# Solar power panels

Does anyone use solar power panels to power modules? If so, what is your environment and which panels do you use?

We've got windy nation brand panels and basic controller, they seem to work fairly well. I use a 15:1 ration to determine wattage needs, we are in solar zone 4.

our way of calculating needs for 100% uptime:

for every 1 watt of load, use 15 watts of solar, so a site with 1 EPMP AP and SM for backhauling would use approximately 12 watts.  (we meter the actual draw to include cabled loss ect.)

so we would install more than 180 watts of panels.

for this setup we would use 2 100 watt 12v panels  if full day sun is available, or double if any day light would be obstructed.

we aim for more than 14 days (336 hours) of battery for bad weather season, so 12 watts gives us  .48ah/hr draw assuming 24.8 average voltage.  we would need 161.28 AH battery capacity or more to make this time frame.

4 100AH 12v batteries would be my choice for this bank (200AH worth of 24v storage) , setting up 2 pair in series then both of those pair in series to give the 24v bank.  this setup would come out to be 17 days on battery assuming no sunlight at all.

there is a 2nd reason for such a large battery bank, the smaller and lighter the  average cycle, the longer your batteries last.

We tend to a bit over kill the power system so we don't have to worry about the power system in the low sun months and extended bad weather.   we found a 10:1 ratio for watts and a 7 day bank generally worked but the batteries would get low and need charged 1 or 2 times in the winter months and we needed to keep the panels clean in the winter.

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We don't use solar yet, however we are switching to use DC battery banks instead of AC UPSes.

How are people driving the 30V CMM from 24V / 48V battery banks? Or are most using an inverter and the normal power supply?

Not trying to hijack the thread but I think this is a pretty decent part of a solar solution.

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Hi. On our older (non-Cambium) gear, we use lots of these type of dc-dc Converters. They are available to convert up or down from pretty much any voltage to pretty much any voltage, plus they can be custom ordered. I think it’s Circuit-Logic that makes them. http://m.ebay.com/itm/400742879860?nav=SEARCH

if your wanting to connect to your banks directly, i'd suggest using voltage regular with your transformers. if you end up with a dead short, you can end with with a fire very easy.

we use DC systems only when standard power is far to costly to get to a site, are match the load controller carefully to the applications for safty reasons.

if your not very familiar with DC power systems, you may want to read up a lot in the subject, its not as directly hazardous as AC to us, but handed incorrectly, you've got far more of a fire risk

if your wanting standby power, check out these tripp lite units...

http://www.tripplite.com/inverter-charger-1250w-automatic-transfer-switching-2-outlets~APS1250/

they will run indefinitely on 12,24,48v power depending on the model and have very heavy load ranges.  much safer than going to an all DC system if your not extremely familiar with them

the tripp lite units will give you the backup your wanting with what ever storage capacity you need and help keep your loads safe from dead shorts or varrying voltage.

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Would the Community like us to have a webinar with  some of the customers here sharing their experiences with a live Q&A session? Let us know. If we have interest and Chris or some of the others are willing to speak, I will set it up.

Ray