Solar charge controller and fully charged batteries?

F

FairweatherDave

Well-Known Member
Joined
28 Sep 2009
Messages
2,089
Location
Solent
Visit site
I have got a dual battery solar charge controller along with 50watt panel from Photonic universe installed in 2018.
12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine
The system has worked fine, but I decided to start this season with new batteries, so bought direct replacements, two of these leisure batteries, sealed lead acid 110Ah Xplorer batteries from Alpha batteries.
12V 110AH Xplorer™ Leisure battery (679) - Alpha Batteries
New batteries installed and solar reconnected as before, the display on the controller showed the batteries were charging. Left the boat for at least a week and returned to find the batteries still charging. I expected to see slow flashing, as I used to see on the old batteries, indicating full charge. Phoned Photonic Universe who suggested maybe the new batteries needed a Mains charge - fair enough - I gave both a mains charge and re-connected. But still, in day light hours, the controller said both batteries were charging. Measured both batteries with a voltmeter at rest at 12,6. Decided maybe the batteries were duff so phoned Alpha batteries who said with those batteries 12.6 is about right.
So why, during the day, is the controller consistently saying the batteries are charging? (And at night the controller is saying the batteries are fully charged?) I remember the display would show steady flashing fully charged during the day with the old batteries.
Should I be concerned about 12.6v as a resting voltage? Would really appreciate some input from here!
 
Alex_Blackwood said:
Have you compared your controller outputs with the tech spec?

12V 110AH Xplorer™ Leisure battery (679) - Alpha Batteries
Click to expand...
I was thinking about this some more (I'm no electrical guru) and from reading what I can find in the links it seems to be saying that whilst charging, the controller "parameters" are 14.4v for charging and 13.8 for floating charge (page 6). I used my multimeter when the engine was running and got a reading of 13.8 at the battery terminals, which I believe is correct for charging from the alternator. Surely if I took a reading at anchor in the morning in sunshine the batteries were being charged so I should have been getting a reading off the batteries of near 14volts (not 12.6volts).?


And thanks LadyInBed, I need to go back and check that at the boat. I didn't change anything to do with battery type and it was set to sealed batteries, the first option, before I changed the batteries.
 
FairweatherDave said:
I was thinking about this some more (I'm no electrical guru) and from reading what I can find in the links it seems to be saying that whilst charging, the controller "parameters" are 14.4v for charging and 13.8 for floating charge (page 6). I used my multimeter when the engine was running and got a reading of 13.8 at the battery terminals, which I believe is correct for charging from the alternator. Surely if I took a reading at anchor in the morning in sunshine the batteries were being charged so I should have been getting a reading off the batteries of near 14volts (not 12.6volts).?


And thanks LadyInBed, I need to go back and check that at the boat. I didn't change anything to do with battery type and it was set to sealed batteries, the first option, before I changed the batteries.
Click to expand...
When the sun is shining, what is the voltage at the battery?- you should be seeing 14.4V or if they are full (in Float) 13.8 V.
Re your alternator output - 13.8 is the float voltage. You should be getting 14.4 at the battery whilst the Alternator is doing its main charge. If its not, the batteries will take a millennium to charge up at 13.8v input rate.
My suspicion is that the controller is not outputting a charge of any sort. 12.6 volts is at the low end of a good battery at rest (ie several hours after charging). On new batteries I would expect 12.7V. So your batteries may not be fully charged (80% ) and will probably never get there with your current charging regime.
 
Check dc current from controller to battery's. Maybe the solar panel is insufficient in output for your new battery bank. Your only looking t a small amount of amps at best. Also check for parasitic drain .
 
Chris_Robb said:
When the sun is shining, what is the voltage at the battery?- you should be seeing 14.4V or if they are full (in Float) 13.8 V.
Re your alternator output - 13.8 is the float voltage. You should be getting 14.4 at the battery whilst the Alternator is doing its main charge. If its not, the batteries will take a millennium to charge up at 13.8v input rate.
My suspicion is that the controller is not outputting a charge of any sort. 12.6 volts is at the low end of a good battery at rest (ie several hours after charging). On new batteries I would expect 12.7V. So your batteries may not be fully charged (80% ) and will probably never get there with your current charging regime.
Click to expand...
Thanks Chris. I've only been measuring the voltage in the morning around 8.30-9am over the Jubilee long weekend. I was not doing it to see if my solar was working, it was to see what impact using our new compressor fridge was having. It is one of these,
https://www.amazon.co.uk/Dometic-CDF-36-Portable-Compressor-Freezer/dp/B071NSP51G
which is supposed to be pretty low consumption as fridges go. (We had it set at 5 degrees , not anything excessively cold)
But from what you are saying, whilst the battery is charging in sunshine the voltage at the battery terminals should be significantly more than 12.6. This is something I will test when next at the boat. (My panel is flat and permanently mounted so does get some shading from the boom, and I will bear in mind as a dual battery charger it prioritises one battery over the other, until the first is charged - I need to check what this is set to). The fridge will be off when I test the batteries, unlike the Jubilee weekend.
Regarding the alternator output, at the moment that is not my focus, although I take your point. It is the first time I have ever measured the batteries while motoring, so I am learning.
 
wingcommander said:
Check dc current from controller to battery's. Maybe the solar panel is insufficient in output for your new battery bank. Your only looking t a small amount of amps at best. Also check for parasitic drain .
Click to expand...
Thanks. I am sure my solar should be ample for the battery bank, if it is working. It is really only to keep the batteries topped up. From what I understand of the new fridge, one leisure battery should be able to supply it for a weekend before it needs any charging. However that is a distraction here as this last weekend is the first time the fridge has been used at all, and the battery charging lights on the controller have been staying on during the day since the start of May. However I reveal my ignorance here regarding using my multimeter - I need to learn how to measure dc current. And although I understand the idea of parasitic drain I have no idea how you check for it....any pointers genuinely welcome.
 
Get a dc clamp meter, much easier than trying to use a multi meter to measure current, also your fridge states 60w power usage, which seems very low but if continuous will soon eat into your battery storage, be interesting when your actually able to measure current draw directly, your 110ah is only 55ah available to use.
 
Last edited:
FairweatherDave said:
Thanks Chris. I've only been measuring the voltage in the morning around 8.30-9am over the Jubilee long weekend. I was not doing it to see if my solar was working, it was to see what impact using our new compressor fridge was having. It is one of these,
https://www.amazon.co.uk/Dometic-CDF-36-Portable-Compressor-Freezer/dp/B071NSP51G
which is supposed to be pretty low consumption as fridges go. (We had it set at 5 degrees , not anything excessively cold)
But from what you are saying, whilst the battery is charging in sunshine the voltage at the battery terminals should be significantly more than 12.6. This is something I will test when next at the boat. (My panel is flat and permanently mounted so does get some shading from the boom, and I will bear in mind as a dual battery charger it prioritises one battery over the other, until the first is charged - I need to check what this is set to). The fridge will be off when I test the batteries, unlike the Jubilee weekend.
Regarding the alternator output, at the moment that is not my focus, although I take your point. It is the first time I have ever measured the batteries while motoring, so I am learning.
Click to expand...
Considering that this has only happened since you changed batteries. I would check, and double check, every connection and every cable in the system that you moved, touched or even looked at while changing the batteries. Yes check the current output from the controller. A DC clamp meter is a good idea saves disturbing connections and easy to use.
 
Bizarrely, given my skill level, I have a clamp meter, I've just never used that part of it. Point taken about the connections, it is a pretty simple installation. We shall see. Just need to organise life to get back to the boat :)
 
FairweatherDave said:
Bizarrely, given my skill level, I have a clamp meter, I've just never used that part of it. Point taken about the connections, it is a pretty simple installation. We shall see. Just need to organise life to get back to the boat :)
Click to expand...
Double check that your clamp meter is DC! Many, if not most, on the market are ac only. Just be aware!
 
Thanks Alex, I will check that. It was one recommended on here ages ago, so hopefully it does DC. Of course it is on the boat and no paperwork here.
 
A 50w panel will be marginal to run the cooler. I had one the same, and had 2 x50w panels to run it. One each side of the spray hood to try and ensure a reasonably continuous charge. I ended up with a 100w one sat on the deck as well to keep the batteries up for a UK summer.

I could then leave the fridge on full time. The 50w x 2 was hardly able to keep up. UK South coast.
 
You must log in or register to reply here.

Share this page

Top