low output from charge controller

[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

[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?

[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.

[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 .

[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

[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]

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]

in my case the input voltage from the panels is 32v, the output voltage to the batteries is 28.8v. not much difference. its the current that is much less. 15 amps in 5 amps out, maybe my CC is not taking that spare 10amps. i took the reading on the cable out of the solar panels b4 the cc

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.

I still suspect operator error, because if you really had 480 watts going in, and only 145 going out, that missing 335 watts would cause your controller to burst into flames in a very short period of time being burnt off as waste heat. 335 watts of resestive heat = a 1150 BTU burner about the size of a small camp stove burning alcohol to make a pot of coffee.

[almac]

Very very simple: They do not take it from the panels in the first place!
A solar panel will be perfectly content to sit in full sun with an open circuit, not producing any electricity and just getting a little hotter over its entire area from the absorbed solar radiation. Or it will happily produce half of the Imp number at a voltage somewhat above Vmp. The load would then get about half the available panel power, and an MPPT CC would feed most of that to the battery, in form of higher current at the lower battery voltage.
It is the combination of high terminal voltage at the input of the CC and low battery voltage at the output of the CC with the same current on both sides that tells you that the CC is dissipating the missing power somewhere.

in my case the input voltage from the panels is 32v, the output voltage to the batteries is 28.8v. not much difference. its the current that is much less. 15amps in 5 amps out, maybe my CC is not taking that spare 10amps. i took the reading on the cable out of the solar panels b4 the cc

[almac]

OK so what is RED HOT and GLOWING in the dark?

Power cannot vanish, where is it going?

where does it go when the batteries are full?

[inetdog]

if this is the case with all CCs what do they do with the energy when the batteries are full??

Very very simple: They do not take it from the panels in the first place!
A solar panel will be perfectly content to sit in full sun with an open circuit, not producing any electricity and just getting a little hotter over its entire area from the absorbed solar radiation. Or it will happily produce half of the Imp number at a voltage somewhat above Vmp. The load would then get about half the available panel power, and an MPPT CC would feed most of that to the battery, in form of higher current at the lower battery voltage.
It is the combination of high terminal voltage at the input of the CC and low battery voltage at the output of the CC with the same current on both sides that tells you that the CC is dissipating the missing power somewhere.

[almac]

Impossible violates the Laws of Physics. It is impossible to have 480 watts Into the controller and only 145 watts outs. Your measurements have to be either wrong, making it up, or your controller is a Hot Plate made for cooking.

Now 480 in and 460 out is a real number meaning your controller is 95% efficient and burning 20 watts of waste heat, but if you really had 480 in and only 145 out your controller would be on fire burning off 335 watts. You have to be doing something wrong or leaving something out.

if this is the case with all CCs what do they do with the energy when the batteries are full??

[Sunking]

thanks for the replies, now i will get rid of the assumptions. i measured the input from the panels at the end of the cable to the CC. 15amps at 32v = 480w. my panels are 3 x 250w panels =750w. its winter here often cloudy so when i took the readings it was a panel INPUT of 32v at 15amps =480w. the CC was providing 5amps at 28.8v =about 145w

OK so what is RED HOT and GLOWING in the dark?

Power cannot vanish, where is it going?

[almac]

Perhaps I can only take him at his word when he said:



If that is true and he has a PWM controller then he would see 31 volts @ 15 amps on the output. If MPPT them would be 16.5 amps at 29 volts.

Now if he assumed he had 32 volts @ 15 amps on the input, and measured with 29 volts at 5 amps, he made an error because he did not measure the input. Thus why I say it is impossible and he had to make an error.

Most likely he just assumed 485 watts. At 29 volts tells me he is already passed 100% SOC and in over charge or EQ. You know what I know Mike, Power does not vanish, the equations have to = 0. Otherwise you believe in Santa Clause, Free Energy, and Perpetual Motion.

thanks for the replies, now i will get rid of the assumptions. i measured the input from the panels at the end of the cable to the CC. 15amps at 32v = 480w. my panels are 3 x 250w panels =750w. its winter here often cloudy so when i took the readings it was a panel INPUT of 32v at 15amps =480w. the CC was providing 5amps at 28.8v =about 145w , the hydrometer readings on my 24v 250ah battery bank put them at 75%. SG 1.225. when i put the batteries on the dc charger off the gen, takes full charge 40amps on a 14.4v charge with the batteries reconfiged for 12v 500ah

[Sunking]

He's likely saying "I have 480 watts of panels and 145watts of charging".

Perhaps I can only take him at his word when he said:

panel output would be 32v x 15amps = 480w

If that is true and he has a PWM controller then he would see 31 volts @ 15 amps on the output. If MPPT them would be 16.5 amps at 29 volts.

Now if he assumed he had 32 volts @ 15 amps on the input, and measured with 29 volts at 5 amps, he made an error because he did not measure the input. Thus why I say it is impossible and he had to make an error.

Most likely he just assumed 485 watts. At 29 volts tells me he is already passed 100% SOC and in over charge or EQ. You know what I know Mike, Power does not vanish, the equations have to = 0. Otherwise you believe in Santa Clause, Free Energy, and Perpetual Motion.