New Solar Panels

[terry735001]

Originally Posted by johnnyreno

Nice until the hail storms hit..or falling coconuts Jus Saying I know for a fact I will break them so I opted out I will run the genny im not worried about the ozone layer and neither are the Chinese who mfg. most of the components on them

thats why you go for the sharp 80 and 120 watt made for RVs and water craft there made to take some really bad hits from trees and hail .. i know and have did and see this with my set if one is lost i can do what i did to get my set go on CL and 80 to 125 $ used here in FL as there every where

[CJBROWN]

Wow, some very useful info here.
The controllers Ronogy is selling look exactly the same as those coming in from china called 'Trace' controllers.

What I'm confused about is just how much difference I would see in amp output over a solar day using 2 100 watt 12v mono panels with a pcm controller, or one 230 watt 35v poly panel with a mppt controller?

Also it seems any controller 20a or smaller is going to limit me to about 300watts of panels, so no expansion beyond. I may not need it, but would have to replace everything or use a parallel system to add on. I'm understanding this correctly?

Looks like another importer with some excellent reviews is Eco-Worthy. they have a 20amp mppt controller that will handle about 300 watts of PV. Either of these smaller controllers could be hooked up with one large grid-type panel.

Lots of comments saying poly panels are better if there's any shading or cloud cover, mono puts out more when there is good light. And MPPT not making that much difference on low-voltage panels where there just isn't that much more voltage than what you're trying to put into the batts.

[caissiel]

Originally Posted by CJBROWN

What do you guys think of this one?
MPPT 20A Solar Panel Regulator Charge Controller Power Boost Remote Meter LCD | eBay

That's a 20a mppt controller with remote meter for $159. They have a 10a for $115 and 40a for $229.

This way any panel could be utilized.

I have bought a 200 watt kit with the same 20 amp MPPT controler.
Its working well and keeping my 3 batteries fully charged. Much better then using the generator for 4 hrs a day and seeing the batteries at less then 90% charge.
I have option to tilt and never done it due to batteries charged fully by 2 pm in winter here in the south.
We use a 29 in LED TV all night and charge our cellphones and computers with a 300 watt inverter.
I see 17 volts at noon and batteries at 14.7 volts most every afternoon. Barely saw 12.3 volts using the generator.
I would run the generator after the sun has maxed out.
My system is installed on the roof and out of site and almost forgotten.
It's so easy to boondock for a week and leave with fully charged batteries.
The remote e-meter is easy to use and give so much information.
My package is possibly the units used for road signs as the instructions are using the systems for sample explanation.
I should not say that. People will steel those for RVs. But if it's good to use year out its good for me.

[Luv2go]

Originally Posted by CJBROWN

Wow, some very useful info here.
The controllers Ronogy is selling look exactly the same as those coming in from china called 'Trace' controllers.

What I'm confused about is just how much difference I would see in amp output over a solar day using 2 100 watt 12v mono panels with a pcm controller, or one 230 watt 35v poly panel with a mppt controller?

You should get a little more output from the MPPT setup, mostly due to the higher wattage panel.

Originally Posted by CJBROWN

Also it seems any controller 20a or smaller is going to limit me to about 300watts of panels, so no expansion beyond. I may not need it, but would have to replace everything or use a parallel system to add on. I'm understanding this correctly?

Yes.

[unyalli]

For the PWM vs MPPT question go here Click.

[CJBROWN]

Originally Posted by unyalli

For the PWM vs MPPT question go here Click.

Yeah, I've read that thread. In fact most all of them on the forum and now researching solar forums and google searches.

That demo is still not totally clear for me. Yes, I understand he's getting a bump by switching to a different controller, but that doesn't take into account using different wattage panels and differing brands of controllers. He has a side by side with VERY low wattage and amperage. So I'm just not clear on that from the two vids.

I understand how mppt works - taking excess voltage from a panel and converting it into extra amperage to feed the charge. That doesn't take into consideration what the bank is able to absorb though. From what I gather you have to use mppt if your panel voltage is over the rated max for the controller, and that the most improvement in performance is when the panel volts are double the charge volts - that way it has something to use to boost more power.

I'm not really getting it for low-voltage panels other than they are a little more efficient.

I was all ready to buy a morningstar sunsaver duo since everybody seems to rave about their products. Then max out the panel amps to it. Depending on whether they are mono or poly, about 400watts for the 25a controller. I like that it has the second battery terminals to include the chassis batt too.

It looks like I could go as many as three 120 or 140 watt PV's, depending, and start out with two add one if we find we need it. When it gets hot out we have to run the gen for the AC anyway, so may not have to solely rely on solar to keep the batts up. We've lived with the 2 GC batts for 5 years now with a totally crappy converter and no solar - so any added charge amps from PV's is just gonna be a bonus. And we don't have any trouble getting through the night running the furnace (8ah rated for 35Kbtu) even when it's been near freezing. I would like to be able to run the TV inverter though and I think it's 400w, which should be no problem for a couple of hours as long as we start out fully charged.

Seems people are having good luck with the cheap chinese controllers - Eco-worthy, Trace/Renogy, even some of the really cheap ones off ebay. I would at least like to see some good user reports on an off brand, but seems Morningstar is just so popular it's hard to buck the trend. It seems the overall performance is better with them than even the cheap mppt's since they don't hold the higher voltage while in absorbtion mode anyway. In other words, the charge programming may not equal what the established brands are able to produce.

I really don't want to tinker nor do it over, just once thank you, and have it work.

I wish someone with real experience and authority (other than handybob LOL) would come along and say something like, "Oh, mppt is just newer technology with a much higher performance level and it is hands down the best way to optimize solar charging for off-grid battery banks." Kind of like comparing a 1964 ford falcon to a 2014 mercedes benz dfi 6-cyl. Or carburated vs fuel injected - easy to tell which one provides more accuruate fueling, and more advanced performance and economy.


EDIT: just did some rough calcs...
TV inverter - 400w for 3 hours = 11ah
Furnace - 8a for 4 hours (liberal est) = 32ah
some lighting, water pump...what else? = 5ah
Total overnight = 48ah
certainly do-able for 220ah battery bank and 200-300w of solar PV's.
Or am I missing something?

[MRUSA14]

Yes, you missed something on the TV. 400W/12V=33A per hour or 100A for 3hrs, plus some for inverter losses.

[CJBROWN]

Originally Posted by MRUSA14

Yes, you missed something on the TV. 400W/12V=33A per hour or 100A for 3hrs, plus some for inverter losses.

So I'm thinking about a led flat screen that will probly only use half the inverter, couple hundred watts. Does that mean the inverter uses less too?
Converting watts @ 110 is not the calc, it's watts @ 12V? I guess that makes sense, you're taking 12v's and making 110 out of it - uses a lot to do that.

So if we rolled 110v back to 2 hours at 200w then the picture improves a lot. Would probly use some back charging phones, tablet and laptop.

Forget the TV eh? LOL

I was thinking about one of the propane catalytic heaters but the furnaced isn't such a big consumer afterall, and it's 12v.

Seems the big issue is trying to power 110v appliances with 12v. And people wanna put their house fridge in their camper...

[hogdriver]

I'm gonna look for one of these instead of panels.

[Shadowcatche]

As I have said else where we have a 185W 66 cell high voltage panel which required an MPPT controller to handle the 41V. Typically a nominal 17V panel is dead when shaded to any extent, not so with the 66 cell. I have seen it produce 17V under a full moon. AM good discussion PMW vs MPPT https://s3.amazonaws.com/ecodirect_d...WM_vs_MPPT.pdf

[CJBROWN]

Originally Posted by Shadowcatche

As I have said else where we have a 185W 66 cell high voltage panel which required an MPPT controller to handle the 41V. Typically a nominal 17V panel is dead when shaded to any extent, not so with the 66 cell. I have seen it produce 17V under a full moon. AM good discussion PMW vs MPPT https://s3.amazonaws.com/ecodirect_d...WM_vs_MPPT.pdf

Good article. Still not definitive for 12v PV's for RV application though. What is interesting is the charge tables look like alkaline battery output compared to nickel-metal or lithium. LOL.

It seems like mppt is a more advanced technology for harvesting PV power, so also seems like the best choice. In choosing an mppt controller then one has to consider whether to take a chance with less expensive chinese imports or one of the US designed/built established units - like morningstar, bluesky, xantrex, etc.

It tempts me to choose eco-worthy or trace for an mppt controller to save $$ - they are fairly comparable to the established brands of pwm controllers, something 25-30a with a remote meter, and then match up to a high voltage grid-style panel(s). An eco-worthy 25a mppt and a 230w grid panel might be an unbeatable combination. As long as the controller doesn't fail prematurely and fry $250 to $450 worth of batteries.

[Riggerone]

Hi Chris,

I was looking at this thread and thought I would my two cents. I went with 24v 235watt panels because of the price ( which was the same for 150watt panels at 12v). I bought two and they do take up some real estate on the roof but thought it was well worth it. This negated any decision on On my way! vs MPPT as I needed to convert 24v to 12v. I bought the Morningstar MPPT 60 based on Handy Bob's blog. You may not agree with his rant but he is right. I wish I had paid more attention to his blog before I had purchased a No Power inverter. This winter I recorded 15.6 volts in the batteries at about 0 degrees F. The inverter would'nt kick in. Luckily I was not using the coach at the time. If you can afford it, get the Morningstar. The capability built into the controller is amazing. I also have a Tri-Metric TM-2025 system monitor. The day we turned the system on at 6:30 in the evening I recorded 14 amps going into the batteries. One other thing, I had checked the monitor after a light snow fall of about 2 inches on the panels, they were still producing about 2 amps. Oh, and the little twelve volt lights in your coach burn up 2 amp hours per light unless they are LED lights.

Tony

[unyalli]

Midnite has closed the book IMO on charge controllers with the introduction of the WizBang Jr. (Nice name, they have a sense of humor.)

You can now tell with no guessing when your batteries are charged and switch to float. If its the middle of the afternoon on a sunny day and you are drawing some power say for the crock pot and stereo etc your solar controller does not know this. All it knows is there is a draw so it pulls from the panels. With this device it now knows how much of this draw is going to the batteries. You can set this "ending amps" so it will switch to float even though there is significant power sill being drawn. This is a game changer big time. I would seriously look at their new Kid for your 200 AH battery bank.


-Jeff

[CJBROWN]

Seems like good electronics.

Their least expensive controller is $400, plus $60 for the Wizbang unit, so $460 before you even buy panels.

Evidently they feel their product does the job and warrants the cost. I would be curious to compare to MorningStar controllers on comparable panels, both 12v with pwm and 24-48v with mppt.

I guess they also series wire 12v panels for higher voltage when mppt is used.