More solar questions

[GATJcampers]

New to solar, trying to figure it out and have some questions. I have 2 brand new 6 volt golf cart batteries from sams club wired in series. I have a new 100 watt solar panel kit that came with the panel, wiring and charge controller. I'm not getting the correct voltage at the batteries. I've run a bunch of tests and suspect the charge controller is bad. So I plugged the panel directly to the batteries. open circuit test show I'm getting about 20 volts from the panel. Then hooked up to the batteries it shows 12.1 and holding for the past hour. It is all hooked up properly. Could the batteries be bad? I have a newer better charge controller on the way but now I don't know if that's the problem. I have a previous post named understanding solar that has a little more back ground info. Any help is appreciated. Thank you

[CA_Traveler]

Point the panel at a clear noon sky with wires unattached, measure the Voc (voltage), short the wires and measure the Isc (amps). Should be about 21V and 5A+. This is the test to determine that the panel is OK.

Then w/o solar or shore power and the batteries connected measure the battery drain. Post the numbers.

[Wild_Bill_888]

If the average charging current is 1 amp over 10 hours per day, that’s 10 amphour per day. If the battery capacity is 200 ah at 50% charge you’ll need at least 10 average days to top off the batteries.

Meanwhile your new batteries are slowly sulfating up. I suggest you plug in a good charger and bring them up to 14.5 - 15 volts, then see if your solar can keep it topped while connected to the rv.

It takes a lot of solar to collect significant energy.

[GATJcampers]

Maximum power 100 watt
Voltage at Pmax 18v
Open circuit voltage voc 21.6
Short circuit current Isc 5.74A
Class A
11 AMP charge controller

[time2roll]

Post the actual specs:

Voc
Vmp
Isc
Imp

[GATJcampers]

Unfortunately that last test wasn't at noon, it was more like 3 pm. When I open circuit tested the panel it was giving 20 + volts. Is it possible to be defective and show 20 + volts? Maybe it's giving hardly any amps? Thoughts?

[time2roll]

If you are getting .73 amps and 12.24 volts from the panels in full sun at noon that is just 9 watts.
Assuming you are measuring correct... the panel is defective.

[GATJcampers]

With the batteries disconnected I am getting .73 amps and 12.24 volts.
I have charged the batteries with that panel for days and the highest I ever got was 13 volts. I also tried this set up with a small 12 volt battery and never got above 12.7.

[CA_Traveler]

BFL13 wrote:
Right now the batteries are connected to the RV so they could be under a small load. That could be eating up any solar you are getting and nothing going to the batteries. Loads come first.

X2

DISCONNECT the batteries. Run wires from the panel to the batteries. Now what do you read?

ie RVs always have loads that cannot be turned off. Smoke detectors, electronics on standby, etc.

[BFL13]

GATJcampers wrote:
The charge controller has a cut in of 13 volts and a cut out at 14.2 volts. I expected it to be in between those numbers. Not the battery volts(I understand 12.7 is full) but during the charge I expected it to be between those numbers. and thanks again for all the responses.

The low batteries can read 12.1 volts with solar on, but then with time in daylight that voltage will rise up past 13 to 14.2. Now you wait till voltage falls to 13 and it should start back up to 14.2.

You need an hydrometer to tell you the true state of those batteries, so you can tell if the solar is doing any good over time.

Right now the batteries are connected to the RV so they could be under a small load. That could be eating up any solar you are getting and nothing going to the batteries. Loads come first.

Too confusing using voltages, not enough info on what is really going on. Just stick an hydrometer in, and there will be no confusion.

[time2roll]

GATJcampers wrote:
With no load on the rv and the batteries still connected I set clamp to DC amps and got .45. Batteries still at 12.1. I understand you say it can take days but I've done that and they are just not charging. I'm sure some of that is my lack of understanding but it just doesn't seem like the panel is any help.
I do have a volt meter also.

If you remove the panel from the battery and short the panel terminals together then what is the amp reading on the meter? s/b close to 5 amps at noon or the Isc rating.

[GATJcampers]

The charge controller has a cut in of 13 volts and a cut out at 14.2 volts. I expected it to be in between those numbers. Not the battery volts(I understand 12.7 is full) but during the charge I expected it to be between those numbers. and thanks again for all the responses.

[2oldman]

..

[GATJcampers]

With no load on the rv and the batteries still connected I set clamp to DC amps and got .45. Batteries still at 12.1. I understand you say it can take days but I've done that and they are just not charging. I'm sure some of that is my lack of understanding but it just doesn't seem like the panel is any help.
I do have a volt meter also.

[time2roll]

GATJcampers wrote:
I have an ammeter( not expert with it). It's the clamp type. What am I measuring? Wouldn't it at least show a higher voltage while it's without the charge controller?

The ammeter should show close to Isc rating into the battery.
Is it DC rated? Slam dunk if it is.

[CA_Traveler]

deleted