Share this post


Link to post
Share on other sites

Your responses have been great and I really appreciate your help.  I have narrowed my choices down to 3.

Victron 150 85 @$687

Midnight Solar 150 SL 96A@ $575

Outback Flex Max @ $459

All 3 seem to do about the same thing but there is a significant price difference.  Many have suggested the Victron but is it that much better?  I got these panels for $.35 a watt and I am trying to keep the overall cost down.  On the other hand we will probably boondock all summer and I don't want any problems.

For simplicity and shading I was going to wire all 4 panels in parallel.   The feed to the controller is 12' of #2 copper so voltage loss is minimal.  Each panel will be wired to the combine box with #10 copper.

Edited by Randyretired
Spelling Outback

Share this post


Link to post
Share on other sites
18 minutes ago, Randyretired said:

Your responses have been great and I really appreciate your help.  I have narrowed my choices down to 3.

Victron 150 85 @$687

Midnight Solar 150 SL 96A@ $575

Out Back Flex Max @ $459

All 3 seem to do about the same thing but there is a significant price difference.  Many have suggested the Victron but is it that much better?  I got these panels for $.35 a watt and I am trying to keep the overall cost down.  On the other hand we will probably boondock all summer and I don't want any problems.

For simplicity and shading I was going to wire all 4 panels in parallel.   The feed to the controller is 12' of #2 copper so voltage loss is minimal.  Each panel will be wired to the combine box with #10 copper.

One reason the Victron is so much more is it has bluetooth built in so you can see all your data on your phone in their app and it integrates with a lot of their other products including their battery monitor? What battery monitor were you going to use? The other charge controllers probably show stuff on their screen, but if you want to see like history and stuff, you probably need to add an accessory display controller. I looked and the Outback has a $400+ MATE system display and controller you need. I'm not sure about the midnight solar, but I would imagine it's similar and requires some sort of add on display. The Victron does this all in their app.  That's where some of the price difference comes from. The Victron battery monitor and the Victron Charge controller can talk to each other also and join a "BT network". 

Do you ever plan to expand? the 150/85 gives you room to expand, but the 150/70 would work just fine and it's price of $589 is more in line with the midnight solar at the expense of not quite as much charging capability. However, from the info old John gave you, you would never see that with your setup. Even if you got 950 watts out of the 1060, at 13.6v, that's just 69.85 amps. And by the time you get to absorb, the watts are falling way off anyways. 950 watts at 14.4v = 65.97 amps. The 150/70 however doesn't leave you any room to expand unless you just want to be way overpanled as frater Jason explained.  Some of the others may leave you room to expand especially the midnight solar 150 SL 

If you don't care about the BT you could step down to the Blue Solar 150/70 for $539.75. (https://www.amazon.com/Victron-BlueSolar-MPPT-Charge-Controller/dp/B01E3W6KPE/ref=sr_1_fkmr0_1?keywords=victron+blue+solar+150%2F70&qid=1549908534&s=gateway&sr=8-1-fkmr0)

You can buy the BT dongle for about $50 which is where the price difference comes in between the blue solar and smart solar.  (https://www.amazon.com/Victron-Energy-ASS030536010-VE-Direct-Bluetooth/dp/B01CGFF8Q2/ref=sr_1_1?keywords=victron+by+dongle&qid=1549908597&s=gateway&sr=8-1

I have no experience with the midnight solar or out back, but the Outback has been around a long time. 

Edited by BlueLghtning

Share this post


Link to post
Share on other sites

I wasn't planning on a battery monitor.  This system is replacing a 400 watt "colection" of panels I have accumulated over many years.  In fact, the first 50 watt panel I bought about 32 years ago is up there.  Anyhow I have kinda of learned to keep track of my batteries by voltage readings.

I have updated the spelling of Outback.  Sorry for the error.

Share this post


Link to post
Share on other sites

Have had the Outback, Midnite Solar and now  2 Victons, a 150/70 and a 100/30. Victron''s are a little more money, but much more user friendly, and the bluetooth readout without running wires into the coach a big plus.

Another plus, if your tablet or phone is also on wifi or cell, firmware will automatically update when new versions are released.

Edited by jcussen

Share this post


Link to post
Share on other sites
On 2/11/2019 at 2:32 PM, Randyretired said:

I wasn't planning on a battery monitor.  This system is replacing a 400 watt "colection" of panels I have accumulated over many years.  In fact, the first 50 watt panel I bought about 32 years ago is up there.  Anyhow I have kinda of learned to keep track of my batteries by voltage readings.

 

Well, you certainly will have a much better solar setup. Depending on how it's currently wired, that 50watt panel could be bringing all the other panels down to its level? Do you have multiple controllers now? 

I could have sworn I posted this yesterday, but maybe not? 

How come no battery monitor? 6 6v battery is a decent investment in batteries. I'm running 6 6v myself at 690ah. A battery monitor is the only way to know the true DOD (Depth of Discharge) of your batteries and truly know when they get back to 100%. Voltage is very misleading when the batteries are under load or being charged. Lead Acid batteries like to be kept at 100% and some people say don't take them below 50%. The difference in voltage between being down 75-100ah and charge isn't much. 

Share this post


Link to post
Share on other sites

We are not heavy power users.  The existing system has mostly met our needs with only occasional generator use.  We currently have 4 batteries.  These batteries are 10 years old now and need to be replaced.  If we reach anywhere near 50% SOC I run the generator the next morning while doing coffee.  This usually allows the batteries to be fully charged by noon.  All of our lights are LED and other than coffee and a little TV, there isn't much.  A system about 1/2 the size would probably have worked but the panels were cheap.  I just bought enough to cover the simple to use spots on the roof.  After this summer I don't know how much boon docking we may be doing but we seldom stay in a campground.  We bought 140 acres in the Colorado mountains and we are preparing to build a house on it.  We have septic and will do a well but the county will not let us have electricity until we actually start building.   Thus the solar.  This summer I will finish some fencing and a couple of cattle guards.  Then an outbuilding and road improvement.  Not much time to use power.  That old 50 watt panel has been on 3 rigs but has only spent a little more than half of its life outdoors.  When not in use we keep our 5er and HDT garaged.  The biggest problem with our existing system is the voltages on these panels we picked up over the years vary a little.  A couple of the panels are dragging down the rest.

The differences in controllers over the years is night and day.  Our first system used a relay controller with on/off.  On at about 12.6 and off about 13.8 but we were the talk of the campground as very few had solar.  Back then most of our camping was just a few days then once home the batteries received a full charge.  Our current controller is an older Blue Sky MPPT but it throttles at 13.9v.  Better than the first couple of controllers but still requires a lot of attention with the generator to keep from going to long without a full charge.  I am used to watching battery voltage and adding the generator when needed but I am hoping the new system won't require much.

I sure appreciate everyone's  help and I will monitor this thread for a week or 2 before I purchase a controller.

Edited by Randyretired

Share this post


Link to post
Share on other sites

Randy, of course any of those controllers will "work" it's just that more money gets you more bells n whistles and convenience. That being said, one way to look at it is the Midnight Solar is $575 you will spend anyway soooooooooooo the Victron is ONLY another 112 bucks and with your solar panel bargain prices that's not all that much MORE to spend perhaps???  IE if I was spending 575 anyway why  not invest another 112 for more features???

NOTE My above figures reflective of how I was only getting 50 amps while in theory (not withstanding inefficiency and losses) I was capable of 72 IS FOR FLAT PANELS IN CENTRAL FLORIDA IN WINTER (sun lower in sky) so if it was summer and the sun was more direct overhead, sure I would get a bit closer to the limits of my system. Your case is 1060 watts at lets use 13.2 float volts = 80 amps although you likely wont get that much in the real world, so an 85 amp controller should suffice BUT NOT MUCH EXPANSION CAPABILITY !!!

FWIW I also wired my four panels (940 watts) in parallel and I get by like you by monitoring voltage levels without a battery monitor system but hey Id like to have one as it offers advantages.

When sizing a system I figure one should compute how many amp hours he consumes from say 6 PM to 9 AM and then have enough solar charging capacity to fully recharge his battery bank (plus supply active loads) by morning to early afternoon the next day with enough cushion to allow for cloudy n rainy days.    

FWIW of the three I like Victron for only another $112  but I don't know how many total battery amps you have and all the details.

John T

 

Share this post


Link to post
Share on other sites

Slightly off topic question:

My new to me rig when I get it has a flat mounted Zamp panel & Zamp controller. I also have a Renogy 100 watt portable suitcase kit with a 50 amp controller. Can I also connect the portable set out in the sun when camping in the trees?

 

Share this post


Link to post
Share on other sites
1 minute ago, noteven said:

Can I also connect the portable set out in the sun when camping in the trees?

YES you can. I'm NOT saying its the absolute best and prefect arrangement, but sure it will "work" and provide a degree of additional charging. Its when you try to mix n match different panels all connected to a common charge controller more issues arrive. I understand your Zamp and Renogy each have their own charge controllers.

John T   NOT a solar expert so no warranty, but believe the Zamp and Renogy systems each with their own controller can be connected to your house battery and still "work". I've seen it done quite often.

Share this post


Link to post
Share on other sites
2 hours ago, noteven said:

Thanks John T - yes both systems have their own controller.

You're welcome, different controllers can have different charging algorithms (maybe a tad of interference or mis match) which isn't the ideal perfect situation (but hey you're still gonna get charging from one or the other or both) when two are connected to the same battery, but especially with the relatively small systems you're talking about I don't forsee any major problems subject to the controllers design. As always check with the manufacturers and solar experts, NOT ME lol. 

John T

Edited by oldjohnt

Share this post


Link to post
Share on other sites

Lots of good suggestions above.

I can tell you that the FM80 will handle those panels without a problem. My last system had 1110w @ 90v wired into one and almost never maxed out the controller. I also loved the easy to read display, quickly attainable data,  and low light output when compared to the Magnum PT100 I use now.

Share this post


Link to post
Share on other sites
2 minutes ago, CrazyCooter said:

Lots of good suggestions above.

I can tell you that the FM80 will handle those panels without a problem. My last system had 1110w @ 90v wired into one and almost never maxed out the controller. I also loved the easy to read display, quickly attainable data,  and low light output when compared to the Magnum PT100 I use now.

Thank you for replying.  I was just looking at the data available with the Outback and it seems pretty complete.  The comparable Victron is $200+ more am I am wondering if it is worth it?

Share this post


Link to post
Share on other sites
7 minutes ago, Randyretired said:

Thank you for replying.  I was just looking at the data available with the Outback and it seems pretty complete.  The comparable Victron is $200+ more am I am wondering if it is worth it?

I have no experience with Victron, but the equipment, specs, and color displays look nice. I'll likely give them a try when I build out the next RV.

Low light example.....This morning woke up to 1' snow on the roof, array voltage at 19.2v, and the Magnum was snoozing. I have a pic somewhere of my Outback charging from moonlight just because the array voltage exceeded battery voltage.

Only problem I had was the fan that got noisy after about 58 months which they sent a replacement for and was a 10 min change out without moving the unit. The desert dust may have been its demise? It also didn't completely fail to charge, but output was reduced depending on component temp. Put a 12v box fan next to it and it started increasing current.

Edited by CrazyCooter

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

RVers Online University

campgroundviews.com

Our program provides accurate individual wheel weights for your RV, toad, and tow vehicle, and will help you trim the pounds if you need to.

Rv Share

Dish For My RV.

Find out more or sign up for Escapees RV'ers Bootcamp.

Advertise your product or service here.



×