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Old 10-04-2019, 02:00 PM   #1
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Solar Panel Wattage Question.

So I have just finished wiring all my solar components together. I have (6) 100 watt 12 v solar panels wired in series/parallel down into a 45 mppt Tristar. Everything is on and running but my Charge controller is reading that Im only pulling in 110 watts and itís very sunny out. My voltage reads 12.9v which is low and only 2.8 amps. Should I wire my panels in a different configuration?

Thanks,

Elias
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Old 10-04-2019, 02:11 PM   #2
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What are you using to get your readings from?
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Old 10-04-2019, 02:15 PM   #3
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What are you using to get your readings from?
The tristar morningstar ts-m-2 digital meter. Itís just a meter that connects to my Tristar charge controller.
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Old 10-04-2019, 03:19 PM   #4
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Originally Posted by yippie! View Post
So I have just finished wiring all my solar components together. I have (6) 100 watt 12 v solar panels wired in series/parallel down into a 45 mppt Tristar. Everything is on and running but my Charge controller is reading that Im only pulling in 110 watts and it’s very sunny out. My voltage reads 12.9v which is low and only 2.8 amps. Should I wire my panels in a different configuration?

Thanks,

Elias
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Old 10-04-2019, 03:27 PM   #5
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Originally Posted by yippie! View Post
So I have just finished wiring all my solar components together. I have (6) 100 watt 12 v solar panels wired in series/parallel down into a 45 mppt Tristar. Everything is on and running but my Charge controller is reading that Im only pulling in 110 watts and it’s very sunny out. My voltage reads 12.9v which is low and only 2.8 amps. Should I wire my panels in a different configuration?

Thanks,

Elias
What exactly do you mean by "wired in series/parallel"? Can you draw or describe how the 6 panels are connected.

Also, 2.8 Ampere @ 12.9 Volt is nowhere near 110 Watt; more like 36.12 Watt. If the values you posted were seen on the controller display roughly at the same time, I would assume that the controller has 'lost its mind' and needs to be serviced or replaced.
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Old 10-04-2019, 03:30 PM   #6
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Yeah sorry I just realized I was giving you the numbers from the two diff times I checked. It was at 110 earlier when it was sunny and then dropped down to 37 or so when it was cloudy and that was when I read the 12.9v and 2.8A. When it was at 110 it was at about 13.4v and 4.5A. Which still doesnt add up.
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Old 10-04-2019, 03:38 PM   #7
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What exactly do you mean by "wired in series/parallel"? Can you draw or describe how the 6 panels are connected.

.
Either 3S2P or 2S3P..

Two strings, of three three panels in series, connected in parallel or three strings of two panels in in series connected in parallel.
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Old 10-04-2019, 03:49 PM   #8
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Either 3S2P or 2S3P..

Two strings, of three three panels in series, connected in parallel or three strings of two panels in in series connected in parallel.
What was it for the measurements posted?

And what is the voltage of your battery bank?
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Old 10-04-2019, 03:54 PM   #9
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Yeah sorry I just realized I was giving you the numbers from the two diff times I checked. It was at 110 earlier when it was sunny and then dropped down to 37 or so when it was cloudy and that was when I read the 12.9v and 2.8A. When it was at 110 it was at about 13.4v and 4.5A. Which still doesnt add up.
12.9 times 2.8 is close enough to 37 but you are right that the voltage and current for the 110 Watt reading is way off. Something is goofy there.

Do you have a multimeter that can measure higher currents or a clamp-on Amp probe?
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Old 10-04-2019, 04:47 PM   #10
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I’m more concerned that 2 12v banks wired in series is giving 12v

Unhook everything and start over, starting with testing each panel individually. Something is seriously wrong...
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Old 10-04-2019, 05:05 PM   #11
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What was it for the measurements posted?

And what is the voltage of your battery bank?
I was answering your question. "What is series/paralell"

Not sure how it is relevant but my battery bank is 24 volt.
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Old 10-04-2019, 06:29 PM   #12
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I was answering your question. "What is series/paralell"

Not sure how it is relevant but my battery bank is 24 volt.
Oops, I did not pay attention to who was answering my question and assumed it was the OP. Now, the ambiguous answer -how the panels could be wired instead of how they are wired- makes more sense.

So we still do not know how the OP wired the panels in what he called "series/parallel" and we do not know what wiring he needs depending on his battery voltage.

3S2P ~36 Volt but 2S3P ~24 Volt with 6 panels rated at 12 Volt each.

BTW: Did you get my PM yesterday?
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Old 10-04-2019, 09:51 PM   #13
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Iím more concerned that 2 12v banks wired in series is giving 12v

Unhook everything and start over, starting with testing each panel individually. Something is seriously wrong...
Two 12v banks in series will yield 24 volts.

Series batteries the voltage is additive and the a/h rating stays the same. Two 12v 150a/h batteries in series you will have a 24v 150a/h bank.

Parallel batteries the a/h rating is additive and voltage remains the same. Two 12v 150a/h batteries in parallel you will have a 12v 300a/h bank.
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Old 10-04-2019, 10:14 PM   #14
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I don’t understand your point I already know that that’s why I told him that it doesn’t make sense

Or was that meant for the OP?
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Old 10-04-2019, 10:47 PM   #15
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I donít understand your point I already know that thatís why I told him that it doesnít make sense

Or was that meant for the OP?
"Iím more concerned that 2 12v banks wired in series is giving 12v"

No. Two 12v banks in series will yield a 24v bank.
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Old 10-04-2019, 10:49 PM   #16
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"Iím more concerned that 2 12v banks wired in series is giving 12v"

No. Two 12v banks in series will yield a 24v bank.

Right, so the fact that the OP is reporting that itís not is a big concern....
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Old 10-05-2019, 09:53 AM   #17
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Originally Posted by yippie! View Post
So I have just finished wiring all my solar components together. I have (6) 100 watt 12 v solar panels wired in series/parallel down into a 45 mppt Tristar. Everything is on and running but my Charge controller is reading that Im only pulling in 110 watts and itís very sunny out. My voltage reads 12.9v which is low and only 2.8 amps. Should I wire my panels in a different configuration?

Thanks,

Elias
If you wire 6 100 watt panels in series the watts and amps stay the same but the voltage increases. If you wire them in parallel the watts increase and amps increase but the voltage stays the same. You should be reading in the 60+ volts on that system. Your wiring or connections could be faulty. Take a multi meter and check the output at each connection in the series. It should increase voltage at each jump.
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Old 10-05-2019, 10:33 AM   #18
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solar

Hopefully you put some breakers or fuses inline so you can disconnect each panel or at the very least disconnect all the panels from the charge controller, makes your life easier when needing to test or replace items, same thing goes with a breaker between the charge controller and the batteries.
Each battery will need a 30 to 40 amp breaker/fuse on the positive wire to prevent surges in case of a damaged battery.


I would suggest you either turn off the charge controller or disconnect the panels or cover them for a few days, then at noon on a sunny day reconnect them, then ever few minutes for 30 minutes check their voltage, when it is in the beginning states of bulk charging it should hit 14.4 to 14.8v, with the lower volts you are getting it could just mean the batteries are topped off and dont need full bulk charging.


For my system I have six 150watt panels, hooked up in pairs on the roof for 24v, these 3 pairs them come down and connect in the bus to a 80 amp QO square D house breaker panel, this panel serves as a combiner box and as handy on/off switches, the wire then feeds to my charge controller, another 12v breaker, it then feeds to my positive and negative bus bars, which then feed individual wires to my 12v batteries, which are hooked up to provide 12v to my inverter.


I connected a 20 slot 12v fuse panel to the bus bar to feed items that need 12v, which allows me to add appropriately sized fuses as needed.
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Old 10-05-2019, 11:04 AM   #19
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+1 for troubleshooting by testing one string at a time.
Are you connected to your battery bank? If so, is it full?
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Old 10-05-2019, 12:26 PM   #20
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Quote:
Originally Posted by yippie! View Post
So I have just finished wiring all my solar components together. I have (6) 100 watt 12 v solar panels wired in series/parallel down into a 45 mppt Tristar. Everything is on and running but my Charge controller is reading that Im only pulling in 110 watts and it’s very sunny out. My voltage reads 12.9v which is low and only 2.8 amps. Should I wire my panels in a different configuration?

Thanks,

Elias
So, a couple of things:
- Background Info:
1. the power output will be dependent on both how sunny it is AND how low your batteries are and what "stage" the charge controller is in. They only time you'll see max power drawn is when the batteries are discharged ( about 12.5V or so, assuming you have a 12V battery bank).

2. most MPPT charge controllers are "buck" inverters, meaning the output voltage must be lower than the input voltage by some amount. Configuring the series/parallel arrangement tends to be a tradeoff between total current, "shadow" sensitivity and maximum input voltage capability of the SCC (charge controller). With only six panels, I doubt you would exceed the SCC max input voltage so I would recommend connecting groups of 3 panels in parallel and then series connecting those groups (~ 15A) OR groups of 2 panels in parallel and series connecting those groups (~ 10A)... Depending on whether you've installed large enough wire (~8# for 15A, ~10# for 10A)

3. The SCC is an Inverter. this means it converts whatever input voltage you have to the output voltage you need for the batteries, all the while maintaining as close to 100% efficiency (power in -> power out). So, if the input voltage is 24V @ 4 A, the output to the battery would be around 12V @ 8 A.


I have to assume you do have a battery bank connected, right?

So.. If your meter is reading the battery voltage (probably). At 12.9V, you would most likely be in the "bulk" charging phase. You should be getting several hundred watts on a sunny day.. check your wiring ?

If your meter is reading the Solar array voltage, it's way too low for a 12V battery AND for any series parallel arrangement (unless it's a boost type inverter). again, Check the wiring.

If the current reading is only 2.8A, This is indeed really low at full sun and a not fully charged battery...

And I have to ask, you did connect series as + to -, parallel connections are + to + and - to -, Right?
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