OK. So I have these panels. 280 watt LG,s I currently use one with an ecoworth 20 amp mppt. Max volts is 50 volts for controller hence one panel..I can get 17 amps or so out of it normally...This is panel specs..Max Power Voltage (Vmp): 31.5 VoltsMax Power Current (Impp): 8.97 AmpsOpen Circuit Voltage (Voc): 38.9 VoltsShort Circuit Current (Isc): 9.56 AmpsSo I want to carry another panel and upgrade the mppt. I would assume I should get a 40 amp..I was looking at the cheap tracers, or the renogy rover..Since this is my first solar set up I have nothing to compare it too.. so here are some questions I have..1. Does the one panel above specs dictate that 17 amps is about the most I can get from just the one? I figure IMPP at 9 amps im kind of doubling it because of the higher voltage panels and I only need 14.8 for bulk... I dont quite understand it somewhat.( Side note: When I was 5300 ft in NC I was blasting out 19 plus amps at 5pm...lol. Panel showed 240 watts.You see how late in the day it was... ( Balsam Mountain NC)2. With that said if I get normally 16 amps then if I use 2 panels and get a new controller (40amp) then I should be looking at 32 amps or so.. Does this sound correct?3. Here is the kicker and I probably will not know until I try.. I this I need to understand .. If I have two identical panels as specs show above, Would I get more amps putting the two panels in series . Putting in series would get me closer to the max 100v the controllers could handle. Or, Put two in parallel? Will that net me max amps since this method doubles the amps.4. The other trouble is both controllers I believe have a max of 520 watts. ( Ill have 560 watts) This large panels are portable. I am not interested in more then two panels...Eventually I have a plan for flex panels on the roof with a separate charge controller. But that will be another time.

Two in parallel is the same voltage but double the current. Two in series is double the voltage with the same current as one. Either way gives the same capacity.

I would be inclined to put the two panels in parallel. If two panels are in series, your current will drop to the output of the lower panel. If even a few cells are in shade the current will drop quite a bit.

I dont think ill have a shading problem as I will be moving them around..Same exact panels/specs.so 62 volts and 9 amps with series through mppt will produce what amps out?31 volts, 18 amps in parallel through mppt will produce what amps out?Is it a wash that they will both produce @ max 560 watts?560 watts / by 13.5 volts = about 40 amps... series Say it was 66 volts.. 66v - 13.5v = 52 volts. What is the math equation to determine how many amps does the mppt convert the remaining 52 volts to?Parallel it would be 33-13.5 = 19 volts left. But 18 amps... Whats the math...I just dont get it... Using the above #'s as an example..Or can we say it this way... What configuration will produce the most wattage... 560 watts / 13.5v = 41 amps...After all in the above pic in my first post, with one panel I was producing 240 watts @ 12.5 volts = 19.2 amps...

If you disregard losses through the wire, both series and parallel would result in the same amps going to the batteries. Each panel will produce about 9 amps at 31 volts. Parallel totals 18amps x 31volts = 558 watts. Series totals 9amps x 62volts = 558 watts. 558watts / 12volts = 46.5amps to the batteries. Connecting the panels in series will reduce the voltage loss in the wire from the panels to the controller. The result will be more amps delivered to the batteries. How much more will depend on your wire size and length of wire.

I’ll have to measure the wire. I believe it’s about 40 ft of 8 gauge. Would it be true series would get me charging earlier and better I low light conditions. ?

Solar question. Two panels same 24v , Series/parallel math

lawrosa
Explorer
Dec 28, 2017
Oh the 150v thing... good catch... I didnt really notice that... Probably why it has a huge heat sink... I thought it was the newer version of the A series... OK..
BFL13
Explorer II
Dec 28, 2017
Stay in parallel and save money by using the A. The BN can do 150Voc while the A does 100. Only matters if you go high in series.

A couple of "24s" in series is ok with the A but not three. I run three "12s" (23Voc each) in series with the A no problem, but prefer parallel anyway for any shading issues. Same amps no shading. More amps if part shaded when in parallel.

The 50 more Voc costs a bunch more--you can buy fatter wire for the array to controller if needed in parallel for less than that.

You have to know what is "good enough" for your scenario and not pay for more than that. Nobody else can know what you think is good enough :)
lawrosa
Explorer
Dec 27, 2017
OK I got the green light from the admiral to get my MPPT..

I have one question...

Should I get the Tracer A series?? 169$ with everything..

http://www.epsolarpv.com/en/index.php/Product/index/id/653/am_id/134

https://www.amazon.com/EPEVER-Controller-Display-Battery-Charging/dp/B077HHYYHT/ref=sr_1_10?ie=UTF8&qid=1514408878&sr=8-10&keywords=EPEVER+40A+MPPT

Or whats the difference in the BN series... I see 219$ for everything?

http://www.epsolarpv.com/en/index.php/Product/index/id/571/am_id/134

https://www.amazon.com/EPEVER-Controller-Regulator-Battery-Charging/dp/B077HQPV1Y/ref=sr_1_10?ie=UTF8&qid=1514421847&sr=8-10&keywords=tracer+4215bn

Im trying to read through the spec but am not sure why they carry two same units that do the same thing... maybe I am missing something IDK...
BFL13
Explorer II
Dec 21, 2017
lawrosa wrote:
Whats disturbing with the EP units is the reboot issues and the trouble to find max powerpoint...

Also over heat issues..

Ill have to test my eco, but I would say the eco has been flawless in this are..

Im going to hold off on an EP and look elsewhere... Ill need to re read this thread as I know someone mentioned the Renogy rover flaws...

https://www.youtube.com/watch?v=dFuZywwpfaU

I have the same Eco-W 20 amper and the Tracer 2210A and have run both off my 255w panel (taking turns depending on what I am doing with my 12v panels) with no such issues for two summers now. They get the same results for daily AH haul.

The place I got the Tracer 20 amper said their tests showed the 30 amper was a bit better than the 20 in some respect, I forget what, but ISTR it was the tracking speed.

The thing is, as an RVer you won't notice any of that. You do not have lab equipment and recorders. You are just camping and getting some sunshine to recharge the batts somewhat. For that, almost any controller will do.

IMO ignore all scientific "purist" talk about tracking speed or whatever, and see it in the context of your own typical camping day with solar. Mostly make sure you have the voltages that match the charging specs of your batteries.

In my case, the 12v AGMs and the Wet batts I have all call for 14.8 Vabs and a 13.7 Float (at 77F) so the fixed Tracer is just right set at Wet even for my AGMs, and the Eco-W is adjustable to that (except Vabs time is nil, so if you want any, you need to set Float at its highest of 14.5, and then drop that to 13.x later if it is not dark yet.)

With the ability to adjust the Tracer's charging profile you can't go wrong for any battery specs.

There are no doubt other controllers that are just as good or better, but there is no sense getting "features" for more money that won't do you any good in real life. Of course people do that all the time, being people. Got to have a 4x4 to go to the grocery store and back. :)
lawrosa
Explorer
Dec 20, 2017
Whats disturbing with the EP units is the reboot issues and the trouble to find max powerpoint...

Also over heat issues..

Ill have to test my eco, but I would say the eco has been flawless in this are..

Im going to hold off on an EP and look elsewhere... Ill need to re read this thread as I know someone mentioned the Renogy rover flaws...

https://www.youtube.com/watch?v=dFuZywwpfaU
lawrosa
Explorer
Dec 20, 2017
MEXICOWANDERER wrote:
Site Q & A

Ask how a warranty proceaa would work

I think its from amazon...Y solar who sells it is in china.. Comes with two year warranty... But since fulfilled by amazon I would assume you go through them...

Reviews are so so but it depends on what you read... Getting hot is an issue it seems and its slow to track... Something with the power point and reboot issues...

Im not sure how to compare that to the eco I have... My eco gets hot too, but no issues.. Im not sure how to compare my eco to its tracking ability..
MEXICOWANDERER
Explorer
Dec 20, 2017
Site Q & A

Ask how a warranty proceaa would work
red31
Explorer
Dec 20, 2017
some CC seem to have decent set pts and short abs time, that is what I adjust

momma said there would be days like this

after a few days like that longer abs time is in order for me.
pianotuna
Nomad III
Dec 20, 2017
Make sure the charging voltages can be adjusted.
lawrosa
Explorer
Dec 19, 2017
Is this a crazy deal??? Fufilled by amazon. 40 amp, MT50 and temp probe...

Should I be wary?

https://www.amazon.com/EPEVER-Controller-Display-Battery-Charging/dp/B077HHYYHT/ref=sr_1_6?ie=UTF8&qid=1513731197&sr=8-6&keywords=EPEVER%2B40A%2BMPPT&th=1

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