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solar charging problem - troubleshooting help please!

4K views 20 replies 7 participants last post by  copacabana 
#1 ·
I have been noticing that my two 65w solar panels have been increasingly unable to charge my batteries. The batteries seem to charge fine with the alternator and hold a charge well (they are less than 2 years old). I am thinking that perhaps there is a corroded connection somewhere between the panels and the batteries. Before I start looking at every possible culprit, perhaps someone with more experience might know where to start looking first. I'm not exactly a McGyver with things electrical ... :D

Thanks in advance!
 
#2 ·
Do you have any monitoring capability that can tell you/us specifically how much the panels are making?

I'm going to assume you've cleaned the panels, but you'll also need to do the eyeball check on all the connections coming from them. You'll need to take a crash course in what's what on your system.
If you don't have an installed monitor that says specifically what the panels are making regarding voltage and amps you'll have to find the leads coming from the panels and take a voltage reading during normal sunlight, it should be over 14.3 v, if not they are defective.
If you don't know where to start, the place to start is taking LOTS of pictures so we can tell you what's what.
 
#3 ·
I have experience with solar systems and am willing to help you out.
I have some questions.
1 - Are you charging through a solar charge controller?
2 - Is your system properly protected with fuses or DC Breakers?
2 - Do you have a way of measuring voltage and amperage?
3 - Is the wiring clean and corrosion free?

Also if you wish to learn about this (and a ton of other maintence things) There is a good book out there by Nigel Calder - Boatowner's Mechanical and Electrical Manual. (McGraw Hill)
I will send you a PM with my e-mail adress if you want to get back to me quicker.
 
#5 · (Edited by Moderator)
I have experience with solar systems and am willing to help you out.
I have some questions.
1 - Are you charging through a solar charge controller?
2 - Is your system properly protected with fuses or DC Breakers?
2 - Do you have a way of measuring voltage and amperage?
3 - Is the wiring clean and corrosion free?
Hello Norah and thanks for the PM. I'll get back to you with more data when I get back from the boat in about 12 days.

To answer your questions:

1) Yes, I have a charge controller (regulator), but for the life of me, I can't remember the brand and model!
2) I have a switch and fuse on my main panel. I checked the fuse and the wiring at the switch. All OK.
3) Yes, I have a decent handheld voltmeter, but no way of measuring amps such as with a battery monitor. I also have a fishfinder that also gives the voltage of the battery and it's all over the place measuring 10v and then 12.5v and oscillating like mad. When I start the engine and the alternator is engaged the voltmeter gives me a steady reading of 13v to 14v (in my mind showing the batteries are being charged and the voltmeter function of the fishfinder is working properly).
4) I have checked the battery terminals, battery switch connections and connections at fuse panel. These all check out OK. I suppose my next step is to look at the panels and all other connections between there and the batteries (diodes, regulator etc).

I should add that the batteries charge fine with the alternator and hold a charge normally. They seem to almost discharge when hooked up to the panels.
 
#4 ·
I recently had a loss too. It turned out to be some corrosion on the panel connections. I have kyocera panels they are a watertight box, but the holes you punch through must also be watertight or it is worthless.

First, throw a blanket over your panels and block ALL the light. I usually throw a few heavy things on top of that to make sure I don't get bit.

Disconnect the charge controller. I have a switch. Not sure what you have.

Open the box and pull a reading on the output. It should be zero. Next, polish up all your terminals. I usually use some emory cloth 220 wet/dry paper. Remember to clean both sides of the Ring terms and the terminals on the panels where they connect.

Next, just to make sure, I took the blanket off and took an OCV (Open Circut Voltage) across the panels (basically where your two ring terms connect). You need to read your panels theoretical output, but it is likely close to 17-20v. THe open voltage should be pasted to the bottom of your panel. If the panels are not putting out, you either have a bad panel or a bad blocking diode. The blocking diodes on my panels are inside the box so you can jump around them if you want to (I do not). If that is the case, check the open side of the diodes for open voltage. You may see some voltage gain if you don't run through the diodes. If you still have no voltage, time to buy new panel(s) though I would be curious why...

If you are getting the proper voltage, re-cover each panel with the blanket and coat each side of the ring terms and the connections with dielectric grease and tightly connect them. I wouldn't use any connection outside without using dielectric, but that is just me. I also prefer heat shrinking everything, but you may not want to.

Take everything off and see what you are putting out. If you still are not getting the correct V/A, you know the problem is after the panels. I am assuming you looked for a fuse to start off with, so assuming that is ok, I wuold go to the charge controller and take an open voltage reading. Depending on how you wired your panels, you should see no less than a panel puts out to all of them in series. Again, without knowing how they are wired, hard to say. Also, if you did not properly size your wiring, you will see V loss there, but should still work.

If you are getting the right voltage there, you know the problem is after that (charge controller - batteries). Make sure your charge controller is putting out the proper voltage to your batteries. Also check the connections to your batteries and see what they are receiving. If you are getting everything to your battery terms that it is rated for, you know the problem lies with your batteries.

Anyways, it is a process to figure these things out. I suspect your problem lies in corrosion at the panels as that is the most common issue. If you are getting corrosion there, you have not properly installed your panels. The dielectric will help, but you need to run water tight conduit and connections between the panels and to the boat. I used LeakTight conduit and connectors from Home Depot. $2/connector and probably $15-20 for the conduit. Make sure to get the all plastic ones and avoid the crappy galvanic metal rings as they never seem to last in a marine environment.

My opinions!!!

Brian
 
#6 ·
Thanks for the thoughtful advice Cruisingdad. I'm going to print your post and take it with me to the boat on Friday. I'm going to be about 12 days cruising on the coast of Rio with my brother who is visiting so I'll have some time to troubleshoot the problem. I suspect you're right about the problem being a corroded connection somewhere. Hopefully it's something simple.
 
#12 ·
I agree and dissagree.

The grease IS an insulator. I know many people put it on the rubber sleeve of spark plugs and other rubber items for a lubricant that won't pass electricity. This also makes the use of it (in my opinion) on items like your raymarine cords or other data cords or low voltage item a poor choice.

However, when used where there is a strong mechanical connection, it is awesome. I think the leading cause for failure in marine electrical items is corrosion. By using the dielctric, you will reduce the potential for corrosion. I have used it for many years and will say that on items I use them on, I keep a good connection without corrosion failure. On the items I do not, I eventually get corrosion if exposed to the elements.

My experience,

Brian
 
#9 ·
Re your solar system - info is helpful, almost sounds like something may be connected wrong. Check that the connections on the charge controler are proper. If they are ok then you seem to be feeding back into the panels when they are not chagring. Also one more point - some charge controlers have to be connected in the right sequence when installed. You could always try disconnecting all the wires at the controler and reconnecting them in the following order.
1 battery negative
2 battery positive
3 solar negative
4 solar positive
5 if your controler has a load circuit leave the wires off until sorting out the charging problem and then re-connect the load and see if it affects things.
This is the most common sequence and may solve your problen. If not then you will have to get a clamp on amp meter and go from there. Let me know how the reconnecting works out please.
Also the brand and model of controler will help me out.
Luck 2 you
 
#10 ·
Norah, thanks for the tips. I believe everything is connected properly as it has (had) been working fine for years. In any case, I'll check the connections as you suggest. I'm going to the boat tomorrow morning and I'll start putting this advice into practice. I'll let you know how it goes when I get back from sailing!
 
#11 ·
Stu-
I've got to disagree with your advice not to use dielectric grease. Yes, logically, you would be right. But in practice? B&H and some instrument companies actually SHIP the stuff and instruct customers to use it when making connections in their wiring.
In practice what happens is that you make a metal-to-metal contact when you make the connection, even with a screw terminal. The dielectric grease simply keeps water and air from penetrating to attack that metal to metal contact.
It works, and works so well that I won't make a connection without it, and have seen zero failures with it. Heck, if you look at "Gen-you-whine" Western Electric telco splices, the little "button" splaces that they use to connect 24G individual telephone wires? Those button splices are all SILICON FILLED for this purpose. MaBell didn't like doing remakes. (G)

Unlike the old standby of Vaseline, which conducts a little and migrates as it melts in the heat, the silicon dielectric grease (aka brake grease, light bulb grease, vacuum grease, ignition point grease) does a good job of staying put. Sold as "brake grease" for about $6/6oz tube that's usually not quite as thick but way cheaper than buying Ancor brand at the same price for a half ounce.

Copa-
With just a voltmeter...you actually can check amperage, you just need to run the numbers for Ohm's low and use one carefully cut foot of cable or something similar as your measurement base. Basically, you insert the cable in the circuit you want to measure, and then carefully measure the voltage drop across that one foot of cable. If you know what the cable type is (copper, aluminum, gauge) you can look up the resistance, and the voltage drop will give you a good idea of the amperage going through it. That's actually the way ammeters work, except they'll use a "shunt" instead of the foot of cable.

But two 65W panels probably can be safely tested with a $20 multimeter if you find one (Walmart, Target) that has a 10A DC scale on it. Many do.

And if you've just got a 2A scale, there are ways to kludge that too.

Or you may get lucky and find the problem with what you've got.
 
#14 ·
Sorry for not getting back sooner. I spent 10 days aboard, sailing around the Paraty and Ilha Grande region of Rio and was having such a good time that I didn't bother looking into the problem! I'm going to take a day off in a week or so and go over every connection to check for corrosion. I have a good local electrician that I will bring along to keep me from frying things. :laugher

I will get back with the results soon.
 
#15 ·
Well, on Saturday I went down to the boat to see about the charging problem and after a few hours of testing and checking things and troubleshooting I discovered a loose connection from the controller to the positive bus (from where it would go to the battery). I cleaned and tightened the connection and it seems to have fixed the problem. I also cleaned up the negative connection as well. I will be certain all is working again when I next go to the boat. I expect to find the main battery bursting with 12.8 volts. If not, something could be still wrong, including the battery itself.

From this experience I realize that I really should have some sort of battery monitor to measure amps in and out (not just voltage). Is there a simple, reliable (and inexpensive) battery monitor you can recommend? FYI, my battery bank has one 180amp main house battery and a 70amp starter battery on its own battery switch. I may upgrade to two 180amp house batteries in the future. I would need a battery monitor that could handle two banks (starter / house). Any suggestions?

Thanks!
 
#16 ·
Not sure it's necessary to monitor the start bank.. as long as it gets charged, should be not an issue.

We're still using an old Link10 on the house bank, but there must be better/smarter stuff out there now. Have just installed an ACR (Blue seas) to look after charging start bank, and do not monitor its in-and-out.

On the house bank its really nice to know how much is 'in the tank'. Are you running refrig? 180A is pretty slim for that, but I guess your sunshine is more reliable than ours.
 
#17 ·
Faster, I don't run the fridge off the batteries so it's just LED lights, radios and sometimes the tiller pilot hooked up to the windvane (when motoring). I mention adding another 180amp battery in the future as I will likely go to a 12v fridge when my propane one dies. I would also increase my solar array at that time. I agree about not needing to monitor the starter battery. I normally charge it up, isolate it and forget about it. I would like to keep a tab, however, on the "in and out" of the house bank. I don't need anything sophisticated though. I believe Mainesail mentioned a few options he thought were good value, but I can't remember the thread.
 
#18 ·
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