Solar Experts....Help

[Apltrez]

The original paperwork that I got with my 01 Bigfoot shows that it has a solar panel on the roof...Solartek brand. Having not discovered a controller I called Solartek in Canada and asked what model I had and what the output was.........and was told I needed to unbolt the panel and check the back of the panel and there would be a tag with all that information.

For a variety of reasons the unbolting process was a challenge and when I was able to tip the panel over, the panel was not a Solartek but was a Photo Watt PWX 200, made in France. Also there were no details as far as out put.

Going online, I found a pdf on a PWX 500 but none on the 200 although there were some obscure references to it.

I am hopeful someone might know what I have. I am assuming it is a trickle charge capacity as it is fused and I assume also has a diode as is typical with trickle charge set ups.

I have some follow up questions but I will wait to see what this query yields

[mszabo]

Photowatt PW-2050-200 (200W) Solar Panel

[Apltrez]

Mike,
I had seen that in my search but I think that it is a different panel. Mine is a PWX 200. Also, size wise it looks to be way larger. I am guessing mine is about 10 X 20 in. The 2050 measures about 19 X 41


However I could certainly be wrong

[Franswa]

the one in the data sheet was five feet by three feet.....200W for that size sounds "ballpark" right.....and would be a "serious" amount of solar to put on a BF....like boondocking indefinitely...

a 10"x20" sounds like a panel people put on their car dashes to "maintain" a starting battery (motorhome in storage kind of thing).....so maybe that "200" is for 200Ma.....or 2 amps.....again ballpark, I'd guess 10-20W panel given the size

good luck in your research

[Apltrez]

Thanks Francois
Based on the original paperwork I am assuming it is a 10 or 20 Watt unit also.

I have been trying to figure out how to test the output and also what it should be. I have figured out that it maintains the battery that cam with the trailer(as older Diehard) at 11.2 V. So I assume it is working.

This is all part of the process on this "new to me" trailer to determine what is working correctly and what isn't. So far everything is great.

[Franswa]

if the battery is giving you a reading of 11.2V it is now a "boat anchor".....

take it out put it on a proper charger for 12 hours...let it sit for an hour...if you still get a reading of 11.2...it is done...dead...useless...

12.65+....fully charged
12.2....50% discharged...the point where you should limit power use otherwise you are shortening the battery's life

best practice: size your power usage, charging power, battery bank so your batteries "at rest" will never give you a reading below 12.4V (this is supposed to give you the maximum (rated) number of expected cycles (charge/discharge) before the battery becomes inefficient (dies of old age)

that's the best info I have found from a couple of different very credible sources....and it's possible to do. It's a balancing act between how much power you are going to use, how fast your can recover that spent power and the size of you battery bank. My voltage now (at rest) never goes below 12.4V....I have found my "optimum" combination...for me....I expect to have my batteries for a LONG time (target is 7-8 years)

good luck...have fun with your new hobby

[Apltrez]

I wondered about that. There is still enough juice to run things, but the battery monitor on the monitor panel showed fair charge after being on the shore working down to dead when disconnected and using the solar power.

Soooooo the next question is how does one check the out put and/or serviceability of the solar panel?

I will put the battery on a slow charge starting this AM

[Franswa]

testing the efficiency of specific panels is beyond my limited technical knowledge I'm afraid....I can only relate what and how things work for me:

I have 70W flat on the roof...then a volt meter on the panel side of an on/off switch. This way I can read what I call "raw voltage" (panels not connected to anything) in moderate sun I get a reading of 18-19V. When I trip the switch (connect to my elec. system) this voltage will quickly drop to near my system voltage (12.4 let's say, on a separate panel meter).

on a bright sunny day the raw voltage might be 20V....connected the voltage drops again but stays a few decimal points higher than the system voltage....now I'm gaining!

If I deploy the 40W portable as well and angle to the sun the raw voltage will get to 22....and the difference between raw and system will be a few more decimal points higher.....gaining more.

at some point system voltage gets to 13.4 ...the charge controller limits further charging and keeps the system at around 13.3

that "raw voltage" on/off switch I have has allowed me to compare efficiency between the rooftop panels and my portable one....and to see the big difference perfect angle to the sun makes....my 40 perfectly angled to the sun probably produces more power on a sunny day that the 70 flat on the roof

I happen to have a picture where the batteries have been brought up to full charge....system voltage at 13.30 (solar charge controller limiting further charging from panels)....raw voltage at 16.3...(I'm producing power I can't use)

so I guess the answer to your question is to check the voltage with a voltmeter when panel is in full sun and not connected to anything.....you'll get a number....is that close to specifications for that exact panel ?? only finding/looking up the specs will tell you that (your original problem)....somebody with way more experience than me would probably be able to answer your question just from a "gut feel" perspective.....I'm still "playing around" experimenting...

good luck and have fun

[Apltrez]

I removed the old Sears Duracell and placed it on a normal 2 amp sharge. At the end, I can't check it with a Hygrometer but I do have a load tester after I determine the charge level at the end of the charge time.
Assuming I will need a new battery(in the early spring) I am debating between an AGM and and Interstate deep cycle, which I have used with good results in the past.

This whole review causes me to want to test the on board power/converter center, Magnatek 6300 Q Series, but not sure how to test the charging side.

[Buggeee]

Originally Posted by Apltrez

...I am debating between an AGM and and Interstate deep cycle...

I vote AGM true deep cycle. the Interstate deep cycle has a cold cranking amp rating which suggests to me its a compromise with medium thickness lead plates. True deep cycle batteries are rated in amp hours, because they really are not designed to start engines at all and have thick lead plates that stand up to our abuse better.

Enjoy the quest!

[Apltrez]

I found a spec sheet after enough searches
it is a 21 W panel Voltage OC, or 18.7 during load conditions. As I understand it, I should be disconnected from the battery and measured in full sun and it is supposed to be 21.6 V.

As near as I can tell with my meter I am getting about 13 mili volts.

I determined by the panel measurement L x W that this spec sheet should be right. Sounds like I have a bad panel

[Byron Kinnaman]

Originally Posted by Apltrez

I found a spec sheet after enough searches
it is a 21 W panel Voltage OC, or 18.7 during load conditions. As I understand it, I should be disconnected from the battery and measured in full sun and it is supposed to be 21.6 V.

As near as I can tell with my meter I am getting about 13 mili volts.

I determined by the panel measurement L x W that this spec sheet should be right. Sounds like I have a bad panel

Output specs are open circuit, bright sun at 90° to panel.

Next question do you need a panel that will recharge a battery that's been run down? To answer that question ask yourself how long you plan to camp in one spot with out electricity. If it's more that 3 or 4 days solar might be a good idea. Less than that is a waste of resources. Also that 20 Watt panel is onlyl good to keep a fully charged battery charged when sitting and nothing running.

[Apltrez]

FINALLY I have it working. PO's incorrect wiring, and faulty/hidden fuse holder have all now been corrected. I connected to the battery at 2:30 in full sun yesterday and at 1:30 today it measured 13.9, up from 11.4.

Now, as I understand on this small 10 or 20 W panel, they are controlled by the inline fuse on the + side and a diode at the panel. Am I right in believing that the diode bypasses the battery somehow when the battery is fully charged?
What is the max charge I should not go past in monitoring the diode is doing it's job.

Thanks to all experts in advance

Greg

[gordon2]

Originally Posted by Apltrez

....
Now, as I understand on this small 10 or 20 W panel, they are controlled by the inline fuse on the + side and a diode at the panel. Am I right in believing that the diode bypasses the battery somehow when the battery is fully charged?...

I think what you are referring to is a diode that basically prevents the panel from working in reverse at night (overly simplified), and draining the battery when its dark. They are usually built in to the panels and not very visible if at all.