Solar component(s) help needed

[johnm1]

I keep bouncing back and forth on what to get and need someone to point me in the right direction ... please.

I have a new TT toy hauler. All LED lights, don't want to run 120AC stuff. Have (2) 6v gc batts (new). Camp in shaded areas (not deep shade) in upstate NY and I'm planning on starting with a portable system of 100 to 200W.

I was thinking a MPPT charge controller was better for me, since it supposedly harvests the sun better in shaded areas but I've been reading that the MPPT units don't work as well as the PWM units with smaller PV systems. I don't mind spending more $$ on something like the MPPT but I want it to do what I need it to do.

Which would people recommend for me with the above criteria?

Thanks and I know there will be follow-on questions!

[Almot]

red31 wrote:
view star 20A would be more than adequate for 200 watts
http://www.amazon.com/EPsolar-Viewstar-VS2024BN-Battery-Controller/dp/B00N4PTJWI

Up to 300W - absolutely. Throw in some $40 AH counter if you need battery monitoring that bad.

[grizzzman]

johnm1 wrote:
Smketter ... thanks for that. I think I'm sort of, kind of, starting to understand ... a little. I've been pondering the Bogart 2030 (?) units for the PWM charge controller and battery monitor (sorry, on cellphone and don't have part #'s) since they talk to each other which is nice.

Just so much info out there and lots of people disagree on what's best for this or that. It's hard to find my way through the forest sometimes.

The Bogart system works really well. My first Bogart system (TM 2030 battery monitor and the SC2030 and related parts) was 200 watts on my MH and the plan was to add panels over time.(adding panels on a MPPT controller over time can easily negate any charge advantage. Do your homework) We bought a trailer and I get to start over. This time I will start with 4 160 watt panels flat on the roof using the Bogart system. Why? Its simple when cloudy,rainy weather I will still get enough power to take care of my needs. And as far as adding panels beyond a good controllers ability, An 8$ adjustable voltage/timer can take care of that chore for bulk.

[Almot]

Don, Bogart PWM is a $120 add-on to Trimetric monitor. I doubt that there is 60A PWM with that much auto-pilot functionality for less. Though Trimetric itself is $200 with shunt and enclosure. I'm one of those few who live without battery monitor 😉

If I needed 60-100A controller, I would get either 24V bank or MPPT (or both).

[-Oz-]

johnm1 wrote:
Smketter ... thanks for that. I think I'm sort of, kind of, starting to understand ... a little. I've been pondering the Bogart 2030 (?) units for the PWM charge controller and battery monitor (sorry, on cellphone and don't have part #'s) since they talk to each other which is nice.

I just upgraded to the two Bogart units. So much more information and control even on my small system. I started with a super generic Renogy controller.

johnm1 wrote:
Just so much info out there and lots of people disagree on what's best for this or that. It's hard to find my way through the forest sometimes.

That is because best is super dependent on: future growth, panels you have (will buy), which controller you're buying, wire runs, etc.

As you've seen even in this thread there are good PWM and crappy PWM controllers and similarly there are good MPPT and crappy MPPT. If you go all PWM you probably want to keep panels run parallel vs MPPT you can run them in series (which can then cause issues with shading).

Obviously this can be really complicated but buying the two bogarts definitely is not a bad way to go. Similarly, an MPPT isn't too bad either but to get the same level of control/knowledge you'll probably still need a battery monitor and then the controller.

[red31]

view star 20A would be more than adequate for 200 watts
http://www.amazon.com/EPsolar-Viewstar-VS2024BN-Battery-Controller/dp/B00N4PTJWI

[pianotuna]

Hi,

Having an array sized too large for the controller makes no sense at all to me. There are controllers that will handle up to 100 amps. If you are going to have 45 amps--then get a controller that can do at least that number. There are PWM that do up to 60 amps. They are less expensive that the Trimetric I believe.

Almot wrote:
45A array won't generate 45A on 30A PWM, but having oversized array - with this particular controller - will be beneficial in low-light conditions. With PWM you normally have to under-size by 20%, but Trimetric monitor will clip the excess current, so you can over-size.

PWM with 12V bank "favors" low-wattage arrays. You have to use 12V panels and wire parallel only. With arrays larger than 300W this becomes awkward. Besides, there are fewer 12v panels on the market now, less choice, more $/W.

The OP with his planned 100-200W portable - he says there is always some sun within 20ft - will be fine with PWM. I would stay within 100W though. Too much weight and bulk.

[Almot]

45A array won't generate 45A on 30A PWM, but having oversized array - with this particular controller - will be beneficial in low-light conditions. With PWM you normally have to under-size by 20%, but Trimetric monitor will clip the excess current, so you can over-size.

PWM with 12V bank "favors" low-wattage arrays. You have to use 12V panels and wire parallel only. With arrays larger than 300W this becomes awkward. Besides, there are fewer 12v panels on the market now, less choice, more $/W.

The OP with his planned 100-200W portable - he says there is always some sun within 20ft - will be fine with PWM. I would stay within 100W though. Too much weight and bulk.

[azrving]

I'm running 520 through my Bogart SC2030. If I recall correctly they said 560 is no problem as it will cut back. Others may offer more advice but if you are going to add more panels later you may want to stick with pwm parallel. If I did it again I would run 600 through it, mine never gets hot. My next issue would be running a residential frig which would need 2 more 6 volts and another 450 watts or so through another Bogart controller. They say you can run 2 controllers and link with the phone cable to the trimetric. I went with narrower 12 volt panels because I can get two strips of them on my roof for a total of 970 w.

Edit: During the winter in socal with tilted panels my system would have no problem replacing 100 amp hours or more with sun left over. In northern Tenn in early April sitting in trees with no leaves I was doing 5 amps in full sun tilted. The waving tree branches killed it.

[time2roll]

Shade itself has too many unknown variables.
Both perform poorly and either could be superior depending on conditions.

[pianotuna]

Hi,

It may depend on the system chosen. I harvest 7 amps at solar noon when I am in leafy shade. My system includes a Blue Sky 3024 di controller and 256 watts of Unisolar panels configured in series parallel to allow a nominal input of 33 volts to the controller. Maximum output if the panels are perfectly clean and it is late June is 17 amps.

Almot wrote:
Partial shade - spatial not temporal - may affect MPPT more than PWM, if it's a single panel or 2 panels in series.

[time2roll]

While I do not have the Bogart it seems to work very well for those that do. You can attach up to 45 amps to that 30 amp controller as it will protect itself. So you could eventually add several 12v panels on the roof and still have a few portables when needed without fear of overload.

[Almot]

johnm1 wrote:
I've been pondering the Bogart 2030 (?) units for the PWM charge controller and battery monitor

This one is truly programmable. Note that you have to buy both units by Bogart. There are monitors that are either better or lower priced, but Bogart controller won't do you any good with a different monitor.

johnm1 wrote:

Just so much info out there and lots of people disagree on what's best for this or that.

Because you need to specify the goals and environment. Too many variables, different goals and different methods.
One limitation of Bogart PWM is that it is PWM. If you ever decide to go big, it will limit your array to ~400W @12V bank, and parallel wiring only.

[Almot]

SMK, I agree that a fixed install will harvest more with MPPT.
Nice thing about fixed is that it works all the time, including time on the road - where there is no shade.

OP wanted to know whether MPPT is better in the shade than PWM. Dense shade is a killer, no light = no charging, doesn't matter MPPT or PWM.
Partial shade - spatial not temporal - may affect MPPT more than PWM, if it's a single panel or 2 panels in series.

[johnm1]

Smketter ... thanks for that. I think I'm sort of, kind of, starting to understand ... a little. I've been pondering the Bogart 2030 (?) units for the PWM charge controller and battery monitor (sorry, on cellphone and don't have part #'s) since they talk to each other which is nice.

Just so much info out there and lots of people disagree on what's best for this or that. It's hard to find my way through the forest sometimes.