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Discussion Starter #1
So I've already ordered a Victron 100/30 MPPT controller but I'm having a heck of a time deciding on what actual panels to use. My daily Ah use should be around 50-60 in summer and maybe 35 in winter. I have a 255Ah AGM with 50% being use able. I also have a sterling battery charger.

Values below are calculated using the PVwattcalculator site with a tilt of 0 in May and December (best and worst months locally)

A single 180W grape solar panel will produce 72Ah a day in May, and 21Ah in December. Two of these will produce 142Ah/40Ah.

Can someone confirm that two of the Grape solar panels will work wired in series with the Victron 100V/30A MPPT? Panel specs are below:

Max System Voltage (IEC/UL) 600V
Maximum Power Pmax 180 W (0%, +3%)
Voltage at Maximum Power Point Vmpp 19.67 V
Current at Maximum Power Point Impp 9.15 A
Open Circuit Voltage Voc 24.06 V
Short Circuit Current Isc 9.77 A
Module Efficiency (%) 18.0%
Temperature Coefficient of Voc -0.28 %/ºC
Temperature Coefficient of Isc +0.04 %/ºC
Temperature Coefficient of Pmax -0.38 %/ºC


Then please confirm that two is WAY overkill and I really only need one. Roof space is a premium for me. I could always add a second 180W if deemed necessary if I mount them sideways (58"x26" panels)
 

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So I've already ordered a Victron 100/30 MPPT controller but I'm having a heck of a time deciding on what actual panels to use. My daily Ah use should be around 50-60 in summer and maybe 35 in winter. I have a 255Ah AGM with 50% being use able. I also have a sterling battery charger.

Values below are calculated using the PVwattcalculator site with a tilt of 0 in May and December (best and worst months locally)

A single 180W grape solar panel will produce 72Ah a day in May, and 21Ah in December. Two of these will produce 142Ah/40Ah.

Can someone confirm that two of the Grape solar panels will work wired in series with the Victron 100V/30A MPPT? Panel specs are below:

Max System Voltage (IEC/UL) 600V
Maximum Power Pmax 180 W (0%, +3%)
Voltage at Maximum Power Point Vmpp 19.67 V
Current at Maximum Power Point Impp 9.15 A
Open Circuit Voltage Voc 24.06 V
Short Circuit Current Isc 9.77 A
Module Efficiency (%) 18.0%
Temperature Coefficient of Voc -0.28 %/ºC
Temperature Coefficient of Isc +0.04 %/ºC
Temperature Coefficient of Pmax -0.38 %/ºC


Then please confirm that two is WAY overkill and I really only need one. Roof space is a premium for me. I could always add a second 180W if deemed necessary if I mount them sideways (58"x26" panels)
I would suggest going with something like the renogy 100w panels. That way it's easy and relatively cheap to add capacity as needed. That said, the grape solar panels will also work fine. Wiring them in series will push 9.15A @ 39V to the charge controller, which it can easily handle. You could also wire them in parallel and still be well within the capacity of the victron 100/30.

If your estimations of usage are accurate, then you should be OK in theory, but I think you'll be relying on good weather too often. Power output from the panels will drop off dramatically on cloudy days and when you're in the shade. You need sunny days to be able to make that up in addition to your daily usage. Alternatively you can drive around for an hour to make up a day's worth of solar (pun intended), but you must do one or the other. Either overprovision or commit to relying on your van engine-as-generator when you have intermittent clouds.
 

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Discussion Starter #3
I would suggest going with something like the renogy 100w panels. That way it's easy and relatively cheap to add capacity as needed. That said, the grape solar panels will also work fine. Wiring them in series will push 9.15A @ 39V to the charge controller, which it can easily handle. You could also wire them in parallel and still be well within the capacity of the victron 100/30.

If your estimations of usage are accurate, then you should be OK in theory, but I think you'll be relying on good weather too often. Power output from the panels will drop off dramatically on cloudy days and when you're in the shade. You need sunny days to be able to make that up in addition to your daily usage. Alternatively you can drive around for an hour to make up a day's worth of solar (pun intended), but you must do one or the other. Either overprovision or commit to relying on your van engine-as-generator when you have intermittent clouds.
Thanks for confirming the controller, I thought it would work but every blogger website seems to calculate it a little different for some reason. The 100W Renogy's measure 47" x 21" and the Grape 180's are 58" x 26". With the width of the roof mounts on the promaster being a little over 58" I'm surprised more people aren't using the grape 180 panels to make better use of the space? Effectively only losing 5" but gaining 80W. The renogys are definitely cheaper. I'm still really torn on wattage needed!!! I'm in Denver where it's pretty much always sunny and most of my trips in the van will be to the desert.
 

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Yep, I’m looking in the 175 - 190 watt range for the same reason. I’m having trouble finding the Grape panels in stock anywhere (Home Depot is no go right now), so I’m looking at other options. I was originally looking at narrower residential panels in the 325-350 watt range, but shipping for those was exorbitant.
 

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I'm still in the process of building, but my setup sounds similar to yours. I have (2) 180w Grape solar panels, a single 245ah AGM battery and a Midnite Solar "The Kid" controller and a Blue Sea charging relay connected to the van battery.


Good news is the 180 watt Grape Solar panels fit perfectly on the ProMaster! I'm using 4 of the Vantech stainless steel adapter feet and some 2" plate aluminum running down the sides to secure them (A 4" piece of plate is at an angle in front to direct air over the panels).
 

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Discussion Starter #6
I'm still in the process of building, but my setup sounds similar to yours. I have (2) 180w Grape solar panels, a single 245ah AGM battery and a Midnite Solar "The Kid" controller and a Blue Sea charging relay connected to the van battery.


Good news is the 180 watt Grape Solar panels fit perfectly on the ProMaster! I'm using 4 of the Vantech stainless steel adapter feet and some 2" plate aluminum running down the sides to secure them (A 4" piece of plate is at an angle in front to direct air over the panels).
Great to hear! Where are you located and do you know what your panel produces?
 

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Discussion Starter #7
Yep, I’m looking in the 175 - 190 watt range for the same reason. I’m having trouble finding the Grape panels in stock anywhere (Home Depot is no go right now), so I’m looking at other options. I was originally looking at narrower residential panels in the 325-350 watt range, but shipping for those was exorbitant.
NOOOOOOOOOO I waited too long. Did you check costco?
 

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@johntyree mentioned this, but you might want to wire in parallel. The controller can handle it, and it will deal better with partial shading. If you cover one entire cell on the panel, both panels are dead. If you wire in parallel, in that same scenario then only that one panel is dead, but the other will work. Sure, you'll need thicker cable to run to the MPPT from the combo box on the roof, but it's worth it.
 

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Discussion Starter #11
@johntyree mentioned this, but you might want to wire in parallel. The controller can handle it, and it will deal better with partial shading. If you cover one entire cell on the panel, both panels are dead. If you wire in parallel, in that same scenario then only that one panel is dead, but the other will work. Sure, you'll need thicker cable to run to the MPPT from the combo box on the roof, but it's worth it.
I'm very much a solar novice but don't you gain the most efficiency from the panels through the wiring to the controller by wiring in series with a MPPT controller that will step down the voltage? Truthfully I'm not concerned about shade. There isn't much of that in the desert anyways ;) I can't think of many places in the last 6 years of living in Colorado where I parked/camped in shade. :)
 

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I'm very much a solar novice but don't you gain the most efficiency from the panels through the wiring to the controller by wiring in series with a MPPT controller that will step down the voltage? Truthfully I'm not concerned about shade. There isn't much of that in the desert anyways ;) I can't think of many places in the last 6 years of living in Colorado where I parked/camped in shade. :)
There is no efficiency gained with series vs parallel. Watts are watts. The benefit of series is you can use a thinner cable. However with installations as small as 360w, you could use a 8awg wire and be fine in parallel. You may even get away with 10awg wire if it's less than 10 feet. Sure you may not get shade in the desert, but if you are in town or somewhere else, shade could be a concern.
 
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I'd 100% wire them in parallel. I have 850w of solar split between 2 MPPT controllers, all wired in parallel. It's totally doable with short runs. 650 of my solar has a Voc of 70v, so that makes it easy to run parallel for that wattage.

I'd look into residential panels and find a seller that is local (ish). I picked up two 325w panels for <$1 per watt. The best part, they are 62"x41.5". They fit perfectly on the Promaster roof (on my Vantech roof rack) and I think that is the most space efficient panel you could get. The high Voc requires a controller than can handle it though and it looks like you have a controller already. My panel is the Panasonic N325.
 

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I'd look into residential panels and find a seller that is local (ish). I picked up two 325w panels for <$1 per watt. The best part, they are 62"x41.5".

...

My panel is the Panasonic N325.
Yeah, I was looking at those based on your build thread. Fine if you live out west, but I’m having trouble sourcing them locally on the east coast. There are a few others near that form factor, but those seem the best.
 

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Yeah, I was looking at those based on your build thread. Fine if you live out west, but I’m having trouble sourcing them locally on the east coast. There are a few others near that form factor, but those seem the best.
Not sure where you are on the East Coast, but my source was Alt-E (http://altestore.com). They are located outside of Boston. It was a hassle trying to find out where each company was located and/or had a warehouse.
 

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One consideration is what are the trees like beside the hiways you travel on? In winter, with the sun at steep angles, those trees will throw full shade right over the hiway and keep you from charging as you drive. Pretty annoying. Bright sunny day and you're driving IN shade. When I find that happening to us, I always park in the sun when we stop for meals and let the panels work better during our breaks.
 
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Discussion Starter #18 (Edited)
One consideration is what are the trees like beside the hiways you travel on? In winter, with the sun at steep angles, those trees will throw full shade right over the hiway and keep you from charging as you drive. Pretty annoying. Bright sunny day and you're driving IN shade. When I find that happening to us, I always park in the sun when we stop for meals and let the panels work better during our breaks.
Here's a photo of I70, the main thoroughfare east to west through colorado. It goes from this to desert. Not much for trees :D

I will wire in parallel if I end up with two panels.

Does anyone have a grape solar 180w panel in the west and know what they receive daily?

The estimations I made are from the PVwattcalculator page which uses your location so I assume it should be fairly accurate accounting for average weather.
 

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I'm still in the process of building, but my setup sounds similar to yours. I have (2) 180w Grape solar panels, a single 245ah AGM battery and a Midnite Solar "The Kid" controller and a Blue Sea charging relay connected to the van battery.


Good news is the 180 watt Grape Solar panels fit perfectly on the ProMaster! I'm using 4 of the Vantech stainless steel adapter feet and some 2" plate aluminum running down the sides to secure them (A 4" piece of plate is at an angle in front to direct air over the panels).

This sounds exactly like the van I'm about to buy. The only thing I don't like about it is that it's very very obvious when looking at an otherwise normal van. I'm considering running a flat piece of aluminum down the sides to hide the gaps between panels and make it look more like there's just a weird rack on top.


 

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This sounds exactly like the van I'm about to buy. The only thing I don't like about it is that it's very very obvious when looking at an otherwise normal van. I'm considering running a flat piece of aluminum down the sides to hide the gaps between panels and make it look more like there's just a weird rack on top.


That's awesome!

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