low output from charge controller

[inetdog]

thanks for all your replies and help with this, it seems i have corrected this problem, it was a loose connection on the gator clip on the end of the cable from the CC, i didnt solder the cable to the gator clip , instead had only crimped them on. i have soldered these and now i get full current. 15amps+

Glad to hear that you found it.
If you used the proper connector and proper crimp tools (not just mashing with pliers) the connection should have been as good in terms of resistance as a soldered connection and would have better mechanical properties.
One problem with soldering, especially with stranded wire, is that you get a stress concentration that will eventually break the wire unless you have strain relief beyond the point where the wire is coated with solder.

[almac]

thanks for all your replies and help with this, it seems i have corrected this problem, it was a loose connection on the gator clip on the end of the cable from the CC, i didnt solder the cable to the gator clip , instead had only crimped them on. i have soldered these and now i get full current. 15amps+

[almac]

They are not in-line, they are clamp-on.

There are two types.

1. That come as either an add-on to a multimeter.

2. Permanent installation with a Hall Effect Transducer.



However at the current ranges of solar they are not real accurate except for industrial models. The most accurate are shunts which are just precision power resistors.



However all of them are pretty much toys and not of much use. For you save your coins and buy a good 150 Voc MPPT controller because what you have now is not going to work. With 3 panels you only have two options:

1. Buy another 4th panel configure panels 2 x 2, and buy a real MPPT controller with a minimum 100 Voc input.

2. The other option is to buy a MPPT controller with a 150 Voc input like a Midnite Solar Kid 30 amp controller, and wire your 3 panels in series.



Take your pick.

thanks, i already have 7 x of these panels. so only need another CC

[Sunking]

that what need, place that inline so i know what is going through the CC

They are not in-line, they are clamp-on.

There are two types.

1. That come as either an add-on to a multimeter.

2. Permanent installation with a Hall Effect Transducer.



However at the current ranges of solar they are not real accurate except for industrial models. The most accurate are shunts which are just precision power resistors.



However all of them are pretty much toys and not of much use. For you save your coins and buy a good 150 Voc MPPT controller because what you have now is not going to work. With 3 panels you only have two options:

1. Buy another 4th panel configure panels 2 x 2, and buy a real MPPT controller with a minimum 100 Voc input.

2. The other option is to buy a MPPT controller with a 150 Voc input like a Midnite Solar Kid 30 amp controller, and wire your 3 panels in series.



Take your pick.

[SunEagle]

that what need, place that inline so i know what is going through the CC

The jaws on that clamp on opens up so you can enclose any wire to measure DC amps.

The inline amp meter I use in my RC systems is something like this.

[almac]

What about using a DC clamp on meter. While not the most accurate device it is pretty good telling me the amount of amps being sent down a wire.

DC Clamp on

that what need, place that inline so i know what is going through the CC

[SunEagle]

I do not know of any multi-meters that can read 15 amps with an inline shunt, not even $400 units. They go up to 10 amps max. We have operator error Houston.

You have to use either a Shunt or a Clamp-On Hall-Effect meter to read current with any accuracy. In other words all your test are invalid. If I had to bet your controller is PWM which means Input Current = Output Current. Makes not real difference with all your panels in parallel means you are going to be fighting undercharged batteries until they fail prematurely.

What about using a DC clamp on meter. While not the most accurate device it is pretty good telling me the amount of amps being sent down a wire.

DC Clamp on

[Sunking]

used method (a) because i can connect it for a few secs at most b4 the multimeter wires burst into flames. forget method (b). its a $10 chi-com multimeter. at least i know when it says 15amps im fairly sure its correct because the wires instantly get hot

I do not know of any multi-meters that can read 15 amps with an inline shunt, not even $400 units. They go up to 10 amps max. We have operator error Houston.

You have to use either a Shunt or a Clamp-On Hall-Effect meter to read current with any accuracy. In other words all your test are invalid. If I had to bet your controller is PWM which means Input Current = Output Current. Makes not real difference with all your panels in parallel means you are going to be fighting undercharged batteries until they fail prematurely.

[almac]

Ah Ha !!

So you used your handheld meter to measure amps. 2 ways to do it:
a) set meter to AMPS mode, and connect to the Solar + & - at the charge controller ?
or
b) set meter to AMPS mode and disconnect a solar wire at the charge controller and insert the meter "Inline" with the controller

Method (b) is the only one that will give a true reading of what is going through the controller. Method (a) will measure the total possible current the panels can put out.

Just because the panels can put out 200watts, does not mean they ALWAYS put out 200w. If you disconnect them, how much power do they put out ? None, because there is no power flow path - it's an open circuit.

Not many meters are capable to measure more than 10A of AC or DC current, so you either have a very special meter, or could be reading it wrong.

used method (a) because i can connect it for a few secs at most b4 the multimeter wires burst into flames. forget method (b). its a $10 chi-com multimeter. at least i know when it says 15amps im fairly sure its correct because the wires instantly get hot

[Mike90250]

ok thanks, i am using 2 different meters to tell me whats happening. one is the meter in the CC itself. the other is an external multimeter. i have tested the multimeter on known votages. i have faith it is correct. so that leaves the meter in the CC being incorrect. it is telling me it is feeding 5amps to the batteries while the multimeter is telling me the panels are feeding 15amps to the CC. so will i assume the meter in the CC is faulty?

Ah Ha !!

So you used your handheld meter to measure amps. 2 ways to do it:
a) set meter to AMPS mode, and connect to the Solar + & - at the charge controller ?
or
b) set meter to AMPS mode and disconnect a solar wire at the charge controller and insert the meter "Inline" with the controller

Method (b) is the only one that will give a true reading of what is going through the controller. Method (a) will measure the total possible current the panels can put out.

Just because the panels can put out 200watts, does not mean they ALWAYS put out 200w. If you disconnect them, how much power do they put out ? None, because there is no power flow path - it's an open circuit.

Not many meters are capable to measure more than 10A of AC or DC current, so you either have a very special meter, or could be reading it wrong.

[almac]

There is part of your problem.

No you are screwed. With 3 panels, a Prime number, you only have two options. All 3 in parallel or all 3 in series. That is what happens with Prime numbers.

Now if you had a real MPPT controller with a Voc input of 150 Voc you could wire all three in series. I suspect your controller will not even allow you to just use 2 of your panels in series. If the Voc input of your controller is less than 100 volts, you are screwed and can only operate into a 12 volt battery.

You would be just better off connecting all three panel in parallel directly to the battery than disconnect them when charged.

isnt 32v a bit high? today the CC is putting amps in amps out, it might have been loose connections to the gator clips.

[Sunking]

thanks, yes the vmp is 30.5v the voc is 37.8v

There is part of your problem.

. the 32v reading was done when the cc was putting a load on the panels. when read in voc its about 36v, have 3 x 250w panels in parallel. should i try 2 x in series?

No you are screwed. With 3 panels, a Prime number, you only have two options. All 3 in parallel or all 3 in series. That is what happens with Prime numbers.

Now if you had a real MPPT controller with a Voc input of 150 Voc you could wire all three in series. I suspect your controller will not even allow you to just use 2 of your panels in series. If the Voc input of your controller is less than 100 volts, you are screwed and can only operate into a 12 volt battery.

You would be just better off connecting all three panel in parallel directly to the battery than disconnect them when charged.

[almac]

I do not question the voltage, it is the current that is suspect, especially on the input and how it is being measured.

With a PWM controller Output Current = Input Current
With MPPT Output Current = Panel Wattage / Battery Voltage

Regardless if your controller is PWM or MPPT, some of them when in Absorb, Float or EQ modes the controller is operating in PWM mode. Only time you are working MPPT is in BULK on some of the MPPT controllers. Only your high end MPPT Controllers are boost in all modes. So you need to get your mind wrapped around that, and you ave a cheap Chi-Com unit which most are PWM and fraudulently labeled MPPT.

First thing is you need to know is: what is the total Vmp of your panels? It has to be at least 36 volts. You are seeing 32 volts which means one of two things.

1. Your controller is working in PWM mode.
2. You do not have a high enough panel Vmp voltage for a 24 volt battery. 36 volt is minimum requirement for both PWM and MPPT.

32 volts indicates you might have a problem with panel configuration of too low of a voltage. Like wiring your panels in parallel when they should be in series. If your panel Vmp total is say 60 volts, you should never see 32 volts. With a True MPPT the voltage will be as low as Vmp or as higgh as Voc when the controller cuts of. Example lets say you have two panels wired in series. Each panel has a Voc = 40 volts, and VMP = 30 volts. So total Voc = 80 volts, and Vmp = 60 volts. That means anytime you have sun on the panels you should be seeing 60 to 80 volts. If PWM anywhere from 80 volts down to Battery Voltage.

I am not trying to bust your balls, but walk you through this so you have an idea what is going on.

thanks, yes the vmp is 30.5v the voc is 37.8v . the 32v reading was done when the cc was putting a load on the panels. when read in voc its about 36v, have 3 x 250w panels in parallel. should i try 2 x in series? could it also have been a loose connection? just soldered the gator clips on the end of the leads. in a brief pocket of sunshine just now the cc put out 14amps. thats it for today. 5mins of sun , maybe 2mor

[Sunking]

here is mikes spin on the controller varying output. no mention of missing watts

I cannot read Mike's mind and what he was thinking at the time. He is right, but I think you have taken him out of context and heard what you though was right.

Just for the moment lets say it is high solar noon. Batteries are fully charged, in float mode, and no load is demanding power. At that point the panels are not generating any power. If you were to look at the panel voltage it would be Voc (voltage open circuit) or 80 volts in my example above because the controller has shut off. Essentially no current is flowing or 0 watts.

Now you turn on say a 200 watt device. Now you see 7.4 amps from the controller at 27 volts. You check panel voltage and it has dropped from 80 volts to 62 volts and 3.4 amps. What has happened is the controller is no turning on the panels and demanding 210 watts from them to supply your load of 200 watts. You batteries are just floating and all load power is supplied by the panels. It also means the controller is 95% efficient with 210 in, and 200 out. The controller is burning 10 watts as waste heat from the conversion. That is what I think Mike is telling you.

What it appears you are thinking is the panels produce power anytime sun hit them which is totally false. If the batteries are charged or close to being charged, very little power is taken from the panels because there is no place for it to go or being demanded.

In a normal charge cycle starting in the morning, the controller will convert as much power as the panels can to get the panels charged up in Bulk Mode aka Constant Current. As the batteries charges they reach Absorb which is a constant Voltage mode. In a constant Voltage mode current and power are going to taper down to 0 when the batteries are fully charged. So at noon no power is being generated or used. You cannot put any more gas in a full tank.

[Sunking]

ok thanks, i am using 2 different meters to tell me whats happening. one is the meter in the CC itself. the other is an external multimeter.

I do not question the voltage, it is the current that is suspect, especially on the input and how it is being measured.

With a PWM controller Output Current = Input Current
With MPPT Output Current = Panel Wattage / Battery Voltage

Regardless if your controller is PWM or MPPT, some of them when in Absorb, Float or EQ modes the controller is operating in PWM mode. Only time you are working MPPT is in BULK on some of the MPPT controllers. Only your high end MPPT Controllers are boost in all modes. So you need to get your mind wrapped around that, and you ave a cheap Chi-Com unit which most are PWM and fraudulently labeled MPPT.

First thing is you need to know is: what is the total Vmp of your panels? It has to be at least 36 volts. You are seeing 32 volts which means one of two things.

1. Your controller is working in PWM mode.
2. You do not have a high enough panel Vmp voltage for a 24 volt battery. 36 volt is minimum requirement for both PWM and MPPT.

32 volts indicates you might have a problem with panel configuration of too low of a voltage. Like wiring your panels in parallel when they should be in series. If your panel Vmp total is say 60 volts, you should never see 32 volts. With a True MPPT the voltage will be as low as Vmp or as higgh as Voc when the controller cuts of. Example lets say you have two panels wired in series. Each panel has a Voc = 40 volts, and VMP = 30 volts. So total Voc = 80 volts, and Vmp = 60 volts. That means anytime you have sun on the panels you should be seeing 60 to 80 volts. If PWM anywhere from 80 volts down to Battery Voltage.

I am not trying to bust your balls, but walk you through this so you have an idea what is going on.