RussNM
Solar Enthusiast
No. Your charge controller will either be programmed by you or most likely itll figure out the battery voltage and charge at that.
Newbe new cabin system
- Thread starter Gfrost
- Start date
Rednecktek
Solar Wizard
Those will be the terms used on the label on the back of the panel.
MisterSandals
Participation Medalist
Sorry, these are all from your pic in post #7. Unfortunately they are not labeled with abbreviations.
There are 2 panel voltages. One is the open circuit voltage (Voc) and this is the no-load voltage that a panel will achieve under the specified test conditions at 25C. This is the equivalent of revving your car while in neutral. This voltage is used for configuring the array and making sure it does not exceed your SCCs max input voltage.
The second voltage is max power voltage (Vmp) and its pretty much the expected working voltage. This voltage (along with Imp) is used in calculating panel watts (more on that later).
There are 2 panel amperages. One is the "worst case" short circuit amperage used for sizing panel/array wiring and fusing. It can be measured easiest with a clamp meter with the panels + and - wires connected. It sounds bad but its ok for short periods of testing.
The second amperage is max power current (Imp, "I" ... capital i, is the symbol for current). Imp is the working current in amps, or commonly just called amps.
So to get back to your question in post, you use the Vmp value (the sum for each 3 panels in series) and Imp value (the sum for each of the 3 strings connected in parallel)
Each panel: 30.3Vmp x 8.27Imp = 250.5W
(3 x 30.3V) x (3 x 8.27) = 2255W
Hopefully this makes sense and is helpful. Please ask if its not clear.
One thing is should add is that when you have 3 or more strings connected in parallel, each string needs to be fused. So you will need 3 of these MC4 fuses to add to the + lines to your panels at the 3:1 Y connector.
Rednecktek
Solar Wizard
Or you can use what's called a Combiner Box that will do the fusing on all the strings plus give you a breaker/disconnect so you can isolate the arrays if you ever have to.
MisterSandals
Participation Medalist
One for each series string, so just 3.
The link for 5 looked cheaper than 3 individually.
The combiner box a nice bit of kit too. Knowing where to place it and thinking thru wiring it is the key. I found the wiring to it (6 wires for 3 strings) difficult if the combiner awash from array and out of elements.
One benefit of conbiner box is it’s cutoff functionality so having that in a convenient location a big plus.
Yes 15A. Your panel label says 15A fuse too.
I like the combiner box idea, issue is that I am not positive if the plan in my head is really going to work once I get there.
Any suggestions as far as the combiner box? The rating are what always throw me off.
What would be going in per series string would be about 250watts but what would be coming out would be 2255watts, so the below unit would work??
I'm really trying to get this all straight in my head.
4) WIDE RANGE OF APPLICATIONS: Suitable for photovoltaic grid-connected and off-grid power generation systems, solar panel systems, photovoltaic arrays, RV solar energy, and household solar panel systems. It can support solar panel systems up to 720W in 12V systems, 1440W in 24V systems, and 2880W in 48V systems. Compatible with any brand of solar panels and solar connectors
Any suggestions as far as the combiner box? The rating are what always throw me off.
What would be going in per series string would be about 250watts but what would be coming out would be 2255watts, so the below unit would work??
I'm really trying to get this all straight in my head.
4) WIDE RANGE OF APPLICATIONS: Suitable for photovoltaic grid-connected and off-grid power generation systems, solar panel systems, photovoltaic arrays, RV solar energy, and household solar panel systems. It can support solar panel systems up to 720W in 12V systems, 1440W in 24V systems, and 2880W in 48V systems. Compatible with any brand of solar panels and solar connectors
Rednecktek
Solar Wizard
That one would work just fine.
Yesterday I partially put my system together out in the driveway,
Three of the above solar panels in series going into the combiner box then out to the Flexmax charge controller.
Everything fired up no problem with a deep cycle battery that I pulled out of the boat.
I roughly adjusted the parameters.
I noticed that I was taking in about 110 volts, but as far as the amps it was only reading .1 amp
It was a partly sunny day
Just wondering if that sounds normal???
I am trying to assemble this system prior to traveling to the cabin in alaska so I can screw the system to the wall, hook up some batteries and panel and use it without spending a lot of time configuring wiring etc.
Gary
Three of the above solar panels in series going into the combiner box then out to the Flexmax charge controller.
Everything fired up no problem with a deep cycle battery that I pulled out of the boat.
I roughly adjusted the parameters.
I noticed that I was taking in about 110 volts, but as far as the amps it was only reading .1 amp
It was a partly sunny day
Just wondering if that sounds normal???
I am trying to assemble this system prior to traveling to the cabin in alaska so I can screw the system to the wall, hook up some batteries and panel and use it without spending a lot of time configuring wiring etc.
Gary
Rednecktek
Solar Wizard
If the battery was full it will also not really draw anything. The solar panels don't push power, they give power when requested by the rest of the system.
Rednecktek
Solar Wizard
The next step while you've got it out for testing is to throw a good load on it while the sun is up and make sure your SCC is ramping up the charge. A few minutes would be plenty for testing. If it doesn't ramp up then it's in a good place for troubleshooting.
Yeah, I ordered a bunch more parts that I won't see till next week so I can do it properly.
Not planning on adding an inverter this time around so I'll have to hook an electric trolling motor to it or something, that should pull some amps.
Not planning on adding an inverter this time around so I'll have to hook an electric trolling motor to it or something, that should pull some amps.
Does anyone have any suggestions as far as batteries?? Brand and Model??
I was initially thinking about just getting Napa brand deep cycle batteries since there is a Napa there but now I'm second guessing myself.
I would like to initially build a 4 battery 24volt system, I'm thinking agm since the cabin will be unattended during the winter months.
I don't think Petersburg Alaska gets extended periods of time below 20, but based on the winters I've been having in idaho who knows.
Gary
I was initially thinking about just getting Napa brand deep cycle batteries since there is a Napa there but now I'm second guessing myself.
I would like to initially build a 4 battery 24volt system, I'm thinking agm since the cabin will be unattended during the winter months.
I don't think Petersburg Alaska gets extended periods of time below 20, but based on the winters I've been having in idaho who knows.
Gary
