# 15 amp meter Help

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## Comments

• Registered Users Posts: 360 ✭✭✭
edited June 2016 #32
watts measurement goes like this.    amps X volts = watts so for the 1st panel you listed...

2.6 X 21.2 = 55 watts

Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

21 SW280 panels on Schletter ground mount

48v Rolls 6CS 27P

• Registered Users Posts: 20 ✭✭
Thank you guys for the help.
• Super Moderators, Administrators Posts: 32,741 admin
OK--Approximately 21 volts at the solar panels? What charge controller do you have (was it a MorningStar PWM TS model?)?

That is a "high voltage" for these panels if your battery is less than 80% charged. Two possibilities--1) you have too long of wire runs with to small of diameter cables--or 2) the charge controller "thinks" the battery is fully charged and cutting back on current usage from the solar panels (and/or you have too long/too small of cables from battery bank to charge controller and/or bad electrical connections)--Or 3) charge controller is not programmed correctly or has some other issue.

What is the voltage at the charge controller terminals? The input voltage from the array and the output voltage to the battery bank in the middle of the day?

With a PWM charge controller and a battery bank at less than 80% state of charge, the voltage on the solar array should be around 15-16 volts maximum. Running at ~21 volts usually means that the charge controller is not taking 100% of the available current from the solar array (note--Digital volt meters can be "confusing" when reading "pulsed" DC voltages--They "sample" the voltage and you may read the minimum or maximum voltage at any particular point in time).

If you put a jumper wire from the solar array + to the battery + terminals--That will simulate the charge controller being full "on"--And you can measure voltages/current and see what your system is capable of.

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Registered Users Posts: 20 ✭✭
I have a mppt CC from my panels to my cc it's about 34 ft with 10 awg cable . All other cables are 8 awg and 2 awg.
• Registered Users Posts: 20 ✭✭
I have fog just about every day it will clear up for about 2 or 3 hours that's when I try to test my amp meter or hook it up . What am I doing wrong this is my second analog amp meter
This is a 30 amp analog meter with a built in shunt . Am I wiring this wrong? When I hook this up the needle will move to around 5 amps it will hold for about 20 seconds or so then go's back to 0 won't move Again at all.... I took a picture. One wire go's to the + cc the other one to the + incoming solar panels.
• Super Moderators, Administrators Posts: 32,741 admin
Probably OK (keep battery to charge controller relatively short).

Can you measure the voltage at the charge controller connections with a volt meter (Vpanel input; Vbatt output) in the middle of a sunny day with you battery "needing charging" (less than 80% full)?

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Registered Users Posts: 20 ✭✭
I will do that , like I said before most of the time it's foggy ... as for my amp meter is it wired right?
• Super Moderators, Administrators Posts: 32,741 admin
I guess yes...

I lived my first 30 years in Pacifica--And I know that there are summers and locations in the area where you might not see sun for the whole summer.

Even if it is foggy, can you measure the voltages on the charge controller terminals during middle of the day? It will help with the 30% state of charge indicator on the charge controller.

If you do not have enough sun--You may need to connect a battery charger to the battery bank... Letting lead acid batteries sit at 30% state of charge for days/weeks/months will kill the batteries pretty quickly.

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Registered Users Posts: 20 ✭✭
At the CC it's 20.7 V ,CC 12v it's at 14.5 charging. It later drops and holds at 12.8
• Registered Users Posts: 20 ✭✭
Am in Daly City, am not using the battery's at all right know on a good day I'll use my inverter to charge all my small rechargeable batteries am trying to figure out my problems befor I use them daly..
• Super Moderators, Administrators Posts: 32,741 admin
For AGM batteries, ~14.4 volts is the set point, so 14.5 is certainly "close enough"--Batteries are being charged and if this is common during the day (i.e., holds a few hours at 14.4 volts every day)--The batteries are probably nearly fully charged.

12.8 at night is a fully charged lead acid batteries (although, AGMs sometimes hold closer to 13.0 volts sometimes).

The 20.7 volts on the solar panel side--Usually indicates that the charge controller is drawing less than full current from the array (sometimes the voltage is approximately ~15-16 volts when the controller is "on" and ~21 volts when the controller is "off" -- The controller turns "on/off" quickly to give an "average current" to the battery bank to maintain ~14.4 volt volts).

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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