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pteck · 07-03-2017, 06:57 PM

I've heard it said that the money spent on an mppt controller could more effectively gone towards a 3rd panel. Though I've also read that some controllers may charge the battery bank more effectively to 100% capacity (ie higher voltage). Wasn't sure if this was a function of a quality controller vs mppt.

TravlinMan · 07-03-2017, 07:07 PM

Well I'm hopin someone who understands the technology a little better will help ya out but I do know the 30 amp pwm with LCD is a good charger it was the one that came with the unit and I still use it with my truck and my aux battery.

But the rover was 120 so not that bad. I just needed 2 controllers so when I bought a 2nd I bought what I am told is better technology, mppt, and it does seem to do a very good job on cloudy days, better than my pwm. But the pwm can handle 1 more panel cause it's 30 amp.

So it depends what your goal is.

gandttimes · 07-03-2017, 08:41 PM

If you go to bogartengineering.com. support and frequently answered questions on the sc2030 you will find a good explanation of the PWM vs MPPT. good points for both depending on application

TravlinMan · 07-03-2017, 08:49 PM

Quote:

Originally Posted by gandttimes

If you go to bogartengineering.com. support and frequently answered questions on the sc2030 you will find a good explanation of the PWM vs MPPT. good points for both depending on application

This was very helpful, thank you.

pteck · 07-04-2017, 08:53 AM

That synopsis was perfect. That tells me that PWM is not wholly inferior to MPPT and that I surely could be better served by sinking the cost premium into another panel.

TravlinMan · 07-04-2017, 09:43 AM

What panels you gonna buy? My new eclipses arrive tomorrow, I'm excited but I still wonder if I shoulda got flexible ones, everyone just says they ain't that great yet but the review ain't bad.

I'm still thinkin of gettin one flexible for the truck and seeing how it does.....

rodsterinfl · 07-04-2017, 10:00 AM

I have two Renogy 100watt suitcases and I added two quick-connects to each side of the battery case. They both have controllers and can keep my batteries up with the roof solar quite well. I haven't used them enough to know about full recharge yet but I would recommend Renogy. On the MPPT and PWM thing, two solar engineers (Zamp and Renogy) told me that in small systems, the difference is negligible.

TravlinMan · 07-04-2017, 07:28 PM

Ya see this is why I stick with Velcro and quick connects cause I'm still learnin, the technology is movin quick and I don't wanna permanently install the wrong stuff.

TravlinMan · 07-05-2017, 10:51 AM

Also for anyone that's cheap like me, the little plastic folder ya got from airstream with all the manuals in it makes a great carryin case for a controller and extension cable.

TravlinMan · 07-05-2017, 11:16 AM

Quote:

Originally Posted by gandttimes

If you go to bogartengineering.com. support and frequently answered questions on the sc2030 you will find a good explanation of the PWM vs MPPT. good points for both depending on application

So, my panels are 21v at open circuit. if I run em in parallel, which I do, and they usually show a readin of 15-18v dependin on sun, seems like my mppt is the better choice? If I rewired them in series I'd be feedin it 5-7 amps at up to 42v instead of 10-14 amps at up to 21v.... Would series be better with my mppt controller that has a max voltage of 100? Right now I have em connected with a 30' 8 guage wire to the trailer controller. Seems like I don't need to have thinner wire or more wirin... Which is a point for the pwm?

I don't have a ton of knowledge on this stuff, I just know what's been workin for me so far.

**Rocinante** · 07-05-2017, 04:03 PM

Series can be better if you've no shade issues, and the higher voltage from panels in series can reduce DC losses en-route to the controller if your cables are a little thin. (This assumes your controller can handle the higher voltage.)

Parallel can be better if one panel gets shaded, but the lower voltage means that in general you should try to use thicker, heavier gauge, cables to reduce losses between the panels and the controller.

With shade you lose output either way, but with parallel, if one panel is shaded the other panel still produces full output. With series, one shaded panel will more severely reduce total output.

TravlinMan · 07-05-2017, 07:45 PM

Quote:

Originally Posted by Rocinante

Series can be better if you've no shade issues, and the higher voltage from panels in series can reduce DC losses en-route to the controller if your cables are a little thin. (This assumes your controller can handle the higher voltage.)

Parallel can be better if one panel gets shaded, but the lower voltage means that in general you should try to use thicker, heavier gauge, cables to reduce losses between the panels and the controller.

With shade you lose output either way, but with parallel, if one panel is shaded the other panel still produces full output. With series, one shaded panel will more severely reduce total output.

Thank you, that makes sense. My cables are all 8 guage on the trailer and between panels, though the controller I use for the truck is 12 guage but I only use 100 watts for that.

I'm gonna have to do a bunch of experimentin with my 2 controllers and 4 panels.... it's fun though!

TravlinMan · 07-08-2017, 08:29 AM

Well I have to say I'm very impressed so far with these renogy eclipse panels. They are so much lighter and easier to move around than the portable one is. I'm glad I got these and not flexible ones cause these are easier to make legs and stands for. I'm still testin output but they seem to output more amps than my old 100w suutcase, too. Great deal for 175 each.