Solar Output in Shade?

[mbopp]

I'm still toying with adding solar to alleviate running the genny every day. But since out favorite no-hookup sites are shaded, what % of rated output can I expect from a 24V panel and MPPT controller? Can I get 50 watts out of a 200W panel?

[BFL13]

For a while back when, I had one 24v set with MPPT and another 12v set with PWM so it did need two different controllers. No sweat--both set to 14.8 on same battery bank, added their amps, worked great.

[pianotuna]

Hedge the Grape is only $45.00

[ktmrfs]

hedge wrote:
maybe, my plan is to wire in an Anderson connector to be able to hook up a portable panel. This will be wired to bank 2 on the switch, the roof mounted panels will be mounted to bank 1 on the switch. This way I can cut them all off, choose individual banks, or combine them.

I'm not sure how often I'll be using the portable panel and I have quite a spendy controller so I'd rather just use it.

anderson connectors work IMHO very well for portable panel connections. Many people I know, myself included, that use them for portable panels.

One issue you need to be aware of with the switch is that the panels Hot AND neutral must be connected to the charge control input. the neutral MUST not be connected to battery ground!!

[CA_Traveler]

While the switch gives you options there is no need for anything other than a on/off for the controller input, assuming the panels are the same voltage (or close). Just plug in the portables when desired. Use heavy wire for long runs.

No need for a second CC as long as one is adequate for all of the panels.

[hedge]

maybe, my plan is to wire in an Anderson connector to be able to hook up a portable panel. This will be wired to bank 2 on the switch, the roof mounted panels will be mounted to bank 1 on the switch. This way I can cut them all off, choose individual banks, or combine them.

I'm not sure how often I'll be using the portable panel and I have quite a spendy controller so I'd rather just use it.

[pianotuna]

Hi,

It would be almost as cheap to use two Grape controllers. Then you would always get the benefit from both banks.

hedge wrote:
I'm planning on using a 2 bank battery cutoff switch in reverse to allow me to choose which solar source upstream of the controller.

[hedge]

I'm planning on using a 2 bank battery cutoff switch in reverse to allow me to choose which solar source upstream of the controller.

[westend]

maxum1989 wrote:

ktmrfs wrote:

westend wrote:
I'd suggest to mount one on the roof and carry one as a portable. You'll have the best solution possible. The portable one can be smallish to ease setup and tear down or use multiples. Remember, you'll be driving on the road and harvesting, along with the excellent battery maintenance solar does while in storage.

that is certainly a good option, and the two panels can still be connected to one charge controller.

And, if you do much driving vs. camping, the days drive can pick up lots of AH, combined with what you can get from the TV charge current can be a big boost.

I have thought of the two different options of solar for my needs.(fixed and portable). Doing both seems the best. Is there an easy way to have things wired so the portable panel can be quickly hooked up using both panels or not used at all leaving the roof panel on its own working?

Yes, the easiest alignment being the panels wired in parallel before the charge controller. A receptacle that will handle frequent disconnections/connections and be located towards the entrance point of the portable panel is best practices.

[Searching_Ut]

maxum1989 wrote:

ktmrfs wrote:

westend wrote:
I'd suggest to mount one on the roof and carry one as a portable. You'll have the best solution possible. The portable one can be smallish to ease setup and tear down or use multiples. Remember, you'll be driving on the road and harvesting, along with the excellent battery maintenance solar does while in storage.

that is certainly a good option, and the two panels can still be connected to one charge controller.

And, if you do much driving vs. camping, the days drive can pick up lots of AH, combined with what you can get from the TV charge current can be a big boost.

I have thought of the two different options of solar for my needs.(fixed and portable). Doing both seems the best. Is there an easy way to have things wired so the portable panel can be quickly hooked up using both panels or not used at all leaving the roof panel on its own working?

You could tie in both sets of panels in a parallel configuration using a junction box prior to the solar controller, assuming the controller is large enough to handle the current and the panels are similar enough to be paralleled efficiently. You could also use two separate solar controllers, one for the rooftop panels, one for the portable. If configured right charge controllers tend to play well together. Either way, I'd use a disconnect switch in the wiring between the portable panels and controller so I didn't have to make my connections with the wiring hot. The arching that can occur when hooking up live connections can create connection issues over time.

[BFL13]

Use both by putting each's controller on the same battery bank to add their amps. You can have the roof one with installed wires and the portable controller output to wires with clamps.

You want the controllers to be near the same "high set point" voltage, but the roof panel and controller can be different brand/model/size from the portable's.

Only thing that needs to be nearly the same is their output voltages so they add their amps. (and be for the same battery voltage ("12v", "24v", whatever) You can even have one set MPPT and the other PWM, doesn't matter.

[maxum1989]

ktmrfs wrote:

westend wrote:
I'd suggest to mount one on the roof and carry one as a portable. You'll have the best solution possible. The portable one can be smallish to ease setup and tear down or use multiples. Remember, you'll be driving on the road and harvesting, along with the excellent battery maintenance solar does while in storage.

that is certainly a good option, and the two panels can still be connected to one charge controller.

And, if you do much driving vs. camping, the days drive can pick up lots of AH, combined with what you can get from the TV charge current can be a big boost.

I have thought of the two different options of solar for my needs.(fixed and portable). Doing both seems the best. Is there an easy way to have things wired so the portable panel can be quickly hooked up using both panels or not used at all leaving the roof panel on its own working?

[CA_Traveler]

ktmrfs wrote:
Now, with panels in series you minimize resistive loss in the cable, but risk low output if one or more panel gets shaded. output current will be limited to lowest panel output.

Unless the panels have bypass diodes then series can easily outperform parallel.

[ktmrfs]

westend wrote:
I'd suggest to mount one on the roof and carry one as a portable. You'll have the best solution possible. The portable one can be smallish to ease setup and tear down or use multiples. Remember, you'll be driving on the road and harvesting, along with the excellent battery maintenance solar does while in storage.

that is certainly a good option, and the two panels can still be connected to one charge controller.

And, if you do much driving vs. camping, the days drive can pick up lots of AH, combined with what you can get from the TV charge current can be a big boost.

[westend]

I'd suggest to mount one on the roof and carry one as a portable. You'll have the best solution possible. The portable one can be smallish to ease setup and tear down or use multiples. Remember, you'll be driving on the road and harvesting, along with the excellent battery maintenance solar does while in storage.