So I currently have 300w(2 each 150w panels), a Samlex 30a Controller. It feeds 4ea. 6v batteries in series and paralleled. My rig came prewired for Solar. It has the Samlex panels and the Samlex wiring from the panels to the controller. Then the pre-wire from the controller to the battery is 8ga. Probably about ten feet from the controller to the battery. So my plan is to add one more panel and add an MPPT controller. Thinking I will move the controller closer to the batteries, say with in 5 feet and use 6ga. wire. I will rearrange the layout of the 2 panels that are there to allow room for the new panel and the installation of a Fantastic Vent over the bed for ventilation. There is tons of room in the truss area to run wires and with the new hole in the roof for the Fantastic Vent this will ease the wire running too. So, my questions are:1. What's the best MPPT Controller out there?2. When I put the third 150w up on the roof, how do I gather up all the solar output wires from the panels and get them into the controller? Thinking most of the Controllers have one or two input ports for the panels.3. Are most cables from the panels large enough? Seems to me these are 10ga. from my Samlex panels? 4. Are all panel cables interchangeable? Are there aftermarket cables that are 8ga? Would that be necessary if it were possible?5. When I move the controller down closer to the battery, the cables that come from the panel to the controller will now be longer. How much will that affect the charging with longer cables from the panels to the controller?Thanks in advance!

Are those 150w panels "12v" or "24v" is the first question. Second is what is the brand and model of the controller (Edited) you have now, so we can read up on its manual for its specs etc.I can explain how MPPT works for "amps to the battery" vs PWM , but first answer my questions above. Thanks.

I would not go MPPT with a 12v panel system. If your panels have MC4 connectors you can get a 3 into 1 connector and some #8 MC4 cable for the run down to the controller.If the panels have the same ratings and you are going series I recommend a Morningstar MPPT controller. Others are good too.

"Ass-uming" 12V panels...#1: It depends on your criteria of "good" and your budget. Off the top of my head, EP 30 will do, subject to input volts limit (BFL probably remembers that number). Morningstar Tristar 45 will be nice, for much more money.#2: Controllers normally have ONE input for panels, i.e. Pos and Neg. Any combining of panel wires is normally done on the roof waay before the controller. In case of series it's just plugging panels pigtails one into another.#3: Normally, panel pigtails are #12 or #10. Plenty thick for series, not enough for parallel 3*150W.#4: Did you mean "MC4 extension cables"? Yes. Panel pigtails - not really, because they are normally soldered to the panels. Yes, there are #8 extension cables with the same MC4 connectors (again, "assuming" you have MC4 since you didn't tell this). No, #8 is not necessary for series 3*150W, but for parallel you might need to combine pigtails into #8 or #6 before routing into the trailer.#5: Will hardly affect in series. In parallel you might need combiner box and #6-#8 cable.

Victron MPPT seem to be well thought of.

BFL13 wrote:Are those 150w panels "12v" or "24v" is the first question. Second is what is the brand and model of the controller (Edited) you have now, so we can read up on its manual for its specs etc.I can explain how MPPT works for "amps to the battery" vs PWM , but first answer my questions above. Thanks.Mine are 12v panels and the controller is a SCC-30AB

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Vintage465
Nomad
Dec 07, 2018
allen8106 wrote:
Vintage465 wrote:

So, my questions are:
1. What's the best MPPT Controller out there?

2. When I put the third 150w up on the roof, how do I gather up all the solar output wires from the panels and get them into the controller? Thinking most of the Controllers have one or two input ports for the panels.

3. Are most cables from the panels large enough? Seems to me these are 10ga. from my Samlex panels?

4. Are all panel cables interchangeable? Are there aftermarket cables that are 8ga? Would that be necessary if it were possible?

5. When I move the controller down closer to the battery, the cables that come from the panel to the controller will now be longer. How much will that affect the charging with longer cables from the panels to the controller?

1. Morningstar, Tristar model.
2. Needs to be combined into the wiring setup prior to going to the controller.
3. Mine are 6 ga from combiner box to controller and 10 ga from panels to combiner box.
4. I got nothing for you on this one.
5. You need the controller as close to the batteries as possible so that should be your priority. the length from the panels or combiner box is secondary.

Thanks for the great feed back. Gonna plan on using the 2-#8 wires as P.V. wires from the existing controller location(over the bed) to the new controller location in the pass thru as close to the batteries as possible. Looking forward to getting this project underway!
allen8106
Explorer
Dec 05, 2018
Vintage465 wrote:

So, my questions are:
1. What's the best MPPT Controller out there?

2. When I put the third 150w up on the roof, how do I gather up all the solar output wires from the panels and get them into the controller? Thinking most of the Controllers have one or two input ports for the panels.

3. Are most cables from the panels large enough? Seems to me these are 10ga. from my Samlex panels?

4. Are all panel cables interchangeable? Are there aftermarket cables that are 8ga? Would that be necessary if it were possible?

5. When I move the controller down closer to the battery, the cables that come from the panel to the controller will now be longer. How much will that affect the charging with longer cables from the panels to the controller?

1. Morningstar, Tristar model.
2. Needs to be combined into the wiring setup prior to going to the controller.
3. Mine are 6 ga from combiner box to controller and 10 ga from panels to combiner box.
4. I got nothing for you on this one.
5. You need the controller as close to the batteries as possible so that should be your priority. the length from the panels or combiner box is secondary.
Almot
Explorer III
Nov 30, 2018
My budget is actually flexible since I’m going to be doing this over few months. If something is $300.00 more and there is a night and day improvement, then yes. If something is $300.00 more and there is a fractional improvement, then obviously, no.

EP Tracer 30 MPPT costs $150 on Amazon EP 30.
Can't comment how much improvement this would be, neither your Samlex or EP 30 are top-notch. Main difference (in this scenario) would be MPPT vs PWM, and the ease of series wiring with MPPT. Morningstsr 45 MPPT costs over $400 and is reportedly better than EP. Though I doubt that MPPT in itself would get you a lot more solar harvest with these panels, no matter what MPPT model.

Hard to tell more when it's not clear what connectors your panels (and extension cables) have.

Btw, I am also being seen as a bot in the last few days - don't know why.
CA_Traveler
Explorer III
Nov 30, 2018
BTW US and I suspect Canadian residential power is 120/240V so less than 1.5A to the grid. :@ :h
CA_Traveler
Explorer III
Nov 30, 2018
BFL13 wrote:
Vintage465 wrote:
Another question I would have is the actual charge that the controller puts out. I've heard that 14.4v is acceptable. Then I read that Trojan recommends 14.8v. I dont see that any of the units I check out have the charging volts in their specs?......................... Are any of these adjustable? And I mean fine tune adjustable, like from 14.4 to 14.8 and not from 12v to 24v selections.

thanks,

You have just revealed that you have not read the manual for your controller.

Last post from me because of that :( --check out table 6.1 !!!!!
Be nice - I actually started to read the manual you posted BUT one of the first diagrams shows grid tie with a 30A controller and a DC to AC converter. Really? One would use that controller to supply less than 3A 120V AC to an inverter with no battery??? Not to mention grid tie... And my blood ran cold with the bypass diode explanation. For fairness I scanned more pages and it appears to have hopefully good information. But the manual to me in general should be questioned.
Vintage465
Nomad
Nov 30, 2018
red31 wrote:
Vintage465 wrote:

#2. The installer of the panel did not combine the solar panel wires on the roof, nor did they utilize the factory installed collector box. They actually ran the panel wires under the factory installed box for one reason or another and I really can’t tell how they are gathered prior to the controller input.

let us know when you figure it out. Do the panels connect to additional wire via MC4?

I'll have to find out this when I dig in a bit.
Vintage465
Nomad
Nov 30, 2018
BFL13 wrote:
Vintage465 wrote:
Another question I would have is the actual charge that the controller puts out. I've heard that 14.4v is acceptable. Then I read that Trojan recommends 14.8v. I dont see that any of the units I check out have the charging volts in their specs?......................... Are any of these adjustable? And I mean fine tune adjustable, like from 14.4 to 14.8 and not from 12v to 24v selections.

thanks,

You have just revealed that you have not read the manual for your controller.

Last post from me because of that :( --check out table 6.1 !!!!!

Thanks for that bit of info. Just looked it up and good to go @ 14.8. I've read that page before but only to select "flooded" and not voltage amount. Your delivery wasn't the nicest......this is just for fun you know.......no one got their thumb smashed in the exchanges.....no reason to get that frustrated.

Thanks,
red31
Explorer
Nov 30, 2018
Vintage465 wrote:

#2. The installer of the panel did not combine the solar panel wires on the roof, nor did they utilize the factory installed collector box. They actually ran the panel wires under the factory installed box for one reason or another and I really can’t tell how they are gathered prior to the controller input.

let us know when you figure it out. Do the panels connect to additional wire via MC4?
BFL13
Explorer II
Nov 30, 2018
Vintage465 wrote:
Another question I would have is the actual charge that the controller puts out. I've heard that 14.4v is acceptable. Then I read that Trojan recommends 14.8v. I dont see that any of the units I check out have the charging volts in their specs?......................... Are any of these adjustable? And I mean fine tune adjustable, like from 14.4 to 14.8 and not from 12v to 24v selections.

thanks,

You have just revealed that you have not read the manual for your controller.

Last post from me because of that :( --check out table 6.1 !!!!!
CA_Traveler
Explorer III
Nov 30, 2018
Ideally the controller should charge to the battery specs. That includes bulk, absorb, float AND have remote battery voltage sense and temperature sense.

But 14.4V will get the job done even if not ideal.

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