Which Model Classic to get?

[acousticart]

By way of introduction, I am a Solar newbie here… I am installing 836 W of flexible PV Laminate Solar Panels on the roof of our 36 foot motorhome. These panels are mixed and matched to fit the space on top of our coach. They include 2 24v Unisolar 136 Watt panels in parallel, 3 12v Unisolar 68 Watt panels in series, and 4 12v Global Solar 90 Watt panels in series/parallel. These three groups would then be put in series for a nominal operating voltage 84v... At least that is my current thinking about how to wire them. Reading the specs for STC VOC for each of these; Unisolar 136 Watt panels=46.2 V (x2 in parallel=46.2 V), Unisolar 68 Watt panels=23.1 V (x3 in series =69.3 V), Global Solar 90 Watt Panels=22.0 V (x2 in series/parallel=44 V), that would put the STC VOC of the array at 159.5 V. Is this doable for the Classic 150? The mixing and matching is based on the sizes of the panels and where they will fit on our roof. I wish I could put one more of the 68 Watt Unisolar panels, then I could do another series/parallel set, but I just don't think I can unless I was to remove the luggage rack. I have already had to relocate one of the Air Horns to make space for the two 136 Watt panels (they are nearly 18' long but only about 15" wide). Alternatively, I could lose one of the 68 Watt panels and end up with 768 Watts worth which just doesn't sound as good Am I thinking about this in the right way?

I have a Magnum MSH3012M inverter, ARC50 Remote, and BMK battery monitor to install as well. Currently, we have 2 8D 225AH MK GEL batteries which I plan to upgrade to 1000AH Balqon LifeP0, but I want to get everything under control with the solar and new inverter etc. before take that step. We do have an 8KW PowerTech diesel generator on board, but I am looking to minimize its use. I welcome any constructive input you might have. I already have the Solar cells and am not really open to going with conventional panels for this application, but if you have suggestions on how best to make this setup work, then that will be great!
Don

[Westbranch]

You have an error in the sums shown for the pv panels... 
when in series you add the voltage, amps stay the same
When in parallel you add the amps, voltage stays the same

hth

[dgd]

Hi Don,
The specs for these PVs show that the mpV (maximum power voltage) is 33v and 16.5v, the uniolars at 4.1A and the others at 5.4A
You usually do serial/parallel calculations based on the mpV and not the ocV (open circuit voltage)
Two 136w unisolars in parallel is 33v at 8.2A
Two 68w unisolars in series is 33v at 4.1A
Four Global Solar 90w in two groups in parallel of two in series is 33v at 10.8A
So the plan I assume is to have all these groups in parallel giving an mpV of 33v at  8.2+4.1+10.8 = 23.1A

The third 68w unisolar cannot fit into this configuration, you need to either remove it or get a fourth 68w unisolar, wire these two in series to give 33v at 4.1A  and then parallel this group to the others.

Classic 150 with 12v battery would work good
dgd

[acousticart]

Thanks for the reply, but I am aware of that and don't see the error you are referring to. Two 24 V panels in parallel = 24 V. Two groups of two 12 V panels in series parallel configuration =24V. Three 12 V panels in series = 36 V. 24V + 24V + 36V = 84V as far as the nominal operating voltage. I didn't say anything about current... I may be wrong about the best way to hook them up, but that is why I am here...
Don

You have an error in the sums shown for the pv panels... 
when in series you add the voltage, amps stay the same
When in parallel you add the amps, voltage stays the same

hth

[benharuna]

Why do you decide to go complex? Its always better to go simple as much as you can. If you do not have the panels already in place I will advice you use the same panels with the same ratings, in that way it will make your calculations easier.

[zoneblue]

Mate, you need to understand the iv curves of the panels.  Its critical that the Vmp be matched for mixed arrays. Strings in parallel must have a Vmp within a small tolerance. Then any panels in series they must have matched Imps.

If you really want to use these arrays you might want to consider a couple of kids, it will be way simpler.

[acousticart]

Thanks for the replies. I obviously have some studying to do... This is some good info. The kids sound like a possibility. (Dumb question alert!) If you have more than one charge controller, are the charging outputs combined at the battery cabling? The inverter? Please be gentle...
Don

[TomW]

Thanks for the replies. I obviously have some studying to do... This is some good info. The kids sound like a possibility. (Dumb question alert!) If you have more than you charge controller, are the charging outputs combined at the battery cabling? The inverter? Please be gentle...
Don

Yes, multiple controllers can charge (connect to) one battery bank. Both the Kids and the Classics can communicate and follow the same charge profile.

If I understand the question.

Tom

[Westbranch]

Hi Don, I'll hi-lite the sections(s) I latched onto

They include
2 24v Unisolar 136 Watt panels in parallel, Nominal 24V
3 12v Unisolar 68 Watt panels in series, and Nom. 36V
4 12v Global Solar 90 Watt panels in series/parallel. Nom. 24V
These three groups would then be put in series for a nominal operating voltage 84v...NO you have to drop or add one panel  in this group, All 3 should be 24V nominal
At least that is my current thinking about how to wire them.

Reading the specs for STC VOC for each of these;
Unisolar 136 Watt panels=46.2 V (x2 in parallel=46.2 V),
Unisolar 68 Watt panels=23.1 V (x3 in series =69.3 V),
Global Solar 90 Watt Panels=22.0 V (x2 in series/parallel=44 V),

that would put the STC VOC of the array at 159.5 V. No will be about 44V, use lowest of groups

Is this doable for the Classic 150? The mixing and matching is based on the sizes of the panels and where they will fit on our roof. I wish I could put one more of the 68 Watt Unisolar panels, then I could do another series/parallel set,

hope this helps, as others have noted, you  are probably best to change out some panels and/or charge controller(s) for a more balanced system.  Enjoy.

[acousticart]

Thanks for looking at this dgd... I can see now that I need to find a way to add the extra 68 W UniSolar or lose one. I have these panels already and any extras can be used (even if it takes one cheap controller per panel) on my 40' Storage container/Shop to help with venting and lights.
Where did you find the max power voltage for the GS panels? Is that a calculation based on the Temperature Coefficients vs the VOC? Doh! Never mind, I see it now...
I really want to figure out a way to get the max from these strings because there really is no room to add more in my limited space. Anyway, thanks for the help!
Don
Last edit to attach Spec sheets for all you kind souls who are are curious enough to take a look but too busy to search them ou

Hi Don,
The specs for these PVs show that the mpV (maximum power voltage) is 33v and 16.5v, the uniolars at 4.1A and the others at 5.4A
You usually do serial/parallel calculations based on the mpV and not the ocV (open circuit voltage)
Two 136w unisolars in parallel is 33v at 8.2A
Two 68w unisolars in series is 33v at 4.1A
Four Global Solar 90w in two groups in parallel of two in series is 33v at 10.8A
So the plan I assume is to have all these groups in parallel giving an mpV of 33v at  8.2+4.1+10.8 = 23.1A

The third 68w unisolar cannot fit into this configuration, you need to either remove it or get a fourth 68w unisolar, wire these two in series to give 33v at 4.1A  and then parallel this group to the others.

Classic 150 with 12v battery would work good
dgd

[zoneblue]

Go to the manufacturers website and download the spec sheets for both panels. Thats the place to start.