low output from charge controller

[almac]

Where is it going? Again power does not vanish. Where that power is going is generating a whole lot of heat, enough it would burn up your controller unless you put a pot of water on it to boil and keep cool.

you tell me where the power goes when a battery is nearly full and the amps trail off. where is it going? all CCs do this

[Sunking]

you tell me where the power goes when a battery is nearly full and the amps trail off. where is it going? all CCs do this

Wrong. the power goes no where, it simply tapers off to ZERO. Just like a light switch, you turn it off and no power is transferring from one location to another.

You cannot make or destroy energy. You can only convert it from one form to another. It is the very simple basic laws of physics.

[almac]

Wrong. the power goes no where, it simply tapers off to ZERO. Just like a light switch, you turn it off and no power is transferring from one location to another.

You cannot make or destroy energy. You can only convert it from one form to another. It is the very simple basic laws of physics.

sure most of us know this. and you can even convert energy to matter as happens in a supernova where all heavy elements heavier than iron are made in a fusion reaction that requires energy to fuze elements heavier than iron. wow. but my problem relates to my little cheap chinese CC. i know its not sucking up all that 15amps because its not getting hot. and its not giving it to my batteries that greedy little CC. i think mike was on the money when he suggested it might be in absorb mode. because when i put a load on the batteries.. presto the cc kicks out 14amps. so how do i trick this CC to stay in bulk mode

[Raul]

Some have a temperature compensating us much as 30mvpc and the temperature will throw it in float sooner; if is a cheap Chinese you can't expect it to function half decent .

[Sunking]

sure most of us know this.

Apparently you do not or else you would know what is wrong.

but my problem relates to my little cheap Chinese CC. i know its not sucking up all that 15amps because its not getting hot.

It has to go somewhere. That is what you do not understand. You are confusing volts and amps with power. It does not matter if your controller has 480 volts at 1 amp going in (480 watts), if it only has 29 volts @ 5 amps or 145 watts going out, the controller has to be burning off the missing 335 watts as heat. It is very simple math. So if the controller is not getting hot, Houston we have Operator Error who has made a mistake in measurements.

i think mike was on the money when he suggested it might be in absorb mode. because when i put a load on the batteries.. presto the cc kicks out 14 amps. so how do i trick this CC to stay in bulk mode

Either Mike misunderstood you, or you misunderstood him. Mike will be the first to confirm what I and everyone else is trying to tell you.

OK having said that, if you turn on a load when the batteries are charged up, and the panels have sufficient Sun and capacity, the current will increase from the panels. But at the end of the day all power = 0. 335 watts does not vanish.

If your panels are generating 100 watts, every watt has to have a place to go and the Equation must be true and equal 0.

P1 = Panel Watts
P2 = Controller Watts Conversion Loss as heat
P3 = Power to Batter.

P1 - P2 - P3 = 0 Watts all day long even in Chi-Com math. If your controller efficiency is say 95%, then it burns 5 watts out of every 100 passing through it.

So where is the missing 335 watts? My bet it is not missing and Operator Error.

[almac]

Apparently you do not or else you would know what is wrong.



It has to go somewhere. That is what you do not understand. You are confusing volts and amps with power. It does not matter if your controller has 480 volts at 1 amp going in (480 watts), if it only has 29 volts @ 5 amps or 145 watts going out, the controller has to be burning off the missing 335 watts as heat. It is very simple math. So if the controller is not getting hot, Houston we have Operator Error who has made a mistake in measurements.

Either Mike misunderstood you, or you misunderstood him. Mike will be the first to confirm what I and everyone else is trying to tell you.

OK having said that, if you turn on a load when the batteries are charged up, and the panels have sufficient Sun and capacity, the current will increase from the panels. But at the end of the day all power = 0. 335 watts does not vanish.

If your panels are generating 100 watts, every watt has to have a place to go and the Equation must be true and equal 0.

P1 = Panel Watts
P2 = Controller Watts Conversion Loss as heat
P3 = Power to Batter.

P1 - P2 - P3 = 0 Watts all day long even in Chi-Com math. If your controller efficiency is say 95%, then it burns 5 watts out of every 100 passing through it.

So where is the missing 335 watts? My bet it is not missing and Operator Error.

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?

[almac]

When the controller is outputting low amps, try turning on a substantial load, and see if the controller produces more power as the battery voltage sags. It may be that the bulk stage of the charge is done, and you are in Absorb.

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

[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.

[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.

[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]

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]

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.

[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]

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

[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.