My eighth 100 watt panel came earlier this week, but once I started taking it apart, I realized that I didn't have all the connectors I (thought I) needed.
Today the additional cables came, and a trip to the auto store for some butt connectors and I was ready to get on the roof and add the new panel. It is the same brand and model as the others (Grape Solar 100 watt). The system was wired 7 panels in series. That was giving me 156 volts now that winter is coming and my Midnite 150 goes into Hyper Voltage mode at over 150 volts.
With the addition of this 8th panel, I have wired them differently: 4 panels in series paralleled with 4 panels in series. The panels are in a row on the roof - but are intertwined so every other panel is in the same series. The end result will be half the voltage and double the amperage. It's still under 15 amps from the PV array and about 85 V.
I had to cut one of the MC4 extension cables and attach them to the 10 AWG wire that comes from the wire panel. The good thing was I was able to use the hydraulic crimper ... very nice.
Unfortunately it was finished in the dark, so I've not seen it 'work' yet. And the forecast for tomorrow is rain, and the next day, and the next after that. So, it may be a few days before I can observe how it works.
None the less, it is nice to not be over voltage and to add another 100 Watts to the system.
Only thing on my mind to upgrade still is the 2/0 cable to replace the 4 AWG.
Wednesday, November 25, 2015
Thursday, November 19, 2015
Soon to be 800 watts ...
Panel 8 ... arrives in the mail today ... that makes 8x100W Panels.
Currently 7 in series, but experiancing a little time over voltage. I've bought a MC4 Y connection and will make 2 series of 4 pannels which will reduce the output voltage by 40% or so and just over double the current Amps. Today saw a little over 500 watts at it's peak. One more panel should put me in the 570 range (as the panels currently are positioned).
I've discovered that my position is great fro the summer sun, but not so good for the winter sun and trees that are giving shade as early as 1:30 in the afternoon. A tree trim will help, but this trimming would be to 40 feet and higher. May need to rent a 'Cherry Picker' or 'Boom Lift' ... or may need to make a pole mount else where in the yard ... but moving 8 panels will take some thought. May be easier to pay for a tree trim and get 3 more hours of sun.
Currently 7 in series, but experiancing a little time over voltage. I've bought a MC4 Y connection and will make 2 series of 4 pannels which will reduce the output voltage by 40% or so and just over double the current Amps. Today saw a little over 500 watts at it's peak. One more panel should put me in the 570 range (as the panels currently are positioned).
I've discovered that my position is great fro the summer sun, but not so good for the winter sun and trees that are giving shade as early as 1:30 in the afternoon. A tree trim will help, but this trimming would be to 40 feet and higher. May need to rent a 'Cherry Picker' or 'Boom Lift' ... or may need to make a pole mount else where in the yard ... but moving 8 panels will take some thought. May be easier to pay for a tree trim and get 3 more hours of sun.
Saturday, November 14, 2015
Winter HyperVOC woah's...
With the coming of winter (and cold temps), I've had our first 'HyperVOC'. And this is happening most all mornings now.
The system has 7x100 Watt panels in series. Each panel has an "Open Circuit Voltage" Voc of 21.9 Volts. So, a total for the system of 153.3 volts. I never saw this in the summer, but the colder weather this happens - I'm learning. The solution will be to add 1 more 100 W panel of the same model and then breaking the 8 panels into 2 banks of 4 and combining them.
My first plan will be to use one of the MC4 combiners and add the 2 banks and bring them into the gararge on the existing 10 AWG wire. This shouldn't be a problem as the voltage will be going down and the Amps up, but still well within accepteable range for the wire ("Short Circuit Current" Isc of 6.13 Amps). The panels are on sale for $129.
Once installed the system with be 800 watts. It started at 300 watts .. and that was this summer! It started with 1x 12 V battery and is now at 4x 6 V. I'm still using a 12 V 1500 W inverter, but will probably replace it with a 24 V inverter once it fails.
We are running lots of things from the captured energy. Solar power is Great!
The system has 7x100 Watt panels in series. Each panel has an "Open Circuit Voltage" Voc of 21.9 Volts. So, a total for the system of 153.3 volts. I never saw this in the summer, but the colder weather this happens - I'm learning. The solution will be to add 1 more 100 W panel of the same model and then breaking the 8 panels into 2 banks of 4 and combining them.My first plan will be to use one of the MC4 combiners and add the 2 banks and bring them into the gararge on the existing 10 AWG wire. This shouldn't be a problem as the voltage will be going down and the Amps up, but still well within accepteable range for the wire ("Short Circuit Current" Isc of 6.13 Amps). The panels are on sale for $129.
Once installed the system with be 800 watts. It started at 300 watts .. and that was this summer! It started with 1x 12 V battery and is now at 4x 6 V. I'm still using a 12 V 1500 W inverter, but will probably replace it with a 24 V inverter once it fails.
We are running lots of things from the captured energy. Solar power is Great!
12 Ton Hydraulic Crimper
I have only upgraded 1 wire in the last (first) 5 months of this Solar system. My system is still fairly simple: 10 AWG from the PV array, through a 6 A breaker and into the MidNite 150 controller. From there 10 AWG to the battery bank. From the bank I have 4 AWG cable from a set of heavy duty jumper cables. On the ends of the cables I have copper lugs that I've squeezed in a vise and a couple have the allen screw lugs.
This has worked pretty good, except when drawing a large current from the battery bank > 115 Amps. When the current is that high, the wires would get warm and the voltage drop from the battery to the inverter was 0.3 volts -- too much! One consequence of this voltage drop is that some times the inverter would stop due to the low voltage point.
The first change was to replace the 10 AWG from the controller to the battery bank to 6 AWG. I've expressed the benefit in a previous posting.
What I've wanted to do most was upgrade the 4AWG cables with 2/0 cables. This is very expensive to buy pre-made cables - and you have to know exact lengths, and the lugs have to be at the same angle. I see this as a long term investment, so the only real solution is to make my own.
Today I received a 12 Ton Hydraulic crimper in the mail. To which I quickly went out and crimped an end of the current 4 AWG wire. The first photo shows the cable and the thin wires it contains. The second photo shows the hex crimp applied to the lug: I was very impressed with the reduction in size and the resulting crimp.
Today I bought some 2/0 lugs and have started the shopping for 2/0 thin cable. It's pretty expensive, so I'm going to have to shop for a bit. I've only used it once, but am very pleased and am looking forward to replacing the 4 AWG wire with 2/0 cable.
This has worked pretty good, except when drawing a large current from the battery bank > 115 Amps. When the current is that high, the wires would get warm and the voltage drop from the battery to the inverter was 0.3 volts -- too much! One consequence of this voltage drop is that some times the inverter would stop due to the low voltage point.
The first change was to replace the 10 AWG from the controller to the battery bank to 6 AWG. I've expressed the benefit in a previous posting.
What I've wanted to do most was upgrade the 4AWG cables with 2/0 cables. This is very expensive to buy pre-made cables - and you have to know exact lengths, and the lugs have to be at the same angle. I see this as a long term investment, so the only real solution is to make my own.Today I received a 12 Ton Hydraulic crimper in the mail. To which I quickly went out and crimped an end of the current 4 AWG wire. The first photo shows the cable and the thin wires it contains. The second photo shows the hex crimp applied to the lug: I was very impressed with the reduction in size and the resulting crimp.
Today I bought some 2/0 lugs and have started the shopping for 2/0 thin cable. It's pretty expensive, so I'm going to have to shop for a bit. I've only used it once, but am very pleased and am looking forward to replacing the 4 AWG wire with 2/0 cable.
Friday, November 6, 2015
416 AH Off-Grid Battery Bank
I've been wanting to increase the storage of my small system (7x100W Panels) for a while now, but finally did so today. I've doubled the capacity to 416 amp hours.
Battery Bank
The battery bank now consists of four 6V golf cart batteries that I purchased at Costco. They are rated at 208 amp hours each. The bank is composed of two parallel banks of two batteries in series : where the two batteries in series doubles the voltage (6 to 12) and the parallel battery banks doubles the capacity (208 AH to 416 AH).
Cable Upgrade
Last night I changed out the 10 AWG wire from the controller to the battery bank with a 6 AWG wire. I was surprised to see the voltage drop at 40A with the 10 AWG over 6' of wire was 0.48 V. The 6 AWG wire will be 0.19 V now: a loss of 4% down 1.6%.
Future Upgrade
Now that winter is picking up it's stride, I don't want to loose energy when I can make simple changes. The next will be to change the 4 AWG cable from the battery bank to the inverter and replace it with 2/0. That will lower the voltage drop @ 100 Amps from 0.3 to 0.09: very significant : less than 1/3 of the loss. I should have done this earlier, but in the summer there was sunlight to spare. Not so anymore...
COST:
208 AH 6V Battery: approximately $83 each ==> result: storage of 416 AH
6' of 6 AWG cable: approximately $3.50 ==> result: less voltage drop from controller to battery bank
(I will upload the photo when I get data back up...)
Battery Bank
The battery bank now consists of four 6V golf cart batteries that I purchased at Costco. They are rated at 208 amp hours each. The bank is composed of two parallel banks of two batteries in series : where the two batteries in series doubles the voltage (6 to 12) and the parallel battery banks doubles the capacity (208 AH to 416 AH).
Cable Upgrade
Last night I changed out the 10 AWG wire from the controller to the battery bank with a 6 AWG wire. I was surprised to see the voltage drop at 40A with the 10 AWG over 6' of wire was 0.48 V. The 6 AWG wire will be 0.19 V now: a loss of 4% down 1.6%.
Future Upgrade
Now that winter is picking up it's stride, I don't want to loose energy when I can make simple changes. The next will be to change the 4 AWG cable from the battery bank to the inverter and replace it with 2/0. That will lower the voltage drop @ 100 Amps from 0.3 to 0.09: very significant : less than 1/3 of the loss. I should have done this earlier, but in the summer there was sunlight to spare. Not so anymore...
COST:
208 AH 6V Battery: approximately $83 each ==> result: storage of 416 AH
6' of 6 AWG cable: approximately $3.50 ==> result: less voltage drop from controller to battery bank
(I will upload the photo when I get data back up...)
Sunday, November 1, 2015
$3.49 status light for Solar system
My system is on and in the garage - detached from the house, but just a short walk from the back door. I've been wanting a status light for a while now so I can readily see if the inverter is not working. (This goes back to having an inverter that is not as reliable as my next one will be.)
So I recently went to Radio Shack and purchased a 120 V Neon high intensity light; I then drilled a hole through the cover on the outside of the garage where the PV leads enter the garage (which is high, under the eves). I soldered leads to the light and then added a plug. Now when the inverter is on / working, I can see the status light from the house - even in the daytime. And at night, it's very easy to see before going to bed.
It's an inexpensive nice feature. When I wire in a 120 panel I will attach it there, but for now I will run it off of a power strip from the inverter.
So I recently went to Radio Shack and purchased a 120 V Neon high intensity light; I then drilled a hole through the cover on the outside of the garage where the PV leads enter the garage (which is high, under the eves). I soldered leads to the light and then added a plug. Now when the inverter is on / working, I can see the status light from the house - even in the daytime. And at night, it's very easy to see before going to bed.
It's an inexpensive nice feature. When I wire in a 120 panel I will attach it there, but for now I will run it off of a power strip from the inverter.
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