Author Topic: Troubleshooting Lost Watts  (Read 1500 times)

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Offline fourtytwo42

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Re: Troubleshooting Lost Watts
« Reply #25 on: March 31, 2019, 05:06:51 pm »
Because you had a whine and a sook about the comments I made, carried on about safety and regulations and then posted a pic clearly showing you are not meeting the standards you carry on about yourself.

When you going to do that test on the AC breakers to show how stupid and irresponsible my comments were?

Really, and in what way in your world of pathetic insults does that picture infringe on anything ?
 

Offline f4eru

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Re: Troubleshooting Lost Watts
« Reply #26 on: March 31, 2019, 09:17:33 pm »
Guys, dont play with electrical and fire safety.
Solar panels are mostly dangerous.
Breakers are not only necessary for electrical safety, but also for fire safety.

An example how modern safety norms classify electrical and fire hasards:
(in this case IT equipment norm EN62368)




ES1 is not dangerous to touch (except when wet)
ES2 is dangerous and needs one protection
ES3 is dangerous and needs two protections

Note that you can limit either current OR voltage:

max limits for safe to touch in dry conditions :
60V DC
30V RMS AC <1kHz
30 to 70V AC >1kHz
Combination AC+DC have special rules

or

2mA DC
0,5mA AC

p12: https://www.ofca.gov.hk/filemanager/ofca/en/content_751/SSAC_Paper_7_2018.pdf

Fire hasards have separate limits.
« Last Edit: March 31, 2019, 09:22:17 pm by f4eru »
 
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Offline fourtytwo42

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Re: Troubleshooting Lost Watts
« Reply #27 on: April 01, 2019, 05:53:46 am »
And to the OP I am sorry for the spat on your thread, I hope you got the gist of whats appropriate, DC breakers for DC right :) And they can be found for a reasonable cost, I got lucky a guy was unloading some excess stock, just check the spec before you buy.
 
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Offline Zero999

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Re: Troubleshooting Lost Watts
« Reply #28 on: April 01, 2019, 07:28:04 pm »
Guys, dont play with electrical and fire safety.
Solar panels are mostly dangerous.
Breakers are not only necessary for electrical safety, but also for fire safety.
Yes, it's power which causes heating and fire. P = VI.  The voltage could be under 4V from a single cell lithium battery, but a short circuit could result in hundreds of amps, causing a large amount of power to be dissipated in a small area and a lot of heat, resulting in fire.
 

Offline paulca

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Re: Troubleshooting Lost Watts
« Reply #29 on: April 02, 2019, 07:02:01 pm »
The thing to remember about some electrical equipment is "Will you be there when it does fail?".  So working on stuff in the lab or stuff that's only on when you are there to hit the kill switch and/or the fire extinguisher you can play "I'm a big boy, it doesn't frighten me, I know what I'm doing", all you want.



The stuff that you want to leave running while you are out of the house or in bed or that you will leave running while your children play in the house, needs far, far more respect.

On topic.  When taking readings from the MPPT charge controller, remember it will vary the power it takes from the panel by varying the voltage across the panel.  As the battery nears fully charged with no load on it it will allow the panel voltage to rise out of the MPP and the current to fall to balance the charge current to the battery.  With a fully charged battery and no load on my 50W panel the voltage will rise to open circuit voltage and the panel produce nearly zero power, even in direct sunlight (in reality it produces the battery float trickle power).  I think the only way to really test the max power output is to saturate the load with a load that will pull more than the panels can theoretically achieve.  At least enough for the battery to be providing some of the power.  Even then it varies a lot due to insolation.

Also, excuse me if I read wrong, but your charge controller support 12V and 24V systems and claims a maximum of 100V.  I'm fairly sure this does NOT mean you can run 100V of panels into it.  It simply means that when it raises the panel voltage to lower the power your 24V panels can produce at most 100V safely and not fry the charge controller.  Some panels produce close to twice their optimal voltage when open circuit, so that would be 48V and stating an upper limit of 100V just sounds like engineering grace (doubling), not an excuse to run 100V of panel into it.   4x12V panels open circuit will hit as high as 80-100V leaving zero grace on that limit.
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Current Open Projects:  3 Channel Audio mixer with DAC, BT, pre-amps and h/phone amp, WS281x LED controller Version 2 5V/5A w/Atmega328, FY6600 Power supply, 5A DC Load (Still!)
 
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