Solar Panel System Troubleshooting - Charging Battery

[Wolst73]

Do I still need shunt if I can measure amps?

 

[jim hardy]

Do I still need shunt if I can measure amps?

No, just use the ammeter.
You always start your measurement on a high scale and switch down until you get a reading. That way you don't overrange the meter.

 

[sophiecentaur]

No one has picked up on my idea of a Hall meter. That takes care of the connection problem. Not as cheap as the meters mentioned here but sooo useful.

 

[sophiecentaur]

No one has picked up on my idea of a Hall meter. That takes care of the connection problem. Not as cheap as the meters mentioned here but sooo useful. Has anyone else used one?

 

[Jenab2]

I use a similar system for charging flashlight batteries, except that my batteries are Universal 12V lead-acid with 35 mAh, and my solar panels are rated at 50 watts. I use a cheap voltage regulator between the panel and the 12V batteries. I normally discharge the battery into a 1000W (continuous) COBRA 12VDC to 120VAC power inverter, which supplies "house current" voltage through a pair of normal-looking "wall socket" plugs, but it also has a 5V USB charging port. When I charge 18650 batteries, I put them into a small "wall socket charger" and plug them into the 120V plugs on the power inverter. I have similar charger devices for 9V (actually 8.3V) rechargeable batteries, for AA and AAA NIMH batteries, for 3.9V lithium-ion batteries of a size similar to AA and AAA, and for those squat li-ion batteries that are as wide in diameter as 18650 batteries but only half as tall.

 

[jim hardy]

Hall meter would be great. It's difficult to find one with a 1 amp range. I have an old Fluke DC clamp-around with 20 amp range. 20 turns through it would be perfect
the new ones are pricey
http://get.fluke.com/376-fc/?gclid=CJaApsHW3M0CFQMHaQodvnsLyA

An old fashioned dc panel meter in the panel line might make a nice addition to his system
http://www.ebay.com/itm/1pcs-1A-Ana...716457?hash=item43e1a85da9:g:u-IAAOxyyUtScg0q

 

[Wolst73]

No one has picked up on my idea of a Hall meter.

I've looked! Didn't find anywhere to buy from around here. Ordered new multimeter from Amazon last night. Should be here tomorrow. Love Amazon Prime! (Walmart multimeter..."not available in stores").Will the dc panel meter blow if amps are greater than 1? Panel says it "can" produce 1.23? Postal strike looming here (Friday) so ordering off eBay may take a while.

 

[jim hardy]

Will the dc panel meter blow if amps are greater than 1? Panel says it "can" produce 1.23?

it'll just peg high
i was looking for a 2 amp meter

here's where i think we're headed

generic PV characteristic from a random website, http://www.pveducation.org/
http://www.pveducation.org/pvcdrom/solar-cell-operation/short-circuit-current

now this charge controller is 20 amp capacity , at 12 volts that's 240 watts
you're using it at 1.2 amps, maybe 6% of that capacity
and at 13 volts that'd be 13 volts X 1.23 amps = 16 watts
maybe less if your high latitude means lower irradiance
noplace have i found what are the charge contoller's internal losses all they say is "high efficiency"
let us assume they're only 2% of its 240 watt capacity, which would be 4.8 watts
leaving you 11.2 watts to charge the battery

step 3 will tell us a lot i hope...



old jim

 

[jim hardy]

interesting insolation estimator here
http://www.pveducation.org/pvcdrom/properties-of-sunlight/calculation-of-solar-insolation

latitude effect shows less than i expected
try sliding the day to today's date and latitude to yours

it says you should do well this time of year, perhaps as well as the tropics because of long days !
Best noontime intensity is right under the sun, latitude 23 .

 

[Wolst73]

And given that anorlunda and I both think your battery is nearly, or already toast, I would recommend setting everything up to charge the battery until then.
And NO Lights!

Green light on battery indicator on charge controller was on when I got home. Took a bit longer this time I would say. Lights are unhooked from it. According to poorly English translated manual, green light means normal voltage, green flashing light means fully charged. Have never seen that... Will let you know on Saturday the state of things.

 

[sophiecentaur]

latitude effect shows less than i expected

That latitude effect applies for a fixed installation over the whole year with the optimum alt az setting. Pointing the panel at the Sun on a Summer's day will give more than a fixed panel is likely to produce. Leaving the panel in that position will produce rubbish output in winter. It must always be worth while chasing the Sun if you can access the panel.

 

[Wolst73]

Ignore numbers on meters above. Borrowed pic off YouTube.

1. Hooked up as above without the volt measurement. Measured 0.02amps.

2. Hooked up from solar panel as follows. Positive wire from panel into charge controller. Negative wire of panel to red terminal of multimeter. Black of multimeter into negative of charge controller. Measured -0.02amps.

Voltage of panel showing about 19v. Voltage at charge controller terminals for panel and battery 11.8.

 

[sophiecentaur]

If I were in your shoes, I would be measuring pretty well everything that I could and under all conditions. You need short circuit current from the panel with full Sun, charge current with a charged battery and with a battery after it's been discharged to,say, half it's rated capacity. Measure, measure and measure again or the real problem will slip down a crack in your floorboards. We can't help if we don't know much more. Every combination of charge, sunlight and discharge may be needed here. (That's not really much trouble is it?)
I must say, it looks as if the regulator could be the problem but, without many more measurements, you (we) can't have a clue about the real situation. Trying to fault find by remote control is very hard for all the experienced brains that you are connected to here. (Myself not particularly included )

 

[jim hardy]

It's hard to troubleshoot from somebody else's observations
you're always not quite sure exactly what they meant..

2. Hooked up from solar panel as follows. Positive wire from panel into charge controller. Negative wire of panel to red terminal of multimeter. Black of multimeter into negative of charge controller. Measured -0.02amps.

something wasn't allowing current to flow from the panel into the charge controller.

Voltage of panel showing about 19v.
? 19 volts at one end of the wires ?
Voltage at charge controller terminals for panel...11.8.
11.8 volts at other end of wires ?

and battery (11.8) it's sure not connected to that 19 volt solar panel, is it ?

hmmmmm lessee here

Where's the disconnect ?
I'd check connections on back of solar panel

You're reporting 7.2 volts drop along a wire
that should be easy to find

then check for current by steps 1, 2, and 3

 

[sophiecentaur]

The dreaded 'remote control' problem, Jim.

 

[jim hardy]

The dreaded 'remote control' problem,

along the lines of

“ I know you think you understand what you thought I said but I'm not sure you realize that what you heard is not what I meant”― Alan Greenspan

 

[Wolst73]

End of wires coming from solar panel show 19v. But when hooked up to charge controller with battery hooked up, they show 11.8 which is the same as what battery terminals show. Same as what this showed:


Raining now so may not get anymore sun for today.

 

[jim hardy]

End of wires coming from solar panel show 19v. But when hooked up to charge controller with battery hooked up, they show 11.8 which is the same as what battery terminals show. Same as what this showed:

Oh.
So the 19 and 11.8 you reported earlier were measured with two different conditions ?
19 with panel not connected, 11.8 with panel connected ?
That might explain why they are so different. okay
with everything connected , panel to controller and battery hooked up

At top between - terminal and + terminal (where i asked about 19 V,) what voltage do you see? About 12.1 ? __________________ V
At bottom between - terminal and exposed junction of diode&red wire, what voltage do you see? About 11.8 ? ___________________ VNext, with everything still hooked up,

What voltage do you see between - terminal and bare end of black wire ? Zero ? _______________ V...........................Now disconnect panel from controller by lifting the red and black panel wires from the controller
set your meter for 10 amp scale
move the meter plug to correct receptacle as she described at 1:08
post a picture of your meter if it's not clear which one to use , they're not all the same
connect meter set to 10 amp scale right across the two panel wires so panel delivers its short circuit current to the meter
what do you read ? ____________amp
how do you estimate sun ? Strong, weak, or middlin' ?
If sun is strong and you don't get most of an amp, the panel is not delivering current

If the panel delivers current

disconnect battery from controller
hook panel black wire to battery's nehative
put ammeter red wire to panel's red wire
put ammeter black wire to battery's positive
does battery accept current from panel ? _____________ amp

If battery is accepting current let's see if it charges up
With your other meter read battery voltage _____________ V
Wait an hour or two
read battery voltage again ____________________ V
Is voltage increasing ? That should narrow down the trouble

 

[Wolst73]

Couple clarifications needed.

connect meter set to 10 amp scale right across the two panel wires so panel delivers its short circuit current to the meter

I will have the red and black wires from panel and red and black from meter. Connect red to red and black to black?

If battery is accepting current let's see if it charges up
With your other meter read battery voltage _____________ V
Wait an hour or two
read battery voltage again ____________________ V
Is voltage increasing ?

Is this with panel hooked directly to battery or connected through charge controller?

Btw, ammeter says "at 10A range: for continuous measurement </= 10 seconds at intervals not less than 15 minutes." So I can only test for 10 seconds every 15 minutes even if I'm only measuring about 1amp (hopefully)??

 

[jim hardy]

Couple clarifications needed.

Thanks - it is so difficult to communicate in words, isn't it "

..................
connect meter set to 10 amp scale right across the two panel wires so panel delivers its short circuit current to the meter

I will have the red and black wires from panel and red and black from meter. Connect red to red and black to black?
Yes. But if you get them backward you'll just get a negative reading
.........
If battery is accepting current let's see if it charges up
With your other meter read battery voltage _____________ V
Wait an hour or two
read battery voltage again ____________________ V
Is voltage increasing ?
Is this with panel hooked directly to battery or connected through charge controller?
Panel to battery , no controller
next test will be to see if controller let's current through to the battery

..........

Btw, ammeter says "at 10A range: for continuous measurement </= 10 seconds at intervals not less than 15 minutes." So I can only test for 10 seconds every 15 minutes even if I'm only measuring about 1amp (hopefully)??
wow i never saw that before
okay
1 amp will make 1/100th as much power in the internal shunt as will 10 amps
SWAG here, not Uswag ,
at 1/100th the power it takes 100X longer to deposit same heat in the internal shunt
100 X 10 seconds = 1000 seconds which is longer than 15 minutes but not by much
i would say that 1 amp is the limit for continuous measurement
does it have a 2 amp scale ? If so use that.

Would you post the model of your meter so we can lookup the manual ?

 

[sophiecentaur]

Btw, ammeter says "at 10A range: for continuous measurement </= 10 seconds at intervals not less than 15 minutes." So I can only test for 10 seconds every 15 minutes even if I'm only measuring about 1amp (hopefully)??

If this worries you, you can short across the Ammeter contacts with a wire and just remove the short when you want to measure. (Perhaps you can now see the advantage of a non contacting tong type Ammeter.)

 

[jim hardy]

If this worries you, you can short across the Ammeter contacts with a wire and just remove the short when you want to measure. (Perhaps you can now see the advantage of a non contacting tong type Ammeter.)

why didnt i thinkof that ?
Oh- it was 3am...or leave meter on volts and make that shunt.

If i knew of an affordable Hall meter that goes down to 1 amp i'd own several.

 

[Wolst73]

https://www.amazon.com/dp/B00WR42XP2/?tag=pfamazon01-20

 

[sophiecentaur]

https://www.amazon.com/dp/B00WR42XP2/?tag=pfamazon01-20

That isn't a Clamp type meter.http://www.ebay.co.uk/itm/Digital-LCD-Clamp-Multimeter-AC-DC-Current-Voltmeter-Ammeter-Checker-Tester-UK-/152066355863?hash=item2367dc7297:g:mzgAAOSwjKpXHKn6 I think I paid a bit more, though.

 

[Wolst73]

That isn't a Clamp type meter.http://www.ebay.co.uk/itm/Digital-LCD-Clamp-Multimeter-AC-DC-Current-Voltmeter-Ammeter-Checker-Tester-UK-/152066355863?hash=item2367dc7297:g:mzgAAOSwjKpXHKn6 I think I paid a bit more, though.

Oops. Once again proving my ignorance, I didn't know that clamp meter was what you were talking about when you mentioned hall meter...I will know better for the next one!

 

[sophiecentaur]

Oops. Once again proving my ignorance, I didn't know that clamp meter was what you were talking about when you mentioned hall meter...I will know better for the next one!

They used to make AC meters, years ago but now, with the Hall devices, you can measure down to 10mA or less on a 400A DC meter. A brilliant device and not too pricy.
Edit: Treat yourself to one Jim!

 

[jim hardy]

They used to make AC meters, years ago but now, with the Hall devices, you can measure down to 10mA or less on a 400A DC meter. A brilliant device and not too pricy.
Edit: Treat yourself to one Jim!

10 ma ? I didnt know they had that kind of resolution

this thread did inspire me to find my old Fluke DC clamp-around , it was about three layers down in my sedimentary workshop
it makes 0 to ±2 volts at banana jacks on rear for 0 to ±20 amps through the window so you use it with any old meter, i like that because i can use an analog one
ten turns makes it ±2 amp range
it's good from dc to ~2khz
it's the top one in this photo

Fluke was a junkshop find i'd guess it dates from 1970's
bottom one is probably from 1930's, was a recent yard sale treasure
it's extremely handy around the car no batteries or wires.

i'll take a look at your link , a DC clamp-around with that sensitivity used to be just a dream.

BTW here's a related instrument
Gaussmeter is much newer but the similarity is obvious

obviously the Gaussmeter needs a zero adjustment

Oh, the curse of curiosity ! But it sure beats boredom, eh ?

old jim

 

[Wolst73]

with everything connected , panel to controller and battery hooked up

At top between - terminal and + terminal (where i asked about 19 V,) what voltage do you see? About 12.1 ? ________12.25________ V
At bottom between - terminal and exposed junction of diode&red wire, what voltage do you see? About 11.8 ? _______11.93__________ VNext, with everything still hooked up,

What voltage do you see between - terminal and bare end of black wire ? Zero ? ______0_________ V...........................Now disconnect panel from controller by lifting the red and black panel wires from the controller
set your meter for 10 amp scale
move the meter plug to correct receptacle as she described at 1:08
post a picture of your meter if it's not clear which one to use , they're not all the same
connect meter set to 10 amp scale right across the two panel wires so panel delivers its short circuit current to the meter
what do you read ? ______0.12______amp
how do you estimate sun ? STRONG (in and out of cloud but measuring when out)
If sun is strong and you don't get most of an amp, the panel is not delivering current

If the panel delivers current

disconnect battery from controller
hook panel black wire to battery's nehative
put ammeter red wire to panel's red wire
put ammeter black wire to battery's positive
does battery accept current from panel ? ______0.07_______ amp

Appears panel is issue?

Excellent instructions Jim. Thank you very much for all your time.

 

[jim hardy]

does battery accept current from panel ? ______0.07_______ amp

Appears panel is issue?

I think so.
If you want to do a final sanity check
connect ammeter on 10A scale right across those two screws on back of panel
be sure you're on the pane side of that diode not the red wire side
you should see real close to your same 0.12 amp

that's more to build your familiarity with how to test panels than anything else. I think you've circled the problem pretty tight.

Excellent instructions Jim. Thank you very much for all your time.

Nice job on the measurements, and the presentation of same.
and
Thank you for the kind words !

Whats important is to build skills.

Got another minute ?

One point should be mentioned here, for safety's sake
because we can mis-apply things we've learned
and there's a point about current measurements we didn't emphasize

In all this testing we did, there is only one device that can deliver very much current and it's your battery..
We used the ammeter with impunity on your solar panel because we knew the panel inherently limits current to around an amp, and you found more like 1/8 amp.
Notice we never attempted to measure how much current the battery could deliver by using the ammeter.
That's because the ammeter is a ten amp gizmo and Mr Battery can probably deliver over a hundred amps to it. And Mr Battery would feel no guilt about that.
That meter says it's unfused on ten amp scale , meaning it cannot protect itself against overcurrent.
While Mr Battery would probably only let the smoke out of Mr Meter's internal shunt and maybe set fire to his plastic case, we don't want that to happen.

But it would demonstrate a fundamental fact about ammeters :
FACT: AN AMMETER CANNOT LIMIT CURRENT
COROLLARY: NEVER CONNECT AN AMMETER WHERE THERE"S NOT SOMETHING ELSE IN THE CIRCUIT THAT LIMITS CURRENT, and a breaker or fuse does NOT qualify.

If that ammeter were to be connected across incoming power at your house panel , a fireball big as a garbage can would result likely engulfng and severely burning you..
It'd make an impressive shower of sparks at any regular household outlet.I belabor this because i have encouraged you to use an ammeter, without giving you that requisite safety briefing.
So don't use that thing on amps scale around housepower. We'd all feel awful if you had to get skin grafts.
Sounds melodramatic but it's a real danger .

thanks for tolerating me

and thanks also for how much i learned about solar panels and controllers from your adventure !
grumpy old jim

 

[Wolst73]

connect ammeter on 10A scale right across those two screws on back of panel
be sure you're on the pane side of that diode not the red wire side
you should see

Measured across the 2 screws. Got up to 0.35A in full sun but dropped rapidly to 0.12 as sun went behind cloud.

Can someone recommend a good panel that will fit my needs so I don't buy another P.O.S.? You get what you pay for. That one cost me about $50.

Hopefully battery isn't toast too!

Thanks for the caution. I am a long way from doing anything with electricity. I don't like getting zapped.